#include <SDL2/SDL.h>
#include <SDL2/SDL_blendmode.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 <iostream>

#include <array>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <functional>
#include <memory>
#include <stdexcept>

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

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

using namespace crepe;
using namespace std;

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

SDLContext::SDLContext() {
	dbg_trace();

	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
		throw runtime_error(format("SDLContext: SDL_Init error: {}", SDL_GetError()));
	}

	auto & cfg = Config::get_instance().window_settings;
	SDL_Window * tmp_window
		= SDL_CreateWindow(cfg.window_title.c_str(), SDL_WINDOWPOS_CENTERED,
						   SDL_WINDOWPOS_CENTERED, cfg.default_size.x, cfg.default_size.y, 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();
}

// Function that uses the shared table
Keycode SDLContext::sdl_to_keycode(SDL_Keycode sdl_key) {
	static const std::array<Keycode, SDL_NUM_SCANCODES> LOOKUP_TABLE = [] {
        std::array<Keycode, SDL_NUM_SCANCODES> table{};
        table.fill(Keycode::NONE);

        // Map all SDL scancodes to Keycodes
        table[SDL_SCANCODE_SPACE] = Keycode::SPACE;
        table[SDL_SCANCODE_APOSTROPHE] = Keycode::APOSTROPHE;
        table[SDL_SCANCODE_COMMA] = Keycode::COMMA;
        table[SDL_SCANCODE_MINUS] = Keycode::MINUS;
        table[SDL_SCANCODE_PERIOD] = Keycode::PERIOD;
        table[SDL_SCANCODE_SLASH] = Keycode::SLASH;
        table[SDL_SCANCODE_0] = Keycode::D0;
        table[SDL_SCANCODE_1] = Keycode::D1;
        table[SDL_SCANCODE_2] = Keycode::D2;
        table[SDL_SCANCODE_3] = Keycode::D3;
        table[SDL_SCANCODE_4] = Keycode::D4;
        table[SDL_SCANCODE_5] = Keycode::D5;
        table[SDL_SCANCODE_6] = Keycode::D6;
        table[SDL_SCANCODE_7] = Keycode::D7;
        table[SDL_SCANCODE_8] = Keycode::D8;
        table[SDL_SCANCODE_9] = Keycode::D9;
        table[SDL_SCANCODE_SEMICOLON] = Keycode::SEMICOLON;
        table[SDL_SCANCODE_EQUALS] = Keycode::EQUAL;
        table[SDL_SCANCODE_A] = Keycode::A;
        table[SDL_SCANCODE_B] = Keycode::B;
        table[SDL_SCANCODE_C] = Keycode::C;
        table[SDL_SCANCODE_D] = Keycode::D;
        table[SDL_SCANCODE_E] = Keycode::E;
        table[SDL_SCANCODE_F] = Keycode::F;
        table[SDL_SCANCODE_G] = Keycode::G;
        table[SDL_SCANCODE_H] = Keycode::H;
        table[SDL_SCANCODE_I] = Keycode::I;
        table[SDL_SCANCODE_J] = Keycode::J;
        table[SDL_SCANCODE_K] = Keycode::K;
        table[SDL_SCANCODE_L] = Keycode::L;
        table[SDL_SCANCODE_M] = Keycode::M;
        table[SDL_SCANCODE_N] = Keycode::N;
        table[SDL_SCANCODE_O] = Keycode::O;
        table[SDL_SCANCODE_P] = Keycode::P;
        table[SDL_SCANCODE_Q] = Keycode::Q;
        table[SDL_SCANCODE_R] = Keycode::R;
        table[SDL_SCANCODE_S] = Keycode::S;
        table[SDL_SCANCODE_T] = Keycode::T;
        table[SDL_SCANCODE_U] = Keycode::U;
