use bufio;
use fmt;
use net;
use net::tcp;
use net::ip;
use io;
use os;
use fs;
use strings;
use time;
use time::date;
use time::chrono;
use unix::poll;
use drawing;
use drawing::{pos};
use packet_reader;
use bytes;


def PORT: u16 = 41460;

type conn = net::socket;

def CHUNKSIZE = 512;

export fn main() void = {
	// create 4 pictures. later we will have more pictures
	// but for now there are just 4, and they are at fixed positions
	const offs: [_]pos = [
		(0,0), (0,CHUNKSIZE), (CHUNKSIZE,0), (CHUNKSIZE,CHUNKSIZE),
	];

	let pictures: []drawing::picture = alloc([],len(offs));
	for (let i = 0z; i < len(offs); i +=1){
		append(pictures, load_picture_from_file(offs[i])!);
	};


	const listener = match(tcp::listen(ip::ANY_V4, PORT, tcp::reuseaddr)) {
	case let err: net::error =>
		fmt::fatalf(net::strerror(err));
	case let sock: net::socket =>
		yield sock;
	};

	loop(listener, pictures);
};

def save_interval = 20 * time::SECOND;

// caller should free return value
fn filename_from_world_pos(pos: pos) str =
	fmt::asprintf("./c.{}.{}.ppm",pos.0,pos.1);

fn save_world(pictures: []drawing::picture) void = {
	fmt::printfln("saving world!")!;
	for (const pic &.. pictures) {
		const filename = filename_from_world_pos(pic.world_pos);
		fmt::printfln("\t-> {}",filename)!;
		defer free(filename);
		const mode = fs::mode::USER_RW | fs::mode::GROUP_RW;
		const file = os::create(filename, mode)!;
		defer {
			fmt::printfln("\t. {}",filename)!;
			io::close(file)!;
		};

		const header = fmt::asprintf("P6\n{} {}\n{}\n", pic.w, pic.h, 255);
		defer free(header);
		io::writeall(file, strings::toutf8(header))!;

		let buf: []u8 = alloc([0...],3*pic.w*pic.h);
		defer free(buf);
		for (let i = 0z; i < pic.w * pic.h; i += 1) {
			const px = pic.d[i];
			buf[3*i  ] = ((px>>16)&0xff): u8;
			buf[3*i+1] = ((px>>8) &0xff): u8;
			buf[3*i+2] = ((px)    &0xff): u8;
		};
		io::writeall(file, buf)!;
	};
		
};

type bad_header = !void;
fn load_picture_from_file(world_pos: pos) (drawing::picture | fs::error | bad_header) = {
	const filename = filename_from_world_pos(world_pos);
	defer free(filename);
	const file = os::open(filename)?;
	fmt::printfln("reading from {}",filename)!;
	defer {
		fmt::printfln("closing {}",filename)!;
		match (io::close(file)) {
			case let err: io::error => fmt::println("error",io::strerror(err))!;
			case => yield;
		};
	};

	const header = fmt::asprintf("P6\n{} {}\n{}\n",CHUNKSIZE,CHUNKSIZE,255);
	defer free(header);
	const header_bytes = strings::toutf8(header);
	let header_buf: []u8 = alloc([0...],len(header_bytes));
	defer free(header_buf);
	io::readall(file, header_buf)?;
	if (!bytes::equal(header_buf, header_bytes)) return bad_header;

	let file_buf: []u8 = alloc([0...], 3*CHUNKSIZE*CHUNKSIZE);
	defer free(file_buf);
	io::readall(file, file_buf)?;
	let picture_buf: []u32 = alloc([0...], CHUNKSIZE*CHUNKSIZE);
	for (let i = 0z; i < len(picture_buf); i += 1) {
		picture_buf[i] = (file_buf[3*i]:u32<<16)
						|(file_buf[3*i+1]:u32<<8)
						|(file_buf[3*i+2]:u32);
	};
	return drawing::picture {
		w = CHUNKSIZE,
		h = CHUNKSIZE,
		d = picture_buf: *[*]u32,
		world_pos = world_pos,
	};
};







fn loop(listener: net::socket, pictures: []drawing::picture) void = {
	// pollfds[0] is the listener
	// pollfds[n>0] corresponds to packet_readers[n-1]
	let pollfds: []poll::pollfd = alloc([ poll::pollfd {
		fd = listener, events = poll::event::POLLIN, revents = 0
	}]);
	let packet_readers: []packet_reader::packet_reader = [];


	let now = time::now(time::clock::MONOTONIC);
	let next = time::add(now, save_interval);
	save_world(pictures);

	for (true) {
		fmt::println("poll.")!;
		const timeout = time::diff(now, next);
		poll::poll(pollfds, timeout)!;

		now = time::now(time::clock::MONOTONIC);
		if (time::compare(now, next) >= 0) {
			save_world(pictures);
			next = time::add(now, save_interval);
		};

		if (0 != pollfds[0].revents & poll::event::POLLIN) {
			fmt::println("new conn")!;
			const new_conn = tcp::accept(pollfds[0].fd)!;
			fmt::println("a")!;
			append(pollfds, poll::pollfd {
				fd = new_conn,
				events = poll::event::POLLIN, revents = 0
			});
			append(packet_readers, packet_reader::new());
			fmt::printfln("there are now {},{} conns.",len(pollfds),len(packet_readers))!;
			send_world(new_conn, pictures)!;
		};
		for (let connidx = 1z; connidx < len(pollfds); connidx += 1) {
			if (0 != pollfds[connidx].revents & poll::event::POLLIN) {
				match (packet_reader::read(&packet_readers[connidx-1], pollfds[connidx].fd)) {
				case void =>
					for (const packet => packet_reader::next(&packet_readers[connidx-1])!) {
						handle_packet(pictures, pollfds, packet, connidx);
					};
				case let err: io::error =>
					fmt::printfln("#{} error: {}",connidx,io::strerror(err))!;
					delete(pollfds[connidx]);
					delete(packet_readers[connidx-1]);
					connidx -= 1;
				case io::EOF =>
					fmt::printfln("#{} disconnect",connidx)!;
					delete(pollfds[connidx]);
					delete(packet_readers[connidx-1]);
					connidx -= 1;
				};
			};
		};
	};
};

// ehh, really need a struct to put pollfds, pictures, connections... in
fn handle_packet(pictures: []drawing::picture, pollfds: []poll::pollfd, packet: packet_reader::packet, connidx: size) void = {
	match (packet) {
	case let op: packet_reader::packet_drawop =>
		const opc = op as drawing::op_circle;
		fmt::printfln("#{}: drawop  ({:+6},{:+6})",connidx,opc.0,opc.1)!;
		drawing::perform(pictures, opc);
		for (let otheridx = 1z; otheridx < len(pollfds); otheridx += 1) {
			if (otheridx == connidx) continue;
			fmt::printfln("\t -> #{}",otheridx)!;
			// ehhh shouldn't reserialize for each other thing
			packet_reader::send(pollfds[otheridx].fd, packet)!;
		};
	case =>
		abort("other packets not supported yet");
	};
};

fn send_world(conn: io::file, pictures: []drawing::picture) (void | io::error) = {
	for (const pic &.. pictures) {
		fmt::printfln("  sending {},{}",pic.world_pos.0, pic.world_pos.1)!;
		packet_reader::send(conn, packet_reader::packet_sendchunk {
			world_pos = pic.world_pos,
			chunk_data = pic.d[..pic.w*pic.h],
		})?;
	};

};