/*
 * AVS3-P2/IEEE1857.10 video decoder (using the uavs3d library)
 * Copyright (c) 2020 Zhenyu Wang <wangzhenyu@pkusz.edu.cn>
 *                    Bingjie Han <hanbj@pkusz.edu.cn>
 *                    Huiwen Ren  <hwrenx@gmail.com>
 *
 * 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
 */

#include "libavutil/avutil.h"
#include "libavutil/common.h"
#include "libavutil/cpu.h"
#include "libavutil/imgutils.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "avs3.h"
#include "codec_internal.h"
#include "decode.h"
#include "uavs3d.h"

typedef struct uavs3d_context {
    AVCodecContext  *avctx;
    void            *dec_handle;
    int              frame_threads;
    int              got_seqhdr;
    uavs3d_io_frm_t  dec_frame;
} uavs3d_context;

#define UAVS3D_CHECK_START_CODE(data_ptr, PIC_START_CODE) \
        (AV_RL32(data_ptr) != (PIC_START_CODE << 24) + AVS3_NAL_START_CODE)
static int uavs3d_find_next_start_code(const unsigned char *bs_data, int bs_len, int *left)
{
    const unsigned char *data_ptr = bs_data + 4;
    int count = bs_len - 4;

    while (count >= 4 &&
           UAVS3D_CHECK_START_CODE(data_ptr, AVS3_INTER_PIC_START_CODE) &&
           UAVS3D_CHECK_START_CODE(data_ptr, AVS3_INTRA_PIC_START_CODE) &&
           UAVS3D_CHECK_START_CODE(data_ptr, AVS3_SEQ_START_CODE) &&
           UAVS3D_CHECK_START_CODE(data_ptr, AVS3_FIRST_SLICE_START_CODE) &&
           UAVS3D_CHECK_START_CODE(data_ptr, AVS3_SEQ_END_CODE)) {
        data_ptr++;
        count--;
    }

    if (count >= 4) {
        *left = count;
        return 1;
    }

    return 0;
}

static void uavs3d_output_callback(uavs3d_io_frm_t *dec_frame) {
    uavs3d_io_frm_t frm_out;
    AVFrame *frm = (AVFrame *)dec_frame->priv;
    int i;

    if (!frm || !frm->data[0]) {
        dec_frame->got_pic = 0;
        av_log(NULL, AV_LOG_ERROR, "Invalid AVFrame in uavs3d output.\n");
        return;
    }

    frm->pts       = dec_frame->pts;
    frm->pkt_dts   = dec_frame->dts;
    frm->pkt_pos   = dec_frame->pkt_pos;
    frm->pkt_size  = dec_frame->pkt_size;
    frm->coded_picture_number   = dec_frame->dtr;
    frm->display_picture_number = dec_frame->ptr;

    if (dec_frame->type < 0 || dec_frame->type >= FF_ARRAY_ELEMS(ff_avs3_image_type)) {
        av_log(NULL, AV_LOG_WARNING, "Error frame type in uavs3d: %d.\n", dec_frame->type);
    } else {
        frm->pict_type = ff_avs3_image_type[dec_frame->type];
        frm->key_frame = (frm->pict_type == AV_PICTURE_TYPE_I);
    }

    for (i = 0; i < 3; i++) {
        frm_out.width [i] = dec_frame->width[i];
        frm_out.height[i] = dec_frame->height[i];
        frm_out.stride[i] = frm->linesize[i];
        frm_out.buffer[i] = frm->data[i];
    }

    uavs3d_img_cpy_cvt(&frm_out, dec_frame, dec_frame->bit_depth);
}

static av_cold int libuavs3d_init(AVCodecContext *avctx)
{
    uavs3d_context *h = avctx->priv_data;
    uavs3d_cfg_t cdsc;

    cdsc.frm_threads = avctx->thread_count > 0 ? avctx->thread_count : av_cpu_count();
    cdsc.check_md5 = 0;
    h->dec_handle = uavs3d_create(&cdsc, uavs3d_output_callback, NULL);
    h->got_seqhdr = 0;

    if (!h->dec_handle) {
        return AVERROR(ENOMEM);
    }

    return 0;
}

static av_cold int libuavs3d_end(AVCodecContext *avctx)
{
    uavs3d_context *h = avctx->priv_data;

    if (h->dec_handle) {
        uavs3d_flush(h->dec_handle, NULL);
        uavs3d_delete(h->dec_handle);
        h->dec_handle = NULL;
    }
    h->got_seqhdr = 0;

    return 0;
}

static void libuavs3d_flush(AVCodecContext * avctx)
{
    uavs3d_context *h = avctx->priv_data;

    if (h->dec_handle) {
        uavs3d_reset(h->dec_handle);
    }
}

#define UAVS3D_CHECK_INVALID_RANGE(v, l, r) ((v)<(l)||(v)>(r))
static int libuavs3d_decode_frame(AVCodecContext *avctx, AVFrame *frm,
                                  int *got_frame, AVPacket *avpkt)
{
    uavs3d_context *h = avctx->priv_data;
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    const uint8_t *buf_end;
    const uint8_t *buf_ptr = buf;
    int left_bytes;
    int ret, finish = 0;

