<?php
/**
 * Omeka
 *
 * Global functions.
 *
 * @copyright Copyright 2007-2012 Roy Rosenzweig Center for History and New Media
 * @license http://www.gnu.org/licenses/gpl-3.0.txt GNU GPLv3
 * @package Omeka\Function
 */

/**
 * Get an option from the options table.
 *
 * If the returned value represents an object or array, it must be unserialized
 * by the caller before use. For example:
 * <code>
 *     $object = unserialize(get_option('plugin_object'));
 * </code>
 *
 * @package Omeka\Function\Db\Option
 * @param string $name The option name.
 * @return string The option value.
 */
function get_option($name)
{
    $options = Zend_Registry::get('bootstrap')->getResource('Options');
    if (isset($options[$name])) {
        return $options[$name];
    }
}

/**
 * Set an option to the options table.
 *
 * Note that objects and arrays must be serialized before being saved.
 *
 * @package Omeka\Function\Db\Option
 * @param string $name The option name.
 * @param string $value The option value.
 */
function set_option($name, $value)
{
    $db = get_db();
    $sql = "REPLACE INTO {$db->Option} (name, value) VALUES (?, ?)";
    $db->query($sql, array($name, $value));

    // Update the options cache.
    $bootstrap = Zend_Registry::get('bootstrap');
    $options = $bootstrap->getResource('Options');
    $options[$name] = $value;
    $bootstrap->getContainer()->options = $options;
}

/**
 * Delete an option from the options table.
 *
 * @package Omeka\Function\Db\Option
 * @param string $name The option name.
 */
function delete_option($name)
{
    $db = get_db();
    $sql = "DELETE FROM {$db->Option} WHERE `name` = ?";
    $db->query($sql, array($name));

    // Update the options cache.
    $bootstrap = Zend_Registry::get('bootstrap');
    $options = $bootstrap->getResource('Options');
    if (isset($options[$name])) {
        unset($options[$name]);
    }
    $bootstrap->getContainer()->options = $options;
}

/**
 * Return one column of a multidimensional array as an array.
 *
 * @package Omeka\Function\Utility
 * @param string|integer $col The column to pluck.
 * @param array $array The array from which to pluck.
 * @return array The column as an array.
 */
function pluck($col, $array)
{
    $res = array();
    foreach ($array as $k => $row) {
        $res[$k] = $row[$col];
    }
    return $res;
}

/**
 * Return the currently logged in User record.
 *
 * @package Omeka\Function\User
 * @return User|null Null if no user is logged in.
 */
function current_user()
{
    return Zend_Registry::get('bootstrap')->getResource('CurrentUser');
}

/**
 * Get the database object.
 *
 * @package Omeka\Function\Db
 * @throws RuntimeException
 * @return Omeka_Db
 */
function get_db()
{
    $db = Zend_Registry::get('bootstrap')->getResource('Db');
    if (!$db) {
        throw new RuntimeException("Database not available!");
    }
    return $db;
}

/**
 * Log a message with 'DEBUG' priority.
 *
 * @package Omeka\Function\Log
 * @uses _log()
 * @param string $msg
 */
function debug($msg)
{
    _log($msg, Zend_Log::DEBUG);
}

/**
 * Log a message.
 *
 * Enabled via config.ini: log.errors.
 *
 * @package Omeka\Function\Log
 * @param mixed $msg The log message.
 * @param integer $priority See Zend_Log for a list of available priorities.
 */
function _log($msg, $priority = Zend_Log::INFO)
{
    try {
        $bootstrap = Zend_Registry::get('bootstrap');
    } catch (Zend_Exception $e) {
        return;
    }
    if (!($log = $bootstrap->getResource('Logger'))) {
        return;
    }
    $log->log($msg, $priority);
}

/**
 * Declare a plugin hook implementation within a plugin.
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::addHook()
 * @param string $hook Name of hook being implemented.
 * @param mixed $callback Any valid PHP callback.
 */
function add_plugin_hook($hook, $callback)
{
    get_plugin_broker()->addHook($hook, $callback);
}

/**
 * Declare the point of execution for a specific plugin hook.
 *
 * All plugin implementations of a given hook will be executed when this is
 * called. The first argument corresponds to the string name of the hook. The
 * second is an associative array containing arguments that will be passed to
 * the plugin hook implementations.
 *
 * <code>
 * // Calls the hook 'after_save_item' with the arguments '$item' and '$arg2'
 * fire_plugin_hook('after_save_item', array('item' => $item, 'foo' => $arg2));
 * </code>
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::callHook()
 * @param string $name The hook name.
 * @param array $args Arguments to be passed to the hook implementations.
 */
function fire_plugin_hook($name, array $args = array())
{
    if ($pluginBroker = get_plugin_broker()) {
        $pluginBroker->callHook($name, $args);
    }
}

/**
 * Get the output of fire_plugin_hook() as a string.
 *
 * @package Omeka\Function\Plugin
 * @uses fire_plugin_hook()
 * @param string $name The hook name.
 * @param array $args Arguments to be passed to the hook implementations.
 * @return string
 */
function get_plugin_hook_output($name, array $args = array())
{
    ob_start();
    fire_plugin_hook($name, $args);
    $content = ob_get_contents();
    ob_end_clean();
    return $content;
}

/**
 * Get the output of a specific plugin's hook as a string.
 *
 * This is like get_plugin_hook_output() but only calls the hook within the
 * provided plugin.
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::getHook()
 * @param string $pluginName Directory name of the plugin to execute the hook for.
 * @param string $hookName Name of the hook to fire.
 * @param mixed $args Any arguments to be passed to the hook implementation.
 * @return string|null
 */
function get_specific_plugin_hook_output($pluginName, $hookName, $args = array())
{
    // Get the specific hook.
    $pluginBroker = get_plugin_broker();
    $hookNameSpecific = $pluginBroker->getHook($pluginName, $hookName);

    // Return null if the specific hook doesn't exist.
    if (!$hookNameSpecific) {
        return null;
    }

    // Buffer and return any output originating from the hook.
    ob_start();
    foreach ($hookNameSpecific as $cb) {
        call_user_func($cb, $args);
    }
    $content = ob_get_contents();
    ob_end_clean();

    return $content;
}

/**
 * Get the broker object for Omeka plugins.
 *
 * @package Omeka\Function\Plugin
 * @return Omeka_Plugin_Broker|null
 */
function get_plugin_broker()
{
    try {
        return Zend_Registry::get('pluginbroker');
    } catch (Zend_Exception $e) {
        return null;
    }
}

/**
 * Get specified descriptive info for a plugin from its ini file.
 *
 * @package Omeka\Function\Plugin
 * @param string $pluginDirName The directory name of the plugin.
 * @param string $iniKeyName The name of the key in the ini file.
 * @return string|null The value of the specified plugin key. If the key does
 * not exist, it returns null.
 */
function get_plugin_ini($pluginDirName, $iniKeyName)
{
   $pluginIniReader = Zend_Registry::get('plugin_ini_reader');
   if ($pluginIniReader->hasPluginIniFile($pluginDirName)) {
       return $pluginIniReader->getPluginIniValue($pluginDirName, $iniKeyName);
   }
}

/**
 * Add a callback for displaying files with a given mimetype and/or extension.
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_View_Helper_FileMarkup::addMimeTypes() See for info on usage.
 * @param array|string $fileIdentifiers Set of MIME types and/or file extensions
 * to which the provided callback will respond.
 * @param callback $callback Any valid callback.
 * @param array $options
 */
function add_file_display_callback($fileIdentifiers, $callback, array $options = array())
{
    Omeka_View_Helper_FileMarkup::addMimeTypes($fileIdentifiers, $callback, $options);
}

/**
 * Add a fallback image for files of the given mime type or type family.
 *
 * The fallback is used when there are no generated derivative images and one
 * is requested (for example, by a call to file_image()).
 *
 * @since 2.2
 * @package Omeka\Function\Plugin
 * @uses Omeka_View_Helper_FileMarkup::addFallbackImage()
 * @param string $mimeType The mime type this fallback is for, or the mime
 *  "prefix" it is for (video, audio, etc.)
 * @param string $image The name of the image to use, as would be passed to
 *  img()
 */
function add_file_fallback_image($mimeType, $image)
{
    Omeka_View_Helper_FileMarkup::addFallbackImage($mimeType, $image);
}

/**
 * Apply a set of plugin filters to a given value.
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::applyFilters()
 * @param string|array $name The filter name.
 * @param mixed $value The value to filter.
 * @param array $args Additional arguments to pass to filter implementations.
 * @return mixed Result of applying filters to $value.
 */
function apply_filters($name, $value, array $args = array())
{
    if ($pluginBroker = get_plugin_broker()) {
        return $pluginBroker->applyFilters($name, $value, $args);
    }
    // If the plugin broker is not enabled for this request (possibly for
    // testing), return the original value.
    return $value;
}

/**
 * Declare a filter implementation.
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::addFilter()
 * @param string|array $name The filter name.
 * @param callback $callback The function to call.
 * @param integer $priority Defaults to 10.
 */
function add_filter($name, $callback, $priority = 10)
{
    if ($pluginBroker = get_plugin_broker()) {
        $pluginBroker->addFilter($name, $callback, $priority);
    }
}

/**
 * Clear all implementations for a filter (or all filters).
 *
 * @package Omeka\Function\Plugin
 * @uses Omeka_Plugin_Broker::clearFilters()
 * @param string|null $name The name of the filter to clear. If null or omitted,
 *  all filters will be cleared.
 */
function clear_filters($filterName = null)
{
    if ($pluginBroker = get_plugin_broker()) {
        $pluginBroker->clearFilters($filterName);
    }
}

/**
 * Get the ACL object.
 *
 * @package Omeka\Function\User
 * @return Zend_Acl
 */
function get_acl()
{
    try {
        return Zend_Registry::get('bootstrap')->getResource('Acl');
    } catch (Zend_Exception $e) {
        return null;
    }
}

/**
 * Determine whether the script is being executed through the admin interface.
 *
 * Can be used to branch behavior based on whether or not the admin theme is
 * being accessed, but should not be relied upon in place of using the ACL for
 * controlling access to scripts.
 *
 * @package Omeka\Function\View
 * @return boolean
 */
function is_admin_theme()
{
    return (bool) Zend_Controller_Front::getInstance()->getParam('admin');
}

/**
 * Get all record types that may be indexed and searchable.
 *
 * Plugins may add record types via the "search_record_types" filter. The
 * keys should be the record's class name and the respective values should
 * be the human readable and internationalized version of the record type.
 *
 * These record classes must extend Omeka_Record_AbstractRecord and
 * implement this search mixin (Mixin_Search).
 *
 * @package Omeka\Function\Search
 * @see Mixin_Search
 * @return array
 */
function get_search_record_types()
{
    $searchRecordTypes = array(
        'Item'       => __('Item'),
        'File'       => __('File'),
        'Collection' => __('Collection'),
    );
    $searchRecordTypes = apply_filters('search_record_types', $searchRecordTypes);
    return $searchRecordTypes;
}

/**
 * Get all record types that have been customized to be searchable.
 *
 * @package Omeka\Function\Search
 * @uses get_search_record_types()
 * @return array
 */
function get_custom_search_record_types()
{
    // Get the custom search record types from the database.
    $customSearchRecordTypes = unserialize(get_option('search_record_types'));
    if (!is_array($customSearchRecordTypes)) {
        $customSearchRecordTypes = array();
    }

    // Compare the custom list to the full list.
    $searchRecordTypes = get_search_record_types();
    foreach ($searchRecordTypes as $key => $value) {
        // Remove record types that have been omitted.
        if (!in_array($key, $customSearchRecordTypes)) {
            unset($searchRecordTypes[$key]);
        }
    }

    return $searchRecordTypes;
}

/**
 * Get all available search query types.
 *
 * Plugins may add query types via the "search_query_types" filter. The keys
 * should be the type's GET query value and the respective values should be the
 * human readable and internationalized version of the query type.
 *
 * Plugins that add a query type must modify the select object via the
 * "search_sql" hook to account for whatever custom search strategy they
 * implement.
 *
 * @package Omeka\Function\Search
 * @see Table_SearchText::applySearchFilters()
 * @return array
 */
function get_search_query_types()
{
    // Apply the filter only once.
    static $searchQueryTypes;
    if ($searchQueryTypes) {
        return $searchQueryTypes;
    }

    $searchQueryTypes = array(
        'keyword'     => __('Keyword'),
        'boolean'     => __('Boolean'),
        'exact_match' => __('Exact match'),
    );
    $searchQueryTypes = apply_filters('search_query_types', $searchQueryTypes);
    return $searchQueryTypes;
}

