// image.h
//
// Copyright (C) 2001-present, the Celestia Development Team
// Original version by Chris Laurel <claurel@shatters.net>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

#pragma once

#include <cstdint>
#include <filesystem>
#include <memory>

#include <celutil/filetype.h>
#include "pixelformat.h"

namespace celestia::engine
{

/**
 * The image class supports multiple GL formats, including compressed ones.
 * Mipmaps may be stored within an image as well.  The mipmaps are stored in
 * one contiguous block of memory (i.e. there's not an instance of Image per
 * mipmap.)  Mip levels are addressed such that zero is the base (largest) mip
 * level.
 */
class Image
{
public:
    static constexpr std::int32_t MAX_DIMENSION = INT32_C(16384);

    Image(PixelFormat format, std::int32_t w, std::int32_t h, std::int32_t mip = 1);

    bool isValid() const noexcept;
    std::int32_t getWidth() const;
    std::int32_t getHeight() const;
    std::int32_t getPitch() const;
    std::int32_t getMipLevelCount() const;
    PixelFormat getFormat() const;
    std::int32_t getComponents() const;
    std::uint8_t* getPixels();
    const std::uint8_t* getPixels() const;
    std::uint8_t* getPixelRow(std::int32_t row);
    std::uint8_t* getPixelRow(std::int32_t mip, std::int32_t row);
    std::uint8_t* getMipLevel(std::int32_t mip);
    const std::uint8_t* getMipLevel(std::int32_t mip) const;
    std::int32_t getSize() const;
    std::int32_t getMipLevelSize(std::int32_t mip) const;

    bool isCompressed() const;
    bool hasAlpha() const;

    std::unique_ptr<Image> computeNormalMap(float scale, bool wrap) const;

    void forceLinear();

    static bool canSave(ContentType type);
    bool save(const std::filesystem::path &path, ContentType type) const;

    static std::unique_ptr<Image> load(const std::filesystem::path& filename);

private:
    std::int32_t width;
    std::int32_t height;
    std::int32_t pitch;
    std::int32_t mipLevels;
    std::int32_t components;
    PixelFormat format;
    std::int32_t size;
    std::unique_ptr<std::uint8_t[]> pixels;
};

std::unique_ptr<std::uint8_t[]>
expandLuminanceToRGBA(const std::uint8_t* src, std::int32_t width, std::int32_t height);

std::unique_ptr<std::uint8_t[]>
expandLuminanceAlphaToRGBA(const std::uint8_t* src, std::int32_t width, std::int32_t height);

} // namespace celestia::engine
