// 1. Go to: https://play.google.com/music/listen#/all
//
// 2. Open a developer console (F12 for Chrome). Paste the code below into the console.
//
// 3. All scraped songs are stored in the `allSongs` object and copied to the clipboard. I'd recommend saving this somewhere for future use.
//
// 4. If you would like the output in a text format, can call the songsToText() function. You can select a style and choose if only liked/thumbed up songs should be exported. The resulting list will then be pasted into the clipboard. Styles are `artist`, `artistalbum`, `artistsong`, `artistalbumsong`. Likedonly can be left out (defaults to false) or set to true, and will filter all songs with ratings greater or equal to 5. E.g: `songsToText("artistsong",true)` will export all liked songs.
//
// 5. You can then paste the data anywhere you like, for example http://www.ivyishere.org/ if you want to add the songs or albums to your Spotify account. To make Ivy recognize full albums, use the "artistalbum" style. For songs, use the "artistsong" style.

// originally answered here: http://webapps.stackexchange.com/a/73791/77056


var allsongs = [];
(function(){
    var intervalms = 1; //in ms
    var timeoutms = 3000; //in ms
    var retries = timeoutms / intervalms;
    var total = [];
    var seen = {};
    var topId = "";
    var interval = setInterval(function(){
        var songs = document.querySelectorAll("table.song-table tbody tr.song-row");
        if (songs.length > 0) {
            var currId = songs[0].getAttribute("data-id");
            if (currId == topId){ // page has not yet changed
                retries--;
                scrollDiv = document.querySelector("div#music-content");
                isAtBottom = scrollDiv.scrollTop == (scrollDiv.scrollHeight - scrollDiv.offsetHeight)
                if (isAtBottom || retries <= 0) {
                    clearInterval(interval); //done
                    copy(total);
                    allsongs = total;
                    console.log("Done! " + total.length + " songs copied to clipboard.");
                }
            } else {
                retries = timeoutms / intervalms;
                topId = currId;
                // read page
                for (var i = 0; i < songs.length; i++) {
                    var curr = {name: songs[i].childNodes[0].textContent,
                        length: songs[i].childNodes[1].textContent,
                        artist: songs[i].childNodes[2].textContent,
                        album: songs[i].childNodes[3].textContent,
                        plays: songs[i].childNodes[4].textContent,
                        rating: songs[i].childNodes[5].getAttribute("data-rating"),
                        id: songs[i].getAttribute("data-id")
                    }
                    if (!seen.hasOwnProperty(curr.id)){ // hashset
                        total.push(curr);
                        seen[curr.id] = true;
                    }
                }
                songs[songs.length-1].scrollIntoView(true); // go to next page
            }
        }
    }, intervalms);
}());


var songsToText = function(style, likedonly){
    var likedonly = likedonly || false; // defaults to false
    if (likedonly) {
        console.log("Only selecting liked songs");
    }
    var outText = ""
    var numEntries = 0;
    var seen = {};
    for (var i = 0; i < allsongs.length; i++) {
	var curr = ""
        if (!likedonly || (likedonly && allsongs[i].rating >= 5)){ 
	    if (style == "artist"){
	        curr = allsongs[i].artist;
	    } else if (style == "artistalbum"){
	        curr = allsongs[i].artist + " - " + allsongs[i].album;
	    } else if (style == "artistsong"){
	        curr = allsongs[i].artist + " - " + allsongs[i].song;
	    } else if (style == "artistalbumsong"){
	        curr = allsongs[i].artist + " - " + allsongs[i].album + " - " + allsongs[i].song;
	    } else {
	        console.log("style not defined");
	    }
            if (!seen.hasOwnProperty(curr)){ // hashset
                outText = outText + "\n" + curr;
                numEntries++;
                seen[curr] = true;
            }
	}
    }
    copy(outText);
    console.log("Done! " + numEntries + " lines copied to clipboard. Used " + numEntries + " songs out of " + allsongs.length + ".");
}