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/>.

/**

 * Auto-save functionality for during quiz attempts.

 *

 * @module moodle-mod_quiz-autosave

 */

/**

 * Auto-save functionality for during quiz attempts.

 *

 * @class M.mod_quiz.autosave

 */

M.mod_quiz = M.mod_quiz || {};

M.mod_quiz.autosave = {

    /**

     * The amount of time (in milliseconds) to wait between TinyMCE detections.

     *

     * @property TINYMCE_DETECTION_DELAY

     * @type Number

     * @default 500

     * @private

     */

    TINYMCE_DETECTION_DELAY:  500,

    /**

     * The number of times to try redetecting TinyMCE.

     *

     * @property TINYMCE_DETECTION_REPEATS

     * @type Number

     * @default 20

     * @private

     */

    TINYMCE_DETECTION_REPEATS: 20,

    /**

     * The delay (in milliseconds) between checking hidden input fields.

     *

     * @property WATCH_HIDDEN_DELAY

     * @type Number

     * @default 1000

     * @private

     */

    WATCH_HIDDEN_DELAY:      1000,

    /**

     * The number of failures to ignore before notifying the user.

     *

     * @property FAILURES_BEFORE_NOTIFY

     * @type Number

     * @default 1

     * @private

     */

    FAILURES_BEFORE_NOTIFY:     1,

    /**

     * The value to use when resetting the successful save counter.

     *

     * @property FIRST_SUCCESSFUL_SAVE

     * @static

     * @type Number

     * @default -1

     * @private

     */

    FIRST_SUCCESSFUL_SAVE:     -1,

    /**

     * The selectors used throughout this class.

     *

     * @property SELECTORS

     * @private

     * @type Object

     * @static

     */

    SELECTORS: {

        QUIZ_FORM:             '#responseform',

        VALUE_CHANGE_ELEMENTS: 'input, textarea, [contenteditable="true"]',

        CHANGE_ELEMENTS:       'input, select',

        HIDDEN_INPUTS:         'input[type=hidden]',

        CONNECTION_ERROR:      '#connection-error',

        CONNECTION_OK:         '#connection-ok'

    },

    /**

     * The script which handles the autosaves.

     *

     * @property AUTOSAVE_HANDLER

     * @type String

     * @default M.cfg.wwwroot + '/mod/quiz/autosave.ajax.php'

     * @private

     */

    AUTOSAVE_HANDLER: M.cfg.wwwroot + '/mod/quiz/autosave.ajax.php',

    /**

     * The delay (in milliseconds) between a change being made, and it being auto-saved.

     *

     * @property delay

     * @type Number

     * @default 120000

     * @private

     */

    delay: 120000,

    /**

     * A Node reference to the form we are monitoring.

     *

     * @property form

     * @type Node

     * @default null

     */

    form: null,

    /**

     * Whether the form has been modified since the last save started.

     *

     * @property dirty

     * @type boolean

     * @default false

     */

    dirty: false,

    /**

     * Timer object for the delay between form modifaction and the save starting.

     *

     * @property delay_timer

     * @type Object

     * @default null

     * @private

     */

    delay_timer: null,

    /**

     * Y.io transaction for the save ajax request.

     *

     * @property save_transaction

     * @type object

     * @default null

     */

    save_transaction: null,

    /**

     * Failed saves count.

     *

     * @property savefailures

     * @type Number

     * @default 0

     * @private

     */

    savefailures: 0,

    /**

     * Properly bound key change handler.

     *

     * @property editor_change_handler

     * @type EventHandle

     * @default null

     * @private

     */

    editor_change_handler: null,

    /**

     * Record of the value of all the hidden fields, last time they were checked.

     *

     * @property hidden_field_values

     * @type Object

     * @default {}

     */

    hidden_field_values: {},

    /**

     * Initialise the autosave code.

     *

     * @method init

     * @param {Number} delay the delay, in seconds, between a change being detected, and

     * a save happening.

