Proyectos de Subversion Moodle

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Controls the search page of the message drawer.

 *

 * @module     core_message/message_drawer_view_search

 * @copyright  2018 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

define(

[

    'jquery',

    'core/custom_interaction_events',

    'core/notification',

    'core/pubsub',

    'core/str',

    'core/templates',

    'core_message/message_repository',

    'core_message/message_drawer_events',

],

function(

    $,

    CustomEvents,

    Notification,

    PubSub,

    Str,

    Templates,

    Repository,

    Events

) {

    var MESSAGE_SEARCH_LIMIT = 50;

    var USERS_SEARCH_LIMIT = 50;

    var USERS_INITIAL_SEARCH_LIMIT = 3;

    var SELECTORS = {

        BLOCK_ICON_CONTAINER: '[data-region="block-icon-container"]',

        CANCEL_SEARCH_BUTTON: '[data-action="cancel-search"]',

        CONTACTS_CONTAINER: '[data-region="contacts-container"]',

        CONTACTS_LIST: '[data-region="contacts-container"] [data-region="list"]',

        EMPTY_MESSAGE_CONTAINER: '[data-region="empty-message-container"]',

        LIST: '[data-region="list"]',

        LOADING_ICON_CONTAINER: '[data-region="loading-icon-container"]',

        LOADING_PLACEHOLDER: '[data-region="loading-placeholder"]',

        MESSAGES_LIST: '[data-region="messages-container"] [data-region="list"]',

        MESSAGES_CONTAINER: '[data-region="messages-container"]',

        NON_CONTACTS_CONTAINER: '[data-region="non-contacts-container"]',

        NON_CONTACTS_LIST: '[data-region="non-contacts-container"] [data-region="list"]',

        SEARCH_ICON_CONTAINER: '[data-region="search-icon-container"]',

        SEARCH_ACTION: '[data-action="search"]',

        SEARCH_INPUT: '[data-region="search-input"]',

        SEARCH_RESULTS_CONTAINER: '[data-region="search-results-container"]',

        LOAD_MORE_USERS: '[data-action="load-more-users"]',

        LOAD_MORE_MESSAGES: '[data-action="load-more-messages"]',

        BUTTON_TEXT: '[data-region="button-text"]',

        NO_RESULTS_CONTAINTER: '[data-region="no-results-container"]',

        ALL_CONTACTS_CONTAINER: '[data-region="all-contacts-container"]'

    };

    var TEMPLATES = {

        CONTACTS_LIST: 'core_message/message_drawer_contacts_list',

        NON_CONTACTS_LIST: 'core_message/message_drawer_non_contacts_list',

        MESSAGES_LIST: 'core_message/message_drawer_messages_list'

    };

    /**

     * Get the logged in user id.

     *

     * @param  {Object} body Search body container element.

     * @return {Number} User id.

     */

    var getLoggedInUserId = function(body) {

        return body.attr('data-user-id');

    };

    /**

     * Show the no messages container element.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} No messages container element.

     */

    var getEmptyMessageContainer = function(body) {

        return body.find(SELECTORS.EMPTY_MESSAGE_CONTAINER);

    };

    /**

     * Get the search loading icon.

     *

     * @param  {Object} header Search header container element.

     * @return {Object} Loading icon element.

     */

    var getLoadingIconContainer = function(header) {

        return header.find(SELECTORS.LOADING_ICON_CONTAINER);

    };

    /**

     * Get the loading container element.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} Loading container element.

     */

    var getLoadingPlaceholder = function(body) {

        return body.find(SELECTORS.LOADING_PLACEHOLDER);

    };

    /**

     * Get the search icon container.

     *

     * @param  {Object} header Search header container element.

     * @return {Object} Search icon container.

     */

    var getSearchIconContainer = function(header) {

        return header.find(SELECTORS.SEARCH_ICON_CONTAINER);

    };

    /**

     * Get the search input container.

     *

     * @param  {Object} header Search header container element.

