#include "sws_helper.h"

#include "error_define.h"
#include "log_helper.h"

namespace am {
sws_helper::sws_helper()
{
    _inited = false;

    _frame = NULL;

    _buffer = NULL;

    _ctx = NULL;
}

sws_helper::~sws_helper()
{
    cleanup();
}

int sws_helper::init(AVPixelFormat src_fmt,
                     int src_width,
                     int src_height,
                     AVPixelFormat dst_fmt,
                     int dst_width,
                     int dst_height)
{
    if (_inited)
        return AE_NO;

    _ctx = sws_getContext(src_width,
                          src_height,
                          src_fmt,
                          dst_width,
                          dst_height,
                          dst_fmt,
                          SWS_FAST_BILINEAR, // 更快的缩放算法以降低延迟
                          NULL,
                          NULL,
                          NULL);

    if (!_ctx) {
        return AE_FFMPEG_NEW_SWSCALE_FAILED;
    }

    _buffer_size = av_image_get_buffer_size(dst_fmt, dst_width, dst_height, 1);
    _buffer = new uint8_t[_buffer_size];

    _frame = av_frame_alloc();

    av_image_fill_arrays(_frame->data, _frame->linesize, _buffer, dst_fmt, dst_width, dst_height, 1);

    _inited = true;

    return AE_NO;
}

int sws_helper::convert(const AVFrame *frame, uint8_t **out_data, int *len)
{
    int error = AE_NO;
    if (!_inited || !_ctx || !_buffer)
        return AE_NEED_INIT;

    int ret = sws_scale(_ctx,
                        (const uint8_t *const *) frame->data,
                        frame->linesize,
                        0,
                        frame->height,
                        _frame->data,
                        _frame->linesize);

    *out_data = _buffer;
    *len = _buffer_size;

    return error;
}

void sws_helper::cleanup()
{
    _inited = false;

    if (_ctx)
        sws_freeContext(_ctx);

    _ctx = NULL;

    if (_frame)
        av_frame_free(&_frame);

    _frame = NULL;

    if (_buffer)
        delete[] _buffer;

    _buffer = NULL;
}
} // namespace am