#include "dumbLog.h"
#include "entity.h"


void initEntityRG(Entity& e, rg_shader_program& shader, bool use_normals);
bool initEntityROs(Entity& e);
bool convertMeshInfo(meMeshInfo* mesh, render_object* ro, bool use_normals, bool use_texture);

bool
entInit(Entity& e, const char* data_dir, rg_shader_program& shader)
{
	e.world_transform = glm::mat4(1.0);
	entScale(e, e.scale);
	uint max_len = 256; // TODO: define max_len for property strings
	char full_path[max_len];
	if (utilConcatPath(full_path, data_dir, e.model_filename, max_len)) {
		if (meLoadFromFile(e.mesh_group, data_dir, full_path)) {
			initEntityRG(e, shader, e.mesh_group.use_normals);
			entSetWorldPosition(e, e.translation.x, e.translation.y, e.translation.z);

			if (!initEntityROs(e))
				goto cleanup;
		} else {
			goto cleanup;
		}
	} else {
		LOG(Error) << data_dir << " + " << e.model_filename << " is too long\n";
		goto cleanup;
	}

	return true;

cleanup:
	entFree(e);
	return false;
}

void
entFree(Entity& e)
{
	meFreeMeshGroup(e.mesh_group);
	rgFree(e.ren_group);
}

void
entSetWorldPosition(Entity& e, float x, float y, float z)
{
	e.world_transform[3][0] = e.translation.x = x;
	e.world_transform[3][1] = e.translation.y = y;
	e.world_transform[3][2] = e.translation.z = z;
}

void
initEntityRG(Entity& e, rg_shader_program& shader, bool use_normals)
{
	render_group* rg = UTIL_ALLOC(1, render_group);
	e.ren_group = rg;
	e.ren_group->shader = shader;
	rg->draw_indexed = true;
	rg->draw_mode = GL_TRIANGLES;
	rg->use_normals = use_normals;
	uint num_meshes = rg->num_objects = e.mesh_group.num_meshes;
	rg->render_objects = UTIL_ALLOC(num_meshes, render_object*);
}

bool
initEntityROs(Entity& e)
{
	render_group* rg = e.ren_group;

	for (uint i = 0; i < e.mesh_group.num_meshes; i++)
	{
		meMeshInfo* mesh = e.mesh_group.meshes[i];
		uint buffer_len =  mesh->num_vertices * 3;
		uint index_len = mesh->num_indices;

		render_object* ro = rgAllocateRenderObject(buffer_len, index_len);
		rg->render_objects[i] = ro;

		if (ro == nullptr)
			return false;

		if (!convertMeshInfo(mesh, ro, rg->use_normals, mesh->use_texture)) {
			rgFree(rg);
			return false;
		}

		if (mesh->use_texture) {
			ro->use_texture = true;
			if (!rgInitGLTexture(ro->tex_id, mesh->diffuse_texture)) {
				LOG(Error) << "Error initializing GL texture\n";
				return false;
			}
		}
	}

	return true;
}

bool
convertMeshInfo(meMeshInfo* mesh, render_object* ro, bool use_normals, bool use_texture)
{
	uint vertex_buf_len = mesh->num_vertices * 3;
	GLfloat* vertex_buf = ro->vertex_buffer.buffer;
	GLfloat* normal_buf = ro->normal_buffer.buffer;
	GLfloat* uv_buf = ro->uv_buffer.buffer;
	uint* index_buf = ro->index_buffer.buffer;

	if (!vertex_buf || !normal_buf || !index_buf)
		return false;

	// dump vertices, colors, normals, and texture coords into render_group buffers
	uint vertex_index = 0;
	uint vertex_prop_index = 0;

	for (uint i = 0; i < vertex_buf_len; i++) {
		const glm::vec3& vertex = mesh->vertices[vertex_index];

		switch (vertex_prop_index) {
			case 0:	vertex_buf[i] = vertex.x; break;
			case 1: vertex_buf[i] = vertex.y; break;
			case 2: vertex_buf[i] = vertex.z; break;
		}

		if (use_normals) {
			const glm::vec3& normal = mesh->normals[vertex_index];
			switch (vertex_prop_index) {
				case 0:	normal_buf[i] = normal.x; break;
				case 1: normal_buf[i] = normal.y; break;
				case 2: normal_buf[i] = normal.z; break;
			}
		}

		if (use_texture) {
			const glm::vec3& uv = mesh->texture_coords[vertex_index];
			switch (vertex_prop_index) {
				case 0:	uv_buf[i] = uv.x; break;
				case 1: uv_buf[i] = uv.y; break;
				case 2: uv_buf[i] = uv.z; break;
			}
		}

		vertex_prop_index++;

		if (vertex_prop_index == 3) {
			vertex_prop_index = 0;
			vertex_index++;
		}
	}

	// dump indices
	for (uint i = 0; i < mesh->num_indices; i++)
		index_buf[i] = mesh->indices[i];

	rgInitGLFloatBuffer(&ro->vertex_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
	if (use_normals)
		rgInitGLFloatBuffer(&ro->normal_buffer, GL_STATIC_DRAW, GL_ARRAY_BUFFER);
	if (use_texture)
		rgInitGLFloatBuffer(&ro->uv_buffer, GL_STATIC_DRAW, GL_ARRAY_BUFFER);
	rgInitGLIndexBuffer(&ro->index_buffer, GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);

	return true;
}