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

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

#include "common.h"

int main(void)
{
	GLFWwindow *window;
	State state;
	S32 width, height;
	Input input;

	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);
	window = glfwCreateWindow(width, height, "Cubemaps", 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);
	glDepthFunc(GL_LEQUAL);

	U32 skybox_shader = create_shader_program("shaders/skybox.vert", "shaders/skybox.frag");
	U32 reflection_shader = create_shader_program("shaders/reflection.vert", "shaders/reflection.frag");
	U32 refraction_shader = create_shader_program("shaders/refraction.vert", "shaders/refraction.frag");
	U32 cube_shader = create_shader_program("shaders/cube.vert", "shaders/cube.frag");
	U32 grid_texture = load_texture("../../data/textures/grid.png");

	const char *cube_texture_filenames[6] = {
		"../../data/textures/skybox/right.jpg",
		"../../data/textures/skybox/left.jpg",
		"../../data/textures/skybox/top.jpg",
		"../../data/textures/skybox/bottom.jpg",
		"../../data/textures/skybox/front.jpg",
		"../../data/textures/skybox/back.jpg"
	};
	U32 skybox_texture = load_cubemap(cube_texture_filenames);

	F32 a = 0.5f;
	F32 vertices[] = {
		-a, -a, -a,  0.0f, 0.0f,
		 a, -a, -a,  1.0f, 0.0f,
		 a,  a, -a,  1.0f, 1.0f,
		 a,  a, -a,  1.0f, 1.0f,
		-a,  a, -a,  0.0f, 1.0f,
		-a, -a, -a,  0.0f, 0.0f,

		-a, -a,  a,  0.0f, 0.0f,
		 a, -a,  a,  1.0f, 0.0f,
		 a,  a,  a,  1.0f, 1.0f,
		 a,  a,  a,  1.0f, 1.0f,
		-a,  a,  a,  0.0f, 1.0f,
		-a, -a,  a,  0.0f, 0.0f,

		-a,  a,  a,  1.0f, 0.0f,
		-a,  a, -a,  1.0f, 1.0f,
		-a, -a, -a,  0.0f, 1.0f,
		-a, -a, -a,  0.0f, 1.0f,
		-a, -a,  a,  0.0f, 0.0f,
		-a,  a,  a,  1.0f, 0.0f,

		 a,  a,  a,  1.0f, 0.0f,
		 a,  a, -a,  1.0f, 1.0f,
		 a, -a, -a,  0.0f, 1.0f,
		 a, -a, -a,  0.0f, 1.0f,
		 a, -a,  a,  0.0f, 0.0f,
		 a,  a,  a,  1.0f, 0.0f,

		-a, -a, -a,  0.0f, 1.0f,
		 a, -a, -a,  1.0f, 1.0f,
		 a, -a,  a,  1.0f, 0.0f,
		 a, -a,  a,  1.0f, 0.0f,
		-a, -a,  a,  0.0f, 0.0f,
		-a, -a, -a,  0.0f, 1.0f,

		-a,  a, -a,  0.0f, 1.0f,
		 a,  a, -a,  1.0f, 1.0f,
		 a,  a,  a,  1.0f, 0.0f,
		 a,  a,  a,  1.0f, 0.0f,
		-a,  a,  a,  0.0f, 0.0f,
		-a,  a, -a,  0.0f, 1.0f
	};

	Transform cube_positions[] = {
		transform_default(),
		transform_make_translate(v3f(a, 0.0f, -4.0f*a))
	};

	V3F platform_pos = v3f(10.0f, 0.2f, 10.0f);
	V3F platform_scale = v3f(0.0f, -(a+(a*0.2f)+0.01f), 0.0f);
	Transform platform_transform = transform_make_scale_translate(platform_pos, platform_scale);

