/*
 * Copyright (C) 2021  P. J. McDermott
 *
 * This file is part of Maze Fight
 *
 * Maze Fight 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.
 *
 * Maze Fight 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 Maze Fight.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <SDL.h>
#include <SDL_ttf.h>
#include <errno.h>
#include <string.h>
#include "char.h"
#include "defs.h"
#include "dirs.h"
#include "game.h"
#include "maze.h"
#include "tk.h"
#include "util.h"

struct _mf_game {
	struct mftk_widget *timer;
	char                time_buf[6];
	Uint32              beg;
	int                 player_cx;
	int                 player_cy;
	int                 player_travel;
	int                 player_dx;
	int                 player_dy;
	int                 player_x;
	int                 player_y;
};

static int
_mf_game_exit(void *user_data __attribute__((__unused__)))
{
	return 1;
}

static struct mftk_widget *
_mf_game_form(SDL_Renderer *renderer, TTF_Font *text_font,
		struct _mf_game *game)
{
	game->timer = mftk_text_new(MF_DIGITS ":", 5, "00:00", text_font,
			SDL_FALSE, NULL, NULL, NULL, NULL);
	return mftk_grid_new(2, 1, MF_ROW_M, MF_COL_M,
			game->timer,
				MFTK_GRID_HALIGN_R|MFTK_GRID_VALIGN_T,
			mftk_button_new(text_font, "Exit", MF_BTN_P,
				&_mf_game_exit, NULL, renderer),
				MFTK_GRID_HALIGN_R|MFTK_GRID_VALIGN_B
			);
}

static int
_mf_game_fow(SDL_Renderer *renderer, struct _mf_game *game,
		struct mf_maze *maze, int cw)
{
	int      x1;
	int      y1;
	int      travel;
	int      dx;
	int      dy;
	int      x2;
	int      y2;
	SDL_Rect rect;

	if (SDL_SetRenderDrawColor(renderer,
				MF_COLOR_FOGW_R, MF_COLOR_FOGW_G,
				MF_COLOR_FOGW_B, MF_COLOR_FOGW_A) < 0) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
				"Couldn't render fog: %s", \
				SDL_GetError()); \
		return -1; \
	}

	x2 = x1 = game->player_cx;
	y2 = y1 = game->player_cy;
	travel  = game->player_travel;
	dx      = game->player_dx;
	dy      = game->player_dy;
	while (!mf_maze_is_wall(maze, dx >= 0 ? x2 : x1, dy >= 0 ? y2 : y1,
				dx, dy)) {
		if (dx >= 0) x2 += dx;
		else         x1 += dx;
		if (dy >= 0) y2 += dy;
		else         y1 += dy;
	}
	++x2, ++y2;
	x1 *= cw, y1 *= cw, x2 *= cw, y2 *= cw;
	if (dx >= 0) x1 += travel * dx;
	else         x2 += travel * dx;
	if (dy >= 0) y1 += travel * dy;
	else         y2 += travel * dy;
	++x2, ++y2;

#define mf_game_w_ MF_WINDOW_H
#define mf_game_h_ MF_WINDOW_H
#define mf_game_render_() \
	do { \
		if (SDL_RenderFillRect(renderer, &rect) < 0) { \
			SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, \
					"Couldn't render fog: %s", \
					SDL_GetError()); \
			return -1; \
		} \
	} while (0)

	rect.x=  0, rect.y= 0,  rect.w= x1,            rect.h= mf_game_h_;
	mf_game_render_();
	rect.x= x1, rect.y= 0,  rect.w= x2-x1,         rect.h= y1;
	mf_game_render_();
	rect.x= x1, rect.y= y2, rect.w= x2-x1,         rect.h= mf_game_h_-y2;
	mf_game_render_();
	rect.x= x2, rect.y= 0,  rect.w= mf_game_w_-x2, rect.h= mf_game_h_;
	mf_game_render_();

#undef mf_game_w_
#undef mf_game_h_
#undef mf_game_render_

	return 0;
}

int
mf_game(long seed, int size, int fow, int reveal, int enemies,
		SDL_Renderer *renderer)
{
	struct mf_maze      *maze        = NULL;
	struct mf_char      *player      = NULL;
	struct mf_char     **chars       = NULL;
	int                  i;
	SDL_Color            maze_color;
	char                *font_path   = NULL;
	TTF_Font            *text_font   = NULL;
	struct _mf_game      game;
	struct mftk_window  *win         = NULL;
	int                  fr;
	int                  won;
	Uint32               beg;
	int                  secs;
	Uint32               end;
	Uint32               delay;
	SDL_Event            event;

