#define DEBUG
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "board.h"
#include "debug.h"
#include "engine.h"
#include "fbook.h"
#include "gtp.h"
#include "mq.h"
#include "uct/uct.h"
#include "version.h"
#include "timeinfo.h"

#define NO_REPLY (-2)

/* Sleep 5 seconds after a game ends to give time to kill the program. */
#define GAME_OVER_SLEEP 5

void
gtp_prefix(char prefix, int id)
{
	if (id == NO_REPLY) return;
	if (id >= 0)
		printf("%c%d ", prefix, id);
	else
		printf("%c ", prefix);
}

void
gtp_flush(void)
{
	putchar('\n');
	fflush(stdout);
}

void
gtp_output(char prefix, int id, va_list params)
{
	if (id == NO_REPLY) return;
	gtp_prefix(prefix, id);
	char *s;
	while ((s = va_arg(params, char *))) {
		fputs(s, stdout);
	}
	putchar('\n');
	gtp_flush();
}

void
gtp_reply(int id, ...)
{
	va_list params;
	va_start(params, id);
	gtp_output('=', id, params);
	va_end(params);
}

void
gtp_error(int id, ...)
{
	va_list params;
	va_start(params, id);
	gtp_output('?', id, params);
	va_end(params);
}

/* List of known gtp commands. The internal command pachi-genmoves is not exported,
 * it should only be used between master and slaves of the distributed engine. */
static char *known_commands =
	"protocol_version\n"
	"echo\n"
	"name\n"
	"version\n"
	"list_commands\n"
	"known_command\n"
	"quit\n"
	"boardsize\n"
	"clear_board\n"
	"kgs-game_over\n"
	"komi\n"
	"kgs-rules\n"
	"play\n"
	"genmove\n"
	"kgs-genmove_cleanup\n"
	"set_free_handicap\n"
	"place_free_handicap\n"
	"fixed_handicap\n"
	"final_score\n"
	"final_status_list\n"
	"undo\n"
	"pachi-evaluate\n"
	"pachi-result\n"
	"pachi-gentbook\n"
	"pachi-dumptbook\n"
	"kgs-chat\n"
	"time_left\n"
	"time_settings\n"
	"kgs-time_settings";


/* Return true if cmd is a valid gtp command. */
bool
gtp_is_valid(const char *cmd)
{
	if (!cmd || !*cmd) return false;
	const char *s = strcasestr(known_commands, cmd);
	if (!s) return false;
	if (s != known_commands && s[-1] != '\n') return false;

	int len = strlen(cmd);
	return s[len] == '\0' || s[len] == '\n';
}

/* XXX: THIS IS TOTALLY INSECURE!!!!
 * Even basic input checking is missing. */

enum parse_code
gtp_parse(struct board *board, struct engine *engine, struct time_info *ti, char *buf)
{
#define next_tok(to_) \
	to_ = next; \
	next = next + strcspn(next, " \t\r\n"); \
	if (*next) { \
		*next = 0; next++; \
		next += strspn(next, " \t\r\n"); \
	}

	if (strchr(buf, '#'))
		*strchr(buf, '#') = 0;

	char *cmd, *next = buf;
	next_tok(cmd);

	int id = -1;
	if (isdigit(*cmd)) {
		id = atoi(cmd);
		next_tok(cmd);
	}

	if (!*cmd)
		return P_OK;

	if (!strcasecmp(cmd, "protocol_version")) {
		gtp_reply(id, "2", NULL);
		return P_OK;

	} else if (!strcasecmp(cmd, "name")) {
		/* KGS hack */
		gtp_reply(id, "Pachi ", engine->name, NULL);
		return P_OK;

	} else if (!strcasecmp(cmd, "echo")) {
		gtp_reply(id, next, NULL);
		return P_OK;

	} else if (!strcasecmp(cmd, "version")) {
		gtp_reply(id, PACHI_VERSION, ": ", engine->comment, " Have a nice game!", NULL);
		return P_OK;