/**
 * Insert a new item into the Omeka database.
 *
 * @package Omeka\Function\Db\Item
 * @uses Builder_Item
 * @param array $metadata Set of metadata options for configuring the item.
 *  The array can include the following properties:
 *  - 'public' (boolean)
 *  - 'featured' (boolean)
 *  - 'collection_id' (integer)
 *  - 'item_type_id' (integer)
 *  - 'item_type_name' (string)
 *  - 'tags' (string, comma-delimited)
 *  - 'overwriteElementTexts' (boolean) -- determines whether or not to
 *    overwrite existing element texts.  If true, this will loop through the
 *    element texts provided in $elementTexts, and it will update existing records
 *    where possible.  All texts that are not yet in the DB will be added in the
 *    usual manner.  False by default.
 *
 * @param array $elementTexts Array of element texts to assign to the item.
 * This follows the following format::
 *    array(
 *      [element set name] => array(
 *        [element name] => array(
 *          array('text' => [string], 'html' => [false|true]),
 *          array('text' => [string], 'html' => [false|true])
 *         ),
 *        [element name] => array(
 *          array('text' => [string], 'html' => [false|true]),
 *          array('text' => [string], 'html' => [false|true])
 *        )
 *      ),
 *      [element set name] => array(
 *        [element name] => array(
 *          array('text' => [string], 'html' => [false|true]),
 *          array('text' => [string], 'html' => [false|true])
 *        ),
 *        [element name] => array(
 *          array('text' => [string], 'html' => [false|true]),
 *          array('text' => [string], 'html' => [false|true])
 *        )
 *      )
 *    );
 *
 * @param array $fileMetadata Settings and data used to ingest files into Omeka
 *  and add them to this item.  Includes the following options:
 *  - 'file_transfer_type' (string = 'Url|Filesystem|Upload' or
 *    Omeka_File_Transfer_Adapter_Interface). Corresponds to the $transferStrategy
 *    argument for addFiles().
 *  - 'file_ingest_options' (array) Optional array of options to
 *    modify the behavior of the ingest.  Corresponds to the $options
 *    argument for addFiles().
 *  - 'files' (array or string) Represents information indicating the file to
 *    ingest. Corresponds to the $files argument for addFiles().
 *
 * @return Item
 */
function insert_item($metadata = array(), $elementTexts = array(), $fileMetadata = array())
{
    $builder = new Builder_Item(get_db());
    $builder->setRecordMetadata($metadata);
    $builder->setElementTexts($elementTexts);
    $builder->setFileMetadata($fileMetadata);
    return $builder->build();
}

/**
 * Add files to an item.
 *
 * @package Omeka\Function\Db\Item
 * @uses Builder_Item::addFiles()
 * @param Item|integer $item Item record or ID of item to add files to
 * @param string|Omeka_File_Ingest_AbstractIngest $transferStrategy Strategy
 *  to use when ingesting the file. The strings 'Url', 'Filesystem' and 'Upload'
 *  correspond to those built-in strategies. Alternatively a strategy object
 *  can be passed.
 * @param array $files Information about the file(s) to ingest. See addFiles()
 *  for details
 * @param array $options Array of options to
 *  modify the behavior of the ingest. Available options include:
 *  - 'ignore_invalid_files': boolean, false by default. Whether or not to
 *    throw exceptions when a file is not valid.
 *  - 'ignoreNoFile': (for Upload only) boolean, false by default. Whether to
 *    ignore validation errors that occur when an uploaded file is missing, like
 *    when a file input is left empty on a form.
 * @return array The added File records.
 */
function insert_files_for_item($item, $transferStrategy, $files, $options = array())
{
    $builder = new Builder_Item(get_db());
    $builder->setRecord($item);
    return $builder->addFiles($transferStrategy, $files, $options);
}

/**
 * Update an existing item.
 *
 * @package Omeka\Function\Db\Item
 * @see insert_item()
 * @uses Builder_Item
 * @param Item|int $item Either an Item object or the ID for the item.
 * @param array $metadata Set of options that can be passed to the item.
 * @param array $elementTexts Element texts to assign. See insert_item() for details.
 * @param array $fileMetadata File ingest data. See insert_item() for details.
 * @return Item
 */
function update_item($item, $metadata = array(), $elementTexts = array(), $fileMetadata = array())
{
    $builder = new Builder_Item(get_db());
    $builder->setRecord($item);
    $builder->setRecordMetadata($metadata);
    $builder->setElementTexts($elementTexts);
    $builder->setFileMetadata($fileMetadata);
    return $builder->build();
}

/**
 * Update an existing collection.
 *
 * @package Omeka\Function\Db\Collection
 * @see insert_collection()
 * @uses Builder_Collection
 * @param Collection|int $collection Either an Collection object or the ID for the collection.
 * @param array $metadata Set of options that can be passed to the collection.
 * @param array $elementTexts The element texts for the collection.
 * @return Collection
 */
function update_collection($collection, $metadata = array(), $elementTexts = array())
{
    $builder = new Builder_Collection(get_db());
    $builder->setRecord($collection);
    $builder->setRecordMetadata($metadata);
    $builder->setElementTexts($elementTexts);
    return $builder->build();
}

/**
 * Insert a new item type.
 *
 * @package Omeka\Function\Db\ItemType
 * @uses Builder_ItemType
 * @param array $metadata Follows the format:
 * <code>
 * array(
 *   'name'        => [string],
 *   'description' => [string]
 * );
 * </code>
 * @param array $elementInfos An array containing element data. Each entry
 * follows one or more of the following formats:
 * <ol>
 *   <li>An array containing element metadata</li>
 *   <li>An Element object</li>
 * </ol>
 * <code>
 * array(
 *   array(
 *     'name' => [(string) name, required],
 *     'description' => [(string) description, optional],
 *     'order' => [(int) order, optional],
 *   ),
 *   [(Element)],
 * );
 * </code>
 * @return ItemType
 */
function insert_item_type($metadata = array(), $elementInfos = array())
{
    $builder = new Builder_ItemType(get_db());
    $builder->setRecordMetadata($metadata);
    $builder->setElements($elementInfos);
    return $builder->build();
}

/**
 * Insert a collection
 *
 * @package Omeka\Function\Db\Collection
 * @uses Builder_Collection
 * @param array $metadata Follows the format:
 * <code>
 * array(
 *   'public'      => [true|false],
 *   'featured'    => [true|false]
 * )
 * </code>
 * @param array $elementTexts Array of element texts to assign to the collection.
 * This follows the format:
 * <code>
 * array(
 *   [element set name] => array(
 *     [element name] => array(
 *       array('text' => [string], 'html' => [false|true]),
 *       array('text' => [string], 'html' => [false|true])
 *      ),
 *     [element name] => array(
 *       array('text' => [string], 'html' => [false|true]),
 *       array('text' => [string], 'html' => [false|true])
 *     )
 *   ),
 *   [element set name] => array(
 *     [element name] => array(
 *       array('text' => [string], 'html' => [false|true]),
 *       array('text' => [string], 'html' => [false|true])
 *     ),
 *     [element name] => array(
 *       array('text' => [string], 'html' => [false|true]),
 *       array('text' => [string], 'html' => [false|true])
 *     )
 *   )
 * );
 * </code>
 * @return Collection
 */
function insert_collection($metadata = array(), $elementTexts = array())
{
    $builder = new Builder_Collection(get_db());
    $builder->setRecordMetadata($metadata);
    $builder->setElementTexts($elementTexts);
    return $builder->build();
}

/**
 * Insert an element set and its elements into the database.
 *
 * @package Omeka\Function\Db\ElementSet
 * @uses Builder_ElementSet
 * @param string|array $elementSetMetadata Element set information.
 * <code>
 * [(string) element set name]
 * // OR
 * array(
 *   'name'        => [(string) element set name, required, unique],
 *   'description' => [(string) element set description, optional],
 *   'record_type' => [(string) record type name, optional]
 * );
 * </code>
 * @param array $elements An array containing element data. Follows one of more
 * of the following formats:
 * <ol>
 * <li>An array containing element metadata</li>
 * <li>A string of the element name</li>
 * </ol>
 * <code>
 * array(
 *   array(
 *     'name' => [(string) name, required],
 *     'description' => [(string) description, optional],
 *   ),
 *   [(string) element name]
 * );
 * </code>
 * @return ElementSet
 */
function insert_element_set($elementSetMetadata = array(), array $elements = array())
{
    // Set the element set name if a string is provided.
    if (is_string($elementSetMetadata)) {
        $elementSetMetadata = array('name' => $elementSetMetadata);
    }

    $builder = new Builder_ElementSet(get_db());
    $builder->setRecordMetadata($elementSetMetadata);
    $builder->setElements($elements);
    return $builder->build();
}

/**
 * Release an object from memory.
 *
 * Use this fuction after you are done using an Omeka model object to prevent
 * memory leaks.  Required because PHP 5.2 does not do garbage collection on
 * circular references.
 *
 * @package Omeka\Function\Utility
 * @param mixed &$var The object to be released, or an array of such objects.
 */
function release_object(&$var)
{
    if (is_array($var)) {
        array_walk($var, 'release_object');
    } else if (is_object($var)) {
        $var->__destruct();
    }
    $var = null;
}

/**
 * Get a theme option.
 *
 * @package Omeka\Function\Db\Option
 * @uses Theme::getOption()
 * @param string $optionName The option name.
 * @param string $themeName The theme name.  If null, it will use the current
 * public theme.
 * @return string The option value.
 */
function get_theme_option($optionName, $themeName = null)
{
    if (!$themeName) {
        $themeName = Theme::getCurrentThemeName('public');
    }
    return Theme::getOption($themeName, $optionName);
}

/**
 * Set a theme option.
 *
 * @package Omeka\Function\Db\Option
 * @uses Theme::setOption()
 * @param string $optionName The option name.
 * @param string $optionValue The option value.
 * @param string $themeName The theme name. If null, it will use the current
 * public theme.
 * @return
 */
function set_theme_option($optionName, $optionValue, $themeName = null)
{
    if (!$themeName) {
        $themeName = Theme::getCurrentThemeName('public');
    }
    Theme::setOption($themeName, $optionName, $optionValue);
}

/**
 * Get the names of all user roles.
 *
 * @package Omeka\Function\User
 * @uses Zend_Acl::getRoles()
 * @return array
 */
function get_user_roles()
{
    $roles = get_acl()->getRoles();
    foreach($roles as $key => $val) {
        $roles[$val] = __(Inflector::humanize($val));
        unset($roles[$key]);
    }
    return $roles;
}

/**
 * Check whether an element set contains a specific element.
 *
 * @package Omeka\Function\Db\ElementSet
 * @uses Table_Element::findByElementSetNameAndElementName()
 * @param string $elementSetName The element set name.
 * @param string $elementName The element name.
 * @return bool
 */
function element_exists($elementSetName, $elementName) {
    $element = get_db()->getTable('Element')->findByElementSetNameAndElementName($elementSetName, $elementName);
    return (bool) $element;
}


/**
 * Determine whether a plugin is installed and active.
 *
 * May be used by theme/plugin writers to customize behavior based on the
 * existence of certain plugins. Some examples of how to use this function:
 *
 * Check if ExhibitBuilder is installed and activated.
 * <code>
 *     if (plugin_is_active('ExhibitBuilder')):
 * </code>
 *
 * Check if installed version of ExhibitBuilder is at least version 1.0 or
 * higher.
 * <code>
 *     if (plugin_is_active('ExhibitBuilder', '1.0')):
 * </code>
 *
 * Check if installed version of ExhibitBuilder is anything less than 2.0.
 * <code>
 *     if (plugin_is_active('ExhibitBuilder', '2.0', '<')):
 * </code>
 *
 * @package Omeka\Function\Plugin
 * @uses Table_Plugin::findByDirectoryName()
 * @param string $name Directory name of the plugin.
 * @param string $version Version of the plugin to check.
 * @param string $compOperator Comparison operator to use when checking the
 *  installed version of ExhibitBuilder.
 * @return boolean
 */
function plugin_is_active($name, $version = null, $compOperator = '>=')
{
    $plugin = get_db()->getTable('Plugin')->findByDirectoryName($name);
    if (!$plugin) {
        return false;
    }
    if (!$plugin->isActive()) {
        return false;
    }
    if ($version) {
        return version_compare($plugin->getDbVersion(), $version, $compOperator);
    } else {
        return true;
    }
}

