Funkin/source/funkin/play/song/SongData.hx

package funkin.play.song;

import flixel.util.typeLimit.OneOfTwo;
import funkin.play.song.ScriptedSong;
import funkin.util.assets.DataAssets;
import haxe.DynamicAccess;
import haxe.Json;
import openfl.utils.Assets;
import thx.semver.Version;

using StringTools;

/**
 * Contains utilities for loading and parsing stage data.
 */
class SongDataParser
{
	/**
	 * A list containing all the songs available to the game.
	 */
	static final songCache:Map<String, Song> = new Map<String, Song>();

	static final DEFAULT_SONG_ID = 'UNKNOWN';
	static final SONG_DATA_PATH = 'songs/';
	static final SONG_DATA_SUFFIX = '/metadata.json';

	/**
	 * Parses and preloads the game's song metadata and scripts when the game starts.
	 * 
	 * If you want to force song metadata to be reloaded, you can just call this function again.
	 */
	public static function loadSongCache():Void
	{
		clearSongCache();
		trace("[SONGDATA] Loading song cache...");

		//
		// SCRIPTED SONGS
		//
		var scriptedSongClassNames:Array<String> = ScriptedSong.listScriptClasses();
		trace('  Instantiating ${scriptedSongClassNames.length} scripted songs...');
		for (songCls in scriptedSongClassNames)
		{
			var song:Song = ScriptedSong.init(songCls, DEFAULT_SONG_ID);
			if (song != null)
			{
				trace('    Loaded scripted song: ${song.songId}');
				songCache.set(song.songId, song);
			}
			else
			{
				trace('    Failed to instantiate scripted song class: ${songCls}');
			}
		}

		//
		// UNSCRIPTED SONGS
		//
		var songIdList:Array<String> = DataAssets.listDataFilesInPath(SONG_DATA_PATH, SONG_DATA_SUFFIX);
		var unscriptedSongIds:Array<String> = songIdList.filter(function(songId:String):Bool
		{
			return !songCache.exists(songId);
		});
		trace('  Instantiating ${unscriptedSongIds.length} non-scripted songs...');
		for (songId in unscriptedSongIds)
		{
			try
			{
				var song = new Song(songId);
				if (song != null)
				{
					trace('    Loaded song data: ${song.songId}');
					songCache.set(song.songId, song);
				}
			}
			catch (e)
			{
				trace('    An error occurred while loading song data: ${songId}');
				trace(e);
				// Assume error was already logged.
				continue;
			}
		}

		trace('  Successfully loaded ${Lambda.count(songCache)} stages.');
	}

	/**
	 * Retrieves a particular song from the cache.
	 */
	public static function fetchSong(songId:String):Null<Song>
	{
		if (songCache.exists(songId))
		{
			var song:Song = songCache.get(songId);
			trace('[STAGEDATA] Successfully fetch song: ${songId}');
			return song;
		}
		else
		{
			trace('[STAGEDATA] Failed to fetch song, not found in cache: ${songId}');
			return null;
		}
	}

	static function clearSongCache():Void
	{
		if (songCache != null)
		{
			songCache.clear();
		}
	}

	public static function parseSongMetadata(songId:String):Array<SongMetadata>
	{
		var result:Array<SongMetadata> = [];

		var rawJson:String = loadSongMetadataFile(songId);
		var jsonData:Dynamic = null;
		try
		{
			jsonData = Json.parse(rawJson);
		}
		catch (e)
		{
		}

		var songMetadata:SongMetadata = SongMigrator.migrateSongMetadata(jsonData, songId);
		songMetadata = SongValidator.validateSongMetadata(songMetadata, songId);

		if (songMetadata == null)
		{
			return result;
		}

		result.push(songMetadata);

		var variations = songMetadata.playData.songVariations;

		for (variation in variations)
		{
			var variationRawJson:String = loadSongMetadataFile(songId, variation);
			var variationSongMetadata:SongMetadata = SongMigrator.migrateSongMetadata(variationRawJson, '${songId}_${variation}');
			variationSongMetadata = SongValidator.validateSongMetadata(variationSongMetadata, '${songId}_${variation}');
			if (variationSongMetadata != null)
			{
				variationSongMetadata.variation = variation;
				result.push(variationSongMetadata);
			}
		}

		return result;
	}

	static function loadSongMetadataFile(songPath:String, variation:String = ''):String
	{
		var songMetadataFilePath:String = (variation != '') ? Paths.json('$SONG_DATA_PATH$songPath/metadata-$variation') : Paths.json('$SONG_DATA_PATH$songPath/metadata');

		var rawJson:String = Assets.getText(songMetadataFilePath).trim();

		while (!rawJson.endsWith("}"))
		{
			rawJson = rawJson.substr(0, rawJson.length - 1);
		}

		return rawJson;
	}

	public static function parseSongChartData(songId:String, variation:String = ""):SongChartData
	{
		var rawJson:String = loadSongChartDataFile(songId, variation);
		var jsonData:Dynamic = null;
		try
		{
			jsonData = Json.parse(rawJson);
		}
		catch (e)
		{
		}

		var songChartData:SongChartData = SongMigrator.migrateSongChartData(jsonData, songId);
		songChartData = SongValidator.validateSongChartData(songChartData, songId);

		if (songChartData == null)
		{
			trace('Failed to validate song chart data: ${songId}');
			return null;
		}

