#include <stddef.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curses.h>
#include <signal.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdarg.h>

struct ut_state
{
	char tiles[9][9];
	char boards[3][3];
	int playBoard;
	char player;
	char host_player;
};
const struct ut_state ut_initial = {
		.boards = {0},
		.tiles = {0},
		.playBoard = -1,
		.player = 'X',
		.host_player = '\0',
	};

const char *HELP_TEXT = "\
Usage: uttt (--local | --host | --join)\n\
\n\
  --local  play non-network game\n\
  --host   host game at 127.0.0.1:6669\n\
  --join   join game at 127.0.0.1:6669\n\
";

const char *arg_local = "--local";
const char *arg_host = "--host";
const char *arg_join = "--join";

char ut_turn(char player)
{
	switch(player)
	{
		case 'X': return 'O';
		case 'O': return 'X';
		default: return '\0';
	}
}

int ut_random_player(char *player) {
	int random = open("/dev/urandom", O_RDONLY);
	if (read(random, player, 1) < 0) {return errno;}
	*player = *player % 2 == 0 ? 'X' : 'O';
	return 0;
}

#define T(r, c) (tiles[offset + stride * r + c])
char ut_winner(const char *tiles, int offset, int stride) {

	// whoreizontal wins
	for (int y = 0; y < 3; y++)
	{
		char tile = T(y, 0);
		if (tile == '\0') {continue;}
		if (tile == T(y, 1) && tile == T(y, 2)) {return tile;}
	}

	// vertical wins
	for (int x = 0; x < 3; x++)
	{
		char tile = T(0, x);
		if (tile == '\0') {continue;}
		if (tile == T(1, x) && tile == T(2, x)) {return tile;}
	}

	// diagonalz
	char tile = T(1, 1);
	if (tile != '\0')
	{
		if (tile == T(0, 0) && tile == T(2, 2)) {return tile;}
		if (tile == T(2, 0) && tile == T(0, 2)) {return tile;}
	}

	for(int y = 0; y < 3; y++)
	{
		for(int x = 0; x < 3; x++)
		{
			if(T(y, x) == '\0') {return '\0';} // in progress
		}
	}
	return ' '; // draw
}

int ut_move(struct ut_state *new_state, const struct ut_state *old_state, int row, int col)
{
	// bad move - out of bounds
	if(row < 0 || row >= 9 || col < 0 || col >= 9) {return 1;}

	// state->playBoard == -1 means all boards playable; otherwise only one board is playable
	if (old_state->playBoard != -1 && old_state->playBoard != 3 * (row / 3) + (col / 3)) {return 1;}

	// bad move - tile is occupied
	if(old_state->tiles[row][col] != '\0') {return 1;}

	// bad move - board is finished
	if(old_state->boards[row / 3][col / 3] != '\0') {return 1;}

	// copy old_state->{tiles,boards} to new_state->{tiles,boards}
	memmove(new_state->tiles, old_state->tiles, sizeof(old_state->tiles));
	memmove(new_state->boards, old_state->boards, sizeof(old_state->boards));

	// do move
	new_state->tiles[row][col] = old_state->player;
	new_state->boards[row / 3][col / 3] = ut_winner((char *)new_state->tiles, 27 * (row / 3) + 3 * (col / 3), 9);

	//  next play board - if next play board is not playable, play any board
	new_state->playBoard = new_state->boards[row % 3][col % 3] == '\0' ? 3 * (row % 3) + (col % 3) : -1;

	new_state->player = ut_turn(old_state->player);
	return 0;
}

void ut_drawBoard(const char *tiles, int offset, int stride, int iy, int ix, char winner, bool highlight)
{
	// 5x5 board display
	/*
	 * X|X|X
	 * -+-+-
	 * X|X|X
	 * -+-+-
	 * X|X|X
	*/
	for(int r = 0; r < 3; r++)
		for(int c = 0; c < 3; c++)
			mvaddch(iy + 2 * r, ix + 2 * c, T(r, c) != '\0' ? T(r, c) : ' ');
	//char info = winner != '\0' ? winner : highlight ? '*' : ' ';
	for(int r = 0; r < 3; r++)
		for(int c = 0; c < 2; c++)
			mvaddch(iy + 2 * r, ix + 2 * c + 1, winner != '\0' ? winner : '|');
	for(int r = 0; r < 2; r++)
		for(int c = 0; c < 3; c++)
			mvaddch(iy + 2 * r + 1, ix + 2 * c, winner != '\0' ? winner : '-');
	for(int r = 0; r < 2; r++)
		for(int c = 0; c < 2; c++)
			mvaddch(iy + 2 * r + 1, ix + 2 * c + 1, winner != '\0' ? winner : highlight ? '*' : '+');
}