/**
 * Translate a string.
 *
 * @package Omeka\Function\Locale
 * @uses Zend_Translate::translate()
 * @param string|array $msgid The string to be translated, or Array for plural
 *  translations.
 * @param mixed $args string formatting args. If any extra args are passed, the
 *  args and the translated string will be formatted with sprintf().
 * @return string The translated string.
 */
function __($msgid)
{
    // Avoid getting the translate object more than once.
    static $translate;

    if (!isset($translate)) {
        try {
            $translate = Zend_Registry::get('Zend_Translate');
        } catch (Zend_Exception $e) {
            $translate = null;
        }
    }

    if ($translate) {
        $string = $translate->translate($msgid);
    } elseif (is_array($msgid)) {
        $string = ($msgid[2] === 1) ? $msgid[0] : $msgid[1];
    } else {
        $string = $msgid;
    }

    $args = func_get_args();
    array_shift($args);

    if (!empty($args)) {
        return vsprintf($string, $args);
    }

    return $string;
}

/**
 * Transform arguments in an array suitable for __.
 *
 * <code>
 *     $n = count($items);
 *     echo __(plural('one item', '%s items', $n), $n);
 * </code>
 *
 * @package Omeka\Function\Locale
 * @param string $msgid The string to be translated, singular form
 * @param string $msgid_plural The string to be translated, plural form
 * @param int $n Used to determine the plural form
 * @return array Array to pass to __
 */
function plural($msgid, $msgid_plural, $n)
{
    return array($msgid, $msgid_plural, $n);
}

/**
 * Add an translation source directory.
 *
 * The directory's contents should be .mo files following the naming scheme of
 * Omeka's application/languages directory. If a .mo for the current locale
 * exists, the translations will be loaded.
 *
 * @package Omeka\Function\Locale
 * @uses Zend_Translate::addTranslation()
 * @param string $dir Directory from which to load translations.
 */
function add_translation_source($dir)
{
    try {
        $translate = Zend_Registry::get('Zend_Translate');
    } catch (Zend_Exception $e) {
        return;
    }

    $locale = $translate->getAdapter()->getOptions('localeName');

    try {
        $translate->addTranslation(array(
            'content' => "$dir/$locale.mo",
            'locale' => $locale
        ));
    } catch (Zend_Translate_Exception $e) {
        // Do nothing, allow the user to set a locale or dir without a
        // translation.
    }
}

/**
 * Get the HTML "lang" attribute for the current locale.
 *
 * @package Omeka\Function\Locale
 * @return string
 */
function get_html_lang()
{
    try {
        $locale = Zend_Registry::get('Zend_Locale');
    } catch (Zend_Exception $e) {
        return 'en-US';
    }
    return str_replace('_', '-', $locale->toString());
}


/**
 * Format a date for output according to the current locale.
 *
 * @package Omeka\Function\Locale
 * @uses Zend_Date
 * @param mixed $date Date to format. If an integer, the date is intepreted as a
 * Unix timestamp. If a string, the date is interpreted as an ISO 8601 date.
 * @param string $format Format to apply. See Zend_Date for possible formats.
 * The default format is the current locale's "medium" format.
 * @return string
 */
function format_date($date, $format = Zend_Date::DATE_MEDIUM)
{
    if (is_int($date)) {
        $sourceFormat = Zend_Date::TIMESTAMP;
    } else {
        $sourceFormat = Zend_Date::ISO_8601;
    }
    $dateObj = new Zend_Date($date, $sourceFormat);
    return $dateObj->toString($format);
}

/**
 * Add a local JavaScript file or files to the current page.
 *
 * All scripts will be included in the page's head. This needs to be
 * called either before head(), or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_js()
 * @param string|array $file File to use, if an array is passed, each array
 * member will be treated like a file.
 * @param string $dir Directory to search for the file. Keeping the default is
 * recommended.
 * @param array $options An array of options.
 */
function queue_js_file($file, $dir = 'javascripts', $options = array())
{
    if (is_array($file)) {
        foreach ($file as $singleFile) {
            queue_js_file($singleFile, $dir, $options);
        }
        return;
    }

    queue_js_url(src($file, $dir, 'js'), $options);
}

/**
 * Add a JavaScript file to the current page by URL.
 *
 * The script link will appear in the head element. This needs to be called
 * either before head() or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_js()
 * @param string $string URL to script.
 * @param array $options An array of options.
 */
function queue_js_url($url, $options = array())
{
    get_view()->headScript()->appendFile($url, null, $options);
}

/**
 * Add a JavaScript string to the current page.
 *
 * The script will appear in the head element. This needs to be called either
 * before head() or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_js()
 * @param string $string JavaScript string to include.
 * @param array $options An array of options.
 */
function queue_js_string($string, $options = array())
{
    get_view()->headScript()->appendScript($string, null, $options);
}

/**
 * Add a CSS file or files to the current page.
 *
 * All stylesheets will be included in the page's head. This needs to be
 * called either before head(), or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_css()
 * @param string|array $file File to use, if an array is passed, each array
 * member will be treated like a file.
 * @param string $media CSS media declaration, defaults to 'all'.
 * @param string|bool $conditional IE-style conditional comment, used generally
 * to include IE-specific styles. Defaults to false.
 * @param string $dir Directory to search for the file.  Keeping the default is
 * recommended.
 */
function queue_css_file($file, $media = 'all', $conditional = false, $dir = 'css')
{
    if (is_array($file)) {
        foreach ($file as $singleFile) {
            queue_css_file($singleFile, $media, $conditional, $dir);
        }
        return;
    }
    queue_css_url(css_src($file, $dir), $media, $conditional);
}

/**
 * Add a CSS file to the current page by URL.
 *
 * The stylesheet link will appear in the head element. This needs to be called
 * either before head() or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_css
 * @param string $string URL to stylesheet.
 * @param string $media CSS media declaration, defaults to 'all'.
 * @param string|bool $conditional IE-style conditional comment, used generally
 * to include IE-specific styles. Defaults to false.
 */
function queue_css_url($url, $media = 'all', $conditional = false)
{
    get_view()->headLink()->appendStylesheet($url, $media, $conditional);
}

/**
 * Add a CSS string to the current page.
 *
 * The inline stylesheet will appear in the head element. This needs to be
 * called either before head() or in a plugin_header hook.
 *
 * @package Omeka\Function\View\Asset
 * @see head_css
 * @param string $string CSS string to include.
 * @param string $media CSS media declaration, defaults to 'all'.
 * @param string|bool $conditional IE-style conditional comment, used generally
 * to include IE-specific styles. Defaults to false.
 */
function queue_css_string($string, $media = 'all', $conditional = false)
{
    $attrs = array();
    if ($media) {
        $attrs['media'] = $media;
    }
    if ($conditional) {
        $attrs['conditional'] = $conditional;
    }
    get_view()->headStyle()->appendStyle($string, $attrs);
}

/**
 * Get the JavaScript tags that will be used on the page.
 *
 * This should generally be used with echo to print the scripts in the page
 * head.
 *
 * @package Omeka\Function\View\Asset
 * @see queue_js_file()
 * @param bool $includeDefaults Whether the default javascripts should be
 * included. Defaults to true.
 * @return string
 */
function head_js($includeDefaults = true)
{
    $headScript = get_view()->headScript();

    if ($includeDefaults) {
        $dir = 'javascripts';
        $headScript->prependScript('jQuery.noConflict();')
                   ->prependScript('window.jQuery.ui || document.write(' . js_escape(js_tag('vendor/jquery-ui')) . ')')
                   ->prependFile('//ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js')
                   ->prependScript('window.jQuery || document.write(' . js_escape(js_tag('vendor/jquery')) . ')')
                   ->prependFile('//ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js');
    }
    return $headScript;
}

/**
 * Get the CSS link tags that will be used on the page.
 *
 * This should generally be used with echo to print the scripts in the page
 * head.
 *
 * @package Omeka\Function\View\Asset
 * @see queue_css_file()
 * @return string
 */
function head_css()
{
    return get_view()->headLink() . get_view()->headStyle();
}

/**
 * Get the URL to a local css file.
 *
 * @package Omeka\Function\View\Asset
 * @uses src()
 * @param string $file Should not include the .css extension
 * @param string $dir Defaults to 'css'
 * @return string
 */
function css_src($file, $dir = 'css')
{
    return src($file, $dir, 'css');
}

/**
 * Get the URL to a local image file.
 *
 * @package Omeka\Function\View\Asset
 * @uses src()
 * @param string $file Filename, including the extension.
 * @param string $dir Directory within the theme to look for image files.
 * Defaults to 'images'.
 * @return string
 */
function img($file, $dir = 'images')
{
    return src($file, $dir);
}

/**
 * Get a tag for including a local JavaScript file.
 *
 * @package Omeka\Function\View\Asset
 * @uses src()
 * @param string $file The name of the file, without .js extension.
 * @param string $dir The directory in which to look for javascript files.
 * Recommended to leave the default value.
 * @return string
 */
function js_tag($file, $dir = 'javascripts')
{
    $href = src($file, $dir, 'js');
    return '<script type="text/javascript" src="' . html_escape($href) . '" charset="utf-8"></script>';
}

/**
 * Get a URL for a given local file.
 *
 * @package Omeka\Function\View\Asset
 * @uses web_path_to()
 * @param string $file The filename.
 * @param string|null $dir The file's directory.
 * @param string $ext The file's extension.
 * @return string
 */
function src($file, $dir = null, $ext = null)
{
    if ($ext !== null) {
        $file .= '.' . $ext;
    }
    if ($dir !== null) {
        $file = $dir . '/' . $file;
    }
    return web_path_to($file);
}

/**
 * Get the filesystem path for a local asset.
 *
 * @package Omeka\Function\View\Asset
 * @throws InvalidArgumentException
 * @param string $file The filename.
 * @return string
 */
function physical_path_to($file)
{
    $paths = get_view()->getAssetPaths();
    foreach ($paths as $path) {
        list($physical, $web) = $path;
        if (file_exists($physical . '/' . $file)) {
            return $physical . '/' . $file;
        }
    }
    throw new InvalidArgumentException(__("Could not find file %s!", $file));
}

/**
 * Get the URL for a local asset.
 *
 * @package Omeka\Function\View\Asset
 * @throws InvalidArgumentException
 * @param string $file The filename.
 * @return string
 */
function web_path_to($file)
{
    $view = get_view();
    $paths = $view->getAssetPaths();
    foreach ($paths as $path) {
        list($physical, $web) = $path;
        if (file_exists($physical . '/' . $file)) {
            return $web . '/' . $file;
        }
    }
    throw new InvalidArgumentException( __("Could not find file %s!",$file) );
}


/**
 * Get HTML for displaying a random featured collection.
 *
 * @package Omeka\Function\View
 * @return string
 */
function random_featured_collection()
{
    $collection = get_random_featured_collection();
    if ($collection) {
        $html = get_view()->partial('collections/single.php', array('collection' => $collection));
        release_object($collection);
    } else {
        $html = '<p>' . __('No featured collections are available.') . '</p>';
    }
    return $html;
}

/**
 * Get the Collection object for the current item.
 *
 * @package Omeka\Function\Db\Item
 * @param Item|null $item Check for this specific item record (current item if null).
 * @return Collection
 */
function get_collection_for_item($item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    return $item->Collection;
}

/**
 * Get the most recently added collections.
 *
 * @package Omeka\Function\Db\Collection
 * @uses get_records()
 * @param integer $num The maximum number of recent collections to return
 * @return array
 */
function get_recent_collections($num = 10)
{
    return get_records('Collection', array('sort_field' => 'added', 'sort_dir' => 'd'), $num);
}

/**
 * Get a random featured collection.
 *
 * @package Omeka\Function\Db\Collection
 * @uses Collection::findRandomFeatured()
 * @return Collection
 */
function get_random_featured_collection()
{
    return get_db()->getTable('Collection')->findRandomFeatured();
}

/**
 * Get the latest available version of Omeka.
 *
 * @package Omeka\Function\Utility
 * @return string|false The latest available version of Omeka, or false if the
 * request failed for some reason.
 */
function latest_omeka_version()
{
    $omekaApiUri = 'http://api.omeka.org/latest-version';
    $omekaApiVersion = '0.1';

