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

#include <SDL.h>
#include <SDL_ttf.h>
#include <config.h>
#include "collision.h"
#include "defs.h"
#include "dirs.h"
#include "help.h"
#include "output.h"
#include "util.h"

const char *_db_help_text =
	PACKAGE_NAME " version " PACKAGE_VERSION "\n"
	"\n"
	"Press Esc or Enter to exit help\n"
	"\n"
	"Evade the balls and get to the target!  Dodge Balls is a simple "
	"puzzle game with obstacle courses consisting of moving balls.\n"
	"\n"
	"The classic game is a liberated remake of a 2007 game, Dodgeball "
	"v3.0, by the same author.  It features 10 levels, each harder than "
	"the last.\n"
	"\n"
	"How to Play\n"
	"\n"
	"Move your character (a smiley face in the classic game) through the "
	"obstacle course to reach the target (a star in the classic game).  If "
	"you are hit by a ball, the level is restarted.\n"
	"\n"
	"Controls\n"
	"\n"
	"Up:    Move up\n"
	"Down:  Move down\n"
	"Left:  Move left\n"
	"Right: Move right\n"
	"...\n"
	"\n"
	"Hints\n"
	"\n"
	"Use the map to your advantage.  You can go through walls that appear "
	"to be hollow.  Try to anticipate where balls will be.  Remember that "
	"they bounce off walls in the opposite direction.  To stop, move "
	"against a wall.";

static int _db_help_quit;

static void
_db_help_triangle(SDL_Renderer *renderer, Uint8 r, Uint8 g, Uint8 b, Uint8 a,
		int x_min, int y_min, int dir)
{
	int       i;
	int       y;
	int       x;
	SDL_Point points[(DB_SCROLL_W * (DB_SCROLL_W + 2)) / 4];

	i = 0;
	for (y = 0; y < DB_SCROLL_H; ++y) {
		for (x = y; x < (DB_SCROLL_W - y); ++x) {
			points[i].x = x_min + x;
			if (dir > 0) {
				points[i].y = y_min + y;
			} else {
				points[i].y = y_min + DB_SCROLL_H - 1 - y;
			}
			++i;
		}
	}
	SDL_SetRenderDrawColor(renderer, r, g, b, a);
	SDL_RenderDrawPoints(renderer, points, i);
}

int
db_help(SDL_Window *window)
{
	char         *font_path;
	SDL_Renderer *renderer;
	TTF_Font     *font;
	SDL_Color     color;
	SDL_Surface  *surface;
	SDL_Texture  *texture;
	SDL_Rect      text_src_rect;
	SDL_Rect      text_dst_rect;
	SDL_Rect      up_rect;
	SDL_Rect      dn_rect;
	int           up_over;
	int           dn_over;
	SDL_Event     event;

	font_path = db_strcat(db_get_fonts_dir(), "/UbuntuTitling-Bold.ttf");

	renderer = SDL_GetRenderer(window);
	if (renderer == NULL) {
		db_err("Failed to get renderer (%s)", SDL_GetError());
		return -1;
	}

	font = TTF_OpenFont(font_path, DB_FONT_TEXT_SIZE);
	if (font == NULL) {
		db_err("Failed to open font (%s)", TTF_GetError());
		free(font_path);
		return -1;
	}

	color.r = DB_COLOR_FORE_R;
	color.g = DB_COLOR_FORE_G;
	color.b = DB_COLOR_FORE_B;
	color.a = DB_COLOR_FORE_A;

	surface = TTF_RenderText_Blended_Wrapped(font, _db_help_text, color,
			DB_WINDOW_W - DB_WINDOW_P * 2 - DB_SCROLL_W);
	if (surface == NULL) {
		db_err("Failed to create surface (%s)", TTF_GetError());
		return -1;
	}

	TTF_CloseFont(font);

	texture = SDL_CreateTextureFromSurface(renderer, surface);
	if (texture == NULL) {
		db_err("Failed to create texture (%s)", SDL_GetError());
		return -1;
	}

	text_src_rect.x =   0;
	text_src_rect.y =   0;
	text_src_rect.w = DB_WINDOW_W - DB_WINDOW_P * 2 - DB_SCROLL_W;
	text_src_rect.h = DB_WINDOW_H - DB_WINDOW_P * 2;

	text_dst_rect.x = DB_WINDOW_P;
	text_dst_rect.y = DB_WINDOW_P;
	text_dst_rect.w = DB_WINDOW_W - DB_WINDOW_P * 2 - DB_SCROLL_W;
	text_dst_rect.h = DB_WINDOW_H - DB_WINDOW_P * 2;

	up_rect.x = DB_WINDOW_W - DB_WINDOW_P - DB_SCROLL_W;
	up_rect.y = DB_WINDOW_P;
	up_rect.w = DB_SCROLL_W;
	up_rect.h = DB_SCROLL_H;