	/* Create maze */
	maze = mf_maze_new(seed, size, size, reveal);
	if (maze == NULL) {
		goto err;
	}
	maze_color.r = MF_COLOR_MAZE_R;
	maze_color.g = MF_COLOR_MAZE_G;
	maze_color.b = MF_COLOR_MAZE_B;
	maze_color.a = MF_COLOR_MAZE_A;

	chars = calloc(enemies, sizeof(*chars));
	if (chars == NULL) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't allocate characters: %s",
				strerror(errno));
		goto err;
	}
	player = mf_player_new(maze, MF_WINDOW_H / size);
	if (player == NULL) {
		goto err;
	}
	for (i = 0; i < enemies; ++i) {
		chars[i] = mf_enemy_new(maze, MF_WINDOW_H / size, size,
				enemies, chars);
		if (chars[i] == NULL) {
			goto err;
		}
	}

	font_path = mf_strcat(mf_get_fonts_dir(), "/FifteenTwenty-Regular.ttf");
	text_font = TTF_OpenFont(font_path, MF_TEXT_FONT_S);
	if (text_font == NULL) {
		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
				"Couldn't open font: %s",
				TTF_GetError());
		goto err;
	}
	free(font_path);
	font_path = NULL;

	win = mftk_window_new(MF_WINDOW_H, 0, mftk_box_new(
				MF_WINDOW_W - MF_WINDOW_H, MF_WINDOW_H,
				MF_WINDOW_W - MF_WINDOW_H, MF_WINDOW_H,
				MF_FORM_P,
				_mf_game_form(renderer, text_font, &game)));

	game.beg = SDL_GetTicks();

	fr = 10;
	won = SDL_FALSE;
	while(1) {
		beg = SDL_GetTicks();
		while (SDL_PollEvent(&event)) {
			switch (event.type) {
				case SDL_QUIT:
					goto quit;
				case SDL_KEYDOWN:
					switch (event.key.keysym.sym) {
						case SDLK_ESCAPE:
							goto exit;
					default:
						break;
					}
				default:
					break;
			}
			mf_player_key_event(player, &event);
			switch (mftk_window_event(win, &event)) {
				case 0:
					break;
				case 1:
					goto exit;
				default:
					goto err;
			}
		}
		if (won == SDL_FALSE) {
			mf_char_update(player);
			for (i = 0; i < enemies; ++i) {
				mf_char_update(chars[i]);
			}
			mf_char_get_vector(player, &game.player_cx,
					&game.player_cy, &game.player_travel,
					&game.player_dx, &game.player_dy);
			game.player_x = game.player_cx * MF_WINDOW_H / size;
			game.player_y = game.player_cy * MF_WINDOW_H / size;
			game.player_x += game.player_travel * game.player_dx;
			game.player_y += game.player_travel * game.player_dy;
			if (game.player_cx == size - 1 &&
					game.player_cy == size - 1) {
				won = SDL_TRUE;
			}
		}
		SDL_SetRenderDrawColor(renderer,
				MF_COLOR_BACK_R, MF_COLOR_BACK_G,
				MF_COLOR_BACK_B, MF_COLOR_BACK_A);
		SDL_RenderClear(renderer);
		mf_char_render(player, renderer);
		for (i = 0; i < enemies; ++i) {
			mf_char_render(chars[i], renderer);
		}
		if (fow == SDL_TRUE && _mf_game_fow(renderer, &game, maze,
					MF_WINDOW_H / size) < 0) {
			goto err;
		}
		mf_maze_render(maze, renderer, &maze_color, MF_WINDOW_H / size);
		if (won == SDL_FALSE) {
			secs = (beg - game.beg) / 1000;
			if (sprintf(game.time_buf, "%02d:%02d",
						secs / 60, secs % 60) < 0) {
				SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
						"Couldn't allocate string: %s",
						strerror(errno));
				goto err;
			}
			mftk_text_set_value(game.timer, game.time_buf);
		}
		mftk_window_render(win, renderer);
		SDL_RenderPresent(renderer);
		end = SDL_GetTicks();
		if ((Uint32) (1000 / fr) > (end - beg)) {
			delay = 1000 / fr - (end - beg);
		} else {
			SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
					"Frame took longer than frame period");
			delay = 0;
		}
		SDL_LogDebug(SDL_LOG_CATEGORY_APPLICATION,
				"Frame took %u ms, delaying %u ms",
				end - beg, delay);
		SDL_Delay(delay);
	}

 exit:
	mftk_window_destroy(&win);
	TTF_CloseFont(text_font);
	text_font = NULL;
	mf_maze_destroy(&maze);
	mf_char_destroy(&player);
	if (chars != NULL) {
		for (i = 0; i < enemies; ++i) {
			mf_char_destroy(&chars[i]);
		}
		free(chars);
	}
	return 0;

 quit:
	mftk_window_destroy(&win);
	TTF_CloseFont(text_font);
	text_font = NULL;
	mf_maze_destroy(&maze);
	mf_char_destroy(&player);
	if (chars != NULL) {
		for (i = 0; i < enemies; ++i) {
			mf_char_destroy(&chars[i]);
		}
		free(chars);
	}
	return 1;

 err:
	if (font_path != NULL) {
		free(font_path);
	}
	if (text_font != NULL) {
		TTF_CloseFont(text_font);
	}
	mftk_window_destroy(&win);
	mf_maze_destroy(&maze);
	mf_char_destroy(&player);
	if (chars != NULL) {
		for (i = 0; i < enemies; ++i) {
			mf_char_destroy(&chars[i]);
		}
		free(chars);
	}
	return -1;
}