(function () {
    "use strict";

    var _ = require('underscore'),
        moment = require('moment'),
        when = require('when'),
        navHelper = require('./ghostNav'),
        hbs = require('express-hbs'),
        coreHelpers;

    coreHelpers = function (ghost) {
        /**
         * [ description]
         * @todo ghost core helpers + a way for themes to register them
         * @param  {Object} context date object
         * @param  {*} block
         * @return {Object} A Moment time / date object
         */
        ghost.registerThemeHelper('dateFormat', function (context, block) {
            var f = block.hash.format || "MMM Do, YYYY";
            return moment(context).format(f);
        });

        /**
         * [ description]
         *
         * @param String key
         * @param String default translation
         * @param {Object} options
         * @return String A correctly internationalised string
         */
        ghost.registerThemeHelper('e', function (key, defaultString, options) {
            var output;

            if (ghost.config().defaultLang === 'en' && _.isEmpty(options.hash) && !ghost.config().forceI18n) {
                output = defaultString;
            } else {
                output = ghost.polyglot().t(key, options.hash);
            }

            return output;
        });

        ghost.registerThemeHelper('json', function (object, options) {
            return JSON.stringify(object);
        });

        ghost.registerThemeHelper('foreach', function (context, options) {
            var fn = options.fn,
                inverse = options.inverse,
                i = 0,
                j = 0,
                key,
                ret = "",
                data;

            if (options.data) {
                data = hbs.handlebars.createFrame(options.data);
            }

            if (context && typeof context === 'object') {
                if (context instanceof Array) {
                    for (j = context.length; i < j; i += 1) {
                        if (data) {
                            data.index = i;
                            data.first = data.last = data.even = data.odd = false;
                            if (i === 0) {
                                data.first = true;
                            }
                            if (i === j - 1) {
                                data.last = true;
                            }
                            // first post is index zero but still needs to be odd
                            if (i % 2 === 1) {
                                data.even = true;
                            } else {
                                data.odd = true;
                            }
                        }
                        ret = ret + fn(context[i], { data: data });
                    }
                } else {
                    for (key in context) {
                        if (context.hasOwnProperty(key)) {
                            j += 1;
                        }
                    }
                    for (key in context) {
                        if (context.hasOwnProperty(key)) {
                            if (data) {
                                data.key = key;
                                data.first = data.last = data.even = data.odd = false;
                                if (i === 0) {
                                    data.first = true;
                                }
                                if (i === j - 1) {
                                    data.last = true;
                                }
                                // first post is index zero but still needs to be odd
                                if (i % 2 === 1) {
                                    data.even = true;
                                } else {
                                    data.odd = true;
                                }
                            }
                            ret = ret + fn(context[key], {data: data});
                            i += 1;
                        }
                    }
                }
            }

            if (i === 0) {
                ret = inverse(this);
            }
            return ret;
        });

        return when.all([
            // Just one async helper for now, but could be more in the future
            navHelper.registerWithGhost(ghost)
        ]);
    };


    module.exports.loadCoreHelpers = coreHelpers;
}());