    // Determine if we have already checked for the version lately.
    $check = unserialize(get_option('omeka_update')) or $check = array();
    // This a timestamp corresponding to the last time we checked for
    // a new version.  86400 is the number of seconds in a day, so check
    // once a day for a new version.
    if (array_key_exists('last_updated', $check)
        and ($check['last_updated'] + 86400) > time()) {
        // Return the value we got the last time we checked.
        return $check['latest_version'];
    }

    try {
        $client = new Zend_Http_Client($omekaApiUri);
        $client->setParameterGet('version', $omekaApiVersion);
        $client->setMethod('GET');
        $result = $client->request();
        if ($result->getStatus() == '200') {
            $latestVersion = $result->getBody();
            // Store the newer values
            $check['latest_version'] = $latestVersion;
            $check['last_updated'] = time();
            set_option('omeka_update', serialize($check));
           return $result->getBody();
        } else {
           debug("Attempt to GET $omekaApiUri with version=$omekaApiVersion "
                 . "returned with status=" . $result->getStatus() . " and "
                 . "response body=" . $result->getBody());
        }
    } catch (Zend_Http_Client_Exception $e) {
        debug('Error in retrieving latest Omeka version: ' . $e->getMessage());
    }
    return false;
}

/**
 * Get the maximum file upload size.
 *
 * @package Omeka\Function\Utility
 * @return string
 */
function max_file_size()
{
    $helper = new Omeka_View_Helper_MaxFileSize;
    return $helper->maxFileSize();
}

/**
 * Get HTML for a set of files.
 *
 * @package Omeka\Function\View\File
 * @uses Omeka_View_Helper_FileMarkup::fileMarkup()
 * @param File $files A file record or an array of File records to display.
 * @param array $props Properties to customize display for different file types.
 * @param array $wrapperAttributes Attributes HTML attributes for the div that
 * wraps each displayed file. If empty or null, this will not wrap the displayed
 * file in a div.
 * @return string HTML
 */
function file_markup($files, array $props = array(), $wrapperAttributes = array('class' => 'item-file'))
{
    if (!is_array($files)) {
        $files = array($files);
    }
    $helper = new Omeka_View_Helper_FileMarkup;
    $output = '';
    foreach ($files as $file) {
        $output .= $helper->fileMarkup($file, $props, $wrapperAttributes);
    }
    return $output;
}

/**
 * Return HTML for a file's ID3 metadata.
 *
 * @package Omeka\Function\View\File
 * @uses Omeka_View_Helper_FileId3Metadata::fileId3Metadata()
 * @param array $options Options for varying the display. Currently ignored.
 * @param File|null $file File to get the metadata for. If omitted, the current
 *  file is used.
 * @return string|array
 */
function file_id3_metadata(array $options = array(), $file = null)
{
    if (!$file) {
        $file = get_current_record('file');
    }
    return get_view()->fileId3Metadata($file, $options);
}

/**
 * Get the most recent files.
 *
 * @package Omeka\Function\Db
 * @uses get_records()
 * @param integer $num The maximum number of recent files to return
 * @return array
 */
function get_recent_files($num = 10)
{
    return get_records('File', array('sort_field' => 'added', 'sort_dir' => 'd'), $num);
}

/**
 * Generate attributes for an HTML tag.
 *
 * @package Omeka\Function\View
 * @param array|string $attributes Attributes for the tag.  If this is a string,
 * it will assign both 'name' and 'id' attributes that value for the tag.
 * @return string
 */
function tag_attributes($attributes)
{
    if (is_string($attributes)) {
        $toProcess['name'] = $attributes;
        $toProcess['id'] = $attributes;
    } else {
        //don't allow 'value' to be set specifically as an attribute (why = consistency)
        unset($attributes['value']);
        $toProcess = $attributes;
    }

    $attr = array();
    foreach ($toProcess as $key => $attribute) {
        // Reject weird attribute names (a little more restrictively than necessary)
        if (preg_match('/[^A-Za-z0-9_:.-]/', $key)) {
            continue;
        }
        if (is_string($attribute)) {
            $attr[$key] = $key . '="' . html_escape( $attribute ) . '"';
        }  else if ($attribute === true) {
            $attr[$key] = $key;
        }
    }
    return join(' ',$attr);
}

/**
 * Get the site-wide search form.
 *
 * @package Omeka\Function\Search
 * @param array $options Valid options are as follows:
 * - show_advanced (bool): whether to show the advanced search; default is false.
 * - submit_value (string): the value of the submit button; default "Submit".
 * - form_attributes (array): an array containing form tag attributes.
 * @return string The search form markup.
 */
function search_form(array $options = array())
{
    return get_view()->searchForm($options);
}

/**
 * Get a list of current site-wide search filters in use.
 *
 * @package Omeka\Function\Search
 * @uses Omeka_View_Helper_SearchFilters::searchFilters()
 * @param array $options Valid options are as follows:
 * - id (string): the value of the div wrapping the filters.
 * @return string
 */
function search_filters(array $options = array())
{
    return get_view()->searchFilters($options);
}

/**
 * Get the HTML for a form input for a given Element.
 *
 * Assume that the given element has access to all of its values (for example,
 * all values of a Title element for a given Item).
 *
 * This will output as many form inputs as there are values for a given element.
 * In addition to that, it will give each set of inputs a label and a span with
 * class="tooltip" containing the description for the element. This span can
 * either be displayed, hidden with CSS or converted into a tooltip with
 * javascript.
 *
 * All sets of form inputs for elements will be wrapped in a div with
 * class="field".
 *
 * @package Omeka\Function\View\Form
 * @uses Omeka_View_Helper_ElementForm::elementForm()
 * @param Element|array $element
 * @param Omeka_Record_AbstractRecord $record
 * @param array $options
 * @return string HTML
 */
function element_form($element, $record, $options = array())
{
    $html = '';
    // If we have an array of Elements, loop through the form to display them.
    if (is_array($element)) {
        foreach ($element as $key => $e) {
            $html .= get_view()->elementForm($e, $record, $options);
        }
    } else {
        $html = get_view()->elementForm($element, $record, $options);
    }
    return $html;
}

/**
 * Return a element set form for a record.
 *
 * @package Omeka\Function\View\Form
 * @uses element_form()
 * @param Omeka_Record_AbstractRecord $record
 * @param string $elementSetName The name of the element set or 'Item Type
 * Metadata' for an item's item type data.
 * @return string
 */
function element_set_form($record, $elementSetName)
{
    $recordType = get_class($record);
    if ($recordType == 'Item' && $elementSetName == 'Item Type Metadata') {
        $elements = $record->getItemTypeElements();
    } else {
        $elements = get_db()->getTable('Element')->findBySet($elementSetName);
    }
    $filterName = array('ElementSetForm', $recordType, $elementSetName);
    $elements = apply_filters(
        $filterName,
        $elements,
        array('record_type' => $recordType, 'record' => $record, 'element_set_name' => $elementSetName)
    );
    $html = element_form($elements, $record);
    return $html;
}

/**
 * Add a "Select Below" or other label option to a set of select options.
 *
 * @package Omeka\Function\View\Form
 * @param array $options
 * @param string|null $labelOption
 * @return array
 */
function label_table_options($options, $labelOption = null)
{
    if ($labelOption === null) {
        $labelOption = __('Select Below ');
    }
    return array('' => $labelOption) + $options;
}

/**
 * Get the options array for a given table.
 *
 * @package Omeka\Function\View\Form
 * @uses Omeka_Db_Table::findPairsForSelectForm()
 * @param string $tableClass
 * @param string $labelOption
 * @param array $searchParams search parameters on table.
 */
function get_table_options($tableClass, $labelOption = null, $searchParams = array())
{
    $options = get_db()->getTable($tableClass)->findPairsForSelectForm($searchParams);
    $options = apply_filters(Inflector::tableize($tableClass) . '_select_options', $options);
    return label_table_options($options, $labelOption);
}

/**
 * Get the view object.
 *
 * Should be used only to avoid function scope issues within other theme helper
 * functions.
 *
 * @package Omeka\Function\View
 * @return Omeka_View
 */
function get_view()
{
    return Zend_Registry::get('view');
}

/**
 * Get link tags for the RSS and Atom feeds.
 *
 * @package Omeka\Function\View\Layout
 * @return string HTML
 */
function auto_discovery_link_tags()
{
    $html = '<link rel="alternate" type="application/rss+xml" title="'. __('Omeka RSS Feed') . '" href="'. html_escape(items_output_url('rss2')) .'" />';
    $html .= '<link rel="alternate" type="application/atom+xml" title="'. __('Omeka Atom Feed') .'" href="'. html_escape(items_output_url('atom')) .'" />';
    return $html;
}

/**
 * Get HTML from a view file in the common/ directory.
 *
 * Optionally, parameters can be passed to the view, and the view can be loaded
 * from a different directory.
 *
 * @package Omeka\Function\View\Layout
 * @uses Zend_View_Helper_Partial::partial()
 * @param string $file Filename
 * @param array $vars A keyed array of variables to be extracted into the script
 * @param string $dir Defaults to 'common'
 * @return string
 */
function common($file, $vars = array(), $dir = 'common')
{
    return get_view()->partial($dir . '/' . $file . '.php', $vars);
}

/**
 * Get the view's header HTML.
 *
 * @package Omeka\Function\View\Layout
 * @uses common
 * @param array $vars Keyed array of variables
 * @param string $file Filename of header script (defaults to 'header')
 * @return string
 */
function head($vars = array(), $file = 'header')
{
    return common($file, $vars);
}

/**
 * Get the view's footer HTML.
 *
 * @package Omeka\Function\View\Layout
 * @uses common()
 * @param array $vars Keyed array of variables
 * @param string $file Filename of footer script (defaults to 'footer')
 * @return string
 */
function foot($vars = array(), $file = 'footer')
{
    return common($file, $vars);
}

/**
 * Return a flashed message from the controller.
 *
 * @package Omeka\Function\View
 * @uses Omeka_View_Helper_Flash::flash()
 * @return string
 */
function flash()
{
    return get_view()->flash();
}

/**
 * Get the value of a particular site setting for display.
 *
 * Content for any specific option can be filtered by using a filter named
 * 'display_option_(option)' where (option) is the name of the option, e.g.
 * 'display_option_site_title'.
 *
 * @package Omeka\Function\View
 * @uses get_option()
 * @param string $name The name of the option
 * @return string
 */
function option($name)
{
    $name = apply_filters("display_option_$name", get_option($name));
    $name = html_escape($name);
    return $name;
}

/**
 * Get a set of records from the database.
 *
 * @package Omeka\Function\Db
 * @uses Omeka_Db_Table::findBy
 * @param string $recordType Type of records to get.
 * @param array $params Array of search parameters for records.
 * @param integer $limit Maximum number of records to return.
 *
 * @return array An array of result records (of $recordType).
 */
function get_records($recordType, $params = array(), $limit = 10)
{
    return get_db()->getTable($recordType)->findBy($params, $limit);
}

/**
 * Get a single record from the database.
 *
 * @since 2.1
 * @package Omeka\Function\Db
 * @uses Omeka_Db_Table::findBy
 * @param string $recordType Type of records to get.
 * @param array $params Array of search parameters for records.
 * @return object An object of result records (of $recordType).
 */
function get_record($recordType, $params = array())
{
    $record = get_records($recordType, $params, 1);
    return reset($record);
}

/**
 * Get the total number of a given type of record in the database.
 *
 * @package Omeka\Function\Db
 * @uses Omeka_Db_Table::count()
 * @param string $recordType Type of record to count.
 * @return integer Number of records of $recordType in the database.
 */
function total_records($recordType)
{
    return get_db()->getTable($recordType)->count();
}

/**
 * Get an iterator for looping over an array of records.
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_Loop::loop()
 * @param string $recordsVar The name of the variable the records are stored in.
 * @param array|null $records
 * @return Omeka_Record_Iterator
 */
function loop($recordsVar, $records = null)
{
    return get_view()->loop($recordsVar, $records);
}

/**
 * Set records to the view for iteration with loop().
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_SetLoopRecords::setLoopRecords()
 * @param string $recordsVar The name of the variable to store the records in.
 * @param array $records The records to store for later looping.
 */
function set_loop_records($recordsVar, array $records)
{
    get_view()->setLoopRecords($recordsVar, $records);
}

/**
 * Get records from the view for iteration.
 *
 * Note that this function will return an empty array if it is set to the
 * records variable. Use has_loop_records() to check if records exist.
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_GetLoopRecords::getLoopRecords()
 * @throws Omeka_View_Exception
 * @param string $recordsVar The name of the variable the records are stored in.
 * @param boolean $throwException Whether to throw an exception if the
 *  $recordsVar is unset. Default is to throw.
 * @return array|bool
 */
function get_loop_records($recordsVar, $throwException = true)
{
    return get_view()->getLoopRecords($recordsVar, $throwException);
}

/**
 * Check if records have been set to the view for iteration.
 *
 * Note that this function will return false if the records variable is set but
 * is an empty array, unlike get_loop_records(), which will return the empty
 * array.
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_HasLoopRecords::hasLoopRecords()
 * @param string $recordsVar View variable to check.
 * @return bool
 */
function has_loop_records($recordsVar)
{
    return get_view()->hasLoopRecords($recordsVar);
}

