{ config, pkgs, lib, ... }:

let
  # ────────────────────────────────────────────────────────────────
  # Legacy libxml2 (2.9.x) — Tibia requires libxml2.so.2
  # ────────────────────────────────────────────────────────────────
  libxml2_2_9 = pkgs.stdenv.mkDerivation {
    pname = "libxml2-2.9";
    version = "2.9.14";

    src = pkgs.fetchurl {
      url = "https://download.gnome.org/sources/libxml2/2.9/libxml2-2.9.14.tar.xz";
      sha256 = "sha256-YNdKJX0czsBHXnScui8hVZ5IE577pv8oIkNXx8eY3+4=";
    };

    nativeBuildInputs = [ pkgs.pkg-config ];
    buildInputs = [ pkgs.zlib pkgs.xz ];

    configureFlags = [
      "--disable-static"
      "--without-python"
    ];

    enableParallelBuilding = true;
  };

  # ────────────────────────────────────────────────────────────────
  # Centralized runtime library path for Tibia
  # ────────────────────────────────────────────────────────────────
  tibiaLibPath = lib.makeLibraryPath [
    pkgs.nss
    pkgs.nspr
    pkgs.libxkbfile
    libxml2_2_9
  ];

  exportLibs = ''
    export LD_LIBRARY_PATH="${tibiaLibPath}:$LD_LIBRARY_PATH"
  '';

  # ────────────────────────────────────────────────────────────────
  # System-wide wrapper for the Tibia client binary
  # ────────────────────────────────────────────────────────────────
  tibiaClientWrapper = pkgs.writeShellScriptBin "tibia-client" ''
    #!/usr/bin/env bash
    ${exportLibs}
    exec steam-run "$HOME/.local/share/CipSoft GmbH/Tibia/packages/Tibia/bin/client" "$@"
  '';

  # ────────────────────────────────────────────────────────────────
  # Patcher for Tibia's package.json (launcher → wrapper redirect)
  # ────────────────────────────────────────────────────────────────
  tibiaPatcher = pkgs.writeShellScriptBin "tibia-patch" ''
    #!/usr/bin/env bash
    set -e

    PKGDIR="$HOME/.local/share/CipSoft GmbH/Tibia/packages/Tibia"
    PKGJSON="$PKGDIR/package.json"
    LOCALWRAPPER="$PKGDIR/tibia-client-wrapper"

    if [ ! -f "$PKGJSON" ]; then
      echo "package.json not found — run the launcher once first."
      exit 0
    fi

    cat > "$LOCALWRAPPER" <<EOF
#!/usr/bin/env bash
${exportLibs}
exec /run/current-system/sw/bin/tibia-client "\$@"
EOF
    chmod +x "$LOCALWRAPPER"

    sed -i 's#"executable": "bin/client"#"executable": "tibia-client-wrapper"#' "$PKGJSON"

    echo "Tibia client patched to use tibia-client-wrapper."
  '';

  # ────────────────────────────────────────────────────────────────
  # Wrapper for the Tibia launcher (runs patcher + launcher)
  # ────────────────────────────────────────────────────────────────
  tibiaLauncherWrapper = pkgs.writeShellScriptBin "tibia" ''
    #!/usr/bin/env bash
    set -e

    LAUNCHER="$HOME/Gry/Tibia/Tibia"

    if [ ! -x "$LAUNCHER" ]; then
      echo "Tibia launcher not found at:"
      echo "  $LAUNCHER"
      exit 1
    fi

    tibia-patch

    ${exportLibs}
    exec steam-run "$LAUNCHER"
  '';

  # ────────────────────────────────────────────────────────────────
  # Desktop icon (copied from ~/Gry/Tibia/tibia.ico)
  # ────────────────────────────────────────────────────────────────
  tibiaIcon = pkgs.runCommand "tibia-icon" {} ''
    mkdir -p $out/share/icons/hicolor/256x256/apps
    cp "${/home/sasza/Gry/Tibia/tibia.ico}" \
       "$out/share/icons/hicolor/256x256/apps/tibia.ico"
  '';

  # ────────────────────────────────────────────────────────────────
  # Desktop entry for Tibia
  # ────────────────────────────────────────────────────────────────
  tibiaDesktop = pkgs.writeTextFile {
    name = "tibia.desktop";
    destination = "/share/applications/tibia.desktop";
    text = ''
      [Desktop Entry]
      Type=Application
      Name=Tibia
      Comment=Launch the Tibia MMORPG
      Exec=tibia
      Icon=tibia.ico
      Terminal=false
      Categories=Game;RolePlaying;
    '';
  };

in
{
  environment.systemPackages = [
    pkgs.steam-run
    libxml2_2_9
    tibiaClientWrapper
    tibiaPatcher
    tibiaLauncherWrapper
    tibiaIcon
    tibiaDesktop
  ];
}