#pragma once

#include <stdexcept>
#include <string>


inline void Enforce(bool eval, const std::string& msg) {
  if (!eval) {
    throw std::runtime_error {msg};
  }
}

inline void CopyNal(std::vector<uint8_t>& v, const uint8_t* buf, size_t sz) noexcept {
  v.resize(sz+4);
  v[0] = 0;
  v[1] = 0;
  v[2] = 0;
  v[3] = 1;
  std::memcpy(&v[4], buf, sz);
}


struct Frame {
  std::vector<uint8_t> Y;
  std::vector<uint8_t> U;
  std::vector<uint8_t> V;

  int32_t w, h;
  int32_t hw, hh;

  Frame() = default;
  Frame(uint8_t* yuv[3], const SBufferInfo& frame) {
    w = static_cast<int32_t>(frame.UsrData.sSystemBuffer.iWidth);
    h = static_cast<int32_t>(frame.UsrData.sSystemBuffer.iHeight);
    hw = w/2;
    hh = h/2;

    const auto ystride  = static_cast<int32_t>(frame.UsrData.sSystemBuffer.iStride[0]);
    const auto uvstride = static_cast<int32_t>(frame.UsrData.sSystemBuffer.iStride[1]);

    Y.resize(w*h);
    for (int32_t y = 0; y < h; ++y) {
      const auto src = yuv[0]   + y*ystride;
      const auto dst = Y.data() + y*w;
      std::memcpy(dst, src, w);
    }

    U.resize(hw*hh);
    V.resize(hw*hh);
    for (int32_t y = 0; y < hh; ++y) {
      const auto offset = y*uvstride;
      const auto srcu = yuv[1]   + y*uvstride;
      const auto srcv = yuv[2]   + y*uvstride;
      const auto dstu = U.data() + y*hw;
      const auto dstv = V.data() + y*hw;
      std::memcpy(dstu, srcu, hw);
      std::memcpy(dstv, srcv, hw);
    }
  }

  SSourcePicture GetSourcePic() noexcept {
    SSourcePicture ret;
    ret.iPicWidth    = w;
    ret.iPicHeight   = h;
    ret.iColorFormat = videoFormatI420;
    ret.iStride[0]   = w;
    ret.iStride[1]   = hw;
    ret.iStride[2]   = hw;

    ret.pData[0] = Y.data();
    ret.pData[1] = U.data();
    ret.pData[2] = V.data();
    return ret;
  }
};