/**
 * Set a record to the view as the current record.
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_SetCurrentRecord::setCurrentRecord()
 * @param string $recordVar View variable to store the current record in.
 * @param Omeka_Record_AbstractRecord $record
 * @param bool $setPreviousRecord Whether to store the previous "current" record,
 *  if any. The default is to not store the previous record.
 */
function set_current_record($recordVar, Omeka_Record_AbstractRecord $record, $setPreviousRecord = false)
{
    get_view()->setCurrentRecord($recordVar, $record, $setPreviousRecord);
}

/**
 * Get the current record from the view.
 *
 * @package Omeka\Function\View\Loop
 * @uses Omeka_View_Helper_GetCurrentRecord::getCurrentRecord()
 * @throws Omeka_View-Exception
 * @param string $recordVar View variable the current record is stored in.
 * @param bool $throwException Whether to throw an exception if no current
 *  record was set. The default is to throw.
 * @return Omeka_Record_AbstractRecord|false
 */
function get_current_record($recordVar, $throwException = true)
{
    return get_view()->getCurrentRecord($recordVar, $throwException);
}

/**
 * Get a record by its ID.
 *
 * @package Omeka\Function\Db
 * @uses Omeka_Db_Table::find()
 * @param string $modelName Name of the Record model being looked up
 *  (e.g., 'Item')
 * @param int $recordId The ID of the specific record to find.
 * @return Omeka_Record_AbstractRecord|null The record, or null if it cannot
 *  be found.
 */
function get_record_by_id($modelName, $recordId)
{
    return get_db()->getTable(Inflector::camelize($modelName))->find($recordId);
}

/**
 * Get all output formats available in the current action.
 *
 * @package Omeka\Function\View\OutputFormat
 * @return array A sorted list of contexts.
 */
function get_current_action_contexts()
{
    $actionName = Zend_Controller_Front::getInstance()->getRequest()->getActionName();
    $contexts = Zend_Controller_Action_HelperBroker::getStaticHelper('contextSwitch')->getActionContexts($actionName);
    sort($contexts);
    return $contexts;
}

/**
 * Get an HTML list of output formats for the current action.
 *
 * @package Omeka\Function\View\OutputFormat
 * @uses get_current_action_contexts()
 * @param bool $list If true or omitted, return an unordered list, if false,
 *  return a simple string list using the delimiter.
 * @param string $delimiter If the first argument is false, use this as the
 *  delimiter for the list.
 * @return string|bool HTML
 */
function output_format_list($list = true, $delimiter = ', ')
{
    return get_view()->partial(
        'common/output-format-list.php',
        array('output_formats' => get_current_action_contexts(), 'query' => $_GET,
              'list' => $list, 'delimiter' => $delimiter)
    );
}

/**
 * Get the list of links for sorting displayed records.
 *
 * @package Omeka\Function\View
 * @param array $links The links to sort the headings. Should correspond to
 *  the metadata displayed.
 * @param array $wrapperTags The tags and attributes to use for the browse headings
 * - 'list_tag' The HTML tag to use for the containing list
 * - 'link_tag' The HTML tag to use for each list item (the browse headings)
 * - 'list_attr' Attributes to apply to the containing list tag
 * - 'link_attr' Attributes to apply to the list item tag
 *
 * @return string
 */
function browse_sort_links($links, $wrapperTags = array())
{
    $sortParam = Omeka_Db_Table::SORT_PARAM;
    $sortDirParam = Omeka_Db_Table::SORT_DIR_PARAM;
    $req = Zend_Controller_Front::getInstance()->getRequest();
    $currentSort = trim($req->getParam($sortParam));
    $currentDir = trim($req->getParam($sortDirParam));

    $defaults = array(
        'link_tag' => 'li',
        'list_tag' => 'ul',
        'link_attr' => array(),
        'list_attr' => array( 'id' => 'sort-links-list' )
    );

    $sortlistWrappers = array_merge($defaults, $wrapperTags);

    $linkAttrArray = array();
    foreach ($sortlistWrappers['link_attr'] as $key => $attribute) {
        $linkAttrArray[$key] = $key . '="' . html_escape( $attribute ) . '"';
    }
    $linkAttr = join(' ', $linkAttrArray);

    $listAttrArray = array();
    foreach ($sortlistWrappers['list_attr'] as $key => $attribute) {
        $listAttrArray[$key] = $key . '="' . html_escape( $attribute ) . '"';
    }
    $listAttr = join(' ', $listAttrArray);

    $sortlist = '';
    if(!empty($sortlistWrappers['list_tag'])) {
        $sortlist .= "<{$sortlistWrappers['list_tag']} $listAttr>";
    }

    foreach ($links as $label => $column) {
        if($column) {
            $urlParams = $_GET;
            $urlParams[$sortParam] = $column;
            $class = '';
            if ($currentSort && $currentSort == $column) {
                if ($currentDir && $currentDir == 'd') {
                    $class = 'class="sorting desc"';
                    $urlParams[$sortDirParam] = 'a';
                } else {
                    $class = 'class="sorting asc"';
                    $urlParams[$sortDirParam] = 'd';
                }
            }
            $url = html_escape(url(array(), null, $urlParams));
            if ($sortlistWrappers['link_tag'] !== '') {
                $sortlist .= "<{$sortlistWrappers['link_tag']} $class $linkAttr><a href=\"$url\">$label</a></{$sortlistWrappers['link_tag']}>";
            } else {
                $sortlist .= "<a href=\"$url\" $class $linkAttr>$label</a>";
            }
        } else {
            $sortlist .= "<{$sortlistWrappers['link_tag']}>$label</{$sortlistWrappers['link_tag']}>";
        }
    }
    if(!empty($sortlistWrappers['list_tag'])) {
        $sortlist .= "</{$sortlistWrappers['list_tag']}>";
    }
    return $sortlist;
}

/**
 * Get a <body> tag with attributes.
 *
 * Attributes can be filtered using the 'body_tag_attributes' filter.
 *
 * @package Omeka\Function\View
 * @uses tag_attributes()
 * @param array $attributes
 * @return string An HTML <body> tag with attributes and their values.
 */
function body_tag($attributes = array())
{
    $attributes = apply_filters('body_tag_attributes', $attributes);
    if ($attributes = tag_attributes($attributes)) {
        return "<body ". $attributes . ">\n";
    }
    return "<body>\n";
}

/**
 * Get a list of the current search item filters in use.
 *
 * @package Omeka\Function\Search
 * @uses Omeka_View_Helper_SearchFilters::searchFilters()
 * @params array $params Params to override the ones read from the request.
 * @return string
 */
function item_search_filters(array $params = null)
{
    return get_view()->itemSearchFilters($params);
}

/**
 * Get metadata for a record.
 *
 * @package Omeka\Function\View
 * @uses Omeka_View_Helper_Metadata::metadata()
 * @param Omeka_Record_AbstractRecord|string $record The record to get metadata
 * for. If an Omeka_Record_AbstractRecord, that record is used. If a string,
 * that string is used to look up a record in the current view.
 * @param mixed $metadata The metadata to get. If an array is given, this is
 * Element metadata, identified by array('Element Set', 'Element'). If a string,
 * the metadata is a record-specific "property."
 * @param array $options Options for getting the metadata.
 * @return mixed
 */
function metadata($record, $metadata, $options = array())
{
    return get_view()->metadata($record, $metadata, $options);
}

/**
 * Get all element text metadata for a record.
 *
 * @package Omeka\Function\View
 * @uses Omeka_View_Helper_AllElementTexts::allElementTexts()
 * @param Omeka_Record_AbstractRecord|string $record The record to get the
 * element text metadata for.
 * @param array $options Options for getting the metadata.
 * @return string|array
 */
function all_element_texts($record, $options = array())
{
    return get_view()->allElementTexts($record, $options);
}

/**
 * Get HTML for all files assigned to an item.
 *
 * @package Omeka\Function\View\Item
 * @uses file_markup()
 * @param array $options
 * @param array $wrapperAttributes
 * @param Item|null $item Check for this specific item record (current item if null).
 * @return string HTML
 */
function files_for_item($options = array(), $wrapperAttributes = array('class' => 'item-file'), $item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    return file_markup($item->Files, $options, $wrapperAttributes);
}

/**
 * Get the next item in the database.
 *
 * @package Omeka\Function\View\Item
 * @uses Item::next()
 * @param Item|null $item Check for this specific item record (current item if null).
 * @return Item|null
 */
function get_next_item($item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    return $item->next();
}

/**
 * Get the previous item in the database.
 *
 * @package Omeka\Function\View\Item
 * @uses Item::previous()
 * @param Item|null $item Check for this specific item record (current item if null).
 * @return Item|null
 */
function get_previous_item($item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    return $item->previous();
}

/**
 * Get an image tag for a record.
 *
 * @package Omeka\Function\View
 * @throws InvalidArgumentException If an invalid record is passed.
 * @uses Omeka_View_Helper_FileMarkup::image_tag()
 * @param Omeka_Record_AbstractRecord|string $record
 * @param string $imageType Image size: thumbnail, square thumbnail, fullsize
 * @param array $props HTML attributes for the img tag
 * @return string
 */
function record_image($record, $imageType = null, $props = array())
{
    if (is_string($record)) {
        $record = get_current_record($record);
    }

    if (!($record instanceof Omeka_Record_AbstractRecord)) {
        throw new InvalidArgumentException('An Omeka record must be passed to record_image.');
    }
    $fileMarkup = new Omeka_View_Helper_FileMarkup;
    return $fileMarkup->image_tag($record, $props, $imageType);
}

/**
 * Get a customized item image tag.
 *
 * @package Omeka\Function\View\Item
 * @uses Omeka_View_Helper_FileMarkup::image_tag()
 * @param string $imageType Image size: thumbnail, square thumbnail, fullsize
 * @param array $props HTML attributes for the img tag
 * @param integer $index Which file within the item to use, by order. Default
 *  is the first file.
 * @param Item|null Check for this specific item record (current item if null).
 */
function item_image($imageType = null, $props = array(), $index = 0, $item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    $imageFile = $item->getFile($index);
    $fileMarkup = new Omeka_View_Helper_FileMarkup;
    return $fileMarkup->image_tag($imageFile, $props, $imageType);
}

/**
 * Get a customized file image tag.
 *
 * @since 2.2
 * @package Omeka\Function\View\File
 * @uses Omeka_View_Helper_FileMarkup::image_tag()
 * @param string $imageType Image size: thumbnail, square thumbnail, fullsize
 * @param array $props HTML attributes for the img tag.
 * @param File|null Check for this specific file record (current file if null).
 */
function file_image($imageType, $props = array(), $file = null)
{
    if (!$file) {
        $file = get_current_record('file');
    }
    $fileMarkup = new Omeka_View_Helper_FileMarkup;
    return $fileMarkup->image_tag($file, $props, $imageType);
}

/**
 * Get a gallery of file thumbnails for an item.
 *
 * @package Omeka\Function\View\Item
 * @param array $attrs HTML attributes for the components of the gallery, in
 *  sub-arrays for 'wrapper', 'linkWrapper', 'link', and 'image'. Set a wrapper
 *  to null to omit it.
 * @param string $imageType The type of derivative image to display.
 * @param boolean $filesShow Whether to link to the files/show. Defaults to
 *  false, links to the original file.
 * @param Item $item The Item to use, the current item if omitted.
 * @return string
 */
function item_image_gallery($attrs = array(), $imageType = 'square_thumbnail', $filesShow = false, $item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }

    $files = $item->Files;
    if (!$files) {
        return '';
    }

    $defaultAttrs = array(
        'wrapper' => array('id' => 'item-images'),
        'linkWrapper' => array(),
        'link' => array(),
        'image' => array()
    );
    $attrs = array_merge($defaultAttrs, $attrs);

    $html = '';
    if ($attrs['wrapper'] !== null) {
        $html .= '<div ' . tag_attributes($attrs['wrapper']) . '>';
    }
    foreach ($files as $file) {
        if ($attrs['linkWrapper'] !== null) {
            $html .= '<div ' . tag_attributes($attrs['linkWrapper']) . '>';
        }

        $image = file_image($imageType, $attrs['image'], $file);
        if ($filesShow) {
            $html .= link_to($file, 'show', $image, $attrs['link']);
        } else {
            $linkAttrs = $attrs['link'] + array('href' => $file->getWebPath('original'));
            $html .= '<a ' . tag_attributes($linkAttrs) . '>' . $image . '</a>';
        }

        if ($attrs['linkWrapper'] !== null) {
            $html .= '</div>';
        }
    }
    if ($attrs['wrapper'] !== null) {
        $html .= '</div>';
    }
    return $html;
}

