#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_keycode.h>
#include <SDL2/SDL_rect.h>
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_surface.h>
#include <SDL2/SDL_video.h>
#include <cmath>
#include <cstddef>
#include <functional>
#include <memory>
#include <stdexcept>

#include "../api/Camera.h"
#include "../api/Sprite.h"
#include "../api/Texture.h"
#include "../api/Transform.h"
#include "../util/Log.h"

#include "types.h"
#include "SDLContext.h"

using namespace crepe;
using namespace std;

SDLContext & SDLContext::get_instance() {
	static SDLContext instance;
	return instance;
}

SDLContext::SDLContext() {
	dbg_trace();
	// FIXME: read window defaults from config manager

	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
		throw runtime_error(format("SDLContext: SDL_Init error: {}", SDL_GetError()));
	}
	SDL_Window * tmp_window
		= SDL_CreateWindow("Crepe Game Engine", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
						   this->viewport.w, this->viewport.h, 0);
	if (!tmp_window) {
		throw runtime_error(format("SDLContext: SDL_Window error: {}", SDL_GetError()));
	}
	this->game_window = {tmp_window, [](SDL_Window * window) { SDL_DestroyWindow(window); }};

	SDL_Renderer * tmp_renderer
		= SDL_CreateRenderer(this->game_window.get(), -1, SDL_RENDERER_ACCELERATED);
	if (!tmp_renderer) {
		throw runtime_error(
			format("SDLContext: SDL_CreateRenderer error: {}", SDL_GetError()));
	}

	this->game_renderer
		= {tmp_renderer, [](SDL_Renderer * renderer) { SDL_DestroyRenderer(renderer); }};

	int img_flags = IMG_INIT_PNG;
	if (!(IMG_Init(img_flags) & img_flags)) {
		throw runtime_error("SDLContext: SDL_image could not initialize!");
	}
}

SDLContext::~SDLContext() {
	dbg_trace();

	this->game_renderer.reset();
	this->game_window.reset();

	// TODO: how are we going to ensure that these are called from the same
	// thread that SDL_Init() was called on? This has caused problems for me
	// before.
	IMG_Quit();
	SDL_Quit();
}
void SDLContext::handle_events(bool & running) {
	//TODO: wouter i need events
	/*
	SDL_Event event;
	SDL_PollEvent(&event);
	switch (event.type) {
		case SDL_QUIT:
			running = false;
			break;
		case SDL_KEYDOWN:
			triggerEvent(KeyPressedEvent(getCustomKey(event.key.keysym.sym)));
			break;
		case SDL_MOUSEBUTTONDOWN:
			int x, y;
			SDL_GetMouseState(&x, &y);
			triggerEvent(MousePressedEvent(x, y));
			break;
	}
	*/
}

void SDLContext::clear_screen() {
	SDL_SetRenderDrawColor(this->game_renderer.get(), 0, 0, 0, 255);
	SDL_RenderClear(this->game_renderer.get());
}
void SDLContext::present_screen() { SDL_RenderPresent(this->game_renderer.get()); }

SDL_Rect SDLContext::get_src_rect(const Sprite & sprite) const {
	return SDL_Rect{
		.x = sprite.sprite_rect.x,
		.y = sprite.sprite_rect.y,
		.w = sprite.sprite_rect.w,
		.h = sprite.sprite_rect.h,
	};
}
SDL_Rect SDLContext::get_dst_rect(const Sprite & sprite, const vec2 & pos,
								  const vec2 & cam_pos, const double & img_scale,
								  const vec2 & cam_scale) const {

	int pixel_width, pixel_height;

	if (sprite.sprite_rect.w > sprite.sprite_rect.h) {
		pixel_width = static_cast<int>(sprite.width * cam_scale.x);
		pixel_height = static_cast<int>(pixel_width / sprite.aspect_ratio);
	} else {
		pixel_height = static_cast<int>(sprite.height * cam_scale.y);
		pixel_width = static_cast<int>(pixel_height * sprite.aspect_ratio);
	}

	pixel_width *= img_scale;
	pixel_height *= img_scale;

	int pixel_x = static_cast<int>((pos.x - cam_pos.x + this->viewport.w / 2 - pixel_width / 2));
	int pixel_y = static_cast<int>((pos.y - cam_pos.y + this->viewport.h / 2 - pixel_height / 2));

	return SDL_Rect{
		.x = pixel_x,
		.y = pixel_y,
		.w = pixel_width,
		.h = pixel_height,
	};
}

void SDLContext::draw_particle(const Sprite & sprite, const vec2 & pos,
							   const double & angle, const vec2 & cam_pos,
							   const double & img_scale, const vec2 & cam_scale) {

	SDL_RendererFlip render_flip
		= (SDL_RendererFlip) ((SDL_FLIP_HORIZONTAL * sprite.flip.flip_x)
							  | (SDL_FLIP_VERTICAL * sprite.flip.flip_y));