        table[SDL_SCANCODE_V] = Keycode::V;
        table[SDL_SCANCODE_W] = Keycode::W;
        table[SDL_SCANCODE_X] = Keycode::X;
        table[SDL_SCANCODE_Y] = Keycode::Y;
        table[SDL_SCANCODE_Z] = Keycode::Z;
        table[SDL_SCANCODE_LEFTBRACKET] = Keycode::LEFT_BRACKET;
        table[SDL_SCANCODE_BACKSLASH] = Keycode::BACKSLASH;
        table[SDL_SCANCODE_RIGHTBRACKET] = Keycode::RIGHT_BRACKET;
        table[SDL_SCANCODE_GRAVE] = Keycode::GRAVE_ACCENT;
        table[SDL_SCANCODE_ESCAPE] = Keycode::ESCAPE;
        table[SDL_SCANCODE_RETURN] = Keycode::ENTER;
        table[SDL_SCANCODE_TAB] = Keycode::TAB;
        table[SDL_SCANCODE_BACKSPACE] = Keycode::BACKSPACE;
        table[SDL_SCANCODE_INSERT] = Keycode::INSERT;
        table[SDL_SCANCODE_DELETE] = Keycode::DELETE;
        table[SDL_SCANCODE_RIGHT] = Keycode::RIGHT;
        table[SDL_SCANCODE_LEFT] = Keycode::LEFT;
        table[SDL_SCANCODE_DOWN] = Keycode::DOWN;
        table[SDL_SCANCODE_UP] = Keycode::UP;
        table[SDL_SCANCODE_PAGEUP] = Keycode::PAGE_UP;
        table[SDL_SCANCODE_PAGEDOWN] = Keycode::PAGE_DOWN;
        table[SDL_SCANCODE_HOME] = Keycode::HOME;
        table[SDL_SCANCODE_END] = Keycode::END;
        table[SDL_SCANCODE_CAPSLOCK] = Keycode::CAPS_LOCK;
        table[SDL_SCANCODE_SCROLLLOCK] = Keycode::SCROLL_LOCK;
        table[SDL_SCANCODE_NUMLOCKCLEAR] = Keycode::NUM_LOCK;
        table[SDL_SCANCODE_PRINTSCREEN] = Keycode::PRINT_SCREEN;
        table[SDL_SCANCODE_PAUSE] = Keycode::PAUSE;
        table[SDL_SCANCODE_F1] = Keycode::F1;
        table[SDL_SCANCODE_F2] = Keycode::F2;
        table[SDL_SCANCODE_F3] = Keycode::F3;
        table[SDL_SCANCODE_F4] = Keycode::F4;
        table[SDL_SCANCODE_F5] = Keycode::F5;
        table[SDL_SCANCODE_F6] = Keycode::F6;
        table[SDL_SCANCODE_F7] = Keycode::F7;
        table[SDL_SCANCODE_F8] = Keycode::F8;
        table[SDL_SCANCODE_F9] = Keycode::F9;
        table[SDL_SCANCODE_F10] = Keycode::F10;
        table[SDL_SCANCODE_F11] = Keycode::F11;
        table[SDL_SCANCODE_F12] = Keycode::F12;
        table[SDL_SCANCODE_KP_0] = Keycode::KP0;
        table[SDL_SCANCODE_KP_1] = Keycode::KP1;
        table[SDL_SCANCODE_KP_2] = Keycode::KP2;
        table[SDL_SCANCODE_KP_3] = Keycode::KP3;
        table[SDL_SCANCODE_KP_4] = Keycode::KP4;
        table[SDL_SCANCODE_KP_5] = Keycode::KP5;
        table[SDL_SCANCODE_KP_6] = Keycode::KP6;
        table[SDL_SCANCODE_KP_7] = Keycode::KP7;
        table[SDL_SCANCODE_KP_8] = Keycode::KP8;
        table[SDL_SCANCODE_KP_9] = Keycode::KP9;
        table[SDL_SCANCODE_LSHIFT] = Keycode::LEFT_SHIFT;
        table[SDL_SCANCODE_LCTRL] = Keycode::LEFT_CONTROL;
        table[SDL_SCANCODE_LALT] = Keycode::LEFT_ALT;
        table[SDL_SCANCODE_LGUI] = Keycode::LEFT_SUPER;
        table[SDL_SCANCODE_RSHIFT] = Keycode::RIGHT_SHIFT;
        table[SDL_SCANCODE_RCTRL] = Keycode::RIGHT_CONTROL;
        table[SDL_SCANCODE_RALT] = Keycode::RIGHT_ALT;
        table[SDL_SCANCODE_RGUI] = Keycode::RIGHT_SUPER;
        table[SDL_SCANCODE_MENU] = Keycode::MENU;