void ut_draw(const struct ut_state *state)
{
	for(int r = 0; r < 3; r++)
		for(int c = 0; c < 3; c++)
			ut_drawBoard((char *)state->tiles,
			    27 * r + 3 * c, 9,
			    7 * r + 1, 7 * c + 1,
			    state->boards[r][c],
			    state->playBoard == -1 || state->playBoard == 3 * r + c);
	//refresh();
}

int ut_click(const struct ut_state *state, int *r, int *c)
{
#define P(r, c, d) ((state->playBoard == -1 || state->playBoard == 3 * (r / 3) + (c / 3)) && \
	            (state->boards[r / 3][c / 3] == '\0' || d % 3 == 1))
	MEVENT event;
	mvaddstr(21, 0, "Select move with arrow keys or mouse.");
	if(state->playBoard == -1)
	{
		*r = 3 * (*r / 3) + 1;
		*c = 3 * (*c / 3) + 1;
	}
	else
	{
		*r = 3 * (state->playBoard / 3) + 1;
		*c = 3 * (state->playBoard % 3) + 1;
	}
	for(;;)
	{
		/*if(state->boards[*r / 3][*c / 3] != '\0')
		{
			*r = 3 * (*r / 3) + 1;
			*c = 3 * (*c / 3) + 1;
		}*/
		move((7 * (*r / 3) + 1) + (2 * (*r % 3)),
		     (7 * (*c / 3) + 1) + (2 * (*c % 3)));
		refresh();
		switch(getch())
		{
			case KEY_MOUSE:
				if(getmouse(&event) == OK && (event.bstate & BUTTON1_CLICKED))
				{
					if(event.y < 0 || event.y >= 21) {break;}
					if(event.x < 0 || event.x >= 21) {break;}
					*r = (event.y % 7 - 1) / 2 + 3 * (event.y / 7);
					*c = (event.x % 7 - 1) / 2 + 3 * (event.x / 7);
					if(((event.y % 7) - 1) % 2 != 0) {break;}
					if(((event.x % 7) - 1) % 2 != 0) {break;}
					return 0;
				}
				break;
			case 'k':  /* FALLTHROUGH */
			case 'w':  /* FALLTHROUGH */
			case KEY_UP:
				//*r = (((*r - 1) % 9) + 9) % 9;
				for(int i = 0; i < 9 + 1; i++)
				{
					*r = (*r + 9 - 1) % 9;
					if(P(*r, *c, *r)) {break;}
				}
				break;
			case 'h':  /* FALLTHROUGH */
			case 'a':  /* FALLTHROUGH */
			case KEY_LEFT:
				//*c = (((*c - 1) % 9) + 9) % 9;
				for(int i = 0; i < 9 + 1; i++)
				{
					*c = (*c + 9 - 1) % 9;
					if(P(*r, *c, *c)) {break;}
				}
				break;
			case 'j':  /* FALLTHROUGH */
			case 's':  /* FALLTHROUGH */
			case KEY_DOWN:
				//*r = (*r + 1) % 9;
				for(int i = 0; i < 9 + 1; i++)
				{
					*r = (*r + 1) % 9;
					if(P(*r, *c, *r)) {break;}
				}
				break;
			case 'l':  /* FALLTHROUGH */
			case 'd':  /* FALLTHROUGH */
			case KEY_RIGHT:
				//*c = (*c + 1) % 9;
				for(int i = 0; i < 9 + 1; i++)
				{
					*c = (*c + 1) % 9;
					if(P(*r, *c, *c)) {break;}
				}
				break;
			case ' ':  /* FALLTHROUGH */
			case '\r': /* FALLTHROUGH */
			case KEY_ENTER:
				return 0;
			case ERR:  /* FALLTHROUGH */
			default:
				break;
		}
	}
#undef P
}