	} else if (!strcasecmp(cmd, "list_commands")) {
		gtp_reply(id, known_commands, NULL);
		return P_OK;

	} else if (!strcasecmp(cmd, "known_command")) {
		char *arg;
		next_tok(arg);
		if (gtp_is_valid(arg)) {
			gtp_reply(id, "true", NULL);
		} else {
			gtp_reply(id, "false", NULL);
		}
		return P_OK;
	}

	if (engine->notify && gtp_is_valid(cmd)) {
		char *reply;
		enum parse_code c = engine->notify(engine, board, id, cmd, next, &reply);
		if (c == P_NOREPLY) {
			id = NO_REPLY;
		} else if (c == P_DONE_OK) {
			gtp_reply(id, reply, NULL);
			return P_OK;
		} else if (c == P_DONE_ERROR) {
			gtp_error(id, reply, NULL);
			/* This is an internal error for the engine, but
			 * it is still OK from main's point of view. */
			return P_OK;
		} else if (c != P_OK) {
			return c;
		}
	}
	    
	if (!strcasecmp(cmd, "quit")) {
		gtp_reply(id, NULL);
		exit(0);

	} else if (!strcasecmp(cmd, "boardsize")) {
		char *arg;
		next_tok(arg);
		int size = atoi(arg);
		if (size < 1 || size > BOARD_MAX_SIZE) {
			gtp_error(id, "illegal board size", NULL);
			return P_OK;
		}
		board_resize(board, size);
		board_clear(board);
		gtp_reply(id, NULL);
		return P_ENGINE_RESET;

	} else if (!strcasecmp(cmd, "clear_board")) {
		board_clear(board);
		if (DEBUGL(3) && debug_boardprint)
			board_print(board, stderr);
		gtp_reply(id, NULL);
		return P_ENGINE_RESET;

	} else if (!strcasecmp(cmd, "kgs-game_over")) {
		/* The game may not be really over, just adjourned.
		 * Do not clear the board to avoid illegal moves
		 * if the game is resumed immediately after. KGS
		 * may start directly with genmove on resumption. */
		if (DEBUGL(1)) {
			fprintf(stderr, "game is over\n");
			fflush(stderr);
		}
		/* Sleep before replying, so that kgs doesn't
		 * start another game immediately. */
		sleep(GAME_OVER_SLEEP);
		gtp_reply(id, NULL);

	} else if (!strcasecmp(cmd, "komi")) {
		char *arg;
		next_tok(arg);
		sscanf(arg, PRIfloating, &board->komi);

		if (DEBUGL(3) && debug_boardprint)
			board_print(board, stderr);
		gtp_reply(id, NULL);

	} else if (!strcasecmp(cmd, "kgs-rules")) {
		char *arg;
		next_tok(arg);
		if (!board_set_rules(board, arg)) {
			gtp_error(id, "unknown rules", NULL);
			return P_OK;
		}
		gtp_reply(id, NULL);

	} else if (!strcasecmp(cmd, "play")) {
		struct move m;

		char *arg;
		next_tok(arg);
		m.color = str2stone(arg);
		next_tok(arg);
		coord_t *c = str2coord(arg, board_size(board));
		m.coord = *c; coord_done(c);
		next_tok(arg);
		char *enginearg = arg;
		char *reply = NULL;

		if (DEBUGL(5))
			fprintf(stderr, "got move %d,%d,%d\n", m.color, coord_x(m.coord, board), coord_y(m.coord, board));

		// This is where kgs starts the timer, not at genmove!
		time_start_timer(&ti[stone_other(m.color)]);

		if (engine->notify_play)
			reply = engine->notify_play(engine, board, &m, enginearg);
		if (board_play(board, &m) < 0) {
			if (DEBUGL(0)) {
				fprintf(stderr, "! ILLEGAL MOVE %d,%d,%d\n", m.color, coord_x(m.coord, board), coord_y(m.coord, board));
				board_print(board, stderr);
			}
			gtp_error(id, "illegal move", NULL);
		} else {
			if (DEBUGL(4) && debug_boardprint)
				board_print_custom(board, stderr, engine->printhook);
			gtp_reply(id, reply, NULL);
		}

