/* vim:ts=4:sts=4:sw=4:
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Skywriter.
 *
 * The Initial Developer of the Original Code is
 * Mozilla.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Joe Walker (jwalker@mozilla.com)
 *   Julian Viereck (jviereck@mozilla.com)
 *   Kevin Dangoor (kdangoor@mozilla.com)
 *   Irakli Gozalishvili <rfobic@gmail.com> (http://jeditoolkit.com)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {

/**
 * This plug-in manages settings.
 */

var console = require('pilot/console');
var oop = require('pilot/oop');
var types = require('pilot/types');
var EventEmitter = require('pilot/event_emitter').EventEmitter;
var catalog = require('pilot/catalog');

var settingExtensionSpec = {
    name: 'setting',
    description: 'A setting is something that the application offers as a ' +
            'way to customize how it works',
    register: 'env.settings.addSetting',
    indexOn: 'name'
};

exports.startup = function(data, reason) {
    catalog.addExtensionSpec(settingExtensionSpec);
};

exports.shutdown = function(data, reason) {
    catalog.removeExtensionSpec(settingExtensionSpec);
};


/**
 * Create a new setting.
 * @param settingSpec An object literal that looks like this:
 * {
 *   name: 'thing',
 *   description: 'Thing is an example setting',
 *   type: 'string',
 *   defaultValue: 'something'
 * }
 */
function Setting(settingSpec, settings) {
    this._settings = settings;

    Object.keys(settingSpec).forEach(function(key) {
        this[key] = settingSpec[key];
    }, this);

    this.type = types.getType(this.type);
    if (this.type == null) {
        throw new Error('In ' + this.name +
            ': can\'t find type for: ' + JSON.stringify(settingSpec.type));
    }

    if (!this.name) {
        throw new Error('Setting.name == undefined. Ignoring.', this);
    }

    if (!this.defaultValue === undefined) {
        throw new Error('Setting.defaultValue == undefined', this);
    }

    if (this.onChange) {
        this.on('change', this.onChange.bind(this))
    }

    this.set(this.defaultValue);
}
Setting.prototype = {
    get: function() {
        return this.value;
    },

    set: function(value) {
        if (this.value === value) {
            return;
        }

        this.value = value;
        if (this._settings.persister) {
            this._settings.persister.persistValue(this._settings, this.name, value);
        }

        this._dispatchEvent('change', { setting: this, value: value });
    },

    /**
     * Reset the value of the <code>key</code> setting to it's default
     */
    resetValue: function() {
        this.set(this.defaultValue);
    },
    toString: function () {
        return this.name;
    }
};
oop.implement(Setting.prototype, EventEmitter);


/**
 * A base class for all the various methods of storing settings.
 * <p>Usage:
 * <pre>
 * // Create manually, or require 'settings' from the container.
 * // This is the manual version:
 * var settings = plugins.catalog.getObject('settings');
 * // Add a new setting
 * settings.addSetting({ name:'foo', ... });
 * // Display the default value
 * alert(settings.get('foo'));
 * // Alter the value, which also publishes the change etc.
 * settings.set('foo', 'bar');
 * // Reset the value to the default
 * settings.resetValue('foo');
 * </pre>
 * @constructor
 */
function Settings(persister) {
    // Storage for deactivated values
    this._deactivated = {};

    // Storage for the active settings
    this._settings = {};
    // We often want sorted setting names. Cache
    this._settingNames = [];

    if (persister) {
        this.setPersister(persister);
    }
};

Settings.prototype = {
    /**
     * Function to add to the list of available settings.
     * <p>Example usage:
     * <pre>
     * var settings = plugins.catalog.getObject('settings');
     * settings.addSetting({
     *     name: 'tabsize', // For use in settings.get('X')
     *     type: 'number',  // To allow value checking.
     *     defaultValue: 4  // Default value for use when none is directly set
     * });
     * </pre>
     * @param {object} settingSpec Object containing name/type/defaultValue members.
     */
    addSetting: function(settingSpec) {
        var setting = new Setting(settingSpec, this);
        this._settings[setting.name] = setting;
        this._settingNames.push(setting.name);
        this._settingNames.sort();
    },

    addSettings: function addSettings(settings) {
        Object.keys(settings).forEach(function (name) {
            var setting = settings[name];
            if (!('name' in setting)) setting.name = name;
            this.addSetting(setting);
        }, this);
    },

    removeSetting: function(setting) {
        var name = (typeof setting === 'string' ? setting : setting.name);
        setting = this._settings[name];
        delete this._settings[name];
        util.arrayRemove(this._settingNames, name);
        settings.removeAllListeners('change');
    },

    removeSettings: function removeSettings(settings) {
        Object.keys(settings).forEach(function(name) {
            var setting = settings[name];
            if (!('name' in setting)) setting.name = name;
            this.removeSettings(setting);
        }, this);
    },

    getSettingNames: function() {
        return this._settingNames;
    },

    getSetting: function(name) {
        return this._settings[name];
    },

    /**
     * A Persister is able to store settings. It is an object that defines
     * two functions:
     * loadInitialValues(settings) and persistValue(settings, key, value).
     */
    setPersister: function(persister) {
        this._persister = persister;
        if (persister) {
            persister.loadInitialValues(this);
        }
    },

    resetAll: function() {
        this.getSettingNames().forEach(function(key) {
            this.resetValue(key);
        }, this);
    },

    /**
     * Retrieve a list of the known settings and their values
     */
    _list: function() {
        var reply = [];
        this.getSettingNames().forEach(function(setting) {
            reply.push({
                'key': setting,
                'value': this.getSetting(setting).get()
            });
        }, this);
        return reply;
    },

    /**
     * Prime the local cache with the defaults.
     */
    _loadDefaultValues: function() {
        this._loadFromObject(this._getDefaultValues());
    },

    /**
     * Utility to load settings from an object
     */
    _loadFromObject: function(data) {
        // We iterate over data rather than keys so we don't forget values
        // which don't have a setting yet.
        for (var key in data) {
            if (data.hasOwnProperty(key)) {
                var setting = this._settings[key];
                if (setting) {
                    var value = setting.type.parse(data[key]);
                    this.set(key, value);
                } else {
                    this.set(key, data[key]);
                }
            }
        }
    },

    /**
     * Utility to grab all the settings and export them into an object
     */
    _saveToObject: function() {
        return this.getSettingNames().map(function(key) {
            return this._settings[key].type.stringify(this.get(key));
        }.bind(this));
    },

    /**
     * The default initial settings
     */
    _getDefaultValues: function() {
        return this.getSettingNames().map(function(key) {
            return this._settings[key].spec.defaultValue;
        }.bind(this));
    }
};
exports.settings = new Settings();

/**
 * Save the settings in a cookie
 * This code has not been tested since reboot
 * @constructor
 */
function CookiePersister() {
};

CookiePersister.prototype = {
    loadInitialValues: function(settings) {
        settings._loadDefaultValues();
        var data = cookie.get('settings');
        settings._loadFromObject(JSON.parse(data));
    },

    persistValue: function(settings, key, value) {
        try {
            var stringData = JSON.stringify(settings._saveToObject());
            cookie.set('settings', stringData);
        } catch (ex) {
            console.error('Unable to JSONify the settings! ' + ex);
            return;
        }
    }
};

exports.CookiePersister = CookiePersister;

});