     * @return {Object} Search input container.

     */

    var getSearchInput = function(header) {

        return header.find(SELECTORS.SEARCH_INPUT);

    };

    /**

     * Get the search results container.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} Search results container.

     */

    var getSearchResultsContainer = function(body) {

        return body.find(SELECTORS.SEARCH_RESULTS_CONTAINER);

    };

    /**

     * Get the search contacts container.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} Search contacts container.

     */

    var getContactsContainer = function(body) {

        return body.find(SELECTORS.CONTACTS_CONTAINER);

    };

    /**

     * Get the search non contacts container.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} Search non contacts container.

     */

    var getNonContactsContainer = function(body) {

        return body.find(SELECTORS.NON_CONTACTS_CONTAINER);

    };

    /**

     * Get the search messages container.

     *

     * @param  {Object} body Search body container element.

     * @return {Object} Search messages container.

     */

    var getMessagesContainer = function(body) {

        return body.find(SELECTORS.MESSAGES_CONTAINER);

    };

    /**

     * Show the messages empty container.

     *

     * @param {Object} body Search body container element.

     */

    var showEmptyMessage = function(body) {

        getEmptyMessageContainer(body).removeClass('hidden');

    };

    /**

     * Hide the messages empty container.

     *

     * @param {Object} body Search body container element.

     */

    var hideEmptyMessage = function(body) {

        getEmptyMessageContainer(body).addClass('hidden');

    };

    /**

     * Show the loading icon.

     *

     * @param {Object} header Search header container element.

     */

    var showLoadingIcon = function(header) {

        getLoadingIconContainer(header).removeClass('hidden');

    };

    /**

     * Hide the loading icon.

     *

     * @param {Object} header Search header container element.

     */

    var hideLoadingIcon = function(header) {

        getLoadingIconContainer(header).addClass('hidden');

    };

    /**

     * Show loading placeholder.

     *

     * @param {Object} body Search body container element.

     */

    var showLoadingPlaceholder = function(body) {

        getLoadingPlaceholder(body).removeClass('hidden');

    };

    /**

     * Hide loading placeholder.

     *

     * @param {Object} body Search body container element.

     */

    var hideLoadingPlaceholder = function(body) {

        getLoadingPlaceholder(body).addClass('hidden');

    };

    /**

     * Show search icon.

     *

     * @param {Object} header Search header container element.

     */

    var showSearchIcon = function(header) {

        getSearchIconContainer(header).removeClass('hidden');

    };

    /**

     * Hide search icon.

     *

     * @param {Object} header Search header container element.

     */

    var hideSearchIcon = function(header) {

        getSearchIconContainer(header).addClass('hidden');

    };

    /**

     * Show search results.

     *

     * @param {Object} body Search body container element.

     */

    var showSearchResults = function(body) {

        getSearchResultsContainer(body).removeClass('hidden');

    };

    /**

     * Hide search results.

     *

     * @param {Object} body Search body container element.

     */

    var hideSearchResults = function(body) {

        getSearchResultsContainer(body).addClass('hidden');

    };

    /**

     * Show the no search results message.

     *

     * @param {Object} body Search body container element.

     */

    var showNoSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.ALL_CONTACTS_CONTAINER).addClass('hidden');

        container.find(SELECTORS.MESSAGES_CONTAINER).addClass('hidden');

        container.find(SELECTORS.NO_RESULTS_CONTAINTER).removeClass('hidden');

    };

    /**

     * Hide the no search results message.

     *

     * @param {Object} body Search body container element.

     */

    var hideNoSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.ALL_CONTACTS_CONTAINER).removeClass('hidden');

        container.find(SELECTORS.MESSAGES_CONTAINER).removeClass('hidden');

        container.find(SELECTORS.NO_RESULTS_CONTAINTER).addClass('hidden');

    };

    /**

     * Show the whole contacts results area.

     *

     * @param {Object} body Search body container element.

     */

    var showAllContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.ALL_CONTACTS_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the whole contacts results area.