int info_line; // set this to 21 and reset it on erase TODO
void ut_info(const char *str, int n)
{
	mvaddnstr(info_line, 0, str, n);
//	info_line++; // depends on str not containing newlines
	int y, x;
	getyx(stdscr, y, x);
	info_line = y + 1;
}

int ut_readfill(int fd, char *x, size_t l)
{
	while(l > 0)
	{
		int r = read(fd, x, l);
		if(r < 0)
		{
			if(errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {continue;}
			else {return 1;}
		}
		else if(r == 0) {return 2;}
		x += r; l -= r;
	}
	return 0;
}
int ut_writefill(int fd, const char *x, size_t l)
{
	while(l > 0)
	{
		int r = write(fd, x, l);
		if(r < 0)
		{
			if(errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {continue;}
			else {return 1;}
		}
		x += r; l -= r;
	}
	return 0;
}

#define MAX_LINE 128

int ut_dprintf(int fd, const char *restrict format, ...)
{
	char line[MAX_LINE];
	va_list ap;
	va_start(ap, format);
	int n = vsnprintf(line, MAX_LINE, format, ap);
	va_end(ap);
	if(n < 0 || n > MAX_LINE - 1) {return -1;}
	if(ut_writefill(fd, line, n)) {return -1;}
	return n;
}
int ut_cursprintf(const char *restrict format, ...)
{
	char line[MAX_LINE];
	va_list ap;
	va_start(ap, format);
	int n = vsnprintf(line, MAX_LINE, format, ap);
	va_end(ap);
	if(n < 0 || n > MAX_LINE - 1) {return -1;}
	ut_info(line, n);
	return n;
}

void ut_show(const struct ut_state *state, int fd, bool as_comment) {
	#define tiles state->tiles
	ut_dprintf(fd, "%sTurn: %c\n%sPlay board: %d\n", as_comment ? "| " : "", (int)state->player, as_comment ? "| " : "", state->playBoard);
	int play_board_row = -1;
	int play_board_col = -1;
	if (state->playBoard != -1) {
		play_board_row = state->playBoard / 3;
		play_board_col = state->playBoard % 3;
	}
	ut_dprintf(fd, "%s  012 345 678\n", as_comment ? "| " : "");
	for(int y = 0; y < 9; y++)
	{
		if (y == 3 || y == 6) {
			ut_dprintf(fd, "%s  ---+---+---\n", as_comment ? "| " : "");
		}
		ut_dprintf(fd, "%s%d ", as_comment ? "| " : "", y);
		for(int x = 0; x < 9; x++)
		{
			if (x == 3 || x == 6) {
				ut_writefill(fd, "|", 1);
			}
			ut_writefill(fd, tiles[y][x] ? &tiles[y][x] : " ", 1);
		}
		if (y / 3 == play_board_row || play_board_row == -1) {
			ut_writefill(fd, "<", 1);
		}
	ut_writefill(fd, "\n", 1);
	}
	if (play_board_col == -1) {
		ut_dprintf(fd, "%s  ^^^ ^^^ ^^^", as_comment ? "| " : "");
	} else {
		ut_dprintf(fd, "%s  ", as_comment ? "| " : "");
		for (int i = 0; i < play_board_col; i++) {
			ut_dprintf(fd, "    ");
		}
		ut_dprintf(fd, "^^^");
	}
	ut_writefill(fd, "\n", 1);
	#undef tiles
}

void ut_show_boards(const struct ut_state *state) {
	for (int j = 0; j < 3; j++) {
		for (int i = 0; i < 3; i++) {
			putchar(state->boards[j][i] ? state->boards[j][i] : ' ');
		}
		putchar('\n');
	}
}

