sync/playlist.js

/*
The MIT License (MIT)
Copyright (c) 2013 Calvin Montgomery

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

ULList = require("./ullist").ULList;
var Media = require("./media").Media;
var InfoGetter = require("./get-info");
var AllPlaylists = {};

function PlaylistItem(media, uid) {
    this.media = media;
    this.uid = uid;
    this.temp = false;
    this.queueby = "";
    this.prev = null;
    this.next = null;
}

PlaylistItem.prototype.pack = function() {
    return {
        media: this.media.pack(),
        uid: this.uid,
        temp: this.temp,
        queueby: this.queueby
    };
}

function Playlist(chan) {
    if(chan.name in AllPlaylists && AllPlaylists[chan.name]) {
        var pl = AllPlaylists[chan.name];
        if("_leadInterval" in pl)
            pl.die();
    }
    this.items = new ULList();
    this.current = null;
    this.next_uid = 0;
    this._leadInterval = false;
    this._lastUpdate = 0;
    this._counter = 0;
    this.leading = true;
    this.callbacks = {
        "changeMedia": [],
        "mediaUpdate": [],
        "remove": [],
    };
    this.lock = false;
    this.action_queue = [];
    this._qaInterval = false;
    AllPlaylists[chan.name] = this;

    if(chan) {
        this.channel = chan;
        var pl = this;
        this.on("mediaUpdate", function(m) {
            chan.sendAll("mediaUpdate", m.timeupdate());
        });
        this.on("changeMedia", function(m) {
            chan.onVideoChange();
            chan.sendAll("setCurrent", pl.current.uid);
            chan.sendAll("changeMedia", m.fullupdate());
        });
        this.on("remove", function(item) {
            chan.broadcastPlaylistMeta();
            chan.sendAll("delete", {
                uid: item.uid
            });
        });
    }
}

Playlist.prototype.queueAction = function(data) {
    this.action_queue.push(data);
    if(this._qaInterval)
        return;
    var pl = this;
    this._qaInterval = setInterval(function() {
        var data = pl.action_queue.shift();
        if(data.waiting) {
            if(!("expire" in data))
                data.expire = Date.now() + 10000;
            if(Date.now() < data.expire)
                pl.action_queue.unshift(data);
        }
        else
            data.fn();
        if(pl.action_queue.length == 0) {
            clearInterval(pl._qaInterval);
            pl._qaInterval = false;
        }
    }, 100);
}

Playlist.prototype.dump = function() {
    var arr = this.items.toArray();
    var pos = 0;
    for(var i in arr) {
        if(this.current && arr[i].uid == this.current.uid) {
            pos = i;
            break;
        }
    }

    var time = 0;
    if(this.current)
        time = this.current.media.currentTime;

    return {
        pl: arr,
        pos: pos,
        time: time
    };
}

Playlist.prototype.die = function () {
    this.clear();
    if(this._leadInterval) {
        clearInterval(this._leadInterval);
        this._leadInterval = false;
    }
    for(var key in this)
        delete this[key];
}

Playlist.prototype.load = function(data, callback) {
    this.clear();
    for(var i in data.pl) {
        var e = data.pl[i].media;
        var m = new Media(e.id, e.title, e.seconds, e.type);
        var it = this.makeItem(m);
        it.temp = data.pl[i].temp;
        it.queueby = data.pl[i].queueby;
        this.items.append(it);
        if(i == parseInt(data.pos)) {
            this.current = it;
        }
    }

    if(callback)
        callback();
}

Playlist.prototype.on = function(ev, fn) {
    if(typeof fn === "undefined") {
        var pl = this;
        return function() {
            for(var i = 0; i < pl.callbacks[ev].length; i++) {
                pl.callbacks[ev][i].apply(this, arguments);
            }
        }
    }
    else if(typeof fn === "function") {
        this.callbacks[ev].push(fn);
    }
}

Playlist.prototype.makeItem = function(media) {
    return new PlaylistItem(media, this.next_uid++);
}

Playlist.prototype.add = function(item, pos) {
    var success;
    if(pos == "append")
        success = this.items.append(item);
    else if(pos == "prepend")
        success = this.items.prepend(item);
    else
        success = this.items.insertAfter(item, pos);

    if(success && this.items.length == 1) {
        this.current = item;
        this.startPlayback();
    }

    return success;
}

Playlist.prototype.addCachedMedia = function(data, callback) {
    var pos = "append";
    if(data.pos == "next") {
        if(!this.current)
            pos = "prepend";
        else
            pos = this.current.uid;
    }

    var it = this.makeItem(data.media);
    it.temp = data.temp;
    it.queueby = data.queueby;

    var pl = this;

    var action = {
        fn: function() {
            if(pl.add(it, pos))
                callback(false, it);
        },
        waiting: false
    };
    this.queueAction(action);
}

Playlist.prototype.addMedia = function(data, callback) {

    if(data.type == "yp") {
        this.addYouTubePlaylist(data, callback);
        return;
    }

    var pos = "append";
    if(data.pos == "next") {
        if(!this.current)
            pos = "prepend";
        else
            pos = this.current.uid;
    }

    var it = this.makeItem(null);
    var pl = this;
    var action = {
        fn: function() {
            if(pl.add(it, pos)) {
                callback(false, it);
            }
        },
        waiting: true
    };
    this.queueAction(action);

