/*
 * Copyright (C) 2024 Niklas Haas
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef SWSCALE_AVSCALE_H
#define SWSCALE_AVSCALE_H

/**
 * @file
 * @ingroup libsws
 * Higher-level wrapper around libswscale + related libraries, which is
 * capable of handling more advanced colorspace transformations.
 */

#include "libavutil/frame.h"
#include "libavutil/log.h"

/**
 * Main external API structure. New fields cannot be added to the end with
 * minor version bumps. Removal, reordering and changes to existing fields
 * require a major version bump. sizeof(AVScaleContext) is not part of the ABI.
 */
typedef struct AVScaleContext {
    const AVClass *av_class;

    /**
     * Private context used for internal data.
     */
    struct AVScaleInternal *internal;

    /**
     * Private data of the user, can be used to carry app specific stuff.
     */
    void *opaque;

    /**
     * Bitmask of AV_SCALE_* flags.
     */
    int64_t flags;

    /**
     * Bitmask of SWS_* flags.
     */
    int sws_flags;

    /**
     * Bitmask of SWS_DITHER_* flags.
     */
    int sws_dither;
} AVScaleContext;

enum {
    /**
     * Skip linearization, speeds up downscaling at the cost of quality.
     */
    AV_SCALE_NOLINEAR   = 1 << 0,
    /**
     * Force full internal conversion to RGB. May improve the quality of
     * certain operations, at the cost of performance.
     */
    AV_SCALE_FULL_RGB   = 1 << 1,
    /**
     * Perform perceptual conversion between colorspaces instead of clipping.
     */
    AV_SCALE_PERCEPTUAL = 1 << 2,

    // ...
};

/**
 * Allocate an AVScaleContext and set its fields to default values. The
 * resulting struct should be freed with avscale_free_context().
 */
AVScaleContext *avscale_alloc_context(void);

/**
 * Free the codec context and everything associated with it, and write NULL
 * to the provided pointer.
 */
void avscale_free_context(AVScaleContext **ctx);

/**
 * Get the AVClass for AVScaleContext. It can be used in combination with
 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
 *
 * @see av_opt_find().
 */
const AVClass *avscale_get_class(void);

/**
 * Scale source data from `src` and write the output to `dst`.
 *
 * @param ctx   The scaling context.
 * @param dst   The destination frame.
 *
 *              The data buffers may either be already allocated by the caller
 *              or left clear, in which case they will be allocated by the
 *              scaler. The latter may have performance advantages - e.g. in
 *              certain cases some output planes may be references to input
 *              planes, rather than copies.
 *
 * @param src   The source frame. If the data buffers are set to NULL, then
 *              this function performs no conversion. It will instead merely
 *              initialize internal state that *would* be required to perform
 *              the operation, as well as returing the correct error code for
 *              unsupported frame combinations.
 *
 * @return 0 on success, a negative AVERROR code on failure.
 */
int avscale_frame(AVScaleContext *ctx, AVFrame *dst, const AVFrame *src);

#endif /* SWSCALE_AVSCALE_H */