open Unix

open Protocol

(* Description of data structures *)

type player = P1 | P2

type game_status =
	| TurnOf of player
	| Won of player
	| Tie
	| Eliminated of player

type game_proc_status =
	| Initializing of game_status
	| Running of game_status
	| Finished of game_status

type player_proc_status =
	| Loading
	| StandBy of float				(* temps restant sur toute la partie *)
	| Thinking of (float * float)	(* temps restant ; heure de début de réflexion *)
	| Saving
	| Dead

module type GAME = sig
	type game		(* mutable structure *)

	val name : string	(* ex: Morpion récursif *)
	val id : string		(* ex: morpion_rec *)

	val new_game : unit -> (game * game_status)

	val turn : game -> player -> string -> game_status
end

module type CORE = sig
	module G : GAME

	type game
	val p1 : game -> player_proc_status
	val p2 : game -> player_proc_status
	val s : game -> game_proc_status
	val g : game -> G.game

	val init : unit -> unit

	val handle_events : unit -> unit   (* is anything happening ? *)

	val add_rounds : unit -> unit      (* adds one game of everyone against everyone *)

	val scores : unit -> (string * int) list
	val games : unit -> game list

end

(* ****************************************** *)
(*           BEGIN IMPLEMENTATION             *)
(* ****************************************** *)

module C (G: GAME) : CORE = struct
	module G : GAME = G

	exception Eliminated_ex

	type player = {
		name: string;
		binary: string;
		dir: string;
		log_out: file_descr;
		mutable score: int;
	}

	type player_proc = {
		pid: int;
		p: player;
		i: in_channel;
		o: out_channel;
		mutable s: player_proc_status;
	}
	let send_m pp m =
		output_string pp.o (encode m ^ "\n");
		flush pp.o

	type game = {
		g: G.game;
		p1: player_proc;
		p2: player_proc;
		mutable s: game_proc_status;
	}
	let p1 g = g.p1.s
	let p2 g = g.p2.s
	let s g = g.s
	let g g = g.g

	let players = Hashtbl.create 12
	let planned_games = Queue.create ()
	let r_games = ref []

	(* program paremeters *)
	let par_games = ref 2				(* default: launch two simultaneous games *)
	let game_time = ref 30.0		(* default: 30 sec for each player *)

	let scores () =
		Hashtbl.fold (fun _ p l -> (p.name, p.score)::l) players []
	let games () = !r_games

	let init () =
		(* 1. PARSE ARGUMENTS *)
		let game_dir = ref "" in
		let args = [
			"-p", Arg.Set_int par_games, "How many games to run in parallel.";
			"-t", Arg.Set_float game_time,
				"Time (seconds) allotted to each player for a game."

		] in
		Arg.parse args (fun s -> game_dir := s)
			"Usage: judge <game_directory>";
		if !game_dir = "" then begin
			Format.eprintf "Error: no game directory specified.@.";
			exit 1
		end;
		let date =
			let d = Unix.gmtime (Unix.time ()) in
			Format.sprintf "%04d%02d%02d%02d%02d" d.tm_year d.tm_mon d.tm_mday d.tm_hour d.tm_min
		in

		(* 2. REDIRECT STDOUT TO LOG FILE *)
		let log_file = Filename.concat !game_dir (date^".log") in
		Format.printf "Juge for '%s' starting up...@." G.name;
		Format.printf "Redirecting standard output to '%s'.@." log_file;
		flush Pervasives.stdout;
		begin try
			let log_out = Unix.openfile log_file [O_APPEND; O_CREAT; O_WRONLY] 0o644 in
			dup2 log_out Unix.stdout
		with _ ->
			Format.eprintf "Could not open log output file.@.";
			exit 1
		end;
		Format.printf "Juge for '%s' starting up...@." G.name;
		Format.printf "Session: %s@." date;

		(* 3. LOAD PLAYER LIST *)
		Format.printf "Loading player list...@.";
		let fd = try opendir !game_dir with _ ->
			Format.printf "Could not open directory %s for listing.@." !game_dir;
			exit 1
		in
		let rec rd () =
			try let s = readdir fd in
				try
					let dir = Filename.concat !game_dir s in
					let b = Filename.concat dir "player" in
					let st =  Unix.stat b in
					if (st.st_kind = S_REG || st.st_kind = S_LNK)
							&& (st.st_perm land 0o100 <> 0) then begin
						Format.printf "- %s@." s;
						(* open log output for player *)
						let p_log_file = Filename.concat dir "stderr.log" in
						let p_log_out = Unix.openfile p_log_file [O_APPEND; O_CREAT; O_WRONLY] 0o644 in
						let f = Format.formatter_of_out_channel (out_channel_of_descr p_log_out) in
						Format.fprintf f "---- Begin session %s@." date;
						Hashtbl.add players	s
							{ name = s;
								binary = b;
								dir;
								log_out = p_log_out;
								score = 0; }
					end
				with _ -> ();	
				rd()
			with End_of_file -> ()
		in rd ()

	let add_rounds () =
		Hashtbl.iter
			(fun p _ -> Hashtbl.iter
				(fun q _ -> if p <> q then Queue.push (p, q) planned_games)
				players)
			players

