function OsuFile() {

}

var OSU = OsuFile.prototype;

const get_bpm = len => (1.0 / len * 60000.00);
const get_beat = bpm => 60000.00 / bpm;

const get_sv = inverse => 100.00 / (-1.0 * inverse);
const get_inverse = sv => (sv / 100.00) * -1.0;

OSU.LoadString = async function(contents) {
	const lines = contents.split(/(\n|\r|\f)+/).where(line => line && line.trim() != "");

	var stage = new Stage();
	stage.giveMany(lines);
	stage.commit();

	await this.LoadTokens(stage);
};

OSU.LoadTokens = async function(tokens) {
	const stages = {
		"General": new Stage(),
		"Editor": new Stage(),
		"Metadata": new Stage(),
		"Difficulty": new Stage(),
		"Events": new Stage(),
		"TimingPoints": new Stage(),
		"HitObjects": new Stage(),
	};

	var line;

	var group = null;

	this.errors = [];
	this.data = {};
	this.spec = {};

	this.futsuu(stages["General"]);
	this.han(stages["Editor"]);
	this.meta(stages["Metadata"]);
	this.muzukashisa(stages["Difficulty"]);
	this.jiken(stages["Events"]);
	this.keiji(stages["TimingPoints"]);
	this.maru(stages["HitObjects"]);
	while(line = await tokens.take()) {
		if(!this.version)
		{
			if(/^osu file format v\d+$/.test(line))
			{
				this.version = line.match(/\d+$/)[0];
			}
			else return ["no version present"];
			continue;
		}
		if(/^\/\//.test(line)) continue;
		if(line.trim() === "") continue;



		let new_Group = line.match(/^\[(\w+)\]$/i);
		console.log(new_Group);
		if(new_Group && new_Group[1]) {
			console.log("Setting new group `"+new_Group[1]+"' from old group "+group);
			if(group) {
				stages[group].commit();
			}

			group = new_Group[1];
			this.data[group] = {};
			stages[group].give(group);
			continue;
		}

		if(!group) continue;
		if(!stages[group]) return ["unknown group "+group];

		stages[group].give(line);
	}
	console.log("----END OF FILE");
	if(group)
		stages[group].commit();

	for(const key of Object.keys(stages))
	{
		stages[key].forceClose();
	}

	this.specialise();
	return this.errors;
};

/// --- Parsers --- ///

OSU.futsuu = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var data = this.data[group];
		var tok;
		while(tok = await tokens.take()) {

			var match = tok.match(/^(\w+):\s(.*)$/i);
			if(match && match[0])
			{
				data[match[1]] = match[2];
			}
			else this.errors.push("futsuu: parsing line `"+tok+"' failed.");
		}
	}
};

OSU.han = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var data = this.data[group];
		var tok;

		while(tok = await tokens.take()) {
			var match = tok.match(/^(\w+):\s(.*)$/i);
			if(match && match[0])
			{
				if(match[1] === "Bookmarks")
				{
					data[match[1]] = match[2].split(/,/);
				}
				else	data[match[1]] = match[2];
			}
			else this.errors.push("han: parsing line `"+tok+"' failed.");
		}
	}
};

OSU.meta = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var data = this.data[group];
		var tok;

		while(tok = await tokens.take()) {
			var match = tok.match(/^(\w+):\s?(.*)$/i);
			if(match && match[0])
			{
				if(match[1] === "Tags")
				{
					data[match[1]] = match[2].split(/\s/);
				}
				else	data[match[1]] = match[2];
			}
			else this.errors.push("meta: parsing line `"+tok+"' failed.");
		}
	}

};

OSU.muzukashisa = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var data = this.data[group];
		var tok;

		while(tok = await tokens.take()) {
			var match = tok.match(/^(\w+):\s?(.*)$/i);
			if(match && match[0])
			{
				data[match[1]] = match[2];
			}
			else this.errors.push("muzukashisa: parsing line `"+tok+"' failed.");
		}
	}

};

OSU.jiken = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var data = this.data[group];
		var tok;

		while(tok = await tokens.take()) {
			var match = tok.match(/^(\w+|\d+),.+$/i);
			
			if(match && match[0])
			{
				//convenience?
				const ar = JSON.parse("[" + tok + "]");
				data[match[1]] = {time: ar[1], params: ar.slice(2)};
			}
			else this.errors.push("jiken: parsing line `"+tok+"' failed");
		}
	}
};

