(function () {
    "use strict";
    angular.module('laz.videoLibrary')
        .provider('videos', function() {

            var preloadedCurrentVideo = null;
            var preloadedCategories = null;
            var currentVideoId = null;

            function videosFactory(videoApi, $q, EventEmitter){

                var eventEmitter = new EventEmitter();
                var CURRENT_VIDEO_CHANGE_EVENT = 'currentVideoChange';
                var videoPromisesByVideoId = {};
                var videoCategoriesPromise = null;

                if(preloadedCurrentVideo){
                    currentVideoId = preloadedCurrentVideo.id;
                    videoPromisesByVideoId[currentVideoId] = $q.resolve(preloadedCurrentVideo);
                }
                if(preloadedCategories){
                    videoCategoriesPromise = $q.resolve(preloadedCategories);
                }

                return {
                    getCurrentVideoId: getCurrentVideoId,
                    setCurrentVideo: setCurrentVideo,
                    getCurrentVideo: getCurrentVideo,
                    onCurrentVideoChanged: onCurrentVideoChanged,
                    getVideoCardCategories: getVideoCardCategories,
                    clearCache: clearCache
                };

                function getCurrentVideoId(){
                    return currentVideoId;
                }

                function setCurrentVideo(videoId){
                    if(videoId && (isNaN(parseInt(videoId)) || parseInt(currentVideoId) === parseInt(videoId))){
                        return;
                    }
                    console.debug("current: " + currentVideoId + " => new: " + videoId);
                    currentVideoId = videoId || undefined;
                    eventEmitter.emit(CURRENT_VIDEO_CHANGE_EVENT, currentVideoId);
                }

                function getCurrentVideo(){
                    var FEATURED_SENTINEL_ID = videoApi.FEATURED_SENTINEL_ID;
                    var idToSearch = currentVideoId || FEATURED_SENTINEL_ID;
                    if(!videoPromisesByVideoId[idToSearch]){
                        var videoPromise = videoApi.findById(idToSearch, videoApi.VIEW_TYPES.PLAYABLE);
                        if(idToSearch === FEATURED_SENTINEL_ID){
                            videoPromise = videoPromise.then(function(video){
                                videoPromisesByVideoId[video.id] = videoPromisesByVideoId[video.id] || videoPromisesByVideoId[FEATURED_SENTINEL_ID];
                                return video;
                            });
                        }
                        videoPromisesByVideoId[idToSearch] = videoPromise;
                    }
                    console.debug(videoPromisesByVideoId);
                    return videoPromisesByVideoId[idToSearch];
                }

                function onCurrentVideoChanged(callback){
                    eventEmitter.on(CURRENT_VIDEO_CHANGE_EVENT, callback);
                    return function(){ eventEmitter.off(CURRENT_VIDEO_CHANGE_EVENT, callback); };
                }

                function getVideoCardCategories(){
                    if(!videoCategoriesPromise){
                        videoCategoriesPromise = videoApi.findCategories(videoApi.VIEW_TYPES.CARD);
                    }
                    return videoCategoriesPromise;
                }

                function clearCache(){
                    videoPromisesByVideoId = {};
                    videoCategoriesPromise = null;
                }
            }

            function loadCurrentVideo(video){
                preloadedCurrentVideo = video;
            }

            function loadVideoCardCategories(categories){
                preloadedCategories = categories;
            }

            return {
                loadCurrentVideo: loadCurrentVideo,
                loadVideoCardCategories: loadVideoCardCategories,
                $get: ['videoApi', '$q', 'EventEmitter', videosFactory ]
            };
        })
})();