#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;
};
const struct ut_state ut_initial = {
		.boards = {0},
		.tiles = {0},
		.playBoard = -1,
		.player = 'X',
};

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";

const char PLAY_BOARDS[][14] = {
	"top left", "top middle", "top right",
	"middle left", "middle", "middle right",
	"bottom left", "bottom middle", "bottom right",
	"all boards",
};

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


int curs_line;
void ut_curserase(void)
{
	curs_line = 0;
	erase();
}
void ut_cursprint(const char *str, int n)
{
	mvaddnstr(curs_line, 0, str, n);
	int y, x;
	getyx(stdscr, y, x);
	curs_line = y;
}
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_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_cursprint(line, n);
	return n;
}
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;
}

// TODO highlight last placed
void ut_drawBoard(void (*mvch)(void*, int, int, char), void *arg, const char *tiles, int offset, int stride, int iy, int ix, char winner, bool highlight)
{
	// 7x7 board display
	/*
	 * X|X|X
	 * -+-+-
	 * X|X|X
	 * -+-+-
	 * X|X|X
	*/
	for(int r = 0; r < 3; r++) // tiles
		for(int c = 0; c < 3; c++)
			mvch(arg, iy + 2 * r + 1, ix + 2 * c + 1, 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++)
			mvch(arg, iy + 2 * r + 1, ix + 2 * c + 1 + 1, winner != '\0' ? winner : '|');
	for(int r = 0; r < 2; r++) // -
		for(int c = 0; c < 3; c++)
			mvch(arg, iy + 2 * r + 1 + 1, ix + 2 * c + 1, winner != '\0' ? winner : '-');
	for(int r = 0; r < 2; r++) // +
		for(int c = 0; c < 2; c++)
			mvch(arg, iy + 2 * r + 1 + 1, ix + 2 * c + 1 + 1, winner != '\0' ? winner : highlight ? '*' : '+');
	for(int r = 0; r < 7; r++) // | boundary
		for(int c = 0; c < 2; c++)
			mvch(arg, iy + r, ix + 6 * c, ' ');
	for(int r = 0; r < 2; r++) // - boundary
		for(int c = 0; c < 7; c++)
			mvch(arg, iy + 6 * r, ix + c, ' ');
}
#define DTILES_Y 21
#define DTILES_X 21
void ut_drawTiles(void (*mvch)(void*, int, int, char), void *arg, const struct ut_state *state, bool numbers)
{
	for(int r = 0; r < 3; r++)
		for(int c = 0; c < 3; c++)
			ut_drawBoard(mvch, arg, (char *)state->tiles,
				    27 * r + 3 * c, 9,
				    7 * r, 7 * c,
				    state->boards[r][c],
				    state->playBoard == -1 || state->playBoard == 3 * r + c);
	if(numbers)
	{
		for(int b = 0; b < 3; b++)
			for(int c = 0; c < 3; c++)
				mvch(arg, 0, 7 * b + 2 * c + 1, '0' + 3 * b + c);
		for(int b = 0; b < 3; b++)
			for(int r = 0; r < 3; r++)
				mvch(arg, 7 * b + 2 * r + 1, 0, '0' + 3 * b + r);
	}
}
#define DBOARDS_Y 7
#define DBOARDS_X 7
void ut_drawBoards(void (*mvch)(void*, int, int, char), void *arg, const struct ut_state *state)
{
	ut_drawBoard(mvch, arg, (char *)state->boards,
		    0, 3,
		    0, 0,
		    '\0', false);
}

void ut_cursmvch(void *arg, int y, int x, char c)
{
	mvaddch(curs_line + y, x, c);
}
void ut_tmvch(void *arg, int y, int x, char c)
{
	((char (*)[DTILES_X])arg)[y][x] = c;
}
void ut_bmvch(void *arg, int y, int x, char c)
{
	((char (*)[DBOARDS_X])arg)[y][x] = c;
}