     *

     * @param {Object} body Search body container element.

     */

    var hideAllContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.ALL_CONTACTS_CONTAINER).addClass('hidden');

    };

    /**

     * Show the contacts results.

     *

     * @param {Object} body Search body container element.

     */

    var showContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.CONTACTS_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the contacts results.

     *

     * @param {Object} body Search body container element.

     */

    var hideContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.CONTACTS_CONTAINER).addClass('hidden');

    };

    /**

     * Show the non contacts results.

     *

     * @param {Object} body Search body container element.

     */

    var showNonContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.NON_CONTACTS_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the non contacts results.

     *

     * @param {Object} body Search body container element.

     */

    var hideNonContactsSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.NON_CONTACTS_CONTAINER).addClass('hidden');

    };

    /**

     * Show the messages results.

     *

     * @param {Object} body Search body container element.

     */

    var showMessagesSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.MESSAGES_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the messages results.

     *

     * @param {Object} body Search body container element.

     */

    var hideMessagesSearchResults = function(body) {

        var container = getSearchResultsContainer(body);

        container.find(SELECTORS.MESSAGES_CONTAINER).addClass('hidden');

    };

    /**

     * Disable the search input.

     *

     * @param {Object} header Search header container element.

     */

    var disableSearchInput = function(header) {

        getSearchInput(header).prop('disabled', true);

    };

    /**

     * Enable the search input.

     *

     * @param {Object} header Search header container element.

     */

    var enableSearchInput = function(header) {

        getSearchInput(header).prop('disabled', false);

    };

    /**

     * Clear the search input.

     *

     * @param {Object} header Search header container element.

     */

    var clearSearchInput = function(header) {

        getSearchInput(header).val('');

    };

    /**

     * Clear all search results

     *

     * @param {Object} body Search body container element.

     */

    var clearAllSearchResults = function(body) {

        body.find(SELECTORS.CONTACTS_LIST).empty();

        body.find(SELECTORS.NON_CONTACTS_LIST).empty();

        body.find(SELECTORS.MESSAGES_LIST).empty();

        hideNoSearchResults(body);

        showAllContactsSearchResults(body);

        showContactsSearchResults(body);

        showNonContactsSearchResults(body);

        showMessagesSearchResults(body);

        showLoadMoreUsersButton(body);

        showLoadMoreMessagesButton(body);

    };

    /**

     * Update the body and header to indicate the search is loading.

     *

     * @param {Object} header Search header container element.

     * @param {Object} body Search body container element.

     */

    var startLoading = function(header, body) {

        hideSearchIcon(header);

        hideEmptyMessage(body);

        hideSearchResults(body);

        showLoadingIcon(header);

        showLoadingPlaceholder(body);

        disableSearchInput(header);

    };

    /**

     * Update the body and header to indicate the search has stopped loading.

     *

     * @param {Object} header Search header container element.

     * @param {Object} body Search body container element.

     */

    var stopLoading = function(header, body) {

        showSearchIcon(header);

        hideEmptyMessage(body);

        showSearchResults(body);

        hideLoadingIcon(header);

        hideLoadingPlaceholder(body);

        enableSearchInput(header);

    };

    /**

     * Show the more users loading icon.

     *

     * @param {Object} root The more users container element.

     */

    var showUsersLoadingIcon = function(root) {

        var button = root.find(SELECTORS.LOAD_MORE_USERS);

        button.prop('disabled', true);

        button.find(SELECTORS.BUTTON_TEXT).addClass('hidden');

        button.find(SELECTORS.LOADING_ICON_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the more users loading icon.

     *

     * @param {Object} root The more users container element.

     */

    var hideUsersLoadingIcon = function(root) {

        var button = root.find(SELECTORS.LOAD_MORE_USERS);

        button.prop('disabled', false);

        button.find(SELECTORS.BUTTON_TEXT).removeClass('hidden');

        button.find(SELECTORS.LOADING_ICON_CONTAINER).addClass('hidden');

    };

    /**

     * Show the load more users button.