    InfoGetter.getMedia(data.id, data.type, function(err, media) {
        if(err) {
            action.expire = 0;
            callback(err, null);
            return;
        }

        if(data.maxlength && media.seconds > data.maxlength) {
            action.expire = 0;
            callback("Media is too long!", null);
            return;
        }

        it.media = media;
        it.temp = data.temp;
        it.queueby = data.queueby;
        action.waiting = false;
    });
}

Playlist.prototype.addMediaList = function(data, callback) {
    var start = false;
    if(data.pos == "next") {
        data.list = data.list.reverse();
        start = data.list[data.list.length - 1];
    }

    if(this.items.length != 0)
        start = false;

    var pl = this;
    for(var i = 0; i < data.list.length; i++) {
        var x = data.list[i];
        (function(i, x) {
            setTimeout(function() {
                x.queueby = data.queueby;
                x.pos = data.pos;
                if(start && x == start) {
                    pl.addMedia(x, function (err, item) {
                        if(err) {
                            callback(err, item);
                        }
                        else {
                            callback(err, item);
                            pl.current = item;
                            pl.startPlayback();
                        }
                    });
                }
                else {
                    pl.addMedia(x, callback);
                }
            }, 500 * i);
        })(i, x);
    }
}

Playlist.prototype.addYouTubePlaylist = function(data, callback) {
    var pos = "append";
    if(data.pos == "next") {
        if(!this.current)
            pos = "prepend";
        else
            pos = this.current.uid;
    }

    var pl = this;
    InfoGetter.getMedia(data.id, data.type, function(err, vids) {
        if(err) {
            callback(err, null);
            return;
        }

        vids.forEach(function(media) {
            var it = pl.makeItem(media);
            it.temp = data.temp;
            it.queueby = data.queueby;
            pl.queueAction({
                fn: function() {
                    if(pl.add(it, pos))
                        callback(false, it);
                },
            });
        });
    });
}

Playlist.prototype.remove = function(uid, callback) {
    var pl = this;
    this.queueAction({
        fn: function() {
            var item = pl.items.find(uid);
            if(pl.items.remove(uid)) {
                if(item == pl.current)
                    pl._next();
                if(callback)
                    callback();
            }
        },
        waiting: false
    });
}

Playlist.prototype.move = function(from, after, callback) {
    var pl = this;
    this.queueAction({
        fn: function() {
            pl._move(from, after, callback);
        },
        waiting: false
    });
}

Playlist.prototype._move = function(from, after, callback) {
    var it = this.items.find(from);
    if(!this.items.remove(from))
        return;

    if(after === "prepend") {
        if(!this.items.prepend(it))
            return;
    }

    else if(after === "append") {
        if(!this.items.append(it))
            return;
    }

    else if(!this.items.insertAfter(it, after))
        return;

    callback();
}

Playlist.prototype.next = function() {
    if(!this.current)
        return;

    var it = this.current;
    this._next();

    if(it.temp) {
        var pl = this;
        this.remove(it.uid, function() {
            pl.on("remove")(it);
        });
    }

    return this.current;
}

Playlist.prototype._next = function() {
    if(!this.current)
        return;
    this.current = this.current.next;
    if(this.current === null && this.items.first !== null)
        this.current = this.items.first;

    if(this.current) {
        this.startPlayback();
    }
}

Playlist.prototype.jump = function(uid) {
    if(!this.current)
        return false;

    var jmp = this.items.find(uid);
    if(!jmp)
        return false;

    var it = this.current;

    this.current = jmp;

    if(this.current) {
        this.startPlayback();
    }

    if(it.temp) {
        var pl = this;
        this.remove(it.uid, function () {
            pl.on("remove")(it);
        });
    }

    return this.current;
}

Playlist.prototype.clear = function() {
    this.items.clear();
    this.next_uid = 0;
    this.current = null;
    clearInterval(this._leadInterval);
}

Playlist.prototype.lead = function(lead) {
    this.leading = lead;
    var pl = this;
    if(!this.leading && this._leadInterval) {
        clearInterval(this._leadInterval);
        this._leadInterval = false;
    }
    else if(this.leading && !this._leadInterval) {
        this._leadInterval = setInterval(function() {
            pl._leadLoop();
        }, 1000);
    }
}

Playlist.prototype.startPlayback = function(time) {
    if(!this.current || !this.current.media)
        return false;
    this.current.media.paused = false;
    this.current.media.currentTime = time || -1;
    var pl = this;
    if(this._leadInterval) {
        clearInterval(this._leadInterval);
        this._leadInterval = false;
    }
    this.on("changeMedia")(this.current.media);
    if(this.leading && !isLive(this.current.media.type)) {
        this._lastUpdate = Date.now();
        this._leadInterval = setInterval(function() {
            pl._leadLoop();
        }, 1000);
    }
}

function isLive(type) {
    return type == "li" // Livestream.com
        || type == "tw" // Twitch.tv
        || type == "jt" // Justin.tv
        || type == "rt" // RTMP
        || type == "jw" // JWPlayer
        || type == "us" // Ustream.tv
        || type == "im";// Imgur album
}

const UPDATE_INTERVAL = 5;

Playlist.prototype._leadLoop = function() {
    if(this.current == null)
        return;

    this.current.media.currentTime += (Date.now() - this._lastUpdate) / 1000.0;
    this._lastUpdate = Date.now();
    this._counter++;

    if(this.current.media.currentTime >= this.current.media.seconds + 2) {
        this.next();
    }
    else if(this._counter % UPDATE_INTERVAL == 0) {
        this.on("mediaUpdate")(this.current.media);
    }
}

module.exports = Playlist;