#include "Engine.hpp"
#include "Platform.hpp"
#include <cstdint>
#include <SDL2/SDL.h>


void constexpr SetBit(uint32_t& x, unsigned long bit)
{
	x |= (1UL << bit);
}

void constexpr ClearBit(uint32_t& x, unsigned long bit)
{
	x &= ~(1UL << bit);
}

static void HandleEvent(Platform& platform, SDL_Event& event);


PlatformStatus Platform_Init(Platform& platform, int width, int height)
{
	int result = SDL_Init(SDL_INIT_VIDEO);
	if (result < 0)
	{
		fprintf(stderr, "Error initializing SDL: %s\n", SDL_GetError());
		return PlatformStatus::Error;
	}


	SDL_Window* window = SDL_CreateWindow(
		"Soft 3D Engine",
		SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
		width, height,
		SDL_WINDOW_SHOWN);
	if (window == nullptr)
	{
		fprintf(stderr, "Error creating SDL window: %s\n", SDL_GetError());
		return PlatformStatus::Error;
	}


	SDL_Surface* surface = SDL_GetWindowSurface(window);
	if (surface == nullptr)
	{
		fprintf(stderr, "Error getting SDL window surface: %s\n", SDL_GetError());
		return PlatformStatus::Error;
	}


	result = SDL_ShowCursor(SDL_DISABLE);
	if (result < 0)
	{
		fprintf(stderr, "Error disabling cursor in SDL window: %s\n", SDL_GetError());
		return PlatformStatus::Error;
	}

	platform.framerateMillis = (1000 / WINDOW_FPS);
	platform.window = window;
	platform.surface = surface;

	return PlatformStatus::Ok;
}

PlatformStatus Platform_CheckForEvents(Platform& platform)
{
	SDL_Event event;

	while (SDL_PollEvent(&event) != 0)
	{
		if (event.type == SDL_QUIT)
		{
			return PlatformStatus::Quit;
		}
		else
		{
			HandleEvent(platform, event);
		}
	}

	return PlatformStatus::Ok;
}

void Platform_ClearWindow(Platform& platform)
{
	SDL_LockSurface(platform.surface);
	SDL_FillRect(platform.surface, nullptr, 0);
}

void Platform_UpdateWindow(Platform& platform)
{
	SDL_UnlockSurface(platform.surface);
	SDL_UpdateWindowSurface(platform.window);
}

void Platform_GetFrameTime(Platform& platform)
{
	platform.frameStartMillis = SDL_GetTicks();
}

void Platform_SyncToFramerate(Platform& platform)
{
	uint32_t stopTimeMillis = SDL_GetTicks();
	uint32_t framerateMillis = stopTimeMillis - platform.frameStartMillis;

	// Delay if time to spare
	if (framerateMillis < platform.framerateMillis)
	{
		uint32_t delayMillis = platform.framerateMillis - framerateMillis;
		SDL_Delay(delayMillis);
	}
}

void Platform_Shutdown(Platform& platform)
{
	SDL_DestroyWindow(platform.window);
	SDL_Quit();
}


// PRIVATE FUNCTIONS
static void HandleEvent(
	Platform& platform, SDL_Event& event)
{
	if (event.type == SDL_KEYDOWN)
	{
		if (event.key.keysym.sym == SDLK_w)
		{
			SetBit(platform.input, TRANSLATE_Z_POS);
		}
		else if (event.key.keysym.sym == SDLK_s)
		{
			SetBit(platform.input, TRANSLATE_Z_NEG);
		}
		else if (event.key.keysym.sym == SDLK_a)
		{
			SetBit(platform.input, TRANSLATE_X_NEG);
		}
		else if (event.key.keysym.sym == SDLK_d)
		{
			SetBit(platform.input, TRANSLATE_X_POS);
		}
		else if (event.key.keysym.sym == SDLK_q)
		{
			SetBit(platform.input, TRANSLATE_Y_POS);
		}
		else if (event.key.keysym.sym == SDLK_e)
		{
			SetBit(platform.input, TRANSLATE_Y_NEG);
		}
		else if (event.key.keysym.sym == SDLK_i)
		{
			SetBit(platform.input, ROTATE_X_POS);
		}
		else if (event.key.keysym.sym == SDLK_k)
		{
			SetBit(platform.input, ROTATE_X_NEG);
		}
		else if (event.key.keysym.sym == SDLK_j)
		{
			SetBit(platform.input, ROTATE_Y_POS);
		}
		else if (event.key.keysym.sym == SDLK_l)
		{
			SetBit(platform.input, ROTATE_Y_NEG);
		}
		else if (event.key.keysym.sym == SDLK_u)
		{
			SetBit(platform.input, ROTATE_Z_POS);
		}
		else if (event.key.keysym.sym == SDLK_o)
		{
			SetBit(platform.input, ROTATE_Z_NEG);
		}
		else if (event.key.keysym.sym == SDLK_UP)
		{
			SetBit(platform.input, SCALE_UP);
		}
		else if (event.key.keysym.sym == SDLK_DOWN)
		{
			SetBit(platform.input, SCALE_DOWN);
		}
	}
	else if (event.type == SDL_KEYUP)
	{
		if (event.key.keysym.sym == SDLK_w)
		{
			ClearBit(platform.input, TRANSLATE_Z_POS);
		}
		else if (event.key.keysym.sym == SDLK_s)
		{
			ClearBit(platform.input, TRANSLATE_Z_NEG);
		}
		else if (event.key.keysym.sym == SDLK_a)
		{
			ClearBit(platform.input, TRANSLATE_X_NEG);
		}
		else if (event.key.keysym.sym == SDLK_d)
		{
			ClearBit(platform.input, TRANSLATE_X_POS);
		}
		else if (event.key.keysym.sym == SDLK_q)
		{
			ClearBit(platform.input, TRANSLATE_Y_POS);
		}
		else if (event.key.keysym.sym == SDLK_e)
		{
			ClearBit(platform.input, TRANSLATE_Y_NEG);
		}
		else if (event.key.keysym.sym == SDLK_i)
		{
			ClearBit(platform.input, ROTATE_X_POS);
		}
		else if (event.key.keysym.sym == SDLK_k)
		{
			ClearBit(platform.input, ROTATE_X_NEG);
		}
		else if (event.key.keysym.sym == SDLK_j)
		{
			ClearBit(platform.input, ROTATE_Y_POS);
		}
		else if (event.key.keysym.sym == SDLK_l)
		{
			ClearBit(platform.input, ROTATE_Y_NEG);
		}
		else if (event.key.keysym.sym == SDLK_u)
		{
			ClearBit(platform.input, ROTATE_Z_POS);
		}
		else if (event.key.keysym.sym == SDLK_o)
		{
			ClearBit(platform.input, ROTATE_Z_NEG);
		}
		else if (event.key.keysym.sym == SDLK_UP)
		{
			ClearBit(platform.input, SCALE_UP);
		}
		else if (event.key.keysym.sym == SDLK_DOWN)
		{
			ClearBit(platform.input, SCALE_DOWN);
		}
	}
}