     *

     * @param {Object} root The users container element.

     */

    var showLoadMoreUsersButton = function(root) {

        root.find(SELECTORS.LOAD_MORE_USERS).removeClass('hidden');

    };

    /**

     * Hide the load more users button.

     *

     * @param {Object} root The users container element.

     */

    var hideLoadMoreUsersButton = function(root) {

        root.find(SELECTORS.LOAD_MORE_USERS).addClass('hidden');

    };

    /**

     * Show the messages are loading icon.

     *

     * @param {Object} root Messages root element.

     */

    var showMessagesLoadingIcon = function(root) {

        var button = root.find(SELECTORS.LOAD_MORE_MESSAGES);

        button.prop('disabled', true);

        button.find(SELECTORS.BUTTON_TEXT).addClass('hidden');

        button.find(SELECTORS.LOADING_ICON_CONTAINER).removeClass('hidden');

    };

    /**

     * Hide the messages are loading icon.

     *

     * @param {Object} root Messages root element.

     */

    var hideMessagesLoadingIcon = function(root) {

        var button = root.find(SELECTORS.LOAD_MORE_MESSAGES);

        button.prop('disabled', false);

        button.find(SELECTORS.BUTTON_TEXT).removeClass('hidden');

        button.find(SELECTORS.LOADING_ICON_CONTAINER).addClass('hidden');

    };

    /**

     * Show the load more messages button.

     *

     * @param  {Object} root The messages container element.

     */

    var showLoadMoreMessagesButton = function(root) {

        root.find(SELECTORS.LOAD_MORE_MESSAGES).removeClass('hidden');

    };

    /**

     * Hide the load more messages button.

     *

     * @param  {Object} root The messages container element.

     */

    var hideLoadMoreMessagesButton = function(root) {

        root.find(SELECTORS.LOAD_MORE_MESSAGES).addClass('hidden');

    };

    /**

     * Find a contact in the search results.

     *

     * @param  {Object} root Search results container element.

     * @param  {Number} userId User id.

     * @return {Object} User container element.

     */

    var findContact = function(root, userId) {

        return root.find('[data-contact-user-id="' + userId + '"]');

    };

    /**

     * Add a contact to the search results.

     *

     * @param {Object} root Search results container.

     * @param {Object} contact User in contacts list.

     */

    var addContact = function(root, contact) {

        var nonContactsContainer = getNonContactsContainer(root);

        var nonContact = findContact(nonContactsContainer, contact.userid);

        if (nonContact.length) {

            nonContact.remove();

            var contactsContainer = getContactsContainer(root);

            contactsContainer.removeClass('hidden');

            contactsContainer.find(SELECTORS.LIST).append(nonContact);

        }

        if (!nonContactsContainer.find(SELECTORS.LIST).children().length) {

            nonContactsContainer.addClass('hidden');

        }

    };

    /**

     * Remove a contact from the contacts results.

     *

     * @param {Object} root Search results container.

     * @param {Object} userId Contact user id.

     */

    var removeContact = function(root, userId) {

        var contactsContainer = getContactsContainer(root);

        var contact = findContact(contactsContainer, userId);

        if (contact.length) {

            contact.remove();

            var nonContactsContainer = getNonContactsContainer(root);

            nonContactsContainer.removeClass('hidden');

            nonContactsContainer.find(SELECTORS.LIST).append(contact);

        }

        if (!contactsContainer.find(SELECTORS.LIST).children().length) {

            contactsContainer.addClass('hidden');

        }

    };

    /**

     * Show the contact is blocked icon.

     *

     * @param {Object} root Search results container.

     * @param {Object} userId Contact user id.

     */

    var blockContact = function(root, userId) {

        var contact = findContact(root, userId);

        if (contact.length) {

            contact.find(SELECTORS.BLOCK_ICON_CONTAINER).removeClass('hidden');

        }

    };

    /**

     * Hide the contact is blocked icon.