	U32 cube_vao, vbo;
	glGenVertexArrays(1, &cube_vao);
	glBindVertexArray(cube_vao);
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)0);
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)(3*sizeof(F32)));
	glBindVertexArray(0);

	a = 1.0f;
	F32 skybox_cube_vertices[] = {
		-a, -a, -a,
		 a, -a, -a,
		 a,  a, -a,
		 a,  a, -a,
		-a,  a, -a,
		-a, -a, -a,

		-a, -a,  a,
		 a, -a,  a,
		 a,  a,  a,
		 a,  a,  a,
		-a,  a,  a,
		-a, -a,  a,

		-a,  a,  a,
		-a,  a, -a,
		-a, -a, -a,
		-a, -a, -a,
		-a, -a,  a,
		-a,  a,  a,

		 a,  a,  a,
		 a,  a, -a,
		 a, -a, -a,
		 a, -a, -a,
		 a, -a,  a,
		 a,  a,  a,

		-a, -a, -a,
		 a, -a, -a,
		 a, -a,  a,
		 a, -a,  a,
		-a, -a,  a,
		-a, -a, -a,

		-a,  a, -a,
		 a,  a, -a,
		 a,  a,  a,
		 a,  a,  a,
		-a,  a,  a,
		-a,  a, -a,
	};

	U32 skybox_cube_vao;
	glGenVertexArrays(1, &skybox_cube_vao);
	glBindVertexArray(skybox_cube_vao);
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(skybox_cube_vertices), skybox_cube_vertices, GL_STATIC_DRAW);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(F32), (void *)0);
	glBindVertexArray(0);

	F32 normals_cube_vertices[] = {
		-0.5f, -0.5f, -0.5f,   0.0f,  0.0f, -1.0f,
		 0.5f, -0.5f, -0.5f,   0.0f,  0.0f, -1.0f,
		 0.5f,  0.5f, -0.5f,   0.0f,  0.0f, -1.0f,
		 0.5f,  0.5f, -0.5f,   0.0f,  0.0f, -1.0f,
		-0.5f,  0.5f, -0.5f,   0.0f,  0.0f, -1.0f,
		-0.5f, -0.5f, -0.5f,   0.0f,  0.0f, -1.0f,

		-0.5f, -0.5f,  0.5f,   0.0f,  0.0f, 1.0f,
		 0.5f, -0.5f,  0.5f,   0.0f,  0.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,   0.0f,  0.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,   0.0f,  0.0f, 1.0f,
		-0.5f,  0.5f,  0.5f,   0.0f,  0.0f, 1.0f,
		-0.5f, -0.5f,  0.5f,   0.0f,  0.0f, 1.0f,

		-0.5f,  0.5f,  0.5f,  -1.0f,  0.0f,  0.0f,
		-0.5f,  0.5f, -0.5f,  -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f, -0.5f,  -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f, -0.5f,  -1.0f,  0.0f,  0.0f,
		-0.5f, -0.5f,  0.5f,  -1.0f,  0.0f,  0.0f,
		-0.5f,  0.5f,  0.5f,  -1.0f,  0.0f,  0.0f,

		 0.5f,  0.5f,  0.5f,   1.0f,  0.0f,  0.0f,
		 0.5f,  0.5f, -0.5f,   1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,   1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,   1.0f,  0.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,   1.0f,  0.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,   1.0f,  0.0f,  0.0f,

		-0.5f, -0.5f, -0.5f,   0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f, -0.5f,   0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,   0.0f, -1.0f,  0.0f,
		 0.5f, -0.5f,  0.5f,   0.0f, -1.0f,  0.0f,
		-0.5f, -0.5f,  0.5f,   0.0f, -1.0f,  0.0f,
		-0.5f, -0.5f, -0.5f,   0.0f, -1.0f,  0.0f,