	} else if (!strcasecmp(cmd, "genmove") || !strcasecmp(cmd, "kgs-genmove_cleanup")) {
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);
		coord_t *c = NULL;
		if (DEBUGL(2) && debug_boardprint)
			board_print_custom(board, stderr, engine->printhook);
		
		if (!ti[color].len.t.timer_start) {
			/* First game move. */
			time_start_timer(&ti[color]);
		}

		coord_t cf = pass;
		if (board->fbook)
			cf = fbook_check(board);
		if (!is_pass(cf)) {
			c = coord_copy(cf);
		} else {
			c = engine->genmove(engine, board, &ti[color], color, !strcasecmp(cmd, "kgs-genmove_cleanup"));
		}
		struct move m = { *c, color };
		if (board_play(board, &m) < 0) {
			fprintf(stderr, "Attempted to generate an illegal move: [%s, %s]\n", coord2sstr(m.coord, board), stone2str(m.color));
			abort();
		}
		char *str = coord2str(*c, board);
		if (DEBUGL(4))
			fprintf(stderr, "playing move %s\n", str);
		if (DEBUGL(1) && debug_boardprint) {
			board_print_custom(board, stderr, engine->printhook);
		}
		gtp_reply(id, str, NULL);
		free(str); coord_done(c);

		/* Account for spent time. If our GTP peer keeps our clock, this will
		 * be overriden by next time_left GTP command properly. */
		/* (XXX: Except if we pass to byoyomi and the peer doesn't, but that
		 * should be absolutely rare situation and we will just spend a little
		 * less time than we could on next few moves.) */
		if (ti[color].period != TT_NULL && ti[color].dim == TD_WALLTIME)
			time_sub(&ti[color], time_now() - ti[color].len.t.timer_start, true);

	} else if (!strcasecmp(cmd, "pachi-genmoves") || !strcasecmp(cmd, "pachi-genmoves_cleanup")) {
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);
		void *stats;
		int stats_size;

		char *reply = engine->genmoves(engine, board, &ti[color], color, next,
					       !strcasecmp(cmd, "pachi-genmoves_cleanup"),
					       &stats, &stats_size);
		if (!reply) {
			gtp_error(id, "genmoves error", NULL);
			return P_OK;
		}
		if (DEBUGL(3))
			fprintf(stderr, "proposing moves %s\n", reply);
		if (DEBUGL(4) && debug_boardprint)
			board_print_custom(board, stderr, engine->printhook);
		gtp_reply(id, reply, NULL);
		if (stats_size > 0) {
			double start = time_now();
			fwrite(stats, 1, stats_size, stdout);
			fflush(stdout);
			if (DEBUGVV(2))
				fprintf(stderr, "sent reply %d bytes in %.4fms\n",
					stats_size, (time_now() - start)*1000);
		}

	} else if (!strcasecmp(cmd, "set_free_handicap")) {
		struct move m;
		m.color = S_BLACK;

		char *arg;
		next_tok(arg);
		do {
			coord_t *c = str2coord(arg, board_size(board));
			m.coord = *c; coord_done(c);
			if (DEBUGL(4))
				fprintf(stderr, "setting handicap %d,%d\n", coord_x(m.coord, board), coord_y(m.coord, board));

			if (board_play(board, &m) < 0) {
				if (DEBUGL(0))
					fprintf(stderr, "! ILLEGAL MOVE %d,%d,%d\n", m.color, coord_x(m.coord, board), coord_y(m.coord, board));
				gtp_error(id, "illegal move", NULL);
			}
			board->handicap++;
			next_tok(arg);
		} while (*arg);
		if (DEBUGL(1) && debug_boardprint)
			board_print(board, stderr);
		gtp_reply(id, NULL);

