#include "renderer.h"
#include "GLFW/glfw3.h"

#include "log.h"
#include "camera.h"
#include "model.h"
#include "texture.h"
#include "framebuffer.h"
#include "array.h"
#include "geometry.h"
#include "shader.h"
#include "num_types.h"
#include "window_system.h"

static int def_fbo = -1;
static int def_render_tex = -1;
static int def_depth_tex = -1;
static int quad_geo = -1;
static int fbo_shader = -1;

void on_framebuffer_size_change(GLFWwindow* window, int width, int height);

void renderer_init(GLFWwindow* window)
{
	glClearColor(0.3f, 0.6f, 0.9f, 1.0f);
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_TEXTURE_2D);
	glfwSetFramebufferSizeCallback(window, on_framebuffer_size_change);

	/* Quad geometry for final render */
	vec3* vertices = array_new(vec3);
	vec2* uvs = array_new(vec2);
	vec3* normals = array_new(vec3);
	uint* indices = array_new(uint);
	vec3 temp_v3; 
	vec2 temp_v2;
	/* Vertices */
	temp_v3.x = -1; temp_v3.y = -1; temp_v3.z = 0;	array_push(vertices, temp_v3, vec3);
	temp_v3.x =  1; temp_v3.y = -1; temp_v3.z = 0;	array_push(vertices, temp_v3, vec3);
	temp_v3.x =  1; temp_v3.y =  1; temp_v3.z = 0;	array_push(vertices, temp_v3, vec3);
	temp_v3.x = -1; temp_v3.y =  1; temp_v3.z = 0;	array_push(vertices, temp_v3, vec3);
	/* Normals */
	temp_v3.x = 0; temp_v3.y = 1; temp_v3.z = 0;	array_push(normals, temp_v3, vec3);
	temp_v3.x = 0; temp_v3.y = 1; temp_v3.z = 0;	array_push(normals, temp_v3, vec3);
	/* Uvs */
	temp_v2.x = 0; temp_v2.y = 0; array_push(uvs, temp_v2, vec2);
	temp_v2.x = 1; temp_v2.y = 0; array_push(uvs, temp_v2, vec2);
	temp_v2.x = 1; temp_v2.y = 1; array_push(uvs, temp_v2, vec2);
	temp_v2.x = 0; temp_v2.y = 1; array_push(uvs, temp_v2, vec2);
	/* Indices */
	array_push(indices, 0, uint); array_push(indices, 1, uint); array_push(indices, 2, uint);
	array_push(indices, 2, uint); array_push(indices, 3, uint); array_push(indices, 0, uint);
	
	quad_geo = geom_create("Quad", vertices, uvs, normals, indices, NULL);
	array_free(vertices);
	array_free(uvs);
	array_free(normals);
	array_free(indices);

/* Textues for default fbo */
	int width = -1, height = -1;
	window_get_size(&width, &height);
	def_render_tex = texture_create("def_render_texture",
									TU_DIFFUSE,
									width, height,
									GL_RGBA,
									GL_RGBA8,
									GL_UNSIGNED_BYTE,
									NULL);
	texture_set_param(def_render_tex, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	texture_set_param(def_render_tex, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	texture_set_param(def_render_tex, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	texture_set_param(def_render_tex, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	def_depth_tex = texture_create("def_depth_texture",
									TU_SHADOWMAP1,
									width, height,
									GL_DEPTH_COMPONENT,
									GL_DEPTH_COMPONENT,
									GL_UNSIGNED_BYTE,
									NULL);
	texture_set_param(def_depth_tex, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	texture_set_param(def_depth_tex, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	texture_set_param(def_depth_tex, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	texture_set_param(def_depth_tex, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	texture_set_param(def_depth_tex, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);
	texture_set_param(def_depth_tex, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);

	def_fbo = framebuffer_create(width, height, 0, 1);
	framebuffer_set_texture(def_fbo, def_render_tex, GL_COLOR_ATTACHMENT0);
	framebuffer_set_texture(def_fbo, def_depth_tex, GL_DEPTH_ATTACHMENT);

	fbo_shader = shader_create("fbo.vert", "fbo.frag");
}

void renderer_draw(void)
{
	struct Camera* camera_list = camera_get_all();
	for(int i = 0; i < array_len(camera_list); i++)
	{
		struct Camera* camera = &camera_list[i];
		if(camera->node < 0)
			continue;

		int fbo = camera->fbo == -1 ? def_fbo : camera->fbo;
		framebuffer_bind(fbo);
		{
			glViewport(0, 0, framebuffer_get_width(fbo), framebuffer_get_height(fbo));
			glDrawBuffer(GL_COLOR_ATTACHMENT0);
			glDepthFunc(GL_LEQUAL);
			glEnable(GL_BLEND);
			glBlendEquation(GL_FUNC_ADD);
			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
			model_render_all(camera);
			glDisable(GL_BLEND);
		}
		framebuffer_unbind();
	}

	int width, height;
	window_get_size(&width, &height);
	glViewport(0, 0, width, height);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	shader_bind(fbo_shader);
	struct Camera* primary_camera = camera_get_primary();
	texture_bind(primary_camera->render_tex);
	geom_render(quad_geo);
	texture_unbind(def_render_tex);
	shader_unbind();
}

void renderer_cleanup(void)
{
	geom_remove(quad_geo);
	framebuffer_remove(def_fbo);
	texture_remove(def_render_tex);
	texture_remove(def_depth_tex);
}

void on_framebuffer_size_change(GLFWwindow* window, int width, int height)
{
	glViewport(0, 0, width, height);
	struct Camera* camera = camera_get(0);
	float aspect = (float)width / (float)height;
	camera->aspect_ratio = aspect > 0.f ? aspect : 4.f / 3.f;
	camera_update_proj(camera);
}

void renderer_set_clearcolor(float red, float green, float blue, float alpha)
{
	glClearColor(red, green, blue, alpha);
}

int renderer_check_glerror(const char* context)
{
	int error = 1;
	GLenum error_code = glGetError();
	const char* errorString = "No Error";
	switch(error_code)
	{
	case GL_INVALID_OPERATION:
		errorString = "Invalid Operation";
		break;
	case GL_NO_ERROR:
		errorString = "No Error";
		break;
	case GL_INVALID_ENUM:
		errorString = "Invalid ENUM";
		break;
	case GL_INVALID_VALUE:
		errorString = "Invalid Value";
		break;
	case GL_INVALID_FRAMEBUFFER_OPERATION:
		errorString = "Invalid FrameBuffer Operation";
		break;
	case GL_OUT_OF_MEMORY:
		errorString = "Out of Memory";
		break;
	case GL_STACK_UNDERFLOW:
		errorString = "Stack Underflow";
		break;
	case GL_STACK_OVERFLOW:
		errorString = "Stack Overflow";
		break;
	}

	if(error_code != GL_NO_ERROR)
		log_error(context, errorString);
	else
		error = 0;

	return error;
}