/**
 * Return the HTML for an item search form.
 *
 * @package Omeka\Function\View\Search
 * @uses Zend_View_Helper_Partial::partial()
 * @param array $props Custom HTML attributes for the form element
 * @param string $formActionUri URL the form should submit to. If omitted, the
 *  form submits to the default items/browse page.
 * @param string $buttonText Custom text for the form submit button. If omitted,
 *  the default text 'Search for items' is used.
 * @return string
 */
function items_search_form($props = array(), $formActionUri = null, $buttonText = null)
{
    return get_view()->partial(
        'items/search-form.php',
        array('formAttributes' => $props, 'formActionUri' => $formActionUri, 'buttonText' => $buttonText)
    );
}

/**
 * Get the most recently added items.
 *
 * @package Omeka\Function\View\Item
 * @uses Table_Item::findBy()
 * @param integer $num The maximum number of recent items to return
 * @return array
 */
function get_recent_items($num = 10)
{
    return get_db()->getTable('Item')->findBy(array('sort_field' => 'added', 'sort_dir' => 'd'), $num);
}

/**
 * Get random featured items.
 *
 * @package Omeka\Function\View\Item
 * @uses get_records()
 * @param integer $num The maximum number of recent items to return
 * @param boolean|null $hasImage
 * @return array|Item
 */
function get_random_featured_items($num = 5, $hasImage = null)
{
    return get_records('Item', array('featured' => 1,
                                     'sort_field' => 'random',
                                     'hasImage' => $hasImage), $num);
}

/**
 * Get HTML for recent items.
 *
 * @since 2.2
 * @package Omeka\Function\View\Item
 * @uses get_random_featured_items()
 * @param int $count Maximum number of recent items to show.
 * @return string
 */
function recent_items($count = 10)
{
    $items = get_recent_items($count);
    if ($items) {
        $html = '';
        foreach ($items as $item) {
            $html .= get_view()->partial('items/single.php', array('item' => $item));
            release_object($item);
        }
    } else {
        $html = '<p>' . __('No recent items available.') . '</p>';
    }
    return $html;
}
/**
 * Get HTML for random featured items.
 *
 * @package Omeka\Function\View\Item
 * @uses get_random_featured_items()
 * @param int $count Maximum number of items to show.
 * @param boolean $withImage Whether or not the featured items must have
 * images associated. If null, as default, all featured items can appear,
 * whether or not they have files. If true, only items with files will appear,
 * and if false, only items without files will appear.
 * @return string
 */
function random_featured_items($count = 5, $hasImage = null)
{
    $items = get_random_featured_items($count, $hasImage);
    if ($items) {
        $html = '';
        foreach ($items as $item) {
            $html .= get_view()->partial('items/single.php', array('item' => $item));
            release_object($item);
        }
    } else {
        $html = '<p>' . __('No featured items are available.') . '</p>';
    }
    return $html;
}

/**
 * Get the set of values for item type elements.
 *
 * @package Omeka\Function\View\ItemType
 * @uses Item::getItemTypeElements()
 * @param Item|null $item Check for this specific item record (current item if null).
 * @return array
 */
function item_type_elements($item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    $elements = $item->getItemTypeElements();
    foreach ($elements as $element) {
        $elementText[$element->name] = metadata($item, array(ElementSet::ITEM_TYPE_NAME, $element->name));
    }
    return $elementText;
}

/**
 * Get a link to a page within Omeka.
 *
 * The controller and action can be manually specified, or if a record is passed
 * this function will hand off to record_url to automatically get a link to
 * that record (either its default action or one explicitly chosen).
 *
 * @package Omeka\Function\View\Navigation
 * @uses record_url()
 * @uses url()
 * @param Omeka_Record_AbstractRecord|string $record The name of the controller
 * to use for the link.  If a record instance is passed, then it inflects the
 * name of the controller from the record class.
 * @param string $action The action to use for the link
 * @param string $text The text to put in the link.  Default is 'View'.
 * @param array $props Attributes for the <a> tag
 * @param array $queryParams the parameters in the uri query
 * @return string HTML
 */
function link_to($record, $action = null, $text = null, $props = array(), $queryParams = array())
{
    // If we're linking directly to a record, use the URI for that record.
    if ($record instanceof Omeka_Record_AbstractRecord) {
        $url = record_url($record, $action, false, $queryParams);
    // Otherwise $record is the name of the controller to link to.
    } else {
        $urlOptions = array();
        //Use Zend Framework's built-in 'default' route
        $route = 'default';
        $urlOptions['controller'] = (string) $record;
        if($action) $urlOptions['action'] = (string) $action;
        $url = url($urlOptions, $route, $queryParams, true);
    }
    if ($text === null) {
        $text = __('View');
    }
    $attr = !empty($props) ? ' ' . tag_attributes($props) : '';
    return '<a href="'. html_escape($url) . '"' . $attr . '>' . $text . '</a>';
}

/**
 * Get HTML for a link to the item search form.
 *
 * @package Omeka\Function\View\Navigation
 * @param string $text Text of the link. Default is 'Search Items'.
 * @param array $props HTML attributes for the link.
 * @param string $uri Action for the form.  Defaults to 'items/browse'.
 * @return string
 */
function link_to_item_search($text = null, $props = array(), $uri = null)
{
    if (!$text) {
        $text = __('Search Items');
    }
    if (!$uri) {
        $uri = apply_filters('items_search_default_url', url('items/search'));
    }
    $props['href'] = $uri . (!empty($_SERVER['QUERY_STRING']) ? '?' . $_SERVER['QUERY_STRING'] : '');
    return '<a ' . tag_attributes($props) . '>' . $text . '</a>';
}

/**
 * Get HTML for a link to the browse page for items.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string $text Text to display in the link.
 * @param array $browseParams Any parameters to use to build the browse page
 * URL, e.g. array('collection' => 1) would build items/browse?collection=1 as
 * the URL.
 * @param array $linkProperties HTML attributes for the link.
 * @return string HTML
 */
function link_to_items_browse($text, $browseParams = array(), $linkProperties = array())
{
    return link_to('items', 'browse', $text, $linkProperties, $browseParams);
}

/**
 * Get a link to the collection to which the item belongs.
 *
 * The default text displayed for this link will be the name of the collection,
 * but that can be changed by passing a string argument.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to_collection()
 * @param string|null $text Text for the link.
 * @param array $props HTML attributes for the <a> tag.
 * @param string $action 'show' by default.
 * @return string
 */
function link_to_collection_for_item($text = null, $props = array(), $action = 'show')
{
    if ($collection = get_collection_for_item()) {
        return link_to_collection($text, $props, $action, $collection);
    }
    return __('No Collection');
}

/**
 * Get a link to the collection items browse page.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string|null $text
 * @param array $props
 * @param string $action
 * @param Collection $collectionObj
 * @return string
 */
function link_to_items_in_collection($text = null, $props = array(),
    $action = 'browse', $collectionObj = null
) {
    if (!$collectionObj) {
        $collectionObj = get_current_record('collection');
    }
    $queryParams = array();
    $queryParams['collection'] = $collectionObj->id;
    if ($text === null) {
        $text = $collectionObj->totalItems();
    }
    return link_to('items', $action, $text, $props, $queryParams);
}

/**
 * Get a link to item type items browse page.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string|null $text
 * @param array $props
 * @param string $action
 * @param Collection $collectionObj
 * @return string
 */
function link_to_items_with_item_type($text = null, $props = array(),
    $action = 'browse', $itemTypeObj = null
) {
    if (!$itemTypeObj) {
        $itemTypeObj = get_current_record('item_type');
    }
    $queryParams = array();
    $queryParams['type'] = $itemTypeObj->id;
    if ($text === null) {
        $text = $itemTypeObj->totalItems();
    }
    return link_to('items', $action, $text, $props, $queryParams);
}

/**
 * Get a link to the file metadata page for a particular file.
 *
 * If no File object is specified, this will determine the file to use through
 * context. The text of the link defaults to the DC:Title of the file record,
 * then to the original filename, unless otherwise specified.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param array $attributes
 * @param string $text
 * @param File|null $file
 * @return string
 */
function link_to_file_show($attributes = array(), $text = null, $file = null)
{
    if (!$file) {
        $file = get_current_record('file');
    }
    if (!$text) {
        $text = metadata($file, 'display_title');
    }
    return link_to($file, 'show', $text, $attributes);
}

/**
 * Get a link to an item.
 *
 * The only differences from link_to are that this function will automatically
 * use the "current" item, and will use the item's title as the link text.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string $text HTML for the text of the link.
 * @param array $props Properties for the <a> tag.
 * @param string $action The page to link to (this will be the 'show' page almost always
 * within the public theme).
 * @param Item $item Used for dependency injection testing or to use this function
 * outside the context of a loop.
 * @return string HTML
 */
function link_to_item($text = null, $props = array(), $action = 'show', $item = null)
{
    if (!$item) {
        $item = get_current_record('item');
    }
    if (empty($text)) {
        $text = metadata($item, 'display_title');
    }
    return link_to($item, $action, $text, $props);
}

/**
 * Get a link the the items RSS feed.
 *
 * @package Omeka\Function\View\Navigation
 * @uses items_output_url()
 * @param string $text The text of the link.
 * @param array $params A set of query string parameters to merge in to the href
 * of the link.  E.g., if this link was clicked on the items/browse?collection=1
 * page, and array('foo'=>'bar') was passed as this argument, the new URI would
 * be items/browse?collection=1&foo=bar.
 */
function link_to_items_rss($text = null, $params=array())
{
    if (!$text) {
        $text = __('RSS');
    }
    return '<a href="' . html_escape(items_output_url('rss2', $params)) . '" class="rss">' . $text . '</a>';
}

/**
 * Get a link to the item immediately following the current one.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string $text
 * @param array $props
 * @return string
 */
function link_to_next_item_show($text = null, $props = array())
{
    if (!$text) {
        $text = __("Next Item &rarr;");
    }
    $item = get_current_record('item');
    if($next = $item->next()) {
        return link_to($next, 'show', $text, $props);
    }
}

/**
 * Get a link to the item immediately before the current one.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string $text
 * @param array $props
 * @return string
 */
function link_to_previous_item_show($text = null, $props = array())
{
    if (!$text) {
        $text = __('&larr; Previous Item');
    }
    $item = get_current_record('item');
    if($previous = $item->previous()) {
        return link_to($previous, 'show', $text, $props);
    }
}

/**
 * Get a link to a collection.
 *
 * The only differences from link_to() are that this function will automatically
 * use the "current" collection, and will use the collection title as the
 * link text.
 *
 * @package Omeka\Function\View\Navigation
 * @uses link_to()
 * @param string $text text to use for the title of the collection.  Default
 * behavior is to use the name of the collection.
 * @param array $props Set of attributes to use for the link.
 * @param array $action The action to link to for the collection.
 * @param array $collectionObj Collection record can be passed to this to
 * override the collection object retrieved by get_current_record().
 * @return string
 */
function link_to_collection($text = null, $props = array(), $action = 'show', $collectionObj = null)
{
    if (!$collectionObj) {
        $collectionObj = get_current_record('collection');
    }

    $collectionTitle = metadata($collectionObj, array('Dublin Core', 'Title'));
    $text = !empty($text) ? $text : $collectionTitle;
    return link_to($collectionObj, $action, $text, $props);
}

/**
 * Get a link to the public home page.
 *
 * @package Omeka\Function\View\Navigation
 * @param null|string $text
 * @param array $props
 * @return string
 */
function link_to_home_page($text = null, $props = array())
{
    if (!$text) {
        $text = option('site_title');
    }
    return '<a href="' . html_escape(WEB_ROOT) . '" '. tag_attributes($props) . '>' . $text . "</a>\n";
}

/**
 * Get a link to the admin home page.
 *
 * @package Omeka\Function\View\Navigation
 * @uses admin_url()
 * @see link_to_home_page()
 * @param null|string $text
 * @param array $props
 * @return string
 */
function link_to_admin_home_page($text = null, $props = array())
{
    if (!$text) {
        $text = option('site_title');
    }
    return '<a href="' . html_escape(admin_url('')) . '" ' . tag_attributes($props)
         . '>' . $text . "</a>\n";
}

