(function () {
    var PlayerJs = window.PlayerJs = function (id) {
        this.el = document.querySelectorAll(id)[0];
        this.origin = this.el.src;
    };

    PlayerJs.prototype.play = function () {
        this._send('play');
    };

    PlayerJs.prototype.pause = function () {
        this._send('pause');
    };

    PlayerJs.prototype.onReady = function (callback) {
        PlayerJsReady.listen(this.el, callback);
    };

    PlayerJs.prototype._send = function (method, value) {
        /**
         * We only want to send messages if player is ready to receive them.
         */
        this.onReady(function () {
            this.el.contentWindow.postMessage(
                JSON.stringify({
                    context: 'player.js',
                    version: '0.0.11',
                    method: method,
                    value: value,
                }),
                this.origin
            );
        }.bind(this));
    };

    /**
     * Subscribes listener for an event coming from player.
     *
     * @todo Optimize to use only one window.addEventListener.
     *
     * @param {string} eventName The event name
     * @param {Function} callback The callback
     * @return {Function} Listener that can be used to later unsubscribe.
     */
    PlayerJs.prototype._on = function (eventName, callback) {
        var listener = function (e) {
            if (e.source !== this.el.contentWindow) {
                return;
            }

            var message = PlayerJsCommon.getPlayerJsMessage(e);

            if (!message || message.event !== eventName) {
                return;
            }

            callback(message, e);
        }.bind(this);

        window.addEventListener('message', listener);

        return listener;
    };

    PlayerJs.prototype._off = function (listener) {
        window.removeEventListener('message', listener);
    };

    PlayerJs.prototype.onFirstPlay = function (callback) {
        /**
         * Ask player inside iframe to send 'play' events.
         */
        this._send('addEventListener', 'play');

        var firstPlayListener = this._on('play', function () {
            /**
             * Make sure this callback is ran only once.
             */
            this._off(firstPlayListener);

            callback();
        }.bind(this));
    };
}());