        return table;
    }();
    if (sdl_key < 0 || sdl_key >= SDL_NUM_SCANCODES) {
        return Keycode::NONE;
    }
    return LOOKUP_TABLE[sdl_key];
}
std::array<bool, Keycode::NUM_KEYCODES> SDLContext::get_keyboard_state() {
    // Array to hold the key states (true if pressed, false if not)
    std::array<bool, SDL_NUM_SCANCODES> keyState;

    const Uint8* current_state = SDL_GetKeyboardState(nullptr);

    for (int i = 0; i < SDL_NUM_SCANCODES; ++i) {
        // Set true if the key is pressed, false if not
        keyState[i] = current_state[i] != 0;
    }

    return keyState;
}

MouseButton SDLContext::sdl_to_mousebutton(Uint8 sdl_button) {
	static const std::array<MouseButton, 5> MOUSE_BUTTON_LOOKUP_TABLE = [] {
		std::array<MouseButton, 5> table{};
		table.fill(MouseButton::NONE);

		table[SDL_BUTTON_LEFT] = MouseButton::LEFT_MOUSE;
		table[SDL_BUTTON_RIGHT] = MouseButton::RIGHT_MOUSE;
		table[SDL_BUTTON_MIDDLE] = MouseButton::MIDDLE_MOUSE;
		table[SDL_BUTTON_X1] = MouseButton::X1_MOUSE;
		table[SDL_BUTTON_X2] = MouseButton::X2_MOUSE;

		return table;
	}();

	if (sdl_button >= MOUSE_BUTTON_LOOKUP_TABLE.size()) {
		// Return NONE for invalid or unmapped button
		return MouseButton::NONE;
	}

	return MOUSE_BUTTON_LOOKUP_TABLE[sdl_button];
}

void SDLContext::clear_screen() { SDL_RenderClear(this->game_renderer.get()); }
void SDLContext::present_screen() {
	SDL_SetRenderDrawColor(this->game_renderer.get(), 0, 0, 0, 255);
	SDL_RenderFillRectF(this->game_renderer.get(), &black_bars[0]);
	SDL_RenderFillRectF(this->game_renderer.get(), &black_bars[1]);
	SDL_RenderPresent(this->game_renderer.get());
}

SDL_Rect SDLContext::get_src_rect(const Sprite & sprite) const {
	return SDL_Rect{
		.x = sprite.mask.x,
		.y = sprite.mask.y,
		.w = sprite.mask.w,
		.h = sprite.mask.h,
	};
}

SDL_FRect SDLContext::get_dst_rect(const DestinationRectangleData & ctx) const {

	const Sprite::Data & data = ctx.sprite.data;

	vec2 size = data.size;
	if (data.size.x == 0 && data.size.y != 0) {
		size.x = data.size.y * ctx.sprite.aspect_ratio;
	}
	if (data.size.y == 0 && data.size.x != 0) {
		size.y = data.size.x / ctx.sprite.aspect_ratio;
	}

	const CameraValues & cam = ctx.cam;

	size *= cam.render_scale * ctx.img_scale * data.scale_offset;

	vec2 screen_pos
		= (ctx.pos + data.position_offset - cam.cam_pos + (cam.zoomed_viewport) / 2)
			  * cam.render_scale
		  - size / 2 + cam.bar_size;

	return SDL_FRect{
		.x = screen_pos.x,
		.y = screen_pos.y,
		.w = size.x,
		.h = size.y,
	};
}

void SDLContext::draw(const RenderContext & ctx) {

	const Sprite::Data & data = ctx.sprite.data;
	SDL_RendererFlip render_flip
		= (SDL_RendererFlip) ((SDL_FLIP_HORIZONTAL * data.flip.flip_x)
							  | (SDL_FLIP_VERTICAL * data.flip.flip_y));