	SDL_Rect srcrect = this->get_src_rect(sprite);
	SDL_Rect dstrect = this->get_dst_rect(sprite, pos, cam_pos, img_scale, cam_scale);

	SDL_RenderCopyEx(this->game_renderer.get(), sprite.sprite_image->texture.get(), &srcrect,
					 &dstrect, angle, NULL, render_flip);
}

void SDLContext::draw(const Sprite & sprite, const Transform & transform,
					  const vec2 & cam_pos, const vec2 & cam_scale) {

	SDL_RendererFlip render_flip
		= (SDL_RendererFlip) ((SDL_FLIP_HORIZONTAL * sprite.flip.flip_x)
							  | (SDL_FLIP_VERTICAL * sprite.flip.flip_y));

	SDL_Rect srcrect = this->get_src_rect(sprite);
	SDL_Rect dstrect
		= this->get_dst_rect(sprite, transform.position, cam_pos, transform.scale, cam_scale);

	SDL_RenderCopyEx(this->game_renderer.get(), sprite.sprite_image->texture.get(), &srcrect,
					 &dstrect, transform.rotation, NULL, render_flip);
}

void SDLContext::set_camera(const Camera & cam, vec2 & scale) {

	// resize window
	if (this->viewport.w != (int) cam.screen.x || this->viewport.h != (int) cam.screen.y) {
		SDL_SetWindowSize(this->game_window.get(), (int) cam.screen.x, (int) cam.screen.y);
		this->viewport.h = (int)cam.screen.y;
		this->viewport.w = (int)cam.screen.x;
	}

	double screen_aspect = cam.screen.x / cam.screen.y;
	double viewport_aspect = cam.viewport.x / cam.viewport.y;
	
	// decide scaling factor for world to screen
	scale = cam.screen / cam.viewport * cam.zoom;

	SDL_Rect view;
	
	// calculate black bars
	if (screen_aspect > viewport_aspect) {
		// lettorboxing
		view.w = static_cast<int>(cam.screen.y * viewport_aspect);
		view.x = static_cast<int>(cam.screen.x - view.w) / 2;
		view.y = 0;
	} else {
		// pillarboxing
		view.h = static_cast<int>(cam.screen.x / viewport_aspect);
		view.w = static_cast<int>(cam.screen.x / cam.zoom);
		view.x = 0;
		view.y = static_cast<int>(cam.screen.y - view.h) / 2;
	}
	// set drawing area 
	SDL_RenderSetViewport(this->game_renderer.get(), &view);

	SDL_RenderSetLogicalSize(this->game_renderer.get(), cam.viewport.x, cam.viewport.y);

	// set bg color
	SDL_SetRenderDrawColor(this->game_renderer.get(), cam.bg_color.r, cam.bg_color.g,
						   cam.bg_color.b, cam.bg_color.a);

	SDL_Rect bg = {
		.x = 0,
		.y = 0,
		.w = static_cast<int>(cam.viewport.x),
		.h = static_cast<int>(cam.viewport.y),
	};
	// fill bg color
	SDL_RenderFillRect(this->game_renderer.get(), &bg);
}

uint64_t SDLContext::get_ticks() const { return SDL_GetTicks64(); }

std::unique_ptr<SDL_Texture, std::function<void(SDL_Texture *)>>
SDLContext::texture_from_path(const std::string & path) {

	SDL_Surface * tmp = IMG_Load(path.c_str());
	if (tmp == nullptr)
		throw runtime_error(format("SDLContext: IMG_Load error: {}", SDL_GetError()));

	std::unique_ptr<SDL_Surface, std::function<void(SDL_Surface *)>> img_surface;
	img_surface = {tmp, [](SDL_Surface * surface) { SDL_FreeSurface(surface); }};

	SDL_Texture * tmp_texture
		= SDL_CreateTextureFromSurface(this->game_renderer.get(), img_surface.get());

	if (tmp_texture == nullptr) {
		throw runtime_error(format("SDLContext: Texture cannot be load from {}", path));
	}

	std::unique_ptr<SDL_Texture, std::function<void(SDL_Texture *)>> img_texture;
	img_texture = {tmp_texture, [](SDL_Texture * texture) { SDL_DestroyTexture(texture); }};

	return img_texture;
}
int SDLContext::get_width(const Texture & ctx) const {
	int w;
	SDL_QueryTexture(ctx.texture.get(), NULL, NULL, &w, NULL);
	return w;
}
int SDLContext::get_height(const Texture & ctx) const {
	int h;
	SDL_QueryTexture(ctx.texture.get(), NULL, NULL, NULL, &h);
	return h;
}
void SDLContext::delay(int ms) const { SDL_Delay(ms); }