	let handle_events () =
		(* 1. IF NOT ENOUGH MATCHES ARE RUNING, LAUNCH ONE *)
		while (List.length
				(List.filter (fun g -> match g.s with Finished _ -> false | _ -> true)
					!r_games)) < !par_games
			&& Queue.length planned_games > 0
		do
			let p1, p2 = Queue.pop planned_games in
			Format.printf "Launching match: %s vs. %s@." p1 p2;

			let open_c p =
				let f = Format.formatter_of_out_channel (out_channel_of_descr p.log_out) in
				Format.fprintf f "--- Begin game (%s vs. %s)@." p1 p2;
				let (j2p_i, j2p_o) = pipe () in
				let (p2j_i, p2j_o) = pipe () in
				let pid = fork() in
				if pid = 0 then begin
					chdir p.dir;
					dup2 j2p_i stdin;
					dup2 p2j_o stdout;
					dup2 p.log_out stderr;
					execv p.binary [| p.binary |];
				end;
				Format.printf "- %s: pid %d@." p.name pid;
				let pl = { pid; p;
					i = in_channel_of_descr p2j_i;
					o = out_channel_of_descr j2p_o;
					s = Loading } in
				send_m pl (Hello G.id);
				pl
			in
			let p1 = open_c (Hashtbl.find players p1) in
			let p2 = open_c (Hashtbl.find players p2) in
			let g, s = G.new_game () in
			let g = { p1; p2; g; s = Initializing s } in
			r_games := g::(!r_games)
		done;

		(* 2. LOOK IF ANYBODY IS TELLING US SOMETHING - IF SO, REACT
					(wait max. 0.01 sec) *)
		let in_fd = List.fold_left
			(fun l g -> match g.s with
				| Finished _ -> l
				| _ ->
					let l = match g.p1.s with
						| Dead -> l
						| _ -> (Unix.descr_of_in_channel g.p1.i)::l
					in match g.p2.s with
						| Dead -> l
						| _ -> (Unix.descr_of_in_channel g.p2.i)::l)
			[] !r_games
		in
		let in_fd, _, _ = select in_fd [] [] 0.01 in
		let do_fd fd =
			let g = List.find
				(fun g -> fd = Unix.descr_of_in_channel g.p1.i
						|| fd = Unix.descr_of_in_channel g.p2.i)
				!r_games
			in
			let pi = if Unix.descr_of_in_channel g.p1.i = fd then P1 else P2 in
			let p = match pi with P1 -> g.p1 | P2 -> g.p2 in
			let op = match pi with P1 -> g.p2 | P2 -> g.p1 in
			begin try match decode (input_line p.i), p.s with
			| Hello x, Loading when x = G.id ->
				p.s <- StandBy !game_time;
				if op.s <> Loading then begin
					match g.s, g.p1.s, g.p2.s with
					| Initializing (TurnOf P1), StandBy t, _ ->
						send_m g.p1 (YourTurn t);
						g.p1.s <- Thinking (t, Unix.time());
						g.s <- Running (TurnOf P1)
					| Initializing (TurnOf P2), _, StandBy t ->
						send_m g.p2 (YourTurn t);
						g.p2.s <- Thinking (t, Unix.time());
						g.s <- Running (TurnOf P2)
					| _ -> assert false
				end
			| Play act, Thinking (time, beg_r) ->
				let end_r = Unix.time () in
				let new_s = G.turn g.g pi act in
				begin match new_s with | Eliminated _ -> raise Eliminated_ex | _ -> () end;
				send_m p OK;
				send_m op (Play act);
				let finished = match new_s with
				| Tie ->
					send_m p Tie;
					send_m op Tie;
					Format.printf "%s vs. %s: tie!@." g.p1.p.name g.p2.p.name;
					true
				| Won x when x = pi ->
					send_m p YouWin;
					send_m op YouLose;
					Format.printf "%s vs. %s: %s wins!@." g.p1.p.name g.p2.p.name p.p.name;
					true
				| Won x ->
					send_m op YouWin;
					send_m p YouLose;
					Format.printf "%s vs. %s: %s wins!@." g.p1.p.name g.p2.p.name op.p.name;
					true
				| TurnOf _ -> false
				| Eliminated x -> assert false
				in
				if finished then begin
					p.s <- Saving;
					op.s <- Saving;
					g.s <- Finished new_s
				end else begin
					p.s <- StandBy (time -. (end_r -. beg_r));
					g.s <- Running new_s;
					match op.s with
						| StandBy t ->
							send_m op (YourTurn t);
							op.s <- Thinking (t, Unix.time())
						| _ -> assert false
				end
			| FairEnough, Saving ->
				kill p.pid 15;		(* 15 : sigterm *)
				p.s <- Dead
			| _ -> raise Eliminated_ex
			| exception _ -> raise Eliminated_ex
			with
			| Eliminated_ex ->
				send_m p Eliminated;
				send_m op YouWin;
				(* since process is not respecting the protocol, we cannot assume
					it is doing anything reasonable, so we kill it... *)
				kill p.pid 15;
				Format.printf "%s vs. %s: %s eliminated!@." g.p1.p.name g.p2.p.name p.p.name;
				p.s <- Dead;
				op.s <- Saving;
				g.s <- Finished (Eliminated pi)
			end;
		in List.iter do_fd in_fd
	
end