    *got_frame = 0;
    frm->pts = -1;
    frm->pict_type = AV_PICTURE_TYPE_NONE;

    if (!buf_size) {
        if (h->got_seqhdr) {
            if (!frm->data[0] && (ret = ff_get_buffer(avctx, frm, 0)) < 0) {
                return ret;
            }
            h->dec_frame.priv = frm;   // AVFrame
        }
        do {
            ret = uavs3d_flush(h->dec_handle, &h->dec_frame);
        } while (ret > 0 && !h->dec_frame.got_pic);
    } else {
        uavs3d_io_frm_t *frm_dec = &h->dec_frame;

        buf_end = buf + buf_size;
        frm_dec->pkt_pos  = avpkt->pos;
        frm_dec->pkt_size = avpkt->size;

        while (!finish) {
            int bs_len;

            if (h->got_seqhdr) {
                if (!frm->data[0] && (ret = ff_get_buffer(avctx, frm, 0)) < 0) {
                    return ret;
                }
                h->dec_frame.priv = frm;   // AVFrame
            }

            if (uavs3d_find_next_start_code(buf_ptr, buf_end - buf_ptr, &left_bytes)) {
                bs_len = buf_end - buf_ptr - left_bytes;
            } else {
                bs_len = buf_end - buf_ptr;
                finish = 1;
            }
            frm_dec->bs = (unsigned char *)buf_ptr;
            frm_dec->bs_len = bs_len;
            frm_dec->pts = avpkt->pts;
            frm_dec->dts = avpkt->dts;
            uavs3d_decode(h->dec_handle, frm_dec);
            buf_ptr += bs_len;

            if (frm_dec->nal_type == NAL_SEQ_HEADER) {
                struct uavs3d_com_seqh_t *seqh = frm_dec->seqhdr;
                if (UAVS3D_CHECK_INVALID_RANGE(seqh->frame_rate_code, 0, 15)) {
                    av_log(avctx, AV_LOG_ERROR, "Invalid frame rate code: %d.\n", seqh->frame_rate_code);
                    seqh->frame_rate_code = 3; // default 25 fps
                } else {
                    avctx->framerate.num = ff_avs3_frame_rate_tab[seqh->frame_rate_code].num;
                    avctx->framerate.den = ff_avs3_frame_rate_tab[seqh->frame_rate_code].den;
                }
                avctx->has_b_frames = seqh->output_reorder_delay;
                avctx->pix_fmt = seqh->bit_depth_internal == 8 ? AV_PIX_FMT_YUV420P : AV_PIX_FMT_YUV420P10LE;
                ret = ff_set_dimensions(avctx, seqh->horizontal_size, seqh->vertical_size);
                if (ret < 0)
                    return ret;
                h->got_seqhdr = 1;

                if (seqh->colour_description) {
                    if (UAVS3D_CHECK_INVALID_RANGE(seqh->colour_primaries, 0, 9) ||
                        UAVS3D_CHECK_INVALID_RANGE(seqh->transfer_characteristics, 0, 14) ||
                        UAVS3D_CHECK_INVALID_RANGE(seqh->matrix_coefficients, 0, 11)) {
                        av_log(avctx, AV_LOG_ERROR,
                               "Invalid colour description: primaries: %d"
                               "transfer characteristics: %d"
                               "matrix coefficients: %d.\n",
                               seqh->colour_primaries,
                               seqh->transfer_characteristics,
                               seqh->matrix_coefficients);
                    } else {
                        avctx->color_primaries = ff_avs3_color_primaries_tab[seqh->colour_primaries];
                        avctx->color_trc       = ff_avs3_color_transfer_tab [seqh->transfer_characteristics];
                        avctx->colorspace      = ff_avs3_color_matrix_tab   [seqh->matrix_coefficients];
                    }
                }
            }
            if (frm_dec->got_pic) {
                break;
            }
        }
    }

    *got_frame = h->dec_frame.got_pic;

    if (!(*got_frame)) {
        av_frame_unref(frm);
    }

    return buf_ptr - buf;
}

const FFCodec ff_libuavs3d_decoder = {
    .p.name         = "libuavs3d",
    CODEC_LONG_NAME("libuavs3d AVS3-P2/IEEE1857.10"),
    .p.type         = AVMEDIA_TYPE_VIDEO,
    .p.id           = AV_CODEC_ID_AVS3,
    .priv_data_size = sizeof(uavs3d_context),
    .init           = libuavs3d_init,
    .close          = libuavs3d_end,
    FF_CODEC_DECODE_CB(libuavs3d_decode_frame),
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_OTHER_THREADS,
    .caps_internal  = FF_CODEC_CAP_NOT_INIT_THREADSAFE |
                      FF_CODEC_CAP_AUTO_THREADS,
    .flush          = libuavs3d_flush,
    .p.pix_fmts     = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
                                                     AV_PIX_FMT_YUV420P10LE,
                                                     AV_PIX_FMT_NONE },
    .p.wrapper_name = "libuavs3d",
};