# Signal Desktop with config/signal/theme.css applied. Signal has no user
# stylesheet, so this repacks the app.asar of nixpkgs' signal-desktop so that it
#   1. loads theme.css as stylesheets/custom.css after Signal's own stylesheets, and
#   2. creates the main window transparent, so Hyprland's blur shows through.
# Nothing else is changed; the electron, flags and profile (~/.config/Signal) are
# those of the stock package.
#
# This replaces signal/launch from the old dotfiles: the copy is built here, once,
# instead of at start-up. Edit theme.css, rebuild, and run config/signal/restart.
# If a Signal update moves one of the two places being patched, the build fails
# rather than shipping an unthemed or half-patched Signal.
{
  lib,
  runCommand,
  signal-desktop,
  asar,
  theme ? ../../config/signal/theme.css,
}:

runCommand "signal-desktop-themed-${signal-desktop.version}"
  {
    nativeBuildInputs = [ asar ];
    inherit (signal-desktop) meta;
    passthru.unthemed = signal-desktop;
  }
  ''
    src=${signal-desktop}
    mkdir -p $out/bin $out/share
    for d in $src/share/*; do
      [ "$(basename "$d")" = signal-desktop ] || [ "$(basename "$d")" = applications ] || ln -s "$d" $out/share/
    done

    mkdir -p $out/share/signal-desktop
    for f in $src/share/signal-desktop/*; do
      case "$(basename "$f")" in app.asar|app.asar.unpacked) ;; *) ln -s "$f" $out/share/signal-desktop/ ;; esac
    done

    asar extract $src/share/signal-desktop/app.asar app
    cp ${theme} app/stylesheets/custom.css

    # 1. Load the theme last, so it wins over Signal's own stylesheets.
    anchor='<link href="stylesheets/tailwind.css" rel="stylesheet" type="text/css" />'
    grep -qF "$anchor" app/background.html
    sed -i "s|$anchor|&\n    <link href=\"stylesheets/custom.css\" rel=\"stylesheet\" type=\"text/css\" />|" app/background.html
    grep -qF 'href="stylesheets/custom.css"' app/background.html

    # 2. Transparent main window. It is the only BrowserWindow created with
    #    sandbox:false, which is what the pattern keys on; exactly one match or stop.
    sed -i 's/backgroundColor:[A-Za-z0-9_$]*,\(webPreferences:{[^}]*sandbox:!1\)/transparent:!0,backgroundColor:`#00000000`,\1/' app/bundles/main.js
    [ "$(grep -o 'transparent:!0,backgroundColor:`#00000000`' app/bundles/main.js | wc -l)" = 1 ]

    asar pack --unpack '*.node' app $out/share/signal-desktop/app.asar

    # Same launcher as the stock package, pointed at the themed app.asar.
    substitute $src/bin/signal-desktop $out/bin/signal-desktop \
      --replace-fail "$src/share/signal-desktop/app.asar" "$out/share/signal-desktop/app.asar"
    chmod +x $out/bin/signal-desktop

    mkdir -p $out/share/applications
    substitute $src/share/applications/signal.desktop $out/share/applications/signal.desktop \
      --replace-quiet "$src/bin/signal-desktop" "$out/bin/signal-desktop"
  ''