#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <string.h>
#include <threads.h>

#include "voxel.h"
#include "window.h"

Window window;
_Atomic double delta_time;

static void key_callback(GLFWwindow *, i32 key, i32, i32 action, i32)
{
	switch (action) {
	case GLFW_PRESS:
		window.key_down[key] = true;
		window.key_pressed[key] = true;
		break;
	case GLFW_RELEASE:
		window.key_down[key] = false;
		break;
	}
}

static void mouse_move_callback(GLFWwindow *, double xpos, double ypos)
{
	window.mouse_x_last = window.mouse_x;
	window.moues_y_last = window.mouse_y;
	window.mouse_x = xpos;
	window.mouse_y = ypos;
}

static void mouse_button_callback(GLFWwindow *, i32 button, i32 action, i32)
{
	switch (action) {
	case GLFW_PRESS:
		window.btn_down[button] = true;
		window.btn_pressed[button] = true;
		break;
	case GLFW_RELEASE:
		window.btn_down[button] = false;
		break;
	}
}

static void framebuffer_callback(GLFWwindow *, i32 width, i32 height)
{
	window.width = width;
	window.height = height;
	window.resize = true;
}

VOXEL_RESULT window_init(void)
{
	if (glfwInit() == GLFW_FALSE) {
		ERROR("GLFW failed to initalize");
		return VOXEL_ERROR;
	}

	memset(&window, 0, sizeof(Window));
	delta_time = 0;

	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	window.window = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, WINDOW_TITLE, NULL, NULL);
	if (window.window == NULL) {
		ERROR("failed to create window");
		return VOXEL_ERROR;
	}

	glfwSetKeyCallback(window.window, key_callback);
	glfwSetCursorPosCallback(window.window, mouse_move_callback);
	glfwSetMouseButtonCallback(window.window, mouse_button_callback);
	glfwSetFramebufferSizeCallback(window.window, framebuffer_callback);

	mtx_init(&window.lock, mtx_plain);

	return VOXEL_OK;
}

VOXEL_RESULT window_init_gl(void)
{
	glfwMakeContextCurrent(window.window);

#ifndef USE_VSYNC
	glfwSwapInterval(0);
#endif

	glewExperimental = GL_TRUE;
	if (glewInit() != GLEW_OK) {
		ERROR("GLEW failed to initalize");
		return VOXEL_ERROR;
	}

	return VOXEL_OK;
}

bool window_closed(void)
{
	return window.close || glfwWindowShouldClose(window.window) == GLFW_TRUE;
}

void window_update(void)
{
	mtx_lock(&window.lock);

	// reset "pressed"
	memset(&window.key_pressed, 0, sizeof(window.key_pressed));
	memset(&window.btn_pressed, 0, sizeof(window.btn_pressed));

	// update delta time
	double time = glfwGetTime();
	delta_time = time - window.last_time;
	window.last_time = time;

	// check for errors
	GLenum error;
	while ((error = glGetError()) != GL_NO_ERROR)
		ERROR("OpenGL error: %d", error);

	glfwPollEvents();

	mtx_unlock(&window.lock);
}

void window_swap(void)
{
	glfwSwapBuffers(window.window);
}

void window_close(void)
{
	mtx_lock(&window.lock);
	glfwDestroyWindow(window.window);
	glfwTerminate();
	mtx_destroy(&window.lock);
}

bool key_down(i32 key)
{
	bool down;
	mtx_lock(&window.lock);
	down = window.key_down[key];
	mtx_unlock(&window.lock);
	return down;
}

bool key_pressed(i32 key)
{
	bool pressed;
	mtx_lock(&window.lock);
	pressed = window.key_pressed[key];
	mtx_unlock(&window.lock);
	return pressed;
}

bool btn_down(i32 btn)
{
	bool down;
	mtx_lock(&window.lock);
	down = window.btn_down[btn];
	mtx_unlock(&window.lock);
	return down;
}

bool btn_pressed(i32 btn)
{
	bool pressed;
	mtx_lock(&window.lock);
	pressed = window.btn_pressed[btn];
	mtx_unlock(&window.lock);
	return pressed;
}