/**
 * Create a navigation menu of links.
 *
 * @package Omeka\Function\View\Navigation
 * @param array $navLinks The array of links for the navigation.
 * @param string $name Optionally, the name of a filter to pass the links
 *  through before using them.
 * @param array $args Optionally, arguments to pass to the filter
 *
 * @return Zend_View_Helper_Navigation_Menu The navigation menu object. Can
 *  generally be treated simply as a string.
 */
function nav(array $navLinks, $name = null, array $args = array())
{
    if ($name !== null) {
        $navLinks = apply_filters($name, $navLinks, $args);
    }

    $menu = get_view()->navigation()->menu(new Omeka_Navigation($navLinks));

    if ($acl = get_acl()) {
        $menu->setRole(current_user())->setAcl($acl);
    }

    return $menu;
}

/**
 * Get HTML for a pagination control for a browse page.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Zend_View_Helper_PaginationControl::paginationControl()
 * @param array $options Configurable parameters for the pagination links. The
 * following options are available:
 * - 'scrolling_style' (string) See Zend_View_Helper_PaginationControl for
 *   more details.  Default 'Sliding'.
 * - 'partial_file' (string) View script to use to render the pagination
 *   HTML. Default is 'common/pagination_control.php'.
 * - 'page_range' (integer) See Zend_Paginator::setPageRange() for details.
 *   Default is 5.
 * - 'total_results' (integer) Total results to paginate through. Default is
 *   provided by the 'total_results' key of the 'pagination' array that is
 *   typically registered by the controller.
 * - 'page' (integer) Current page of the result set.  Default is the 'page'
 *   key of the 'pagination' array.
 * - 'per_page' (integer) Number of results to display per page. Default is
 * the 'per_page' key of the 'pagination' array.
 *
 * @return string HTML for the pagination links.
 */
function pagination_links($options = array())
{
    if (Zend_Registry::isRegistered('pagination')) {
        // If the pagination variables are registered, set them for local use.
        $p = Zend_Registry::get('pagination');
    } else {
        // If the pagination variables are not registered, set required defaults
        // arbitrarily to avoid errors.
        $p = array('total_results' => 1, 'page' => 1, 'per_page' => 1);
    }

    // Set preferred settings.
    $scrollingStyle = isset($options['scrolling_style']) ? $options['scrolling_style'] : 'Sliding';
    $partial = isset($options['partial_file']) ? $options['partial_file'] : 'common/pagination_control.php';
    $pageRange = isset($options['page_range']) ? (int) $options['page_range'] : 5;
    $totalCount = isset($options['total_results']) ? (int) $options['total_results'] : (int) $p['total_results'];
    $pageNumber = isset($options['page']) ? (int) $options['page'] : (int) $p['page'];
    $itemCountPerPage = isset($options['per_page']) ? (int) $options['per_page'] : (int) $p['per_page'];

    // Create an instance of Zend_Paginator.
    $paginator = Zend_Paginator::factory($totalCount);

    // Configure the instance.
    $paginator->setCurrentPageNumber($pageNumber)
              ->setItemCountPerPage($itemCountPerPage)
              ->setPageRange($pageRange);

    return get_view()->paginationControl($paginator, $scrollingStyle, $partial);
}

/**
 * Get the main navigation for the public site.
 *
 * @package Omeka\Function\View\Navigation
 * @return Zend_View_Helper_Navigation_Menu Can be echoed like a string or
 * manipulated by the theme.
 */
function public_nav_main()
{
    $view = get_view();
    $nav = new Omeka_Navigation;
    $nav->loadAsOption(Omeka_Navigation::PUBLIC_NAVIGATION_MAIN_OPTION_NAME);
    $nav->addPagesFromFilter(Omeka_Navigation::PUBLIC_NAVIGATION_MAIN_FILTER_NAME);
    return $view->navigation()->menu($nav);
}

/**
 * Get the navigation for items.
 *
 * @package Omeka\Function\View\Navigation
 * @uses nav()
 * @param array $navArray
 * @param integer|null $maxDepth
 * @return string
 */
function public_nav_items(array $navArray = null, $maxDepth = 0)
{
    if (!$navArray) {
        $navArray = array(
            array(
                'label' =>__('Browse All'),
                'uri' => url('items/browse'),
            ));
            if (total_records('Tag')) {
                $navArray[] = array(
                    'label' => __('Browse by Tag'),
                    'uri' => url('items/tags')
                );
            }
            $navArray[] = array(
                'label' => __('Search Items'),
                'uri' => url('items/search')
            );
    }
    return nav($navArray, 'public_navigation_items');
}

/**
 * Escape a value to display properly as HTML.
 *
 * This uses the 'html_escape' filter for escaping.
 *
 * @package Omeka\Function\Text
 * @param string $value
 * @return string
 */
function html_escape($value)
{
    return apply_filters('html_escape', $value);
}

/**
 * Escape a value for use in javascript.
 *
 * This is a convenience function for encoding a value using JSON notation.
 * Must be used when interpolating PHP output in javascript. Note on usage: do
 * not wrap the resulting output of this function in quotes, as proper JSON
 * encoding will take care of that.
 *
 * @package Omeka\Function\Text
 * @uses Zend_Json::encode()
 * @param string $value
 * @return string
 */
function js_escape($value)
{
    return Zend_Json::encode($value);
}

/**
 * Escape a value for use in XML.
 *
 * @package Omeka\Function\Text
 * @param string $value
 * @return string
 */
function xml_escape($value)
{
    return htmlspecialchars(preg_replace('#[\x00-\x08\x0B\x0C\x0E-\x1F]+#', '',
        $value), ENT_QUOTES);
}

/**
 * Replace newlines in a block of text with paragraph tags.
 *
 * Looks for 2 consecutive line breaks resembling a paragraph break and wraps
 * each of the paragraphs with a <p> tag.  If no paragraphs are found, then the
 * original text will be wrapped with line breaks.
 *
 * @package Omeka\Function\Text
 * @link http://us.php.net/manual/en/function.nl2br.php#73479
 * @param string $str
 * @return string
 */
function text_to_paragraphs($str)
{
  return str_replace('<p></p>', '', '<p>'
       . preg_replace('#([\r\n]\s*?[\r\n]){2,}#', '</p>$0<p>', $str) . '</p>');
}

/**
 * Return a substring of a given piece of text.
 *
 * Note: this will only split strings on the space character.
 * this will also strip html tags from the text before getting a snippet
 *
 * @package Omeka\Function\Text
 * @param string $text Text to take snippet of
 * @param int $startPos Starting position of snippet in string
 * @param int $endPos Maximum length of snippet
 * @param string $append String to append to snippet if truncated
 * @return string Snippet of given text
 */
function snippet($text, $startPos, $endPos, $append = '…')
{
    // strip html tags from the text
    $text = strip_formatting($text);

    $textLength = strlen($text);

    // Calculate the start position. Set to zero if the start position is
    // null or 0, OR if the start offset is greater than the length of the
    // original text.
    $startPosOffset = $startPos - $textLength;
    $startPos = !$startPos || $startPosOffset > $textLength
                ? 0
                : strrpos($text, ' ', $startPosOffset);

    // Calculate the end position. Set to the length of the text if the
    // end position is greater than or equal to the length of the original
    // text, OR if the end offset is greater than the length of the
    // original text.
    $endPosOffset = $endPos - $textLength;
    $endPos = $endPos >= $textLength || $endPosOffset > $textLength
              ? $textLength
              : strrpos($text, ' ', $endPosOffset);

    // Set the snippet by getting its substring.
    $snippet = substr($text, $startPos, $endPos - $startPos);

    // Return the snippet without the append string if the text's original
    // length equals to 1) the length of the snippet, i.e. when the return
    // string is identical to the passed string; OR 2) the calculated
    // end position, i.e. when the return string ends at the same point as
    // the passed string.
    return strlen($snippet) == $textLength || $endPos == $textLength
         ? $snippet
         : $snippet . $append;
}

/**
 * Return a substring of the text by limiting the word count.
 *
 * Note: it strips the HTML tags from the text before getting the snippet
 *
 * @package Omeka\Function\Text
 * @param string $text
 * @param integer $maxWords
 * @param string $ellipsis
 * @return string
 */
function snippet_by_word_count($text, $maxWords = 20, $ellipsis = '...')
{
    // strip html tags from the text
    $text = strip_formatting($text);
    if ($maxWords > 0) {
        $textArray = explode(' ', $text);
        if (count($textArray) > $maxWords) {
            $text = implode(' ', array_slice($textArray, 0, $maxWords)) . $ellipsis;
        }
    } else {
        return '';
    }
    return $text;
}

/**
 * Strip HTML tags from a string.
 *
 * This is essentially a wrapper around PHP's strip_tags() function, with the
 * added benefit of returning a fallback string in case the resulting stripped
 * string is empty or contains only whitespace.
 *
 * @package Omeka\Function\Text
 * @uses strip_tags()
 * @param string $str The string to be stripped of HTML formatting.
 * @param string $allowableTags The string of tags to allow when stripping tags.
 * @param string $fallbackStr The string to be used as a fallback.
 * @return The stripped string.
 */
function strip_formatting($str, $allowableTags = '', $fallbackStr = '')
{
    // Strip the tags.
    $str = strip_tags($str, $allowableTags);
    // Remove non-breaking space html entities.
    $str = str_replace('&nbsp;', '', $str);
    // If only whitepace remains, return the fallback string.
    if (preg_match('/^\s*$/', $str)) {
        return $fallbackStr;
    }
    // Return the deformatted string.
    return $str;
}

/**
 * Convert a word or phrase to a valid HTML ID.
 *
 * For example: 'Foo Bar' becomes 'foo-bar'.
 *
 * This function converts to lowercase, replaces whitespace with hyphens,
 * removes all non-alphanumerics, removes leading or trailing delimiters,
 * and optionally prepends a piece of text.
 *
 * @package Omeka\Function\Text
 * @param string $text The text to convert
 * @param string $prepend Another string to prepend to the ID
 * @param string $delimiter The delimiter to use (- by default)
 * @return string
 */
function text_to_id($text, $prepend = null, $delimiter = '-')
{
    $text = strtolower($text);
    $id = preg_replace('/\s/', $delimiter, $text);
    $id = preg_replace('/[^\w\-]/', '', $id);
    $id = trim($id, $delimiter);
    $prepend = (string) $prepend;
    return !empty($prepend) ? join($delimiter, array($prepend, $id)) : $id;
}

/**
 * Convert any URLs in a given string to links.
 *
 * @package Omeka\Function\Text
 * @param string $str The string to be searched for URLs to convert to links.
 * @return string
 */
function url_to_link($str)
{
    $pattern = "#(\bhttps?://\S+\b)#";
    return preg_replace_callback($pattern, 'url_to_link_callback', $str);
}

/**
 * Callback for converting URLs with url_to_link.
 *
 * @package Omeka\Function\Text
 * @see url_to_link
 * @param array $matches preg_replace_callback matches array
 * @return string
 */
function url_to_link_callback($matches)
{
    return '<a href="' . htmlspecialchars($matches[1]) . '">' . $matches[1] . '</a>';
}

/**
 * Get the most recent tags.
 *
 * @package Omeka\Function\View
 * @uses get_records()
 * @param integer $limit The maximum number of recent tags to return
 * @return array
 */
function get_recent_tags($limit = 10)
{
    return get_records('Tag', array('sort_field' => 'time', 'sort_dir' => 'd'), $limit);
}

/**
 * Create a tag cloud made of divs that follow the hTagcloud microformat
 *
 * @package Omeka\Function\View\Tag
 * @param Omeka_Record_AbstractRecord|array $recordOrTags The record to retrieve
 * tags from, or the actual array of tags
 * @param string|null $link The URI to use in the link for each tag. If none
 * given, tags in the cloud will not be given links.
 * @param int $maxClasses
 * @param bool $tagNumber
 * @param string $tagNumberOrder
 * @return string HTML for the tag cloud
 */
function tag_cloud($recordOrTags = null, $link = null, $maxClasses = 9, $tagNumber = false, $tagNumberOrder = null)
{
    if (!$recordOrTags) {
        $tags = array();
    } else if (is_string($recordOrTags)) {
        $tags = get_current_record($recordOrTags)->Tags;
    } else if ($recordOrTags instanceof Omeka_Record_AbstractRecord) {
        $tags = $recordOrTags->Tags;
    } else {
        $tags = $recordOrTags;
    }

    if (empty($tags)) {
        return '<p>' . __('No tags are available.') . '</p>';
    }