     */

    init: function(delay) {

        this.form = Y.one(this.SELECTORS.QUIZ_FORM);

        if (!this.form) {

            Y.log('No response form found. Why did you try to set up autosave?', 'debug', 'moodle-mod_quiz-autosave');

            return;

        }

        this.delay = delay * 1000;

        this.form.delegate('valuechange', this.value_changed, this.SELECTORS.VALUE_CHANGE_ELEMENTS, this);

        this.form.delegate('change', this.value_changed, this.SELECTORS.CHANGE_ELEMENTS, this);

        this.form.on('submit', this.stop_autosaving, this);

        require(['core_form/events'], function(FormEvent) {

            window.addEventListener(FormEvent.eventTypes.uploadChanged, this.value_changed.bind(this));

        }.bind(this));

        this.init_tinymce(this.TINYMCE_DETECTION_REPEATS);

        this.save_hidden_field_values();

        this.watch_hidden_fields();

    },

    save_hidden_field_values: function() {

        this.form.all(this.SELECTORS.HIDDEN_INPUTS).each(function(hidden) {

            var name = hidden.get('name');

            if (!name) {

                return;

            }

            this.hidden_field_values[name] = hidden.get('value');

        }, this);

    },

    watch_hidden_fields: function() {

        this.detect_hidden_field_changes();

        Y.later(this.WATCH_HIDDEN_DELAY, this, this.watch_hidden_fields);

    },

    detect_hidden_field_changes: function() {

        this.form.all(this.SELECTORS.HIDDEN_INPUTS).each(function(hidden) {

            var name = hidden.get('name'),

                value = hidden.get('value');

            if (!name) {

                return;

            }

            if (!(name in this.hidden_field_values) || value !== this.hidden_field_values[name]) {

                this.hidden_field_values[name] = value;

                this.value_changed({target: hidden});

            }

        }, this);

    },

    /**

     * Initialise watching of TinyMCE specifically.

     *

     * Because TinyMCE might load slowly, and after us, we need to keep

     * trying, until we detect TinyMCE is there, or enough time has passed.

     * This is based on the TINYMCE_DETECTION_DELAY and

     * TINYMCE_DETECTION_REPEATS properties.

     *

     *

     * @method init_tinymce

     * @param {Number} repeatcount The number of attempts made so far.

     */

    init_tinymce: function(repeatcount) {

        if (typeof window.tinyMCE === 'undefined') {

            if (repeatcount > 0) {

                Y.later(this.TINYMCE_DETECTION_DELAY, this, this.init_tinymce, [repeatcount - 1]);

            } else {

                Y.log('Gave up looking for TinyMCE.', 'debug', 'moodle-mod_quiz-autosave');

            }

            return;

        }

        Y.log('Found TinyMCE.', 'debug', 'moodle-mod_quiz-autosave');

        this.editor_change_handler = Y.bind(this.editor_changed, this);

        if (window.tinyMCE.onAddEditor) {

            window.tinyMCE.onAddEditor.add(Y.bind(this.init_tinymce_editor, this));

        } else if (window.tinyMCE.on) {

            var startSaveTimer = this.start_save_timer_if_necessary.bind(this);

            window.tinyMCE.on('AddEditor', function(event) {

                event.editor.on('Change Undo Redo keydown', startSaveTimer);

            });

            // One or more editors might already have been added, so we have to attach

            // the event handlers to these as well.

            window.tinyMCE.get().forEach(function(editor) {

                editor.on('Change Undo Redo keydown', startSaveTimer);

            });

         }

    },

    /**

     * Initialise watching of a specific TinyMCE editor.

     *

     * @method init_tinymce_editor

     * @param {EventFacade} e

     * @param {Object} editor The TinyMCE editor object

     */

    init_tinymce_editor: function(e, editor) {

        Y.log('Found TinyMCE editor ' + editor.id + '.', 'debug', 'moodle-mod_quiz-autosave');

        editor.onChange.add(this.editor_change_handler);

        editor.onRedo.add(this.editor_change_handler);

        editor.onUndo.add(this.editor_change_handler);

        editor.onKeyDown.add(this.editor_change_handler);

    },

    value_changed: function(e) {

        var name = e.target.getAttribute('name');

        if (name === 'thispage' || name === 'scrollpos' || (name && name.match(/_:flagged$/))) {

            return; // Not interesting.

