#include "input.h"
#include "renderer.h"

#include <linux/input-event-codes.h>
#include <stdio.h>
#include <sys/select.h>

#define LIN_PWR 0.0001
#define ROT_PWR 0.001

#define MAX(a, b) ((a) < (b) ? (b) : (a))
#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))

static float aspect;
static bool quit = false;

static struct {
	int rot;
	int fwd;
} input;

static struct {
	vec2_t pos;
	vec2_t vel;
	mat2_t dir;
	float omg;
} state;

static const vec2_t ship[] = {
	{ 0.0, 0.08 },
	{ 0.05, -0.1 },
	{ 0.0, -0.07 },
	{ -0.05, -0.1 },
};
static const vec2_t fire[] = {
	{ 0.015, -0.1 },
	{ -0.015, -0.1 },
	{ 0.0, -0.15 },
};

static const vec2_t thrust = { 0, LIN_PWR };

static void key_press_callback(int key)
{
	switch (key) {
	case KEY_Q:
		quit = true;
		break;

	case KEY_UP:
		++input.fwd;
		break;

	case KEY_LEFT:
		++input.rot;
		break;
	case KEY_RIGHT:
		--input.rot;
		break;

	default:
		break;
	}
}

static void key_release_callback(int key)
{
	switch (key) {
	case KEY_Q:
		quit = true;
		break;

	case KEY_UP:
		--input.fwd;
		break;

	case KEY_LEFT:
		--input.rot;
		break;
	case KEY_RIGHT:
		++input.rot;
		break;

	default:
		break;
	}
}

static mat3_t update()
{
	state.omg += ROT_PWR * (float)input.rot;
	state.dir = mat2_mul_mat2(mat2_rotation(state.omg), state.dir);

	const vec2_t acc
	    = mat2_mul_vec2(state.dir, vec2_scale(thrust, (float)input.fwd));
	state.vel = vec2_add(state.vel, acc);
	state.pos = vec2_add(state.pos, state.vel);

	if (state.pos.y > 1)
		state.pos.y -= 2;
	else if (state.pos.y < -1)
		state.pos.y += 2;
	if (state.pos.x > aspect)
		state.pos.x -= 2 * aspect;
	else if (state.pos.x < -aspect)
		state.pos.x += 2 * aspect;

	return mat3_mul_mat3(
	    mat3_translation(state.pos), mat2_extend(state.dir));
}

int main()
{
	const int input_fd = input_init();
	input_on_press(key_press_callback);
	input_on_release(key_release_callback);

	const renderer_params_t renderer_params = renderer_init();
	aspect = renderer_params.aspect;
	const int drm_fd = renderer_params.drm_fd;
	renderer_clear();
	renderer_swap();

	state.dir = (mat2_t) { { 1, 0 }, { 0, 1 } };

	const int max_fd = MAX(input_fd, drm_fd);
	fd_set set;

	while (!quit) {
		FD_ZERO(&set);
		FD_SET(input_fd, &set);
		FD_SET(drm_fd, &set);

		select(max_fd + 1, &set, nullptr, nullptr, nullptr);

		if (FD_ISSET(input_fd, &set))
			input_handle();

		if (FD_ISSET(drm_fd, &set)) {
			renderer_handle();

			const mat3_t m = update();

			renderer_clear();
			renderer_draw(ship, NELEMS(ship), m);
			if (input.fwd != 0)
				renderer_draw(fire, NELEMS(fire), m);
			renderer_swap();
		}
	}

	renderer_cleanup();
	input_cleanup();

	return 0;
}