# Visual C++ 2019 (MSVC 14.29) x64 runtime DLLs.
# msvcp140.dll, vcruntime140.dll, concrt140.dll, mfc140.dll, and friends.
{
  runCommand,
  fetchurl,
  cabextract,
  p7zip,
}:

let
  redist = fetchurl {
    url = "https://aka.ms/vs/16/release/vc_redist.x64.exe";
    hash = "sha256-avrming/ESkhSRdYRK7Q4s4/JHvAJQ9ssYyTEpWz85k=";
  };
in

runCommand "vcredist2019"
  { nativeBuildInputs = [ cabextract p7zip ]; }
  ''
    # The vcredist bundle is a WiX burn exe. Its structure:
    #   - PE stub (bootstrapper)
    #   - First CAB at offset 479744: bootstrapper UI resources
    #   - Second CAB at offset 684808: payload packages (MSIs + their CABs)
    #
    # We skip straight to the second CAB which contains the DLL payloads
    # in its a11/a12/a13 inner CABs.
    dd if=${redist} bs=1 skip=684808 of=container.cab 2>/dev/null
    cabextract container.cab -d pkgs 2>/dev/null

    mkdir -p $out/windll
    # a11 = vcRuntimeMinimum_x64 payload, a12 = additional, a13 = MFC
    for cab in pkgs/a11 pkgs/a12 pkgs/a13; do
      [ -f "$cab" ] && cabextract "$cab" -F '*.dll' -d $out/windll 2>/dev/null || true
    done
  ''