bool getpos(const struct ut_state *state, int *x, int *y) {
	while (true) {
		printf("Place token %c at position x,y: ", state->player);
		char line[5] = {0};
		if (fgets(line, 5, stdin) == NULL)
			return false;
		// line was too short
		if (line[3] == '\0')
			continue;
		// line was too long
		if (line[3] != '\n') {
			// consume rest of line
			while (true) {
				int garbage = getchar();
				if (garbage == EOF)
					return false;
				if (garbage == '\n')
					break;
			}
			continue;
		}
		int sscanf_result = sscanf(line, "%d,%d", x, y);
		if (sscanf_result == EOF)
			return false;
		if (sscanf_result != 2)
			continue;
		break;
	}
	return true;
}

void getpos_net(const struct ut_state *state, int sock, int *x, int *y) { // TODO
	const int MAX_LINE_LEN = 120;
	char byte;
	int n;
	while (true) {
		n = recv(sock, &byte, 1, 0);
		if (n == 0) {goto conn_closed;}
		if (byte == '|') {
			// ignore this line
			for (int i = 0; i < MAX_LINE_LEN; i++) {
				n = recv(sock, &byte, 1, 0);
				if (n == 0) {goto conn_closed;}
				if (byte == '\n') {break;}
			}
			if (byte != '\n') {
				printf("Partner sent too much data in one comment line - exiting\n");
				close(sock);
				exit(1);
			}
		} else {
			if (byte == '\n') {
				printf("Partner ended line before coords were complete - retrying\n");
				ut_dprintf(sock, "| Invalid coordinates. Try again: ");
				continue;
			}
			*x = byte - 0x30;
			n = recv(sock, &byte, 1, 0);
			if (n == 0) {goto conn_closed;}
			if (byte == '\n') {
				printf("Partner ended line before coords were complete - retrying\n");
				ut_dprintf(sock, "| Invalid coordinates. Try again: ");
				continue;
			}
			n = recv(sock, &byte, 1, 0);
			if (n == 0) {goto conn_closed;}
			if (byte == '\n') {
				printf("Partner ended line before coords were complete - retrying\n");
				ut_dprintf(sock, "| Invalid coordinates. Try again: ");
				continue;
			}
			*y = byte - 0x30;
			n = recv(sock, &byte, 1, 0);
			if (n == 0) {goto conn_closed;}
			if (byte != '\n') {
				printf("Partner sent extra data after coords were complete - ignoring and retrying\n");
				ut_dprintf(sock, "| Invalid coordinates. Try again: ");
				// ignore the rest of this line
				for (int i = 0; i < MAX_LINE_LEN; i++) {
					n = recv(sock, &byte, 1, 0);
					if (n == 0) {goto conn_closed;}
					if (byte == '\n') {break;}
				}
				if (byte != '\n') {
					printf("Partner sent too much extra data - exiting\n");
					close(sock);
					exit(1);
				}
				continue;
			}
			break;
		}
	}
	printf("x=%d y=%d\n", *x, *y);
	return;

	conn_closed:
	printf("Connection closed.\n");
	exit(1);
}

void finish(int sig)
{
//	putchar('\n');
	endwin();
	// other cleanup
	exit(0);
}

/*int main(int argc, char *argv[]) {
	signal(SIGINT, finish);
	initscr();
	keypad(stdscr, TRUE);
	nonl(); // \r instead of \r\n
	cbreak();
	noecho();
	mousemask(BUTTON1_CLICKED, NULL);

	struct ut_state state = ut_initial;
	while (true) {
		int r, c, err;
		erase();
		ut_draw(&state);
		char w = ut_winner((char *)state.boards, 0, 3);
		if(w)
		{
			if(w == ' ')
			{
				mvaddstr(21, 0, "Draw!");
			}
			else
			{
				mvaddch(21, 0, w);
				mvaddstr(21, 1, " Wins!");
			}
			mvaddstr(22, 0, "Press any key to exit.");
			refresh();
			mousemask(0, NULL);
			getch();
			break;
		}
		err = ut_click(&state, &r, &c);
		if (err) {continue;}
		err = ut_move(&state, &state, r, c);
		if (err) {continue;}
	}
	finish(0);
	return 0;
}*/

