// # Ghost Module
// Defines core methods required to build the frontend

/*global module, require, __dirname */
(function () {
    "use strict";

    // ## Setup Prerequisites
    var config = require('./../config'),
        when = require('when'),
        express = require('express'),
        path = require('path'),
        hbs = require('express-hbs'),
        _ = require('underscore'),
        Polyglot = require('node-polyglot'),

        models = require('./shared/models'),
        ExampleFilter = require('../content/plugins/exampleFilters'),

        requireTree = require('./shared/require-tree'),
        themeDirectories = requireTree(path.resolve(__dirname + '../../content/themes')),
        pluginDirectories = requireTree(path.resolve(__dirname + '../../content/plugins')),

        Ghost,
        instance,
        defaults,
        statuses;

    // ## Default values
    /**
     * A hash of default values to use instead of 'magic' numbers/strings.
     * @type {Object}
     */
    defaults = {
        filterPriority: 5,
        maxPriority: 9
    };

    // ## Article Statuses
    /**
     * A list of atricle status types
     * @type {Object}
     */
    statuses = {
        'draft': 'draft',
        'complete': 'complete',
        'approved': 'approved',
        'scheduled': 'scheduled',
        'published': 'published'
    };

    // ## Module Methods
    /**
     * @method Ghost
     * @returns {*}
     * @constructor
     */
    Ghost = function () {
        var app,
            plugin,
            polyglot;

        if (!instance) {
            instance = this;

            // Holds the filters
            instance.filterCallbacks = [];

            // Holds the filter hooks (that are built in to Ghost Core)
            instance.filters = [];

            // Holds the theme directories temporarily
            instance.themeDirectories = {};

            // Holds the plugin directories temporarily
            instance.pluginDirectories = {};


            plugin = new ExampleFilter(instance).init();

            app = express();

            polyglot = new Polyglot();

            // functionality
            // load Plugins...
            // var f = new FancyFirstChar(ghost).init();



            _.extend(instance, {
                app: function () { return app; },
                config: function () { return config; },

                // there's no management here to be sure this has loaded
                globals: function () { return instance.globalConfig; },
                dataProvider: models,
                statuses: function () { return statuses; },
                polyglot: function () { return polyglot; },
                plugin: function () { return plugin; },
                getPaths: function () {
                    return when.all([themeDirectories, pluginDirectories]).then(function (paths) {
                        instance.themeDirectories = paths[0];
                        instance.pluginDirectories = paths[1];
                        return;
                    });
                },
                paths: function () {
                    return {
                        'activeTheme':   __dirname + '/../content/' + config.themeDir + '/' + config.activeTheme + '/',
                        'adminViews':    __dirname + '/admin/views/',
                        'frontendViews': __dirname + '/frontend/views/',
                        'lang':          __dirname + '/lang/',
                        'availableThemes': instance.themeDirectories,
                        'availablePlugins': instance.pluginDirectories
                    };
                }
            });
        }
        return instance;
    };

    Ghost.prototype.init = function () {
        var settings = {},
            self = this,
            configDeferred = when.defer(),
            configPromise = configDeferred.promise;

        models.Settings.findAll().then(function (result) {
            _.map(result.models, function (member) {
                if (!settings.hasOwnProperty(member.attributes.key)) {
                    settings[member.attributes.key] = member.attributes.value;
                }
            });
            configDeferred.resolve(settings);
        });
        return when.all([instance.dataProvider.init(), instance.getPaths(), configPromise]).then(function (results) {
            self.globalConfig = results[2];
            return;
        });
    };

    /**
     * @param  {string}   name
     * @param  {Function} fn
     * @return {method}  hbs.registerHelper
     */
    Ghost.prototype.registerThemeHelper = function (name, fn) {
        hbs.registerHelper(name, fn);
    };

    /**
     * @param  {string}   name
     * @param  {Function} fn
     * @return {*}
     */
    Ghost.prototype.registerTheme = function (name, fn) {
        return this;
    };

    /**
     * @param  {string}   name
     * @param  {Function} fn
     * @return {*}
     */
    Ghost.prototype.registerPlugin = function (name, fn) {
        return this;
    };

    /**
     * @param  {string}   name
     * @param  {integer}  priority
     * @param  {Function} fn
     */
    Ghost.prototype.registerFilter = function (name, priority, fn) {
        // Curry the priority optional parameter to a default of 5
        if (_.isFunction(priority)) {
            fn = priority;
            priority = defaults.filterPriority;
        }

        this.filterCallbacks[name] = this.filterCallbacks[name] || {};
        this.filterCallbacks[name][priority] = this.filterCallbacks[name][priority] || [];

        this.filterCallbacks[name][priority].push(fn);
    };

    /**
     * @param  {string}   name     [description]
     * @param  {*}   args
     * @param  {Function} callback
     * @return {method} callback
     */
    Ghost.prototype.doFilter = function (name, args, callback) {
        var callbacks = this.filterCallbacks[name];

        // Bug out early if no callbacks by that name
        if (!callbacks) {
            return callback(args);
        }

        _.times(defaults.maxPriority + 1, function (priority) {
            // Bug out if no handlers on this priority
            if (!_.isArray(callbacks[priority])) {
                return;
            }

            // Call each handler for this priority level
            _.each(callbacks[priority], function (filterHandler) {
                args = filterHandler(args);
            });
        });

        callback(args);
    };

    /**
     * Initialise Theme
     *
     * @todo  Tod (?) Old comment
     * @param  {Object} app
     */
    Ghost.prototype.initTheme = function (app) {
        var self = this;
        return function initTheme(req, res, next) {
            app.set('view engine', 'hbs');
            if (/(^\/ghost$|^\/ghost\/)/.test(req.url) === false) {
                app.engine('hbs', hbs.express3(
                    {partialsDir: self.paths().activeTheme + 'partials'}
                ));
                app.set('views', self.paths().activeTheme);
            } else {
                app.engine('hbs', hbs.express3({partialsDir: self.paths().adminViews + 'partials'}));
                app.set('views', self.paths().adminViews);
                app.use('/core/admin/assets', express['static'](path.join(__dirname, '/admin/assets')));
            }
            app.use(express['static'](self.paths().activeTheme));
            app.use('/content/images', express['static'](path.join(__dirname, '/../content/images')));
            next();
        };
    };

    // TODO: Expose the defaults for other people to see/manipulate as a static value?
    // Ghost.defaults = defaults;

    module.exports = Ghost;
}());