     *

     * @param {Object} root Search results container.

     * @param {Object} userId Contact user id.

     */

    var unblockContact = function(root, userId) {

        var contact = findContact(root, userId);

        if (contact.length) {

            contact.find(SELECTORS.BLOCK_ICON_CONTAINER).addClass('hidden');

        }

    };

    /**

     * Highlight words in search results.

     *

     * @param  {String} content HTML to search.

     * @param  {String} searchText Search text.

     * @return {String} searchText with search wrapped in matchtext span.

     */

    var highlightSearch = function(content, searchText) {

        if (!content) {

            return '';

        }

        var regex = new RegExp('(' + searchText + ')', 'gi');

        return content.replace(regex, '<span class="matchtext">$1</span>');

    };

    /**

     * Render contacts in the contacts search results.

     *

     * @param {Object} root Search results container.

     * @param {Array} contacts List of contacts.

     * @return {Promise} Renderer promise.

     */

    var renderContacts = function(root, contacts) {

        var container = getContactsContainer(root);

        var frompanel = root.attr('data-in-panel');

        var list = container.find(SELECTORS.LIST);

        return Templates.render(TEMPLATES.CONTACTS_LIST, {contacts: contacts, frompanel: frompanel})

            .then(function(html) {

                list.append(html);

                return html;

            });

    };

    /**

     * Render non contacts in the contacts search results.

     *

     * @param {Object} root Search results container.

     * @param {Array} nonContacts List of non contacts.

     * @return {Promise} Renderer promise.

     */

    var renderNonContacts = function(root, nonContacts) {

        var container = getNonContactsContainer(root);

        var frompanel = root.attr('data-in-panel');

        var list = container.find(SELECTORS.LIST);

        return Templates.render(TEMPLATES.NON_CONTACTS_LIST, {noncontacts: nonContacts, frompanel: frompanel})

            .then(function(html) {

                list.append(html);

                return html;

            });

    };

    /**

     * Render messages in the messages search results.

     *

     * @param {Object} root Search results container.

     * @param {Array} messages List of messages.

     * @return {Promise} Renderer promise.

     */

    var renderMessages = function(root, messages) {

        var container = getMessagesContainer(root);

        var frompanel = root.attr('data-in-panel');

        var list = container.find(SELECTORS.LIST);

        return Templates.render(TEMPLATES.MESSAGES_LIST, {messages: messages, frompanel: frompanel})

            .then(function(html) {

                list.append(html);

                return html;

            });

    };

    /**

     * Load more users from the repository and render the results into the users search results.

     *

     * @param  {Object} root Search results container.

     * @param  {Number} loggedInUserId Current logged in user.

     * @param  {String} text Search text.

     * @param  {Number} limit Number of users to get.

     * @param  {Number} offset Load users from

     * @return {Object} jQuery promise

     */

    var loadMoreUsers = function(root, loggedInUserId, text, limit, offset) {

        var loadedAll = false;

        showUsersLoadingIcon(root);

        return Repository.searchUsers(loggedInUserId, text, limit + 1, offset)

            .then(function(results) {

                var contacts = results.contacts;

                var noncontacts = results.noncontacts;

                if (contacts.length <= limit && noncontacts.length <= limit) {

                    loadedAll = true;

                    return {

                        contacts: contacts,

                        noncontacts: noncontacts

                    };

                } else {

                    return {

                        contacts: contacts.slice(0, limit),

                        noncontacts: noncontacts.slice(0, limit)

                    };

                }

            })

            .then(function(results) {

                var contactsCount = results.contacts.length;

                var nonContactsCount = results.noncontacts.length;

                if (contactsCount) {

                    results.contacts.forEach(function(contact) {

                        contact.highlight = highlightSearch(contact.fullname, text);

                    });

                }

                if (nonContactsCount) {

                    results.noncontacts.forEach(function(contact) {

                        contact.highlight = highlightSearch(contact.fullname, text);

                    });