        }

        // Fallback to the ID when the name is not present (in the case of content editable).

        name = name || '#' + e.target.getAttribute('id');

        Y.log('Detected a value change in element ' + name + '.', 'debug', 'moodle-mod_quiz-autosave');

        this.start_save_timer_if_necessary();

    },

    editor_changed: function(editor) {

        Y.log('Detected a value change in editor ' + editor.id + '.', 'debug', 'moodle-mod_quiz-autosave');

        this.start_save_timer_if_necessary();

    },

    start_save_timer_if_necessary: function() {

        this.dirty = true;

        if (this.delay_timer || this.save_transaction) {

            // Already counting down or daving.

            return;

        }

        this.start_save_timer();

    },

    start_save_timer: function() {

        this.cancel_delay();

        this.delay_timer = Y.later(this.delay, this, this.save_changes);

    },

    cancel_delay: function() {

        if (this.delay_timer && this.delay_timer !== true) {

            this.delay_timer.cancel();

        }

        this.delay_timer = null;

    },

    save_changes: function() {

        this.cancel_delay();

        this.dirty = false;

        if (this.is_time_nearly_over()) {

            Y.log('No more saving, time is nearly over.', 'debug', 'moodle-mod_quiz-autosave');

            this.stop_autosaving();

            return;

        }

        Y.log('Doing a save.', 'debug', 'moodle-mod_quiz-autosave');

        if (typeof window.tinyMCE !== 'undefined') {

            window.tinyMCE.triggerSave();

        }

        // YUI io.form incorrectly (in my opinion) sends the value of all submit

        // buttons in the ajax request. We don't want any submit buttons.

        // Therefore, temporarily change the type.

        // (Yes, this is a nasty hack. One day this will be re-written as AMD, hopefully).

        var allsubmitbuttons = this.form.all('input[type=submit], button[type=submit]');

        allsubmitbuttons.setAttribute('type', 'button');

        this.save_transaction = Y.io(this.AUTOSAVE_HANDLER, {

            method:  'POST',

            form:    {id: this.form},

            on:      {

                success: this.save_done,

                failure: this.save_failed

            },

            context: this

        });

        // Change the button types back.

        allsubmitbuttons.setAttribute('type', 'submit');

    },

    save_done: function(transactionid, response) {

        var autosavedata = JSON.parse(response.responseText);

        if (autosavedata.status !== 'OK') {

            // Because IIS is useless, Moodle can't send proper HTTP response

            // codes, so we have to detect failures manually.

            this.save_failed(transactionid, response);

            return;

        }

        if (typeof autosavedata.timeleft !== 'undefined') {

            Y.log('Updating timer: ' + autosavedata.timeleft + ' seconds remain.', 'debug', 'moodle-mod_quiz-timer');

            M.mod_quiz.timer.updateEndTime(autosavedata.timeleft);

        }

        this.update_saved_time_display();

        Y.log('Save completed.', 'debug', 'moodle-mod_quiz-autosave');

        this.save_transaction = null;

        if (this.dirty) {

            Y.log('Dirty after save.', 'debug', 'moodle-mod_quiz-autosave');

            this.start_save_timer();

        }

        if (this.savefailures > 0) {

            Y.one(this.SELECTORS.CONNECTION_ERROR).hide();

            Y.one(this.SELECTORS.CONNECTION_OK).show();

            this.savefailures = this.FIRST_SUCCESSFUL_SAVE;

        } else if (this.savefailures === this.FIRST_SUCCESSFUL_SAVE) {

            Y.one(this.SELECTORS.CONNECTION_OK).hide();

            this.savefailures = 0;

        }

    },

    save_failed: function() {

        Y.log('Save failed.', 'debug', 'moodle-mod_quiz-autosave');

        this.save_transaction = null;

        // We want to retry soon.

        this.start_save_timer();

        this.savefailures = Math.max(1, this.savefailures + 1);

        if (this.savefailures === this.FAILURES_BEFORE_NOTIFY) {

            Y.one(this.SELECTORS.CONNECTION_ERROR).show();

            Y.one(this.SELECTORS.CONNECTION_OK).hide();

        }

    },

    /**

     * Inform the user that their answers have been saved.

     *

     * @method update_saved_time_display

     */

    update_saved_time_display: function() {

        // We fetch the current language's preferred time format from the language pack.

        var timeFormat = M.util.get_string('strftimedatetimeshortaccurate', 'langconfig');

        var message = M.util.get_string('lastautosave', 'quiz', Y.Date.format(new Date(), {'format': timeFormat}));

        var infoDiv = Y.one('#mod_quiz_navblock .othernav .autosave_info');

        infoDiv.set('text', message);

        infoDiv.show();

    },

    is_time_nearly_over: function() {

        return M.mod_quiz.timer && M.mod_quiz.timer.endtime &&

                (new Date().getTime() + 2 * this.delay) > M.mod_quiz.timer.endtime;

    },

    stop_autosaving: function() {

        this.cancel_delay();

        this.delay_timer = true;

        if (this.save_transaction) {

            this.save_transaction.abort();

        }

    }

};