const async = require('async'),
	Bzip2 = require('compressjs').Bzip2;

class Valve extends require('./core') {
	constructor() {
		super();

		this.options.port = 27015;
		
		// legacy goldsrc info response -- basically not used by ANYTHING now,
		// as most (all?) goldsrc servers respond with the source info reponse
		// delete in a few years if nothing ends up using it anymore
		this.goldsrcInfo = false;
		
		// unfortunately, the split format from goldsrc is still around, but we
		// can detect that during the query
		this.goldsrcSplits = false;

		// some mods require a challenge, but don't provide them in the new format
		// at all, use the old dedicated challenge query if needed
		this.legacyChallenge = false;
		
		// cs:go provides an annoying additional bot that looks exactly like a player,
		// but is always named "Max Players"
		this.isCsGo = false;
		
		// 2006 engines don't pass packet switching size in split packet header
		// while all others do, this need is detected automatically
		this._skipSizeInSplitHeader = false;

		this._challenge = '';
	}

	run(state) {
		async.series([
			(c) => { this.queryInfo(state,c); },
			(c) => { this.queryChallenge(state,c); },
			(c) => { this.queryPlayers(state,c); },
			(c) => { this.queryRules(state,c); },
			(c) => { this.finish(state); }
		]);
	}

	queryInfo(state,c) {
		this.sendPacket(
			0x54,false,'Source Engine Query\0',
			this.goldsrcInfo ? 0x6D : 0x49,
			(b) => {
                const reader = this.reader(b);
				
				if(this.goldsrcInfo) state.raw.address = reader.string();
				else state.raw.protocol = reader.uint(1);

				state.name = reader.string();
				state.map = reader.string();
				state.raw.folder = reader.string();
				state.raw.game = reader.string();
				state.raw.steamappid = reader.uint(2);
				state.raw.numplayers = reader.uint(1);
				state.maxplayers = reader.uint(1);

				if(this.goldsrcInfo) state.raw.protocol = reader.uint(1);
				else state.raw.numbots = reader.uint(1);

				state.raw.listentype = reader.uint(1);
				state.raw.environment = reader.uint(1);
				if(!this.goldsrcInfo) {
					state.raw.listentype = String.fromCharCode(state.raw.listentype);
					state.raw.environment = String.fromCharCode(state.raw.environment);
				}

				state.password = !!reader.uint(1);
				if(this.goldsrcInfo) {
					state.raw.ismod = reader.uint(1);
					if(state.raw.ismod) {
						state.raw.modlink = reader.string();
						state.raw.moddownload = reader.string();
						reader.skip(1);
						state.raw.modversion = reader.uint(4);
						state.raw.modsize = reader.uint(4);
						state.raw.modtype = reader.uint(1);
						state.raw.moddll = reader.uint(1);
					}
				}
				state.raw.secure = reader.uint(1);

				if(this.goldsrcInfo) {
					state.raw.numbots = reader.uint(1);
				} else {
					if(state.raw.folder === 'ship') {
						state.raw.shipmode = reader.uint(1);
						state.raw.shipwitnesses = reader.uint(1);
						state.raw.shipduration = reader.uint(1);
					}
					state.raw.version = reader.string();
                    const extraFlag = reader.uint(1);
					if(extraFlag & 0x80) state.raw.port = reader.uint(2);
					if(extraFlag & 0x10) state.raw.steamid = reader.uint(8);
					if(extraFlag & 0x40) {
						state.raw.sourcetvport = reader.uint(2);
						state.raw.sourcetvname = reader.string();
					}
					if(extraFlag & 0x20) state.raw.tags = reader.string();
					if(extraFlag & 0x01) state.raw.gameid = reader.uint(8);
				}

				// from https://developer.valvesoftware.com/wiki/Server_queries
				if(
					state.raw.protocol === 7 && (
						state.raw.steamappid === 215
						|| state.raw.steamappid === 17550
						|| state.raw.steamappid === 17700
						|| state.raw.steamappid === 240
					)
				) {
					this._skipSizeInSplitHeader = true;
				}
				if(this.debug) {
					console.log("STEAM APPID: "+state.raw.steamappid);
					console.log("PROTOCOL: "+state.raw.protocol);
				}
				if(state.raw.protocol === 48) {
					if(this.debug) console.log("GOLDSRC DETECTED - USING MODIFIED SPLIT FORMAT");
					this.goldsrcSplits = true;
				}

				c();
			}
		);
	}

	queryChallenge(state,c) {
		if(this.legacyChallenge) {
			this.sendPacket(0x57,false,false,0x41,(b) => {
				// sendPacket will catch the response packet and
				// save the challenge for us
				c();
			});
		} else {
			c();
		}
	}

	queryPlayers(state,c) {
		this.sendPacket(0x55,true,false,0x44,(b) => {
            const reader = this.reader(b);
            const num = reader.uint(1);
			for(let i = 0; i < num; i++) {
				reader.skip(1);
                const name = reader.string();
                const score = reader.int(4);
                const time = reader.float();

				if(this.debug) console.log("Found player: "+name+" "+score+" "+time);