#define DTILES_LINE 1
void ut_cursdraw(const struct ut_state *state)
{
	ut_cursprintf("Turn: %c Play board: %d\n", (int)state->player, state->playBoard);
	ut_drawTiles(ut_cursmvch, NULL, state, false);
	curs_line += DTILES_Y;
	//ut_drawBoards(ut_cursmvch, NULL, state);
	
}
void ut_sockdraw(const struct ut_state *state, int fd)
{
	ut_dprintf(fd, "Turn: %c Play board: %d\n", (int)state->player, state->playBoard);
	char dtiles[DTILES_Y][DTILES_X];
	ut_drawTiles(ut_tmvch, dtiles, state, true);
	for(int r = 0; r < DTILES_Y; r++)
	{
		ut_dprintf(fd, "%.*s\n", DTILES_X, dtiles[r]);
	}
}

void ut_show(const struct ut_state *state, int fd) {
	#define tiles state->tiles
	ut_dprintf(fd, "Turn: %c\nPlay board: %s\n", (int)state->player, PLAY_BOARDS[(state->playBoard + 10) % 10]);
	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, "  012 345 678\n");
	for(int y = 0; y < 9; y++)
	{
		if (y == 3 || y == 6) {
			ut_dprintf(fd, "  ---+---+---\n");
		}
		ut_dprintf(fd, "%d ", 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, "  ^^^ ^^^ ^^^");
	} else {
		ut_dprintf(fd, "  ");
		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');
	}
}*/


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_cursgetpos(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;
	ut_cursprintf("Select move with arrow keys or mouse.\n");
	if(*r < 0 || *r >= 9 || *c < 0 || *c >= 9)
	{
		*r = 4; *c = 4;
	}
	else 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(DTILES_LINE + (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))
				{
					event.y -= DTILES_LINE;
					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
}

/*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;
}*/

int ut_ignore_line(int sock) {
	char byte;
	for (int i = 0; i < 128; i++) {
		if (ut_readfill(sock, &byte, 1)) {
			return 1;
		}
		if (byte == '\n') {return 0;}
	}
	return 2;
}

int ut_sockgetpos(const struct ut_state *state, int sock, int *x, int *y, bool readable) { // TODO
	int index = 0;
	char byte;
	while (true) {
		int r = ut_readfill(sock, &byte, 1);
		if (r < 0) {return r;}
		if (r == 0) {
			printf("Connection closed.\n");
			return -1;
		}
		if (index == 0 && byte == '|') {
			if (ut_ignore_line(sock)) {return -1;}
		} else if (index == 0) {
			*x = byte - 0x30;
		} else if (index == 2) {
			*y = byte - 0x30;
		} else if (index == 1 && byte != ',' || index == 3 && byte != '\n') {
			printf("Partner sent malformed coords - retrying\n");
			if (ut_ignore_line(sock)) {return -1;}
			if (readable) {
				ut_dprintf(sock, "Invalid coordinates. Try again: ");
			}
			index = 0;
			continue;
		}
		index++;
		if (index == 4) {break;}
	}
	printf("x=%d y=%d\n", *x, *y);
	return 0;
}

int ut_local_game(struct ut_state *state) {
	int x, y;
	for(;;)
	{
		int r = 4, c = 4;
		ut_curserase();
		ut_cursdraw(state);
		char w = ut_winner((char *)state->boards, 0, 3);
		if(w)
		{
			if(w == ' ')
			{
				ut_cursprintf("Draw!\n");
			}
			else
			{
				ut_cursprintf("%c Wins!\n", (int)w);
			}
			break;
		}
		if(ut_cursgetpos(state, &r, &c)) {continue;}
		if(ut_move(state, state, r, c)) {continue;}
	}
	return 0;
}