		return songChartData;
	}

	static function loadSongChartDataFile(songPath:String, variation:String = ''):String
	{
		var songChartDataFilePath:String = (variation != '') ? Paths.json('$SONG_DATA_PATH$songPath/chart-$variation') : Paths.json('$SONG_DATA_PATH$songPath/chart');

		var rawJson:String = Assets.getText(songChartDataFilePath).trim();

		while (!rawJson.endsWith("}"))
		{
			rawJson = rawJson.substr(0, rawJson.length - 1);
		}

		return rawJson;
	}
}

typedef SongMetadata =
{
	/**
	 * A semantic versioning string for the song data format.
	 * 
	 */
	var version:Version;

	var songName:String;
	var artist:String;
	var timeFormat:SongTimeFormat;
	var divisions:Int;
	var timeChanges:Array<SongTimeChange>;
	var loop:Bool;
	var playData:SongPlayData;
	var generatedBy:String;

	/**
	 * Defaults to ''. Populated later.
	 */
	var variation:String;
};

typedef SongPlayData =
{
	var songVariations:Array<String>;
	var difficulties:Array<String>;

	/**
	 * Keys are the player characters and the values give info on what opponent/GF/inst to use.
	 */
	var playableChars:DynamicAccess<SongPlayableChar>;

	var stage:String;
	var noteSkin:String;
}

typedef RawSongPlayableChar =
{
	var g:String;
	var o:String;
	var i:String;
}

abstract SongPlayableChar(RawSongPlayableChar)
{
	public function new(girlfriend:String, opponent:String, inst:String = "")
	{
		this = {
			g: girlfriend,
			o: opponent,
			i: inst
		};
	}

	public var girlfriend(get, set):String;

	public function get_girlfriend():String
	{
		return this.g;
	}

	public function set_girlfriend(value:String):String
	{
		return this.g = value;
	}

	public var opponent(get, set):String;

	public function get_opponent():String
	{
		return this.o;
	}

	public function set_opponent(value:String):String
	{
		return this.o = value;
	}

	public var inst(get, set):String;

	public function get_inst():String
	{
		return this.i;
	}

	public function set_inst(value:String):String
	{
		return this.i = value;
	}
}

typedef SongChartData =
{
};

typedef RawSongTimeChange =
{
	/**
	 * Timestamp in specified `timeFormat`.
	 */
	var t:Float;

	/**
	 * Time in beats (int). The game will calculate further beat values based on this one,
	 * so it can do it in a simple linear fashion.
	 */
	var b:Int;

	/**
	 * Quarter notes per minute (float). Cannot be empty in the first element of the list,
	 * but otherwise it's optional, and defaults to the value of the previous element.
	 */
	var bpm:Float;

	/**
	 * Time signature numerator (int). Optional, defaults to 4.
	 */
	var n:Int;

	/**
	 * Time signature denominator (int). Optional, defaults to 4. Should only ever be a power of two.
	 */
	var d:Int;

	/**
	 * Beat tuplets (Array<int> or int). This defines how many steps each beat is divided into.
	 * It can either be an array of length `n` (see above) or a single integer number.
	 * Optional, defaults to `[4]`.
	 */
	var bt:OneOfTwo<Int, Array<Int>>;
}

/**
 * Add aliases to the minimalized property names of the typedef,
 * to improve readability.
 */
abstract SongTimeChange(RawSongTimeChange)
{
	public function new(timeStamp:Float, beatTime:Int, bpm:Float, timeSignatureNum:Int = 4, timeSignatureDen:Int = 4, beatTuplets:Array<Int>)
	{
		this = {
			t: timeStamp,
			b: beatTime,
			bpm: bpm,
			n: timeSignatureNum,
			d: timeSignatureDen,
			bt: beatTuplets,
		}
	}

	public var timeStamp(get, set):Float;

	public function get_timeStamp():Float
	{
		return this.t;
	}

	public function set_timeStamp(value:Float):Float
	{
		return this.t = value;
	}

	public var beatTime(get, set):Int;

	public function get_beatTime():Int
	{
		return this.b;
	}

	public function set_beatTime(value:Int):Int
	{
		return this.b = value;
	}

	public var bpm(get, set):Float;

	public function get_bpm():Float
	{
		return this.bpm;
	}

	public function set_bpm(value:Float):Float
	{
		return this.bpm = value;
	}

	public var timeSignatureNum(get, set):Int;

	public function get_timeSignatureNum():Int
	{
		return this.n;
	}

	public function set_timeSignatureNum(value:Int):Int
	{
		return this.n = value;
	}

	public var timeSignatureDen(get, set):Int;

	public function get_timeSignatureDen():Int
	{
		return this.d;
	}

	public function set_timeSignatureDen(value:Int):Int
	{
		return this.d = value;
	}

	public var beatTuplets(get, set):Array<Int>;

	public function get_beatTuplets():Array<Int>
	{
		if (Std.isOfType(this.bt, Int))
		{
			return [this.bt];
		}
		else
		{
			return this.bt;
		}
	}

	public function set_beatTuplets(value:Array<Int>):Array<Int>
	{
		return this.bt = value;
	}
}

enum abstract SongTimeFormat(String) from String to String
{
	var TICKS = "ticks";
	var FLOAT = "float";
	var MILLISECONDS = "ms";
}