                }

                return $.when(

                    contactsCount ? renderContacts(root, results.contacts) : true,

                    nonContactsCount ? renderNonContacts(root, results.noncontacts) : true

                )

                .then(function() {

                    return {

                        contactsCount: contactsCount,

                        nonContactsCount: nonContactsCount

                    };

                });

            })

            .then(function(counts) {

                hideUsersLoadingIcon(root);

                if (loadedAll) {

                    hideLoadMoreUsersButton(root);

                }

                return counts;

            })

            .catch(function(error) {

                hideUsersLoadingIcon(root);

                // Rethrow error for other handlers.

                throw error;

            });

    };

    /**

     * Load more messages from the repository and render the results into the messages search results.

     *

     * @param  {Object} root Search results container.

     * @param  {Number} loggedInUserId Current logged in user.

     * @param  {String} text Search text.

     * @param  {Number} limit Number of messages to get.

     * @param  {Number} offset Load messages from

     * @return {Object} jQuery promise

     */

    var loadMoreMessages = function(root, loggedInUserId, text, limit, offset) {

        var loadedAll = false;

        showMessagesLoadingIcon(root);

        return Repository.searchMessages(loggedInUserId, text, limit + 1, offset)

            .then(function(results) {

                var messages = results.contacts;

                if (messages.length <= limit) {

                    loadedAll = true;

                    return messages;

                } else {

                    return messages.slice(0, limit);

                }

            })

            .then(function(messages) {

                if (messages.length) {

                    messages.forEach(function(message) {

                        message.lastmessage = highlightSearch(message.lastmessage, text);

                    });

                    return renderMessages(root, messages)

                        .then(function() {

                            return messages.length;

                        });

                } else {

                    return messages.length;

                }

            })

            .then(function(count) {

                hideMessagesLoadingIcon(root);

                if (loadedAll) {

                    hideLoadMoreMessagesButton(root);

                }

                return count;

            })

            .catch(function(error) {

                hideMessagesLoadingIcon(root);

                // Rethrow error for other handlers.

                throw error;

            });

    };

    /**

     * Search for users and messages.

     *

     * @param {Object} header Search header container element.

     * @param {Object} body Search body container element.

     * @param {String} searchText Search text.

     * @param {Number} usersLimit The users limit.

     * @param {Number} usersOffset The users offset.

     * @param {Number} messagesLimit The message limit.

     * @param {Number} messagesOffset The message offset.

     * @return {Object} jQuery promise

     */

    var search = function(header, body, searchText, usersLimit, usersOffset, messagesLimit, messagesOffset) {

        var loggedInUserId = getLoggedInUserId(body);

        startLoading(header, body);

        clearAllSearchResults(body);

        return $.when(

            loadMoreUsers(body, loggedInUserId, searchText, usersLimit, usersOffset),

            loadMoreMessages(body, loggedInUserId, searchText, messagesLimit, messagesOffset)

        )

        .then(function(userCounts, messagesCount) {

            var contactsCount = userCounts.contactsCount;

            var nonContactsCount = userCounts.nonContactsCount;

            stopLoading(header, body);

            if (!contactsCount && !nonContactsCount && !messagesCount) {

                showNoSearchResults(body);

            } else {

                if (!contactsCount && !nonContactsCount) {

                    hideAllContactsSearchResults(body);

                } else {

                    if (!contactsCount) {

                        hideContactsSearchResults(body);

                    }

                    if (!nonContactsCount) {

                        hideNonContactsSearchResults(body);

                    }

                }

                if (!messagesCount) {

                    hideMessagesSearchResults(body);

                }

            }

            return;

        });

    };

    /**

     * Listen to and handle events for searching.

     *

     * @param {Object} header Search header container element.

     * @param {Object} body Search body container element.

