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

int main(void)
{
	state_t state = init_state(1600, 800);

	init_glfw(&state);
	init_gl();

	/* meshes */
	Mesh *sphere = mesh_load_obj(state.arena, "../../data/models/sphere.obj");
	Mesh *cube = mesh_load_obj(state.arena, "../../data/models/cube.obj");
	Mesh *quad = mesh_gen_quad(state.arena);

	/* shaders */
	add_shader("pbr.vert",     "pbr.frag",     0);
	add_shader("hdr.vert",     "hdr.frag",     0);

	U32 shader = find_shader("pbr");
	if (!shader)
		die("not again");
	glUseProgram(shader);
	shader_set_1i(shader, "color_map", 0);
	shader_set_1i(shader, "normal_map", 1);
	shader_set_1i(shader, "metallic_map", 2);
	shader_set_1i(shader, "roughness_map", 3);
	shader_set_1i(shader, "ao_map", 4);
	glUseProgram(0);

	light_t lights[4] = {
		{{-6.0f,  0.0f,  7.0f}, {300.0f, 300.0f, 300.0f}},
		{{-4.0f,  0.0f,  6.0f}, {300.0f, 300.0f, 300.0f}},
		{{ 1.0f,  0.0f,  5.0f}, {300.0f, 300.0f, 300.0f}},
		{{ 3.0f,  0.0f,  8.0f}, {300.0f, 300.0f, 300.0f}},
	};

	/* textures */
	U32 color_map = load_texture("../../data/textures/pbr/albedo.png");
	U32 normal_map = load_texture("../../data/textures/pbr/normal.png");
	U32 metallic_map = load_texture("../../data/textures/pbr/metallic.png");
	U32 roughness_map = load_texture("../../data/textures/pbr/roughness.png");
	U32 ao_map = load_texture("../../data/textures/pbr/ao.png");

	/* framebuffers */
	U32 hdr_fbo, hdr_colorbuffer, hdr_rbo;
	glGenFramebuffers(1, &hdr_fbo);
	glGenTextures(1, &hdr_colorbuffer);
	glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, state.width, state.height, 0, GL_RGBA, GL_FLOAT, 0);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glGenRenderbuffers(1, &hdr_rbo);
	glBindRenderbuffer(GL_RENDERBUFFER, hdr_rbo);
	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, state.width, state.height);
	glBindFramebuffer(GL_FRAMEBUFFER, hdr_fbo);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, hdr_colorbuffer, 0);
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, hdr_rbo);
	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
		die("failed to create framebuffer");
	glBindRenderbuffer(GL_RENDERBUFFER, 0);
	glBindTexture(GL_TEXTURE_2D, 0);
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	
	F32 time = 0;

	while (!glfwWindowShouldClose(state.window)) {
		handle_glfw_events(state.window, &state.input);
		F32 dt = lock_framerate(60);
		fps_info(dt, 10);

		/* update */
		update_camera_first_person(&state.camera, &state.input, dt, 2.0f);
		F32 limit = 4.0f;
		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++)
			lights[i].position.y = sinf(2.0f * time + i) * limit;
		time += dt;

		/* render */
		F32 ar = (F32)state.width / (F32)state.height;
		MAT4 projection = camera_persp(state.camera, ar);
		MAT4 view = get_view_matrix(&state.camera);

		glClearColor(0.16f, 0.16f, 0.16f, 1.0f);

		glBindFramebuffer(GL_FRAMEBUFFER, hdr_fbo);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		shader = find_shader("pbr");
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, color_map);
		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, normal_map);
		glActiveTexture(GL_TEXTURE2);
		glBindTexture(GL_TEXTURE_2D, metallic_map);
		glActiveTexture(GL_TEXTURE3);
		glBindTexture(GL_TEXTURE_2D, roughness_map);
		glActiveTexture(GL_TEXTURE4);
		glBindTexture(GL_TEXTURE_2D, ao_map);

		if (!shader) die("wha");
		glUseProgram(shader);
		shader_set_mat4fv(shader, "projection", projection);
		shader_set_mat4fv(shader, "view", view);
		shader_set_3fv(shader, "camera", state.camera.pos);
		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++) {
			char str[512];
			snprintf(str, 512, "lights[%d].position", i);
			shader_set_3fv(shader, str, lights[i].position);
			snprintf(str, 512, "lights[%d].color", i);
			shader_set_3fv(shader, str, lights[i].color);
		}
		S32 rows = 7;
		S32 cols = 7;
		F32 offset = 3.0f;
		for (S32 row = 0; row < rows; row++) {
			for (S32 col = 0; col < cols; col++) {
				V3F pos = {(col - cols / 2.0f) * offset, (row - rows / 2.0f) * offset, 0.0f};
				MAT4 model = mat4_make_translate(pos);
				shader_set_mat4fv(shader, "model", model);
				mesh_draw(cube);
			}
		}

		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++) {
			MAT4 model = mat4_make_scale(v3f(0.5f, 0.5f, 0.5f));
			model = mat4_translate(model, lights[i].position);
			shader_set_mat4fv(shader, "model", model);
			mesh_draw(sphere);
		}

		glUseProgram(0);

		glBindFramebuffer(GL_FRAMEBUFFER, 0);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		shader = find_shader("hdr");
		if (!shader) die("!");
		glUseProgram(shader);
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
		shader_set_mat4fv(shader, "model", mat4_identity());
		mesh_draw(quad);
		glUseProgram(0);

		glfwSwapBuffers(state.window);
	}

	return 0;
}