int ut_local_game(struct ut_state *state) { // TODO replace with from ncurses main
	int x, y;
	while (true) {
		ut_show(state, 1, false);
		ut_show_boards(state);
		bool ok = getpos(state, &x, &y);
		if (!ok) {continue;}
		int err = ut_move(state, state, y, x);
		if (err) {continue;}
		char w = ut_winner((char *)state->boards, 0, 3);
		if(w)
		{
			if(w == ' ')
			{
				printf("\nDraw!\n");
			}
			else
			{
				printf("\n%c wins!\n", (int)w);
			}
			break;
		}
	}
	return 0;
}

int ut_network_game(struct ut_state *state, int sock, char player) { // TODO
	int x, y;
	bool host = player == state->host_player;
	printf("You play as %c.\n", player);
	while (true) {
		ut_show(state, 1, false);
		ut_show_boards(state);
		ut_show(state, sock, true);
		if (state->player == player) {
			if (host) {ut_dprintf(sock, "| Waiting for game partner ...\n");}
			bool ok = getpos(state, &x, &y);
			if (!ok) {continue;}
			ut_dprintf(sock, "%d,%d\n", x, y);
		} else {
			printf("Waiting for game partner ...\n");
			if (host) {
				ut_dprintf(sock, "|\n"); // aligns game board each turn
				ut_dprintf(sock, "| Place token %c in position x,y: ", ut_turn(player));
			}
			getpos_net(state, sock, &x, &y);
		}
		int err = ut_move(state, state, y, x);
		if (err) {continue;}
		ut_dprintf(sock, "|\n");
		char w = ut_winner((char *)state->boards, 0, 3);
		if(w)
		{
			if(w == ' ')
			{
				printf("\nDraw!\n");
			}
			else
			{
				printf("\n%c wins!\n", (int)w);
			}
			break;
		}
	}
	return 0;
}

int ut_host_game(struct ut_state *state) {
	int sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock == -1) {
		int errsv = errno;
		printf("error %d\n", errsv);
		return 1;
	}
	const struct sockaddr_in addr = {
		.sin_family = AF_INET,
		.sin_port = htons(6669),
		.sin_addr = { .s_addr = htonl(0x7f000001) },
	};
	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int));
	if (bind(sock, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
		int errsv = errno;
		printf("error %d\n", errsv);
		return 1;
	}
	if (listen(sock, 128) == -1) {
		int errsv = errno;
		printf("error %d\n", errsv);
		return 1;
	}
	printf("Waiting for game partner at 127.0.0.1:6669 ...\n");
	int conn = accept(sock, NULL, NULL);
	if (conn == -1) {
		int errsv = errno;
		printf("error %d\n", errsv);
		return 1;
	}

	// decide X or O
	if (ut_random_player(&state->host_player) != 0) {return 1;}

	// tell partner X or O
	ut_dprintf(conn, "%c\n", ut_turn(state->host_player)); // TODO

	return ut_network_game(state, conn, state->host_player);
}

int ut_join_game(struct ut_state *state) {
	int sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock == -1) {
		int errsv = errno;
		printf("error %d\n", errsv);
		return 1;
	}
	const struct sockaddr_in addr = {
		.sin_family = AF_INET,
		.sin_port = htons(6669),
		.sin_addr = { .s_addr = htonl(0x7f000001) },
	};
	printf("Connecting to game host at 127.0.0.1:6669 ...\n");
	connect(sock, (struct sockaddr*)&addr, sizeof(addr));

	// host decides X or O
	char player;
	int r = ut_readfill(sock, &player, 1);
	if (r == 2) {printf("Connection closed.\n");}
	if (r != 0) {return 1;}
	state->host_player = ut_turn(player);

	return ut_network_game(state, sock, player);
}

int main(int argc, char **argv) {
	signal(SIGINT, finish);
	struct ut_state state = ut_initial;
	if (argc != 2) {
		printf(HELP_TEXT);
		return 1;
	} else if (strncmp(argv[1], arg_local, strlen(arg_local)) == 0) {
		return ut_local_game(&state);
	} else if (strncmp(argv[1], arg_host, strlen(arg_host)) == 0) {
		return ut_host_game(&state);
	} else if (strncmp(argv[1], arg_join, strlen(arg_join)) == 0) {
		return ut_join_game(&state);
	} else {
		printf(HELP_TEXT, argv[1]);
		return 1;
	}
}