{ pkgs, lib, ... }:
let
  # Start from niri's own default config so we inherit every new default
  # automatically on updates. We patch only what we need to change.
  base = builtins.readFile "${pkgs.niri.doc}/share/doc/niri/default-config.kdl";

  # waybar → noctalia  +  add xwayland-satellite
  r1 = builtins.replaceStrings
    [ "spawn-at-startup \"waybar\"\n" ]
    [ "spawn-at-startup \"noctalia\"\nspawn-at-startup \"xwayland-satellite\"\n" ]
    base;

  # terminal: alacritty → kitty
  r2 = builtins.replaceStrings
    [ "    Mod+T hotkey-overlay-title=\"Open a Terminal: alacritty\" { spawn \"alacritty\"; }\n" ]
    [ "    Mod+T hotkey-overlay-title=\"Open a Terminal: kitty\" { spawn \"kitty\"; }\n" ]
    r1;

  # launcher: fuzzel → noctalia launcher + control-center
  r3 = builtins.replaceStrings
    [ "    Mod+D hotkey-overlay-title=\"Run an Application: fuzzel\" { spawn \"fuzzel\"; }\n" ]
    [ "    Mod+Space hotkey-overlay-title=\"Noctalia: Launcher\"       { spawn \"noctalia-ipc\" \"panel-toggle\" \"launcher\"; }\n    Mod+S     hotkey-overlay-title=\"Noctalia: Control Center\" { spawn \"noctalia-ipc\" \"panel-toggle\" \"control-center\"; }\n" ]
    r2;

  # lock: swaylock → noctalia
  r4 = builtins.replaceStrings
    [ "    Super+Alt+L hotkey-overlay-title=\"Lock the Screen: swaylock\" { spawn \"swaylock\"; }\n" ]
    [ "    Super+Alt+L hotkey-overlay-title=\"Noctalia: Lock\" { spawn \"noctalia-ipc\" \"session\" \"lock\"; }\n" ]
    r3;

  # skip the hotkey overlay pop-up at startup
  r5 = builtins.replaceStrings
    [ "    // skip-at-startup\n" ]
    [ "    skip-at-startup\n" ]
    r4;

  # tighter gaps
  r6 = builtins.replaceStrings
    [ "    gaps 16\n" ]
    [ "    gaps 8\n" ]
    r5;

  # enable animations slowdown
  r7 = builtins.replaceStrings
    [ "    // slowdown 3.0\n" ]
    [ "    slowdown 0.5\n" ]
    r6;

  # Our additions appended after the patched default config.
  # A second `input { touchpad { } }` block overrides earlier touchpad settings.
  customConfig = ''

    // ── Touchpad ─────────────────────────────────────────────────────────────
    input {
        touchpad {
            tap
            natural-scroll
            accel-profile "flat"
            scroll-factor 1.0
        }
    }

    // ── Prefer no client-side decorations ────────────────────────────────────
    prefer-no-csd

    // ── Gestures ─────────────────────────────────────────────────────────────
    gestures {
        hot-corners {
            off
        }
    }

    // ── Rounded corners ──────────────────────────────────────────────────────
    window-rule {
        geometry-corner-radius 12
        clip-to-geometry true
    }

    // ── Floating windows ─────────────────────────────────────────────────────
    window-rule {
        match app-id=r#"^Tk$"#
        match app-id=r#"^gimp$"# title=r#"Preferences"#
        match app-id=r#"^mpv$"#
        match app-id=r#"^soffice$"# title=r#"^Text Import"#
        match app-id=r#"^thunar$"# title=r#"^Rename "#
        match app-id=r#"^xarchiver$"#
        match app-id=r#"firefox$"# title=r#"^Picture-in-Picture$"#

        open-floating true
    }
  '';
in
{
  imports = [ ./noctalia ./polkit ];

  # .text writes a real file (not a nix-store symlink) so niri auto-reloads on rebuild
  xdg.configFile."niri/config.kdl".text = r7 + customConfig;
}