	SDL_Rect srcrect = this->get_src_rect(ctx.sprite);
	SDL_FRect dstrect = this->get_dst_rect(SDLContext::DestinationRectangleData{
		.sprite = ctx.sprite,
		.cam = ctx.cam,
		.pos = ctx.pos,
		.img_scale = ctx.scale,
	});

	double angle = ctx.angle + data.angle_offset;

	this->set_color_texture(ctx.sprite.texture, ctx.sprite.data.color);
	SDL_RenderCopyExF(this->game_renderer.get(), ctx.sprite.texture.texture.get(), &srcrect,
					  &dstrect, angle, NULL, render_flip);
}

SDLContext::CameraValues SDLContext::set_camera(const Camera & cam) {

	const Camera::Data & cam_data = cam.data;
	CameraValues ret_cam;
	// resize window
	int w, h;
	SDL_GetWindowSize(this->game_window.get(), &w, &h);
	if (w != cam.screen.x || h != cam.screen.y) {
		SDL_SetWindowSize(this->game_window.get(), cam.screen.x, cam.screen.y);
	}

	vec2 & zoomed_viewport = ret_cam.zoomed_viewport;
	vec2 & bar_size = ret_cam.bar_size;
	vec2 & render_scale = ret_cam.render_scale;

	zoomed_viewport = cam.viewport_size * cam_data.zoom;
	float screen_aspect = static_cast<float>(cam.screen.x) / cam.screen.y;
	float viewport_aspect = zoomed_viewport.x / zoomed_viewport.y;

	// calculate black bars
	if (screen_aspect > viewport_aspect) {
		// pillarboxing
		float scale = cam.screen.y / zoomed_viewport.y;
		float adj_width = zoomed_viewport.x * scale;
		float bar_width = (cam.screen.x - adj_width) / 2;
		this->black_bars[0] = {0, 0, bar_width, (float) cam.screen.y};
		this->black_bars[1] = {(cam.screen.x - bar_width), 0, bar_width, (float) cam.screen.y};

		bar_size = {bar_width, 0};
		render_scale.x = render_scale.y = scale;
	} else {
		// letterboxing
		float scale = cam.screen.x / (cam.viewport_size.x * cam_data.zoom);
		float adj_height = cam.viewport_size.y * scale;
		float bar_height = (cam.screen.y - adj_height) / 2;
		this->black_bars[0] = {0, 0, (float) cam.screen.x, bar_height};
		this->black_bars[1]
			= {0, (cam.screen.y - bar_height), (float) cam.screen.x, bar_height};

		bar_size = {0, bar_height};
		render_scale.x = render_scale.y = scale;
	}

	SDL_SetRenderDrawColor(this->game_renderer.get(), cam_data.bg_color.r, cam_data.bg_color.g,
						   cam_data.bg_color.b, cam_data.bg_color.a);

	SDL_Rect bg = {
		.x = 0,
		.y = 0,
		.w = cam.screen.x,
		.h = cam.screen.y,
	};

	// fill bg color
	SDL_RenderFillRect(this->game_renderer.get(), &bg);

	return ret_cam;
}

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); }};

	SDL_SetTextureBlendMode(img_texture.get(), SDL_BLENDMODE_BLEND);
	return img_texture;
}

ivec2 SDLContext::get_size(const Texture & ctx) {
	ivec2 size;
	SDL_QueryTexture(ctx.texture.get(), NULL, NULL, &size.x, &size.y);
	return size;
}

void SDLContext::delay(int ms) const { SDL_Delay(ms); }

std::vector<SDLContext::EventData> SDLContext::get_events() {
    std::vector<SDLContext::EventData> event_list;
    SDL_Event event;