	/* TODO: Engine should choose free handicap; however, it tends to take
	 * overly long to think it all out, and unless it's clever its
	 * handicap stones won't be of much help. ;-) */
	} else if (!strcasecmp(cmd, "place_free_handicap")
	          || !strcasecmp(cmd, "fixed_handicap")) {
		char *arg;
		next_tok(arg);
		int stones = atoi(arg);

		gtp_prefix('=', id);
		board_handicap(board, stones, id == NO_REPLY ? NULL : stdout);
		if (DEBUGL(1) && debug_boardprint)
			board_print(board, stderr);
		if (id == NO_REPLY) return P_OK;
		putchar('\n');
		gtp_flush();

	} else if (!strcasecmp(cmd, "final_score")) {
		struct move_queue q = { .moves = 0 };
		if (engine->dead_group_list)
			engine->dead_group_list(engine, board, &q);
		floating_t score = board_official_score(board, &q);
		char str[64];
		if (DEBUGL(1))
			fprintf(stderr, "counted score %.1f\n", score);
		if (score == 0) {
			gtp_reply(id, "0", NULL);
		} else if (score > 0) {
			snprintf(str, 64, "W+%.1f", score);
			gtp_reply(id, str, NULL);
		} else {
			snprintf(str, 64, "B+%.1f", -score);
			gtp_reply(id, str, NULL);
		}

	/* XXX: This is a huge hack. */
	} else if (!strcasecmp(cmd, "final_status_list")) {
		if (id == NO_REPLY) return P_OK;
		char *arg;
		next_tok(arg);
		struct move_queue q = { .moves = 0 };
		if (engine->dead_group_list)
			engine->dead_group_list(engine, board, &q);
		/* else we return empty list - i.e. engine not supporting
		 * this assumes all stones alive at the game end. */
		if (!strcasecmp(arg, "dead")) {
			gtp_prefix('=', id);
			for (unsigned int i = 0; i < q.moves; i++) {
				foreach_in_group(board, q.move[i]) {
					printf("%s ", coord2sstr(c, board));
				} foreach_in_group_end;
				putchar('\n');
			}
			if (!q.moves)
				putchar('\n');
			gtp_flush();
		} else if (!strcasecmp(arg, "seki") || !strcasecmp(arg, "alive")) {
			gtp_prefix('=', id);
			bool printed_group = false;
			foreach_point(board) { // foreach_group, effectively
				group_t g = group_at(board, c);
				if (!g || g != c) continue;

				for (unsigned int i = 0; i < q.moves; i++) {
					if (q.move[i] == g)
						goto next_group;
				}
				foreach_in_group(board, g) {
					printf("%s ", coord2sstr(c, board));
				} foreach_in_group_end;
				putchar('\n');
				printed_group = true;
next_group:;
			} foreach_point_end;
			if (!printed_group)
				putchar('\n');
			gtp_flush();
		} else {
			gtp_error(id, "illegal status specifier", NULL);
		}

	} else if (!strcasecmp(cmd, "undo")) {
		if (board_undo(board) < 0) {
			if (DEBUGL(1)) {
				fprintf(stderr, "undo on non-pass move %s\n", coord2sstr(board->last_move.coord, board));
				board_print(board, stderr);
			}
			gtp_error(id, "cannot undo", NULL);
			return P_OK;
		}
		char *reply = NULL;
		if (engine->undo)
			reply = engine->undo(engine, board);
		if (DEBUGL(3) && debug_boardprint)
			board_print(board, stderr);
		gtp_reply(id, reply, NULL);

	/* Custom commands for handling the tree opening tbook */
	} else if (!strcasecmp(cmd, "pachi-gentbook")) {
		/* Board must be initialized properly, as if for genmove;
		 * makes sense only as 'uct_gentbook b'. */
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);
		if (uct_gentbook(engine, board, &ti[color], color))
			gtp_reply(id, NULL);
		else
			gtp_error(id, "error generating tbook", NULL);

	} else if (!strcasecmp(cmd, "pachi-dumptbook")) {
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);
		uct_dumptbook(engine, board, color);
		gtp_reply(id, NULL);

