#include "GL/glew.h"
#include "GLFW/glfw3.h"

#include "pwyazh.h"
#include "pwyazh_GL.h"

#include "common.h"

int main(void)
{
	GLFWwindow *window;
	Arena *arena = 0;
	Mesh *cube;
	Input input;
	F32 target_fps, target_spf, last_time;
	MAT4 proj, view, model;
	State state;
	S32 width, height;
	U32 color_shader;

	if (glfwInit() == GLFW_FALSE) {
		fprintf(stderr, "[ERROR] Failed to initialize glfw.\n");
		return(1);
	}

	width = 1024;
	height = 768;

	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_SAMPLES, 4);
	window = glfwCreateWindow(width, height, "Anti Aliasing (MSAA)", 0, 0);
	if (!window) {
		fprintf(stderr, "[ERROR] Failed to create window.\n");
		glfwTerminate();
		return(1);
	}

	glfwMakeContextCurrent(window);

	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);

	if (glewInit() != GLEW_OK) {
		fprintf(stderr, "[ERROR] Failed to initialize glew.\n");
		glfwTerminate();
		return(1);
	}

	glEnable(GL_DEPTH_TEST);
	glEnable(GL_MULTISAMPLE);

	arena = arena_alloc(Kilobytes(4));

	cube = mesh_load_obj(arena, "../../data/models/cube.obj");
	color_shader = create_shader_program("shaders/color.vert",
					     "shaders/color.frag");

	state.camera = (Camera) {
		v3f(0.0f, 0.0f, 3.0f),
			90.0f, 0.1f, 1000.0f,
			0.0f, 0.0f
	};
	input = input_init();

	target_fps = 60.0f;
	target_spf = 1.0f/target_fps;
	last_time = glfwGetTime();

	while (!glfwWindowShouldClose(window)) {
		glfwPollEvents();

		/* NOTE(pryazha): Update */
		glfwGetFramebufferSize(window, &width, &height);
		process_glfw_keyboard(window, &input);
		process_glfw_mouse_pos(window, &input);

		if (key_first_press(input.exit))
			glfwSetWindowShouldClose(window, GLFW_TRUE);

		V3F dv = get_dv_camera_first_person(&input, &state.camera,
						    4.0f, state.dt);
		state.camera.pos = v3f_add(state.camera.pos, dv);

		F32 sensitivity = 0.1f;
		input.mouse_offset = v2f_scalef(input.mouse_offset, sensitivity);
		state.camera.yaw += input.mouse_offset.x;
		state.camera.pitch += input.mouse_offset.y;
		if (state.camera.pitch > 89.0f)
			state.camera.pitch = 89.0f;
		if (state.camera.pitch < -89.0f)
			state.camera.pitch = -89.0f;

		input_update_last_state(&input);

		view = get_view_matrix(&state.camera);
		proj = perspective(state.camera.fovx, (F32)width/(F32)height,
				   state.camera.near, state.camera.far);
		model = mat4_identity();

		/* NOTE(pryazha): Render */
		glClearColor(0.15f, 0.15f, 0.15f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glUseProgram(color_shader);
		shader_set_mat4fv(color_shader, "proj", proj);
		shader_set_mat4fv(color_shader, "view", view);
		shader_set_mat4fv(color_shader, "model", model);
		mesh_draw(cube);

		glfwSwapBuffers(window);

		F32 elapsed = glfwGetTime()-last_time;
		if (elapsed < target_spf) {
			U32 sleep_time = (U32)(target_spf-elapsed);
			if (sleep_time > 0)
				sleep(sleep_time);
		}
		F32 current_time = glfwGetTime();
		state.dt = current_time-last_time;
		last_time = current_time;
	}

	arena_release(arena);
	glfwTerminate();
	return(0);
}