/*-
 * Copyright (C) 2025  Alessandro Iezzi <aiezzi AT alessandroiezzi PERIOD it>
 *
 * This file is part of Tris Game.
 *
 * Tris Game is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Tris Game is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Tris Game.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <log.h>
#include "../engine/engine.h"
#include "game.h"
#include "cell.h"

#define WIN_PATTERNS 8

static const char SIGN_CIRCLE = 'o';
static const char SIGN_CROSS  = 'x';

/* There are 8 lines to win:
	 *   - 0, 1, 2 (horizontal)
	 *   - 3, 4, 5 (horizontal)
	 *   - 6, 7, 8 (horizontal)
	 *   - 0, 3, 6 (vertical)
	 *   - 1, 4, 7 (vertical)
	 *   - 2, 5, 8 (vertical)
	 *   - 0, 4, 8 (diagonal)
	 *   - 2, 4, 6 (diagonal)
	 */
static const int win_patterns[WIN_PATTERNS][3] = {
	{0, 1, 2}, {3, 4, 5}, {6, 7, 8}, /* horizontal */
	{0, 3, 6}, {1, 4, 7}, {2, 5, 8}, /* vertical   */
	{0, 4, 8}, {2, 4, 6}             /* diagonal   */
};

static Log *log = NULL;

static void
init_log(void)
{
	if (log != NULL) return;
	log = log_create("Game");
}

static void game_draw_field(TrisGame *game, float box_size);
static char game_next_sign(TrisGame *game);

static void
draw_frames(void *data)
{
	if (data == NULL) return;
	TrisGame *game = data;

	for (int i = 0; i < BOARD_SIZE; i++) {
		Cell *cell = game->cells[i];
		if (cell->sign == SIGN_CIRCLE) {
			engine_render_circle(cell->shape);
		}
	}
}

static void
game_restart(TrisGame *game)
{
	game->ended = false;

	for (int i = 0; i < BOARD_SIZE; i++) {
		Cell *cell = game->cells[i];
		cell->filled = false;
		cell->sign = '\0';

		if (cell->shape != NULL) {
			free(cell->shape);
		}
	}

	engine_set_rendering_background_c(game->engine, game->board->default_color);
}

static void
check_win(TrisGame *game)
{
	/* The minimum number of moves to win the play */
	if (game->moves < 5) return;

	for (int i = 0; i < WIN_PATTERNS; i++) {
		/* These are the indexes of every pattern */
		int i0 = win_patterns[i][0];
		int i1 = win_patterns[i][1];
		int i2 = win_patterns[i][2];

		if (game->cells[i0]->sign != '\0'
				&& game->cells[i0]->sign == game->cells[i1]->sign
				&& game->cells[i1]->sign == game->cells[i2]->sign) {
			engine_set_rendering_background_c(game->engine, game->board->wining_color);
			game->ended = true;
			return;
		}
	}

	if (game->moves >= 9) {
		engine_set_rendering_background_c(game->engine, game->board->draft_color);
		game->ended = true;
	}
}

static void
draw_sign(TrisGame *game, Cell *cell)
{
	float x = cell->cx;
	float y = cell->cy;
	float l = 0.20f;
	char sign = game_next_sign(game);

	cell_set_sign(cell, sign);
	if (sign == SIGN_CIRCLE) {
		cell->shape = engine_circle_new(x, y, l, 120, 1);
		game->sign = SIGN_CROSS;
	} else if (sign == SIGN_CROSS) {
		engine_draw_line(x - l, y + l, x + l, y - l);
		engine_draw_line(x + l, y + l, x - l, y - l);
		game->sign = SIGN_CIRCLE;
	}

	game->moves++;
	check_win(game);
}

static void
loop_cells(TrisGame *game, float x, float y)
{
	init_log();

	for (int i = 0; i < BOARD_SIZE; i++) {
		Cell *cell = game->cells[i];
		if (!cell_is_filled(cell) && cell_within_bounds(cell, x, y)) {
			draw_sign(game, cell);
			cell_set_filled(cell, true);
		}
	}
}

static void
game_mouse_button_pressed(float x, float y, void *data)
{
	TrisGame *game = data;
	if (!game->ended) {
		loop_cells(game, x, y);
	} else {
		game_restart(game);
	}
}

TrisGame *
game_init(int width, int height)
{
	init_log();

	/* Init of the TrisGame */
	TrisGame *game = malloc(sizeof(TrisGame));
	if (game == NULL) {
		log_error(log, "Error allocating memory for the game");
		exit(EXIT_FAILURE);
	}
	game->width = width;
	game->height = height;
	game->sign = SIGN_CIRCLE;
	game->moves = 0;
	game->engine = engine_new(width, height);
	game->board = board_new();
	game->ended = false;

	engine_set_window_title(game->engine, "Tris Game");
	engine_set_mouse_button_listener(game_mouse_button_pressed, game);

	engine_set_rendering_listener(game->engine, draw_frames, game);

	game_draw_field(game, 0.5f);

	return game;
}

void
game_start()
{
	engine_loop();
}

static void
game_draw_field(TrisGame *game, float box_size)
{
	float x = 0.0f;
	float y = 0.0f;

	float half_box = box_size / 2;
	engine_draw_line(x - half_box, y + half_box * 3, x - half_box, y - half_box * 3);
	engine_draw_line(x + half_box, y + half_box * 3, x + half_box, y - half_box * 3);

	engine_draw_line(x - half_box * 3, y + half_box, x + half_box * 3, y + half_box);
	engine_draw_line(x - half_box * 3, y - half_box, x + half_box * 3, y - half_box);

	float xmin = x - half_box * 3;
	float xmax = x + half_box * 3;
	float ymin = y - half_box * 3;
	float ymax = y + half_box * 3;

	float first_row = ymax - box_size;
	float second_row = ymax - box_size * 2;
	float first_col = xmin + box_size;
	float second_col = xmin + box_size * 2;

	/* First row */
	game->cells[0] = cell_new(xmin,       first_col,  ymax, first_row);
	game->cells[1] = cell_new(first_col,  second_col, ymax, first_row);
	game->cells[2] = cell_new(second_col, xmax,       ymax, first_row);

	/* Second row */
	game->cells[3] = cell_new(xmin,       first_col,  first_row, second_row);
	game->cells[4] = cell_new(first_col,  second_col, first_row, second_row);
	game->cells[5] = cell_new(second_col, xmax,       first_row, second_row);

	/* Third row */
	game->cells[6] = cell_new(xmin,       first_col,  second_row, ymin);
	game->cells[7] = cell_new(first_col,  second_col, second_row, ymin);
	game->cells[8] = cell_new(second_col, xmax,       second_row, ymin);
}

static char
game_next_sign(TrisGame *game)
{
	return game->sign;
}