	} else if (!strcasecmp(cmd, "pachi-evaluate")) {
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);

		if (!engine->evaluate) {
			gtp_error(id, "pachi-evaluate not supported by engine", NULL);
		} else {
			gtp_prefix('=', id);
			floating_t vals[board->flen];
			engine->evaluate(engine, board, &ti[color], vals, color);
			for (int i = 0; i < board->flen; i++) {
				if (!board_coord_in_symmetry(board, board->f[i])
				    || isnan(vals[i]) || vals[i] < 0.001)
					continue;
				printf("%s %.3f\n", coord2sstr(board->f[i], board), (double) vals[i]);
			}
			gtp_flush();
		}

	} else if (!strcasecmp(cmd, "pachi-result")) {
		/* More detailed result of the last genmove. */
		/* For UCT, the output format is: = color move playouts winrate dynkomi */
		char *reply = NULL;
		if (engine->result)
			reply = engine->result(engine, board);
		if (reply)
			gtp_reply(id, reply, NULL);
		else
			gtp_error(id, "unknown pachi-result command", NULL);

	} else if (!strcasecmp(cmd, "kgs-chat")) {
		char *loc;
		next_tok(loc);
		bool opponent = !strcasecmp(loc, "game");
		char *from;
		next_tok(from);
		char *msg = next;
		msg += strspn(msg, " \n\t");
		char *end = strchr(msg, '\n');
		if (end) *end = '\0';
		char *reply = NULL;
		if (engine->chat) {
			reply = engine->chat(engine, board, opponent, from, msg);
		}
		if (reply)
			gtp_reply(id, reply, NULL);
		else
			gtp_error(id, "unknown kgs-chat command", NULL);

	} else if (!strcasecmp(cmd, "time_left")) {
		char *arg;
		next_tok(arg);
		enum stone color = str2stone(arg);
		next_tok(arg);
		int time = atoi(arg);
		next_tok(arg);
		int stones = atoi(arg);
		if (!ti[color].ignore_gtp) {
			time_left(&ti[color], time, stones);
		} else {
			if (DEBUGL(2)) fprintf(stderr, "ignored time info\n");
		}

		gtp_reply(id, NULL);

	} else if (!strcasecmp(cmd, "time_settings") || !strcasecmp(cmd, "kgs-time_settings")) {
		char *time_system;
		char *arg;
		if (!strcasecmp(cmd, "kgs-time_settings")) {
			next_tok(time_system);
		} else {
			time_system = "canadian";
		}

		int main_time = 0, byoyomi_time = 0, byoyomi_stones = 0, byoyomi_periods = 0;
		if (!strcasecmp(time_system, "none")) {
			main_time = -1;
		} else if (!strcasecmp(time_system, "absolute")) {
			next_tok(arg);
			main_time = atoi(arg);
		} else if (!strcasecmp(time_system, "byoyomi")) {
			next_tok(arg);
			main_time = atoi(arg);
			next_tok(arg);
			byoyomi_time = atoi(arg);
			next_tok(arg);
			byoyomi_periods = atoi(arg);
		} else if (!strcasecmp(time_system, "canadian")) {
			next_tok(arg);
			main_time = atoi(arg);
			next_tok(arg);
			byoyomi_time = atoi(arg);
			next_tok(arg);
			byoyomi_stones = atoi(arg);
		}

		if (DEBUGL(1))
			fprintf(stderr, "time_settings %d %d/%d*%d\n",
				main_time, byoyomi_time, byoyomi_stones, byoyomi_periods);
		if (!ti[S_BLACK].ignore_gtp) {
			time_settings(&ti[S_BLACK], main_time, byoyomi_time, byoyomi_stones, byoyomi_periods);
			ti[S_WHITE] = ti[S_BLACK];
		} else {
			if (DEBUGL(1)) fprintf(stderr, "ignored time info\n");
		}

		gtp_reply(id, NULL);

	} else {
		gtp_error(id, "unknown command", NULL);
		return P_UNKNOWN_COMMAND;
	}
	return P_OK;

#undef next_tok
}