OSU.keiji = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var _data = this.data[group] = [];
		var tok;

		while(tok = await tokens.take()) {
			var match = tok.match(/^(\d+),(-?\d+(?:\.\d+)?),(\d+),(\d+),(\d+),(\d+),([01]),(\d+)$/i);
			let data = {};	
			if(match && match[0])
			{
				data.time = match[1];
				data.beatLength = match[2];
				data.meter = match[3];
				data.sampleSet = match[4];
				data.sampleIndex = match[5];
				data.volume = match[6];
				data.uninherited = match[7] == "1";
				data.effects = match[8];
			}
			else this.errors.push("keiji: parsing line `"+tok+"' failed.");
			_data.push(data);
		}
	}

};

const BEZIER = 0;
const CENTRIPETAL_CATMULL_ROM = 1;
const LINEAR = 2;
const PERFECT_CIRCLE = 3;
const SLIDER_UNKNOWN = 4;

const parse_params = (params) => {
	const re_slider_1 = /^(B|C|L|P)\|(.+)/i; //slider type

	if(!params[0]) {
		//Is circle
		return {type: "circle"};
	}
	else if(re_slider_1 .test(params[0]))
	{
		//Is slider
		const type = params[0].match(re_slider_1)[1].il_switch({'B': BEZIER,
			'C': CENTRIPETAL_CATMULL_ROM,
			'L': LINEAR,
			'P': PERFECT_CIRCLE
		}, SLIDER_UNKNOWN); 
		const points = params[0].split(/\|/).slice(1).map(x=> x.split(/:/));
		const slides = params[1];
		const length = params[2];
		const edgeSounds = params[3].split(/\|/);
		const edgeSets = params[4].split(/\|/).map(x=> x.split(/:/));

		return {
			type: "slider",
			sliderType: type,
			points: points,
			slides: slides,
			length: length,
			edgeSounds: edgeSounds,
			edgeSets: edgeSets,
		};

	} else {
		//Spinner (or hold? TODO)
		return {type: "spinner", endTime: params[0]};
	}
};

OSU.maru = async function(tokens) {
	const group = await tokens.take();
	if(group) {
		var _data = this.data[group] = [];
		var tok;

		while(tok = await tokens.take()) {
			let data = {};
			var match = tok.match(/^(\d+),(\d+),(\d+),(\d+),(.+)$/i); //i honestly have no fucking idea what regex to get all these so we'll cheat
			if(match && match[0])
			{
				data.x = match[1];
				data.y = match[2];
				data.time = match[2];
				data.hitSound = match[3];
				
				//Parse params and sample
				if(/:i(?:.*\.wav)?$/.test(match[4]))
				{
					//Sample is there
					let param = match[4].split(/,/);
					data.hitSample = param.pop().split(/:/).where(/\d+/.test).associate([
						"normalSet",
						"additionalSet",
						"index",
						"volume",
						"filename",
					]);
					data.params = parse_params(param);
				}
				else {
					//No sample, rest is params
					data.params = parse_params(match[4].split(/,/));
					data.hitSample = {
						normalSet: "0",
						additionalSet: "0",
						index: "0",
						volume: "0",
					};
				}
				_data.push(data);
			}
			else this.errors.push("maru: parsing line `"+tok+"' failed.");

		}
	}
};

OSU.specialise = function() {
	this.spec.Background = this.data.Events[0].params[0];
};

/// --- End parsers --- ///


/// --- Begin Helpers --- ///

OSU.Fullname = function() {
	return this.data.Metadata.ArtistUnicode + " - "+this.data.Metadata.TitleUnicode+" ["+this.data.Metadata.Version+"]";
};

OSU.Shortname = function() {
	return this.data.Metadata.Version;
};

/// --- End helpers --- ///

OSU.okay = function() {
	return !!this.version && this.errors.length<1;
};

OsuFile.Unserialise = (json) => {

	if(typeof(json) === 'string') return OsuFile.Unserialise(JSON.parse(json));

	var osu = new OsuFile();
	osu.errors = [];
	osu.spec = {};
	osu.version = json.version;
	osu.data = json.data;

	osu.specialise();

	return osu;
};

OSU.serialise = function() {
	return {version: this.version, data: this.data};
};

OSU.toString = function() {
	return JSON.stringify(this.serialise());
};

OSU.hash = function() {
	if(this._hash) return this._hash;
	else
		return this._hash = forge_sha256(this.toString());
};

OSU.equals = function(...osu) {
	const hash = this.hash();
	console.log(hash);
	return osu.where(x=> x && x.hash() === hash).length == osu.length;
};