#include "SDL.h"
#include "SDL_image.h"
#include "SDL_mixer.h"
#include "Timer.h"
#include <string>
using namespace::std;

// Contant Variables
const int FPS = 60;
const int SpaceShip_w = 20;
const int SpaceShip_h = 20;

// Images
SDL_Surface *spaceship = NULL;
SDL_Surface *bullet_left = NULL;
SDL_Surface *bullet_right = NULL;
SDL_Surface *game_bg = NULL;
SDL_Surface *screen = NULL;

// Sounds
Mix_Chunk *pass = NULL;

// Events
SDL_Event event;

class SpaceShip {
public:
	int SpaceShip_x, SpaceShip_y;
	int SpaceShip_xVel, SpaceShip_yVel;
	SpaceShip();
	void handle_input();
	void move();
	void show();
};

class Bullet {
public:
	Bullet();
	void Update();
	void Fire(float startX, float startY, float xSpeed, float ySpeed);
	void Draw();
private:
	bool alive;
	float Bullet_x, Bullet_y;
	float Bullet_xVel, Bullet_yVel;
};

SDL_Surface *load_image(string filename) {
	SDL_Surface* loadedImage = NULL;
	SDL_Surface* optimizedImage = NULL;
	loadedImage = IMG_Load(filename.c_str());
	if(loadedImage != NULL) {
		optimizedImage = SDL_DisplayFormatAlpha(loadedImage);
		SDL_FreeSurface(loadedImage);
	}
	return optimizedImage;
}

void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination) {
	SDL_Rect offset;
	offset.x = x;
	offset.y = y;
	SDL_BlitSurface(source, NULL, destination, &offset);
}

bool init()
{
	if(SDL_Init(SDL_INIT_EVERYTHING) == -1) {
		return false;
	}
	const SDL_VideoInfo* myPointer = SDL_GetVideoInfo();
	screen = SDL_SetVideoMode(myPointer->current_w, myPointer->current_h, 32, SDL_FULLSCREEN | SDL_HWSURFACE);
	if(screen == NULL) {
		return false;
	}
	if(Mix_OpenAudio(22050, MIX_DEFAULT_FORMAT, 2, 4096) == -1) {
		return false;
	}
	SDL_WM_SetCaption("Galactic Wars v1", NULL);
	return true;
}

bool load_files() {
	spaceship = load_image("bin/spaceship.png");
	if(spaceship == NULL)
	{
		return false;
	}
	bullet_left = load_image("bin/bullet.png");
	if(bullet_left == NULL)
	{
		return false;
	}
	bullet_right = load_image("bin/bullet.png");
	if(bullet_right == NULL)
	{
		return false;
	}
	game_bg = load_image("bin/game_bg.jpg");
	if(game_bg == NULL) {
		return false;
	}
	pass = Mix_LoadWAV("bin/pass.wav");
	if(pass == NULL) {
		return false;
	}
	return true;
}

void clean_up() {
	SDL_FreeSurface(game_bg);
	SDL_FreeSurface(bullet_left);
	SDL_FreeSurface(bullet_right);
	Mix_FreeChunk(pass);
	SDL_Quit();
}

SpaceShip::SpaceShip() {
	SpaceShip_x = 880;
	SpaceShip_y = 900;
	SpaceShip_xVel = 0;
	SpaceShip_yVel = 0;
}

Bullet::Bullet():alive(false),Bullet_x(0),Bullet_y(0),Bullet_xVel(0),Bullet_yVel(0){}

void SpaceShip::handle_input() {
	if(event.type == SDL_KEYDOWN) {
		switch(event.key.keysym.sym) {
		case SDLK_w: SpaceShip_yVel -= SpaceShip_h / 2; break;
		case SDLK_s: SpaceShip_yVel += SpaceShip_h / 2; break;
		case SDLK_a: SpaceShip_xVel -= SpaceShip_w / 2; break;
		case SDLK_d: SpaceShip_xVel += SpaceShip_w / 2; break;
		}
	}
	else if(event.type == SDL_KEYUP) {
		switch(event.key.keysym.sym) {
		case SDLK_w: SpaceShip_yVel += SpaceShip_h / 2; break;
		case SDLK_s: SpaceShip_yVel -= SpaceShip_h / 2; break;
		case SDLK_a: SpaceShip_xVel += SpaceShip_w / 2; break;
		case SDLK_d: SpaceShip_xVel -= SpaceShip_w / 2; break;
		}
	}
}

void SpaceShip::move() {
	const SDL_VideoInfo* myPointer = SDL_GetVideoInfo();
	SpaceShip_x += SpaceShip_xVel;
	if(SpaceShip_x + SpaceShip_w > myPointer->current_w) {
		SpaceShip_x = -60;
		Mix_PlayChannel(-1, pass, 0) == -1;
	}
	if(SpaceShip_x < -60) {
		SpaceShip_x = SpaceShip_x + SpaceShip_w + myPointer->current_w;
		Mix_PlayChannel(-1, pass, 0) == -1;
	}
	SpaceShip_y += SpaceShip_yVel;
	if(SpaceShip_y + SpaceShip_h > myPointer->current_h) {
		SpaceShip_y = -60;
		Mix_PlayChannel(-1, pass, 0) == -1;
	}
	if(SpaceShip_y < -60) {
		SpaceShip_y = SpaceShip_y + SpaceShip_h + myPointer->current_h;
		Mix_PlayChannel(-1, pass, 0) == -1;
	}
}

void SpaceShip::show() {
	apply_surface(SpaceShip_x, SpaceShip_y, spaceship, screen);
}

void Bullet::Update() {
	if(alive) {
		Bullet_x += Bullet_xVel;
		Bullet_y += Bullet_yVel;
	}
}

void Bullet::Fire(float startX, float startY, float xSpeed, float ySpeed) {
	Bullet_x = startX;
	Bullet_y = startY;
	Bullet_xVel = xSpeed;
	Bullet_yVel = ySpeed;
	alive = true;
}

void Bullet::Draw() {
	if(alive) {
		apply_surface(Bullet_x, Bullet_y, bullet_left, screen);
	}
}

int main(int argc, char* args[]) {
	bool quit = false;
	SpaceShip mySpaceShip;
	Bullet Left_Bullet;
	Timer fps;
	int bgX = 0, bgY = 0;
	if(init() == false) {
		return 1;
	}
	if(load_files() == false) {
		return 1;
	}
	if(SDL_Flip(screen) == -1) {
		return 1;
	}
	while(quit == false) {
		fps.start();
		while(SDL_PollEvent(&event)) {
			if(event.type == SDL_KEYDOWN) {
				switch(event.key.keysym.sym) {
				case SDLK_ESCAPE:
					quit = true;
					break;
				case SDLK_SPACE:
					Left_Bullet.Fire(SpaceShip_x, SpaceShip_y, 0, 1);
					break;
				}
			}
			mySpaceShip.handle_input();
			if(event.type == SDL_QUIT) {
				quit = true;
			}

		}
		bgY += 2;
		if(bgY >= game_bg->h) {
			bgY = 0;
		}
		mySpaceShip.move();
		Left_Bullet.Update();
		apply_surface(bgX, bgY, game_bg, screen);
		apply_surface(bgX, bgY-game_bg->h, game_bg, screen);
		mySpaceShip.show();
		Left_Bullet.Draw();
		if(SDL_Flip(screen) ==-1) {
			return 1;
		}
		if(fps.get_ticks() < 1000 / FPS) {
			SDL_Delay((1000 / FPS) - fps.get_ticks());
		}
	}
	clean_up();
	return 0;
}