		-0.5f,  0.5f, -0.5f,   0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f, -0.5f,   0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,   0.0f,  1.0f,  0.0f,
		 0.5f,  0.5f,  0.5f,   0.0f,  1.0f,  0.0f,
		-0.5f,  0.5f,  0.5f,   0.0f,  1.0f,  0.0f,
		-0.5f,  0.5f, -0.5f,   0.0f,  1.0f,  0.0f
	};
	U32 normals_cube_vao;
	glGenVertexArrays(1, &normals_cube_vao);
	glBindVertexArray(normals_cube_vao);
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(normals_cube_vertices), normals_cube_vertices, GL_STATIC_DRAW);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6*sizeof(F32), (void *)0);
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*sizeof(F32), (void *)(3*sizeof(F32)));
	glBindVertexArray(0);

	state.camera = (Camera) {
		v3f(0.0f, 1.0f, 3.0f), 100.0f,
		0.1f, 100.0f, 0.0f, 0.0f
	};
	input = input_init();

	F32 target_fps = 60.0f;
	F32 target_spf = 1.0f/target_fps;
	F32 last_time = glfwGetTime();

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

		/* INFO(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);

		/* NOTE(pryazha): Render */
		MAT4 view, proj, model;
		view = get_view_matrix(&state.camera);
		proj = perspective(state.camera.fovx, (F32)width/(F32)height,
				   state.camera.near, state.camera.far);

		glClearColor(0.15f, 0.15f, 0.15f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glUseProgram(cube_shader);
		shader_set_mat4fv(cube_shader, "view", view);
		shader_set_mat4fv(cube_shader, "proj", proj);
		glBindTexture(GL_TEXTURE_2D, grid_texture);
		glBindVertexArray(cube_vao);
		for (S32 i = 0; i < (S32)ArrayCount(cube_positions); ++i) {
			model = transform_apply(cube_positions[i]);
			shader_set_mat4fv(cube_shader, "model", model);
			glDrawArrays(GL_TRIANGLES, 0, 36);
		}

		model = transform_apply(platform_transform);
		shader_set_mat4fv(cube_shader, "model", model);
		glDrawArrays(GL_TRIANGLES, 0, 36);
		glBindVertexArray(0);

		glUseProgram(reflection_shader);
		model = mat4_make_translate(v3f(0.0f, 2.0f, 0.0f));
		shader_set_mat4fv(reflection_shader, "model", model);
		shader_set_mat4fv(reflection_shader, "view", view);
		shader_set_mat4fv(reflection_shader, "proj", proj);
		shader_set_3fv(reflection_shader, "camera_pos", state.camera.pos);
		glBindVertexArray(normals_cube_vao);
		glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture);
		glDrawArrays(GL_TRIANGLES, 0, 36);
		glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
		glBindVertexArray(0);

		glUseProgram(refraction_shader);
		model = mat4_make_translate(v3f(2.0f, 2.0f, 0.0f));
		shader_set_mat4fv(refraction_shader, "model", model);
		shader_set_mat4fv(refraction_shader, "view", view);
		shader_set_mat4fv(refraction_shader, "proj", proj);
		shader_set_3fv(refraction_shader, "camera_pos", state.camera.pos);
		glBindVertexArray(normals_cube_vao);
		glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture);
		glDrawArrays(GL_TRIANGLES, 0, 36);
		glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
		glBindVertexArray(0);

		glUseProgram(skybox_shader);
		MAT4 rotate_view = mat4_identity();
		rotate_view.m0 = v4f(view.m0.x, view.m0.y, view.m0.z, 0.0f);
		rotate_view.m1 = v4f(view.m1.x, view.m1.y, view.m1.z, 0.0f);
		rotate_view.m2 = v4f(view.m2.x, view.m2.y, view.m2.z, 0.0f);
		shader_set_mat4fv(skybox_shader, "view", rotate_view);
		shader_set_mat4fv(skybox_shader, "proj", proj);
		glBindVertexArray(skybox_cube_vao);
		glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture);
		glDrawArrays(GL_TRIANGLES, 0, 36);
		glBindVertexArray(0);

		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;
	}

	glfwTerminate();
	return(0);
}