/* SPDX-FileCopyrightText: 2024 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup imbuf
 */

#pragma once

#include <atomic>
#include <cstdint>

namespace blender {

struct ImBuf;

/**
 * Thumbnail creation and retrieval according to the 'Thumbnail Management Standard'
 * supported by Gimp, Gnome (Nautilus), KDE etc.
 * Reference: http://jens.triq.net/thumbnail-spec/index.html
 *
 * This standard is not used for #THB_SOURCE_DIRECT, see its documentation.
 */

enum ThumbSize {
  THB_NORMAL,
  THB_LARGE,
  THB_FAIL,
};

enum ThumbSource : int8_t {
  THB_SOURCE_IMAGE,
  THB_SOURCE_MOVIE,
  THB_SOURCE_BLEND,
  THB_SOURCE_FONT,
  THB_SOURCE_OBJECT_IO,
  /**
   * The thumbnail is not created from some other file, but the given file path refers to the
   * thumbnail itself directly.
   *
   * Can be useful to directly load an image from disk that can be displayed as a thumbnail,
   * without requiring the caller to handle these cases specially.
   *
   * Does _not_ use the thumbnail standard.
   */
  THB_SOURCE_DIRECT,
};

struct ThumbCancellationToken {
 private:
  std::atomic<bool> is_cancelled_ = false;

 public:
  void cancel()
  {
    is_cancelled_.store(true, std::memory_order_release);
  }

  void reset()
  {
    is_cancelled_.store(false, std::memory_order_release);
  }

  bool is_cancelled() const
  {
    return is_cancelled_.load(std::memory_order_acquire);
  }
};

/**
 * Don't generate thumbs for images bigger than this (100mb).
 */
#define THUMB_SIZE_MAX (100 * 1024 * 1024)

#define PREVIEW_RENDER_DEFAULT_HEIGHT 128
#define PREVIEW_RENDER_LARGE_HEIGHT 256

/**
 * Note this can also be used as versioning system,
 * to force refreshing all thumbnails if e.g. we change some thumb generating code or so.
 * Only used by fonts so far.
 */
#define THUMB_DEFAULT_HASH "00000000000000000000000000000000"

/**
 * Create thumbnail for file and returns new ImBuf for thumbnail.
 *
 * Does not support #THB_SOURCE_DIRECT as \a source.
 *
 * \param filepath: File path (but not a library path!) to the thumbnail to be created.
 */
ImBuf *IMB_thumb_create(const char *filepath, ThumbSize size, ThumbSource source, ImBuf *img);

/**
 * Read thumbnail for file and returns new ImBuf for thumbnail.
 * \param file_or_lib_path: File path or library-ID path (e.g. `/a/b.blend/Material/MyMaterial`) to
 *                          the thumbnail to be read.
 */
ImBuf *IMB_thumb_read(const char *file_or_lib_path, ThumbSize size);

/**
 * Delete all thumbs for the file.
 * \param file_or_lib_path: File path or library-ID path (e.g. `/a/b.blend/Material/MyMaterial`) to
 *                          the thumbnail to be deleted.
 */
void IMB_thumb_delete(const char *file_or_lib_path, ThumbSize size);

/**
 * Create the thumb if necessary and manage failed and old thumbs.
 * Will not attempt to (re)create thumbnails of offline files. In this case only a preexisting
 * thumbnail is returned, or null if none was found.
 *
 * \param file_or_lib_path: File path or library-ID path (e.g. `/a/b.blend/Material/MyMaterial`) to
 *                          the thumbnail to be created/managed.
 */
ImBuf *IMB_thumb_manage(const char *file_or_lib_path,
                        ThumbSize size,
                        ThumbSource source,
                        const ThumbCancellationToken *cancel_token = nullptr);

/**
 * Create the necessary directories to store the thumbnails.
 */
void IMB_thumb_makedirs();

/**
 * Special function for loading a thumbnail embedded into a blend file.
 */
ImBuf *IMB_thumb_load_blend(const char *blen_path, const char *blen_group, const char *blen_id);

/**
 * Special function for previewing fonts.
 */
ImBuf *IMB_thumb_load_font(const char *filepath, unsigned int x, unsigned int y);
bool IMB_thumb_load_font_get_hash(char *r_hash);

ImBuf *IMB_font_preview(const char *filepath,
                        unsigned int width,
                        const float color[4],
                        const char *sample_text = nullptr);

/* Threading */

void IMB_thumb_locks_acquire();
void IMB_thumb_locks_release();
void IMB_thumb_path_lock(const char *path);
void IMB_thumb_path_unlock(const char *path);

}  // namespace blender