#include <GL++/Texture.hpp>

#include <GL/glew.h>
#include <SDL.h>
#include <SDL_image.h>
#include <memory>

Texture::Texture(char const* path) : id(0) {
    std::unique_ptr<SDL_Surface, void(*)(SDL_Surface*)> image(IMG_Load(path), SDL_FreeSurface);
    if(image.get() == nullptr) {
        error_log = std::string("could't open the given file (") + SDL_GetError() + ")";
        return;
    }

    glGenTextures(1, &id);
    glBindTexture(GL_TEXTURE_2D, id);

    GLint internalFormat;
    GLenum format;
    if(image->format->BytesPerPixel == 3) {
        internalFormat = GL_RGB;
        if(image->format->Rmask == 0xFF) {
            format = GL_RGB;
        } else {
            format = GL_BGR;
        }
    } else if(image->format->BytesPerPixel == 4) {
        internalFormat = GL_RGBA;
        if(image->format->Rmask == 0xFF) {
            format = GL_RGBA;
        } else {
            format = GL_BGRA;
        }
    } else {
        error_log = "wrong image format";
        glDeleteTextures(1, &id);
        id = 0;
        return;
    }

    glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, image->w, image->h, 0,
                 format, GL_UNSIGNED_BYTE, image->pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glBindTexture(GL_TEXTURE_2D, 0);
}

Texture::Texture(GLsizei width, GLsizei height) {
    glGenTextures(1, &id);
    glBindTexture(GL_TEXTURE_2D, id);
    /* void glTexImage2D(GLenum target, GLint level, GLint internalFormat, GLsizei width,
     *                   GLsizei height, GLint border, GLenum format, GLenum type,
     *                   const GLvoid * data);
     * data may be a null pointer. In this case, texture memory is allocated to accommodate
     * a texture of width width and height height. You can then download subtextures to
     * initialize this texture memory. The image is undefined if the user tries to apply
     * an uninitialized portion of the texture image to a primitive.*/
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glBindTexture(GL_TEXTURE_2D, 0);
}

Texture::Texture(Texture&& texture) : id(texture.id) {
    texture.id = 0;
}

Texture& Texture::operator=(Texture&& texture) {
    if(this != &texture) {
        glDeleteTextures(1, &id);
        id = texture.id;
        texture.id = 0;
    }
    return *this;
}

Texture::~Texture() {
    glDeleteTextures(1, &id);
}

GLuint Texture::get_id() const {
    return id;
}

std::string const& Texture::log() const {
    return error_log;
}

Texture::operator bool() const {
    return !(id == 0);
}