int ut_network_game(struct ut_state *state, int sock, char player, bool readable) { // TODO
	int x, y;
	//printf("You play as %c.\n", player);
	while (true) {
		//ut_show(state, 1, false);
		//ut_show_boards(state);
		ut_show(state, sock);
		if (state->player == player) {
			if (readable) {ut_dprintf(sock, "Waiting for game partner ...\n");}
			bool ok = ut_cursgetpos(state, &x, &y);
			if (!ok) {continue;}
			ut_dprintf(sock, "%d,%d\n", x, y);
		} else {
			printf("Waiting for game partner ...\n");
			if (readable) {
				// line feed aligns game board each turn
				ut_dprintf(sock, "\nPlace token %c in position x,y: ", ut_turn(player));
			}
			int err = ut_sockgetpos(state, sock, &x, &y, readable);
			if (err == -1) {
				printf("Connection closed.\n");
				return 1;
			}
		}
		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");
				if (readable) {ut_dprintf(sock, "\nDraw!\n");}
				close(sock);
			}
			else
			{
				printf("\n%c wins!\n", (int)w);
				if (readable) {ut_dprintf(sock, "\n%c wins!\n", (int)w);}
				close(sock);
			}
			break;
		}
	}
	return 0;
}

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

int ut_host_game(struct ut_state *state) {
	int sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock == -1) {
		printf("error %d\n", errno);
		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) {
		printf("error %d\n", errno);
		return 1;
	}
	if (listen(sock, 128) == -1) {
		printf("error %d\n", errno);
		return 1;
	}
	printf("Waiting for game partner at 127.0.0.1:6669 ...\n");
	int conn = accept(sock, NULL, NULL);
	if (conn == -1) {
		printf("error %d\n", errno);
		return 1;
	}

	// decide X or O
	char player;
	if ((player = ut_random_player()) < 0) {return 1;}

	// check to determine readable
	char byte;
	ut_dprintf(conn, "| Press enter to start: ");
	if (ut_readfill(conn, &byte, 1)) {
		printf("Connection closed.\n");
		return 1;
	}
	bool readable = byte != '\0';
	if (byte != '\n') {
		int err = ut_ignore_line(sock);
		if (err == 1) {
			printf("Connection closed.\n");
			return 1;
		} else if (err == 2) {
			printf("Partner sent too much data - exiting\n");
			return 1;
		}
	}

	// tell partner X or O
	ut_dprintf(conn, "%c\n", ut_turn(player));
	if (readable) {
		ut_dprintf(conn, "You play as: %c\n\n", ut_turn(player));
	}

	return ut_network_game(state, conn, player, readable);
}

int ut_join_game(struct ut_state *state) {
	int sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock == -1) {
		printf("error %d\n", errno);
		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");
	if(connect(sock, (struct sockaddr*)&addr, sizeof(addr)) == -1)
	{
		printf("error %d\n", errno);
		return 1;
	}

	// tell host to deactivate readable
	ut_dprintf(sock, "\0\n");

	// host decides X or O
	char player_buf[2];
	char *player = (char*)&player_buf;
	int r = ut_readfill(sock, player_buf, 2);
	if (r == 2) {printf("Connection closed.\n");}
	if (r != 0) {return 1;}

	return ut_network_game(state, sock, *player, false);
}

void finish(int sig)
{
//	putchar('\n');
	endwin();
	// other cleanup
	exit(0);
}
void waitfinish(int sig)
{
	ut_cursprintf("\nPress any key to exit.");
	refresh();
	mousemask(0, NULL);
	getch();
	finish(sig);
}
void begin(void)
{
	signal(SIGINT, finish);
	initscr();
	keypad(stdscr, TRUE);
	nonl(); // \r instead of \r\n
	cbreak();
	noecho();
	mousemask(BUTTON1_CLICKED, NULL);
}

int main(int argc, char **argv) {

	struct ut_state state = ut_initial;
	if (argc != 2) {
		printf(HELP_TEXT);
		return 1;
	} else if (strncmp(argv[1], arg_local, sizeof(arg_local)) == 0) {
		begin();
		waitfinish(ut_local_game(&state));
	} else if (strncmp(argv[1], arg_host, sizeof(arg_host)) == 0) {
		begin();
		waitfinish(ut_host_game(&state));
	} else if (strncmp(argv[1], arg_join, sizeof(arg_join)) == 0) {
		begin();
		waitfinish(ut_join_game(&state));
	} else {
		printf(HELP_TEXT);
		return 1;
	}
	return 0;
}