    //Get the largest value in the tags array
    $largest = 0;
    foreach ($tags as $tag) {
        if($tag["tagCount"] > $largest) {
            $largest = $tag['tagCount'];
        }
    }
    $html = '<div class="hTagcloud">';
    $html .= '<ul class="popularity">';

    if ($largest < $maxClasses) {
        $maxClasses = $largest;
    }

    foreach( $tags as $tag ) {
        $size = (int)(($tag['tagCount'] * $maxClasses) / $largest - 1);
        $class = str_repeat('v', $size) . ($size ? '-' : '') . 'popular';
        $html .= '<li class="' . $class . '">';
        if ($link) {
            $html .= '<a href="' . html_escape(url($link, array('tags' => $tag['name']))) . '">';
        }
        if($tagNumber && $tagNumberOrder == 'before') {
            $html .= ' <span class="count">'.$tag['tagCount'].'</span> ';
        }
        $html .= html_escape($tag['name']);
        if($tagNumber && $tagNumberOrder == 'after') {
            $html .= ' <span class="count">'.$tag['tagCount'].'</span> ';
        }
        if ($link) {
            $html .= '</a>';
        }
        $html .= '</li>' . "\n";
    }
    $html .= '</ul></div>';

    return $html;
}

/**
 * Return a tag string given an Item, Exhibit, or a set of tags.
 *
 * @package Omeka\Function\View\Tag
 * @param Omeka_Record_AbstractRecord|array $recordOrTags The record to retrieve
 * tags from, or the actual array of tags
 * @param string|null $link The URL to use for links to the tags (if null, tags
 * aren't linked)
 * @param string $delimiter ', ' (comma and whitespace) is the default tag_delimiter option. Configurable in Settings
 * @return string HTML
 */
function tag_string($recordOrTags = null, $link = 'items/browse', $delimiter = null)
{
    // Set the tag_delimiter option if no delimiter was passed.
    if (is_null($delimiter)) {
        $delimiter = get_option('tag_delimiter') . ' ';
    }

    if (!$recordOrTags) {
        $tags = array();
    } else if (is_string($recordOrTags)) {
        $tags = get_current_record($recordOrTags)->Tags;
    } else if ($recordOrTags instanceof Omeka_Record_AbstractRecord) {
        $tags = $recordOrTags->Tags;
    } else {
        $tags = $recordOrTags;
    }

    if (empty($tags)) {
        return '';
    }

    $tagStrings = array();
    foreach ($tags as $tag) {
        $name = $tag['name'];
        if (!$link) {
            $tagStrings[] = html_escape($name);
        } else {
            $tagStrings[] = '<a href="' . html_escape(url($link, array('tags' => $name))) . '" rel="tag">' . html_escape($name) . '</a>';
        }
    }
    return join(html_escape($delimiter), $tagStrings);
}

/**
 * Get a URL given the provided arguments.
 *
 * Instantiates view helpers directly because a view may not be registered.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Omeka_View_Helper_Url::url() See for details on usage.
 * @param mixed $options If a string is passed it is treated as an
 *  Omeka-relative link. So, passing 'items' would create a link to the items
 *  page. If an array is passed (or no argument given), it is treated as options
 *  to be passed to Omeka's routing system.
 *  Note that in the Url Helper, if the first argument is a string, the second
 *  argument, not the third, is the queryParams
 * @param string $route The route to use if an array is passed in the first argument.
 * @param mixed $queryParams A set of query string parameters to append to the URL
 * @param bool $reset Whether Omeka should discard the current route when generating the URL.
 * @param bool $encode Whether the URL should be URL-encoded
 * @return string HTML
 */
function url($options = array(), $route = null, $queryParams = array(),
    $reset = false, $encode = true
) {
    $helper = new Omeka_View_Helper_Url;
    return $helper->url($options, $route, $queryParams, $reset, $encode);
}

/**
 * Get an absolute URL.
 *
 * This is necessary because Zend_View_Helper_Url returns relative URLs, though
 * absolute URLs are required in some contexts. Instantiates view helpers
 * directly because a view may not be registered.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Zend_View_Helper_ServerUrl::serverUrl()
 * @uses Omeka_View_Helper_Url::url()
 * @param mixed $options If a string is passed it is treated as an
 *  Omeka-relative link. So, passing 'items' would create a link to the items
 *  page. If an array is passed (or no argument given), it is treated as options
 *  to be passed to Omeka's routing system.
 * @param string $route The route to use if an array is passed in the first argument.
 * @param mixed $queryParams A set of query string parameters to append to the URL
 * @param bool $reset Whether Omeka should discard the current route when generating the URL.
 * @param bool $encode Whether the URL should be URL-encoded
 * @return string HTML
 */
function absolute_url($options = array(), $route = null, $queryParams = array(),
    $reset = false, $encode = true
) {
    $serverUrlHelper = new Zend_View_Helper_ServerUrl;
    $urlHelper = new Omeka_View_Helper_Url;
    return $serverUrlHelper->serverUrl()
         . $urlHelper->url($options, $route, $queryParams, $reset, $encode);
}

/**
 * Get the current URL with query parameters appended.
 *
 * Instantiates view helpers directly because a view may not be registered.
 *
 * @package Omeka\Function\View\Navigation
 * @param array $params
 * @return string
 */
function current_url(array $params = array())
{
    // Get the URL before the ?.
    $request = Zend_Controller_Front::getInstance()->getRequest();
    $urlParts = explode('?', $request->getRequestUri());
    $url = $urlParts[0];
    if ($params) {
        // Merge $_GET and passed parameters to build the complete query.
        $query = array_merge($_GET, $params);
        $queryString = http_build_query($query);
        $url .= "?$queryString";
    }
    return $url;
}

/**
 * Check if the given URL matches the current request URL.
 *
 * Instantiates view helpers directly because a view may not be registered.
 *
 * @package Omeka\Function\View\Navigation
 * @param string $url
 * @return boolean
 */
function is_current_url($url)
{
    $request = Zend_Controller_Front::getInstance()->getRequest();
    $currentUrl = $request->getRequestUri();
    $baseUrl = $request->getBaseUrl();

    // Strip out the protocol, host, base URL, and rightmost slash before
    // comparing the URL to the current one
    $stripOut = array(WEB_DIR, @$_SERVER['HTTP_HOST'], $baseUrl);
    $currentUrl = rtrim(str_replace($stripOut, '', $currentUrl), '/');
    $url = rtrim(str_replace($stripOut, '', $url), '/');

    if (strlen($url) == 0) {
        return (strlen($currentUrl) == 0);
    }
    return ($url == $currentUrl) or (strpos($currentUrl, $url) === 0);
}

/**
 * Get a URL to a record.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Omeka_View_Helper_RecordUrl::recordUrl()
 * @param Omeka_Record_AbstractRecord|string $record
 * @param string|null $action
 * @param bool $getAbsoluteUrl
 * @param array $queryParams
 * @return string
 */
function record_url($record, $action = null, $getAbsoluteUrl = false, $queryParams = array())
{
    return get_view()->recordUrl($record, $action, $getAbsoluteUrl, $queryParams);
}

/**
 * Get a URL to an output format page.
 *
 * @package Omeka\Function\View\Navigation
 * @uses url()
 * @param string $output
 * @param array $otherParams
 * @return string
 */
function items_output_url($output, $otherParams = array()) {

    $queryParams = array();

    // Provide additional query parameters if the current page is items/browse.
    $request = Zend_Controller_Front::getInstance()->getRequest();
    if ('items' == $request->getControllerName() && 'browse' == $request->getActionName()) {
        $queryParams = $_GET;
        unset($queryParams['submit_search']);
        unset($queryParams['page']);
    }
    $queryParams = array_merge($queryParams, $otherParams);
    $queryParams['output'] = $output;

    return url(array('controller'=>'items', 'action'=>'browse'), 'default', $queryParams);
}

/**
 * Get the provided file's URL.
 *
 * @package Omeka\Function\View\Navigation
 * @uses File::getWebPath()
 * @param File $file
 * @param string $format
 * @return string
 */
function file_display_url(File $file, $format = 'fullsize')
{
    if (!$file->exists()) {
        return false;
    }
    return $file->getWebPath($format);
}

/**
 * Get a URL to the public theme.
 *
 * @package Omeka\Function\View\Navigation
 * @uses set_theme_base_url()
 * @uses revert_theme_base_url()
 * @param mixed $args
 * @return string
 */
function public_url()
{
    set_theme_base_url('public');
    $args = func_get_args();
    $url = call_user_func_array('url', $args);
    revert_theme_base_url();
    return $url;
}

/**
 * Get a URL to the admin theme.
 *
 * @package Omeka\Function\View\Navigation
 * @uses set_theme_base_url()
 * @uses revert_theme_base_url()
 * @param mixed $args
 * @return string
 */
function admin_url()
{
    set_theme_base_url('admin');
    $args = func_get_args();
    $url = call_user_func_array('url', $args);
    revert_theme_base_url();
    return $url;
}

/**
 * Set the base URL for the specified theme.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Zend_Controller_Front::setBaseUrl()
 * @param string $theme
 */
function set_theme_base_url($theme = null)
{
    switch ($theme) {
        case 'public':
            $baseUrl = PUBLIC_BASE_URL;
            break;
        case 'admin':
            $baseUrl = ADMIN_BASE_URL;
            break;
        case 'install':
            $baseUrl = INSTALL_BASE_URL;
        default:
            $baseUrl = CURRENT_BASE_URL;
            break;
    }
    $front = Zend_Controller_Front::getInstance();
    $previousBases = $front->getParam('previousBaseUrls');
    $previousBases[] = $front->getBaseUrl();
    $front->setParam('previousBaseUrls', $previousBases);
    return $front->setBaseUrl($baseUrl);
}

/**
 * Revert the base URL to its previous state.
 *
 * @package Omeka\Function\View\Navigation
 * @uses Zend_Controller_Front::setBaseUrl()
 */
function revert_theme_base_url()
{
    $front = Zend_Controller_Front::getInstance();
    if (($previous = $front->getParam('previousBaseUrls'))) {
        $front->setBaseUrl(array_pop($previous));
        $front->setParam('previousBaseUrls', $previous);
    }
}

/**
 * Get the theme's logo image tag.
 *
 * @package Omeka\Function\View\Head
 * @uses get_theme_option()
 * @return string|null
 */
function theme_logo()
{
    $logo = get_theme_option('Logo');
    if ($logo) {
        $storage = Zend_Registry::get('storage');
        $uri = $storage->getUri($storage->getPathByType($logo, 'theme_uploads'));
        return '<img src="' . $uri . '" alt="' . option('site_title') . '" />';
    }
}

/**
 * Get the theme's header image tag.
 *
 * @package Omeka\Function\View\Head
 * @uses get_theme_option()
 * @return string|null
 */
function theme_header_image()
{
    $headerImage = get_theme_option('Header Image');
    if ($headerImage) {
        $storage = Zend_Registry::get('storage');
        $headerImage = $storage->getUri($storage->getPathByType($headerImage, 'theme_uploads'));
        return '<div id="header-image"><img src="' . $headerImage . '" /></div>';
    }
}

/**
 * Get the theme's header background image style.
 *
 * @package Omeka\Function\View\Head
 * @uses get_theme_option()
 * @return string|null
 */
function theme_header_background()
{
    $headerBg = get_theme_option('Header Background');
    if ($headerBg) {
        $storage = Zend_Registry::get('storage');
        $headerBg = $storage->getUri($storage->getPathByType($headerBg, 'theme_uploads'));
        return '<style type="text/css" media="screen">header {'
           . 'background:transparent url("' . $headerBg . '") center left no-repeat;'
           . '}</style>';
    }
}

/**
 * Check whether the current user has a give permission.
 *
 * @package Omeka\Function\User
 * @uses Zend_Acl::is_allowed()
 * @param string|Zend_Acl_Resource_Interface $resource The name of a resource,
 *  or a record implementing Zend_Acl_Resource_Interface
 * @param string|null $privilege The privilege to check for the resource.
 * @return boolean
 */
function is_allowed($resource, $privilege)
{
    $acl = Zend_Controller_Front::getInstance()->getParam('bootstrap')->acl;
    $user = current_user();

    if (is_string($resource)) {
       $resource = ucwords($resource);
    }

    // User implements Zend_Acl_Role_Interface, so it can be checked directly by the ACL.
    return $acl->isAllowed($user, $resource, $privilege);
}

/**
 * Add a shortcode.
 *
 * @since 2.2
 * @package Omeka\Function\View
 * @uses Omeka_View_Helper_Shortcodes::shortcodeCallbacks()
 * @param string $shortcodeName Name of the new shortcode.
 * @param callback $function Callback to execute for this shortcode.
 */
function add_shortcode($shortcodeName, $function)
{
    return Omeka_View_Helper_Shortcodes::addShortcode($shortcodeName, $function);
}
