#include "texture.hpp"

void flip_surface(SDL_Surface* surface) {
    if (!surface) {
        std::cerr << "Surface is null, cannot flip" << std::endl;
        return;
    }

    int pitch = surface->pitch;
    Uint8* pixels = static_cast<Uint8*>(surface->pixels);
    int height = surface->h;

    for (int y = 0; y < height / 2; ++y) {
        Uint8* top_row = pixels + y * pitch;
        Uint8* bottom_row = pixels + (height - y - 1) * pitch;

        for (int x = 0; x < pitch; ++x) {
            std::swap(top_row[x], bottom_row[x]);
        }
    }
}

Texture::Texture(const char* file_path) {
    ID = 0;
    SDL_Surface* surface = IMG_Load(file_path);
    if (!surface) {
        std::cerr << "Failed to load texture: " << SDL_GetError() << std::endl;
        return; // Texture loading failed
    }

    GLenum format = (surface->format == SDL_PIXELFORMAT_RGBA32) ? GL_RGBA : GL_RGB;
    flip_surface(surface); // Flip the surface vertically

    glGenTextures(1, &ID);
    glBindTexture(GL_TEXTURE_2D, ID);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, format, surface->w, surface->h, 0, format, GL_UNSIGNED_BYTE, surface->pixels);
    glGenerateMipmap(GL_TEXTURE_2D);

    SDL_DestroySurface(surface); // Free the surface after uploading texture data
}

Texture::~Texture() {
    if (ID != 0) {
        glDeleteTextures(1, &ID);
    }
}

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

void Texture::bind(unsigned int unit) const {
    if (unit >= GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS) {
        std::cerr << "Texture unit out of range: " << unit << std::endl;
        return; // Invalid texture unit
    }
    glActiveTexture(GL_TEXTURE0 + unit);
    glBindTexture(GL_TEXTURE_2D, ID);
}

void Texture::unbind() const {
    glBindTexture(GL_TEXTURE_2D, 0);
}