				// connecting players don't count as players.
				if(!name) continue;

				(time === -1 ? state.bots : state.players).push({
					name:name, score:score, time:time
				});
			}

			if(this.isCsGo && state.players.length === 1 && state.players[0].name === 'Max Players') {
				if(this.debug) console.log("CSGO server using limited player details");
				state.players = [];
				for(let i = 0; i < state.raw.numplayers; i++) {
					state.players.push({});
				}
			}
			
			// if we didn't find the bots, iterate
			// through and guess which ones they are
			if(!state.bots.length && state.raw.numbots) {
                let maxTime = 0;
				for (const player of state.players) {
					maxTime = Math.max(player.time,maxTime);
				}
				for(let i = 0; i < state.players.length; i++) {
					const player = state.players[i];
					if(state.bots.length >= state.raw.numbots) continue;
					if(player.time !== maxTime) continue;
					state.bots.push(player);
					state.players.splice(i, 1);
					i--;
				}
			}

			c();
		});
	}

	queryRules(state,c) {
		this.sendPacket(0x56,true,false,0x45,(b) => {
            const reader = this.reader(b);
            const num = reader.uint(2);
			state.raw.rules = {};
			for(let i = 0; i < num; i++) {
                const key = reader.string();
                const value = reader.string();
				state.raw.rules[key] = value;
			}
			c();
		}, () => {
			// no rules were returned after timeout --
			// the server probably has them disabled
			// ignore the timeout
			c();
			return true;
		});
	}

	sendPacket(type,sendChallenge,payload,expect,callback,ontimeout) {
		const packetStorage = {};

        const receivedFull = (reader) => {
            const type = reader.uint(1);

            if(type === 0x41) {
                if(this.debug) console.log('Received challenge key');
                if(this._challenge) return this.fatal('Received more than one challenge key');
                this._challenge = reader.uint(4);

                if(sendChallenge) {
                    if(this.debug) console.log('Restarting query');
                    send();
                    return true;
                }
            }

            if(this.debug) console.log("Received "+type.toString(16)+" expected "+expect.toString(16));
            if(type !== expect) return;
            callback(reader.rest());
            return true;
        };

        const receivedOne = (buffer) => {
            const reader = this.reader(buffer);

            const header = reader.int(4);
            if(header === -1) {
                // full package
                if(this.debug) console.log("Received full packet");
                return receivedFull(reader);
            }
            if(header === -2) {
                // partial package
                const uid = reader.uint(4);
                if(!(uid in packetStorage)) packetStorage[uid] = {};
                const packets = packetStorage[uid];

                let bzip = false;
                if(!this.goldsrcSplits && uid & 0x80000000) bzip = true;

                let packetNum,payload,numPackets;
                if(this.goldsrcSplits) {
                    packetNum = reader.uint(1);
                    numPackets = packetNum & 0x0f;
                    packetNum = (packetNum & 0xf0) >> 4;
                    payload = reader.rest();
                } else {
                    numPackets = reader.uint(1);
                    packetNum = reader.uint(1);
                    if(!this._skipSizeInSplitHeader) reader.skip(2);
                    if(packetNum === 0 && bzip) reader.skip(8);
                    payload = reader.rest();
                }

                packets[packetNum] = payload;

                if(this.debug) {
                    console.log("Received partial packet uid:"+uid+" num:"+packetNum);
                    console.log("Received "+Object.keys(packets).length+'/'+numPackets+" packets for this UID");
                }

                if(Object.keys(packets).length !== numPackets) return;

                // assemble the parts
                const list = [];
                for(let i = 0; i < numPackets; i++) {
                    if(!(i in packets)) {
                        this.fatal('Missing packet #'+i);
                        return true;
                    }
                    list.push(packets[i]);
                }

                let assembled = Buffer.concat(list);
                if(bzip) {
                    if(this.debug) console.log("BZIP DETECTED - Extracing packet...");
                    try {
                        assembled = Buffer.from(Bzip2.decompressFile(assembled));
                    } catch(e) {
                        this.fatal('Invalid bzip packet');
                        return true;
                    }
                }
                const assembledReader = this.reader(assembled);
                assembledReader.skip(4); // header
                return receivedFull(assembledReader);
            }
        };

		const send = (c) => {
			if(typeof payload === 'string') payload = Buffer.from(payload,'binary');
            const challengeLength = sendChallenge ? 4 : 0;
            const payloadLength = payload ? payload.length : 0;

            const b = Buffer.alloc(5 + challengeLength + payloadLength);
			b.writeInt32LE(-1, 0);
			b.writeUInt8(type, 4);
			
			if(sendChallenge) {
                let challenge = this._challenge;
				if(!challenge) challenge = 0xffffffff;
				if(this.byteorder === 'le') b.writeUInt32LE(challenge, 5);
				else b.writeUInt32BE(challenge, 5);
			}
			if(payloadLength) payload.copy(b, 5+challengeLength);

			this.udpSend(b,receivedOne,ontimeout);
		};

        send();
	}
}

module.exports = Valve;