#include "texture.h"

#include <algorithm>

#include "../lib/glew/GL/glew.h"
#include "../lib/glfw/glfw3.h"
#include "../lib/stb_image.h"

#include "logger.h"

Texture::Texture(uint32_t id, const glm::ivec2& size)
    : id_(id), size_(size)
{
}

Texture::~Texture()
{
	if (id_ != 0) {
		glDeleteTextures(1, &id_);
		Logger::info(sstr("Texture ", id_, " destroyed"));
	}
}

std::shared_ptr<Texture> Texture::load(const char* filename)
{
	Logger::info(sstr("Loading texture: ", filename));

	// Load image
	int	 width, height, channels;
	stbi_uc* pixels =
	    stbi_load(filename, &width, &height, &channels, STBI_rgb_alpha);

	if (!pixels) {
		Logger::error(sstr("Failed to load texture: ", filename, " - ",
				   stbi_failure_reason()));
		return nullptr;
	}

	// Flip image vertically (OpenGL expects bottom row first)
	const int row_size   = width * 4; // 4 channels (RGBA)
	auto*	  row_buffer = new stbi_uc[row_size];
	for (int y = 0; y < height / 2; ++y) {
		stbi_uc* row1 = pixels + y * row_size;
		stbi_uc* row2 = pixels + (height - 1 - y) * row_size;
		std::copy(row1, row1 + row_size, row_buffer);
		std::copy(row2, row2 + row_size, row1);
		std::copy(row_buffer, row_buffer + row_size, row2);
	}
	delete[] row_buffer;

	// Generate OpenGL texture
	GLuint texture_id;
	glGenTextures(1, &texture_id);
	glBindTexture(GL_TEXTURE_2D, texture_id);

	// Upload texture data
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
		     GL_UNSIGNED_BYTE, pixels);

	// Set trilinear filtering
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
			GL_LINEAR_MIPMAP_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	// Generate mipmaps
	glGenerateMipmap(GL_TEXTURE_2D);

	// Free image data
	stbi_image_free(pixels);

	Logger::info(sstr("Texture loaded successfully: ", filename, " (",
			  width, "x", height, ", ", channels, " channels)"));

	return std::shared_ptr<Texture>(
	    new Texture(texture_id, glm::ivec2(width, height)));
}

void Texture::bind() const
{
	glBindTexture(GL_TEXTURE_2D, id_);
}