#include "GL/glew.h"
#include "SDL3/SDL.h"

#include "prge.h"

#include "game.h"
#include "game.c"

void process_mouse_pos(Input *input, SDL_MouseMotionEvent *mouseev)
{
	V2	offset;

	input->mouse_pos = v2((F32)mouseev->x, (F32)mouseev->y);

	if (input->first_mouse)
		input->first_mouse = 0;

	offset = v2((F32)mouseev->xrel, (F32)mouseev->yrel);
	input->mouse_offset = v2add(input->mouse_offset, offset);
}

void process_key(B32 down, Key *key)
{
	key->state = (down ? KeyState_PRESS : KeyState_RELEASE);
}

void process_keyboard(Input *input, SDL_KeyboardEvent *keyev)
{
	switch (keyev->scancode) {
	case SDL_SCANCODE_D:
		process_key(keyev->down, &input->move_right);
		break;
	case SDL_SCANCODE_W:
		process_key(keyev->down, &input->move_forward);
		break;
	case SDL_SCANCODE_A:
		process_key(keyev->down, &input->move_left);
		break;
	case SDL_SCANCODE_S:
		process_key(keyev->down, &input->move_backward);
		break;
	case SDL_SCANCODE_E:
		process_key(keyev->down, &input->move_up);
		break;
	case SDL_SCANCODE_Q:
		process_key(keyev->down, &input->move_down);
		break;
	case SDL_SCANCODE_SPACE:
		process_key(keyev->down, &input->jump);
		break;
	case SDL_SCANCODE_RIGHT:
		process_key(keyev->down, &input->action_right);
		break;
	case SDL_SCANCODE_UP:
		process_key(keyev->down, &input->action_up);
		break;
	case SDL_SCANCODE_LEFT:
		process_key(keyev->down, &input->action_left);
		break;
	case SDL_SCANCODE_DOWN:
		process_key(keyev->down, &input->action_down);
		break;
	case SDL_SCANCODE_ESCAPE:
		process_key(keyev->down, &input->exit);
		break;
	default:
		break;
	}
}

void process_mouse_buttons(Input *input, SDL_MouseButtonEvent *buttonev)
{
	if (buttonev->button == SDL_BUTTON_LEFT)
		process_key(buttonev->down, &input->mouse_left);
	else if (buttonev->button == SDL_BUTTON_RIGHT)
		process_key(buttonev->down, &input->mouse_right);
}

void handle_events(Window *wnd, Input *input)
{
	SDL_Event	event;

	while (SDL_PollEvent(&event)) {
		switch (event.type) {
		case SDL_EVENT_KEY_DOWN:
		case SDL_EVENT_KEY_UP:
			process_keyboard(input, &event.key);
			break;
		case SDL_EVENT_MOUSE_MOTION:
			process_mouse_pos(input, &event.motion);
			break;
		case SDL_EVENT_MOUSE_BUTTON_DOWN:
		case SDL_EVENT_MOUSE_BUTTON_UP:
			process_mouse_buttons(input, &event.button);
			break;
		case SDL_EVENT_WINDOW_RESIZED:
			wnd->width = event.window.data1;
			wnd->height = event.window.data2;
			break;
		default:
			break;
		}
	}
}

F32 get_elapsed_seconds(U64 cur, U64 last)
{
	F32	res;
	res = ((F32)cur-(F32)last)/1000.0f;
	return res;
}

F32 lock_framerate(U64 last, F32 target)
{
        F32	target_mspf, elapsed, sleep, dt;

	elapsed = get_elapsed_seconds(SDL_GetTicks(), last)*1000.0f;
	target_mspf = 1000.0f/target;
 
	if (elapsed < target_mspf) {
		sleep = target_mspf-elapsed;
		if (sleep > 0.0f)
			SDL_Delay(sleep);
		/*
		do {
			elapsed = get_elapsed_seconds(SDL_GetTicks(), last)*1000.0f;
		} while (elapsed < target_mspf);
		*/
	}

	dt = get_elapsed_seconds(SDL_GetTicks(), last);

	return dt;
}

B32 sdl_init(Window *wnd, SDL_Window **sdl_window, SDL_GLContext *context)
{
	U32	flags;
	GLenum	error;
	Arena	*tmpar;
	char	*wname;

	if (!SDL_Init(SDL_INIT_VIDEO)) {
		SDL_Log("[ERROR] : SDL : %s\n", SDL_GetError());
		return 0;
	}

	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

	tmpar = arena_alloc(0);
	wname = str8tocstr(tmpar, wnd->name);

	flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE;

	(*sdl_window) = SDL_CreateWindow(wname, wnd->width, wnd->height, flags);
	
	arena_release(tmpar);

	if (!(*sdl_window)) {
		SDL_Log("[ERROR] : SDL : %s\n", SDL_GetError());
		return 0;
	}

	SDL_GetWindowSize(*sdl_window, &wnd->width, &wnd->height);

	(*context) = SDL_GL_CreateContext((*sdl_window));
	if (!(*context)) {
		SDL_Log("[ERROR] : SDL : %s\n", SDL_GetError());
		return 0;
	}

	error = glewInit();
	if (error != GLEW_OK) {
		SDL_Log("[ERROR] : GLEW : %s\n", glewGetErrorString(error));
		return 0;
	}

	return 1;
}

int main(void)
{
	/* NOTE(pryazha): Engine init */
	Input		input;
	Window		wnd;

	input = input_init();
	wnd = window_init(800, 600, str8lit("PRGE example"));

	/* NOTE(pryazha): SDL and OpenGL init */
	SDL_Window	*sdl_window;
	SDL_GLContext	context;
	U64		last;

	if (!sdl_init(&wnd, &sdl_window, &context)) {
		SDL_Quit();
		return 1;
	}

	glEnable(GL_DEPTH_TEST);

	/* NOTE(pryazha): Game init */
	State		state;
	MemoryZero(&state, sizeof(State));
	
	init(&state);

	last = SDL_GetTicks();

	while (input.is_running) {
		SDL_SetWindowRelativeMouseMode(sdl_window, input.capture_mouse);

		handle_events(&wnd, &input);

		input.dt = lock_framerate(last, 60.0f);
		last = SDL_GetTicks();

		update_and_render(&wnd, &state, &input);

		input_update(&input);

		SDL_GL_SwapWindow(sdl_window);
	}

	clear(&state);

	SDL_GL_DestroyContext(context);
	SDL_DestroyWindow(sdl_window);
	SDL_Quit();
	return 0;
}