     */

    var registerEventListeners = function(header, body) {

        var loggedInUserId = getLoggedInUserId(body);

        var searchInput = getSearchInput(header);

        var searchText = '';

        var messagesOffset = 0;

        var usersOffset = 0;

        var searchEventHandler = function(e, data) {

            searchText = searchInput.val().trim();

            if (searchText !== '') {

                messagesOffset = 0;

                usersOffset = 0;

                search(

                    header,

                    body,

                    searchText,

                    USERS_INITIAL_SEARCH_LIMIT,

                    usersOffset,

                    MESSAGE_SEARCH_LIMIT,

                    messagesOffset

                )

                .then(function() {

                    searchInput.focus();

                    usersOffset = usersOffset + USERS_INITIAL_SEARCH_LIMIT;

                    messagesOffset = messagesOffset + MESSAGE_SEARCH_LIMIT;

                    return;

                })

                .catch(Notification.exception);

            }

            data.originalEvent.preventDefault();

        };

        CustomEvents.define(searchInput, [CustomEvents.events.enter]);

        CustomEvents.define(header, [CustomEvents.events.activate]);

        CustomEvents.define(body, [CustomEvents.events.activate]);

        searchInput.on(CustomEvents.events.enter, searchEventHandler);

        header.on(CustomEvents.events.activate, SELECTORS.SEARCH_ACTION, searchEventHandler);

        body.on(CustomEvents.events.activate, SELECTORS.LOAD_MORE_MESSAGES, function(e, data) {

            if (searchText !== '') {

                loadMoreMessages(body, loggedInUserId, searchText, MESSAGE_SEARCH_LIMIT, messagesOffset)

                    .then(function() {

                        messagesOffset = messagesOffset + MESSAGE_SEARCH_LIMIT;

                        return;

                    })

                    .catch(Notification.exception);

            }

            data.originalEvent.preventDefault();

        });

        body.on(CustomEvents.events.activate, SELECTORS.LOAD_MORE_USERS, function(e, data) {

            if (searchText !== '') {

                loadMoreUsers(body, loggedInUserId, searchText, USERS_SEARCH_LIMIT, usersOffset)

                    .then(function() {

                        usersOffset = usersOffset + USERS_SEARCH_LIMIT;

                        return;

                    })

                    .catch(Notification.exception);

            }

            data.originalEvent.preventDefault();

        });

        header.on(CustomEvents.events.activate, SELECTORS.CANCEL_SEARCH_BUTTON, function() {

            clearSearchInput(header);

            showEmptyMessage(body);

            showSearchIcon(header);

            hideSearchResults(body);

            hideLoadingIcon(header);

            hideLoadingPlaceholder(body);

            usersOffset = 0;

            messagesOffset = 0;

        });

        PubSub.subscribe(Events.CONTACT_ADDED, function(userId) {

            addContact(body, userId);

        });

        PubSub.subscribe(Events.CONTACT_REMOVED, function(userId) {

            removeContact(body, userId);

        });

        PubSub.subscribe(Events.CONTACT_BLOCKED, function(userId) {

            blockContact(body, userId);

        });

        PubSub.subscribe(Events.CONTACT_UNBLOCKED, function(userId) {

            unblockContact(body, userId);

        });

    };

    /**

     * Setup the search page.

     *

     * @param {string} namespace The route namespace.

     * @param {Object} header Contacts header container element.

     * @param {Object} body Contacts body container element.

     * @return {Object} jQuery promise

     */

    var show = function(namespace, header, body) {

        if (!body.attr('data-init')) {

            registerEventListeners(header, body);

            body.attr('data-init', true);

        }

        var searchInput = getSearchInput(header);

        searchInput.focus();

        return $.Deferred().resolve().promise();

    };

    /**

     * String describing this page used for aria-labels.

     *

     * @param {string} namespace The route namespace.

     * @param {Object} header Contacts header container element.

     * @return {Object} jQuery promise

     */

    var description = function(namespace, header) {

        if (typeof header !== 'object') {

            return Str.get_string('messagedrawerviewsearch', 'core_message');

        }

        var searchInput = getSearchInput(header);

        var searchText = searchInput.val().trim();