NixOS Davinci 20.2

final: prev:
let
  originalResolve = prev.davinci-resolve-studio;

  # Tools from pkgs
  bash = prev.bash;
  writeText = prev.writeText;
  xkeyboard_config = prev.xkeyboard_config;
  perl = prev.perl;

  # Your patch set
  patches = [
    # JNE -> JMP
    { old = ''\x03\x00\x89\x45\xFC\x83\x7D\xFC\x00\x74\x11\x48\x8B\x45\xC8\x8B''; new = ''\x03\x00\x89\x45\xFC\x83\x7D\xFC\x00\xEB\x11\x48\x8B\x45\xC8\x8B''; }
    # JZ -> JMP
    { old = ''\x74\x11\x48\x8B\x45\xC8\x8B\x55\xFC\x89\x50\x58\xB8\x00\x00\x00''; new = ''\xEB\x11\x48\x8B\x45\xC8\x8B\x55\xFC\x89\x50\x58\xB8\x00\x00\x00''; }
    # SETB 1 -> SETB 0
    { old = ''\x41\xb6\x01\x84\xc0\x0f\x84\xb0\x00\x00\x00\x48\x85\xdb\x74\x08\x45\x31\xf6\xe9\xa3\x00\x00\x00''; new = ''\x41\xb6\x00\x84\xc0\x0f\x84\xb0\x00\x00\x00\x48\x85\xdb\x74\x08\x45\x31\xf6\xe9\xa3\x00\x00\x00''; }
  ];

  # Compose Perl substitutions: s|OLD|NEW|g; s|...|...|g; ...
  perlSubs =
    let lib = prev.lib;
    in lib.concatStringsSep ";" (lib.map (p: ''s|${p.old}|${p.new}|g'') patches);

in {
  davinci-resolve-studio = originalResolve.override (old: {
    buildFHSEnv = fhs:
      (
        let
          # Patch the inner package where binaries live
          davinci = fhs.passthru.davinci.overrideAttrs (innerOld: {
            __intentionallyOverridingVersion = true;
            version = innerOld.version + "-custom-patched-v1";

            nativeBuildInputs = (innerOld.nativeBuildInputs or []) ++ [ perl ];

            # Patch at postFixup when $out is fully assembled
            postFixup = ''
              ${innerOld.postFixup or ""}

              echo "Applying binary patches to Resolve binaries..."

              # Helper to patch a file if it exists
              patch_if_exists() {
                local f="$1"
                if [ -f "$f" ]; then
                  echo "Patching $f"
                  # Read/write as raw bytes; operate on whole file
                  ${perl}/bin/perl -0777 -Mbytes -pe '${perlSubs}' "$f" > "$f.patched" || {
                    echo "ERROR: Patch failed for $f"
                    exit 1
                  }
                  if [ ! -s "$f.patched" ]; then
                    echo "ERROR: Patch produced empty output for $f"
                    exit 1
                  fi
                  mv "$f.patched" "$f"
                  chmod +x "$f" || true
                else
                  echo "Skip: $f not found"
                fi
              }

              # Common locations in the DaVinci package layout
              patch_if_exists "$out/bin/resolve"
              patch_if_exists "$out/opt/resolve/bin/resolve"

              echo "Binary patching complete."
              echo "Installing license file…"
              mkdir -p $out/.license
              # Option B: embed the license text directly
              cat > $out/.license/blackmagic.lic <<'EOF'
LICENSE blackmagic davinciresolvestudio 999999 permanent uncounted
hostid=ANY issuer=CGP customer=CGP issued=28-dec-2023
akey=0000-0000-0000-0000 _ck=00 sig=\"00\"
EOF
            '';
          });
        in
        # Outer FHS wrapper referencing the patched inner package
        old.buildFHSEnv (fhs // {
          extraBwrapArgs = [
          ];
          runScript = "${bash}/bin/bash ${writeText "davinci-wrapper" ''
            export QT_XKB_CONFIG_ROOT="${xkeyboard_config}/share/X11/xkb"
            export QT_PLUGIN_PATH="${davinci}/libs/plugins:$QT_PLUGIN_PATH"
            export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib:/usr/lib32:${davinci}/libs
            unset QT_QPA_PLATFORM
            ${davinci}/bin/resolve
          ''}";
          extraInstallCommands = ''
            mkdir -p $out/share/applications $out/share/icons/hicolor/128x128/apps
            ln -s ${davinci}/share/applications/*.desktop $out/share/applications/
            ln -s ${davinci}/graphics/DV_Resolve.png $out/share/icons/hicolor/128x128/apps/davinci-resolve-studio.png
          '';
          passthru = { inherit davinci; };
        })
      );
  });
}