	dn_rect.x = DB_WINDOW_W - DB_WINDOW_P - DB_SCROLL_W;
	dn_rect.y = DB_WINDOW_H - DB_WINDOW_P - DB_SCROLL_H;
	dn_rect.w = DB_SCROLL_W;
	dn_rect.h = DB_SCROLL_H;

	up_over = 0;
	dn_over = 0;
	_db_help_quit = 0;
	while (SDL_WaitEvent(&event)) {
		switch (event.type) {
			case SDL_QUIT:
				_db_help_quit = 2;
				break;
			case SDL_KEYDOWN:
				switch (event.key.keysym.sym) {
					case SDLK_UP:
						text_src_rect.y -= DB_SCROLL_S;
						if (text_src_rect.y < 0) {
							text_src_rect.y = 0;
						}
						break;
					case SDLK_DOWN:
						text_src_rect.y += DB_SCROLL_S;
						if (text_src_rect.y > surface->h
								-
								text_src_rect.h)
						{
							text_src_rect.y =
								surface->h -
								text_src_rect.h;
						}
						break;
					case SDLK_HOME:
						text_src_rect.y = 0;
						break;
					case SDLK_END:
						text_src_rect.y = surface->h -
							text_src_rect.h;
						break;
					case SDLK_ESCAPE:
					case SDLK_RETURN:
					case SDLK_KP_ENTER:
						_db_help_quit = 1;
						break;
					default:
						break;
				}
				break;
			case SDL_MOUSEMOTION:
				if (event.motion.state != 0) {
					break;
				}
				if (db_pt_in_rect(event.motion.x,
							event.motion.y,
							&up_rect)) {
					up_over = 1;
					break;
				} else {
					up_over = 0;
				}
				if (db_pt_in_rect(event.motion.x,
							event.motion.y,
							&dn_rect)) {
					dn_over = 1;
					break;
				} else {
					dn_over = 0;
				}
				break;
			case SDL_MOUSEBUTTONDOWN:
				if (event.button.button != SDL_BUTTON_LEFT) {
					break;
				}
				if (db_pt_in_rect(event.button.x,
							event.button.y,
							&up_rect)) {
					text_src_rect.y -= DB_SCROLL_S;
					if (text_src_rect.y < 0) {
						text_src_rect.y = 0;
					}
				} else if (db_pt_in_rect(event.button.x,
							event.button.y,
							&dn_rect)) {
					text_src_rect.y += DB_SCROLL_S;
					if (text_src_rect.y > surface->h -
							text_src_rect.h) {
						text_src_rect.y = surface->h -
							text_src_rect.h;
					}
				}
				break;
			default:
				break;
		}
		if (_db_help_quit > 0) {
			break;
		}
		SDL_SetRenderDrawColor(renderer,
				DB_COLOR_BACK_R, DB_COLOR_BACK_G,
				DB_COLOR_BACK_B, DB_COLOR_BACK_A);
		SDL_RenderClear(renderer);
		SDL_RenderCopy(renderer, texture,
				&text_src_rect, &text_dst_rect);
		if (text_src_rect.y <= 0) {
			_db_help_triangle(renderer,
					DB_COLOR_DISA_R, DB_COLOR_DISA_G,
					DB_COLOR_DISA_B, DB_COLOR_DISA_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_P,
					-1);
		} else if (up_over == 1) {
			_db_help_triangle(renderer,
					DB_COLOR_ACTV_R, DB_COLOR_ACTV_G,
					DB_COLOR_ACTV_B, DB_COLOR_ACTV_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_P,
					-1);
		} else {
			_db_help_triangle(renderer,
					DB_COLOR_FORE_R, DB_COLOR_FORE_G,
					DB_COLOR_FORE_B, DB_COLOR_FORE_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_P,
					-1);
		}
		if (text_src_rect.y >= surface->h - text_src_rect.h) {
			_db_help_triangle(renderer,
					DB_COLOR_DISA_R, DB_COLOR_DISA_G,
					DB_COLOR_DISA_B, DB_COLOR_DISA_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_H - DB_WINDOW_P - DB_SCROLL_H,
					 1);
		} else if (dn_over == 1) {
			_db_help_triangle(renderer,
					DB_COLOR_ACTV_R, DB_COLOR_ACTV_G,
					DB_COLOR_ACTV_B, DB_COLOR_ACTV_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_H - DB_WINDOW_P - DB_SCROLL_H,
					 1);
		} else {
			_db_help_triangle(renderer,
					DB_COLOR_FORE_R, DB_COLOR_FORE_G,
					DB_COLOR_FORE_B, DB_COLOR_FORE_A,
					DB_WINDOW_W - DB_WINDOW_P * 2,
					DB_WINDOW_H - DB_WINDOW_P - DB_SCROLL_H,
					 1);
		}
		SDL_RenderPresent(renderer);
	}

	SDL_FreeSurface(surface);
	SDL_DestroyTexture(texture);

	return _db_help_quit - 1;
}