    // Handle general SDL events
    while (SDL_PollEvent(&event)) {
        switch (event.type) {
            case SDL_QUIT:
                event_list.push_back({SDLContext::EventType::SHUTDOWN, {}, {}, {}});
                break;
            case SDL_KEYDOWN:
                event_list.push_back({SDLContext::EventType::KEYDOWN, 
                                      {sdl_to_keycode(event.key.keysym.scancode), event.key.repeat != 0}, {}, {}});
                break;
            case SDL_KEYUP:
                event_list.push_back({SDLContext::EventType::KEYUP, 
                                      {sdl_to_keycode(event.key.keysym.scancode), false}, {}, {}});
                break;
            case SDL_MOUSEBUTTONDOWN:
                event_list.push_back({SDLContext::EventType::MOUSEDOWN, {}, 
                                      {sdl_to_mousebutton(event.button.button), {event.button.x, event.button.y}}, {}});
                break;
            case SDL_MOUSEBUTTONUP:
                event_list.push_back({SDLContext::EventType::MOUSEUP, {}, 
                                      {sdl_to_mousebutton(event.button.button), {event.button.x, event.button.y}}, {}});
                break;
            case SDL_MOUSEMOTION:
                event_list.push_back({SDLContext::EventType::MOUSEMOVE, {}, 
                                      {{}, {event.motion.x, event.motion.y}, -1, INFINITY, {event.motion.xrel, event.motion.yrel}}, {}});
                break;
            case SDL_MOUSEWHEEL:
                event_list.push_back({SDLContext::EventType::MOUSEWHEEL, {}, 
                                      {{}, {}, event.wheel.y < 0 ? -1 : 1, event.wheel.preciseY, {}}, {}});
                break;

            // Forward window events for further processing
            case SDL_WINDOWEVENT:
                this->handle_window_event(event.window, event_list);
                break;
        }
    }

    return event_list;
}

// Separate function for SDL_WINDOWEVENT subtypes
void SDLContext::handle_window_event(const SDL_WindowEvent& window_event,
                                     std::vector<SDLContext::EventData>& event_list) {
    switch (window_event.event) {
        case SDL_WINDOWEVENT_EXPOSED:
            event_list.push_back({SDLContext::EventType::WINDOW_EXPOSE, {}, {}, {}});
            break;
        case SDL_WINDOWEVENT_RESIZED:
			std::cout << "window resize" << std::endl;
            event_list.push_back({SDLContext::EventType::WINDOW_RESIZE, {}, {}, 
                                  {{}, {window_event.data1, window_event.data2}}});
            break;
        case SDL_WINDOWEVENT_MOVED:
            event_list.push_back({SDLContext::EventType::WINDOW_MOVE, {}, {}, 
                                  {{window_event.data1, window_event.data2}, {}}});
            break;
        case SDL_WINDOWEVENT_MINIMIZED:
            event_list.push_back({SDLContext::EventType::WINDOW_MINIMIZE, {}, {}, {}});
            break;
        case SDL_WINDOWEVENT_MAXIMIZED:
            event_list.push_back({SDLContext::EventType::WINDOW_MAXIMIZE, {}, {}, {}});
            break;
        case SDL_WINDOWEVENT_FOCUS_GAINED:
            event_list.push_back({SDLContext::EventType::WINDOW_FOCUS_GAIN, {}, {}, {}});
            break;
        case SDL_WINDOWEVENT_FOCUS_LOST:
            event_list.push_back({SDLContext::EventType::WINDOW_FOCUS_LOST, {}, {}, {}});
            break;
    }
}




void SDLContext::set_color_texture(const Texture & texture, const Color & color) {
	SDL_SetTextureColorMod(texture.texture.get(), color.r, color.g, color.b);
	SDL_SetTextureAlphaMod(texture.texture.get(), color.a);
}