# settings/desktop.nix — display manager, lightweight fallback session, GTK/Qt theming
{ config, pkgs, lib, inputs, ... }:
{
  config = lib.mkIf (lib.elem config.networking.hostName [ "FredOS-Gaming" "FredOS-Macbook" ]) {
    services.xserver.enable = true;
    # Autologin straight into Hyprland; the quickshell lockscreen engages
    # immediately (see Lock.qml), so the lock *is* the login prompt.
    services.greetd = {
      enable = true;
      # We handle the plymouth handoff ourselves below — don't wait for
      # plymouth-quit-wait (that wait is what dropped boot to a console
      # flash between splash and Hyprland).
      greeterManagesPlymouth = true;
      settings.default_session = {
        # start-hyprland prints an ASCII logo to the VT, which repaints the
        # console over the retained splash frame — silence it (Hyprland still
        # logs to $XDG_RUNTIME_DIR/hypr/*/hyprland.log).
        command = toString (pkgs.writeShellScript "hyprland-session" ''
          exec ${config.programs.hyprland.package}/bin/start-hyprland >/dev/null 2>&1
        '');
        user = "fred";
      };
    };

    # GDM-style splash→session handoff: nothing else quits plymouth at boot;
    # greetd freezes the last splash frame (--retain-splash) right before it
    # spawns Hyprland, which then flips straight to the lockscreen.
    systemd.services.plymouth-quit.wantedBy = lib.mkForce [ ];
    # ...and plymouth-quit-wait must go too: greetd is Type=idle, so it defers
    # its ExecStart while any job is pending — and the only pending job is
    # plymouth-quit-wait, which waits for the splash that greetd itself quits.
    # That circle only broke on systemd's 5s idle timeout, costing 6s of boot.
    systemd.services.plymouth-quit-wait.wantedBy = lib.mkForce [ ];
    systemd.services.greetd = {
      after = [ "plymouth-start.service" ];
      serviceConfig.ExecStartPre = "-${pkgs.plymouth}/bin/plymouth quit --retain-splash";
    };
    boot.plymouth.enable = true;
    boot.initrd.verbose = false;
    boot.consoleLogLevel = 3;
    boot.kernelParams = [ "quiet" "udev.log_level=3" ];

    # Flatpak for ad-hoc app installs via Bazaar
    services.flatpak.enable = true;

    # Secret Service for Chromium/Electron credential encryption.
    # Autologin can't unlock the keyring (no password typed), so greetd only
    # *starts* the daemon; the quickshell lockscreen authenticates against the
    # "login" PAM service, where pam_gnome_keyring unlocks it on first unlock.
    services.gnome.gnome-keyring.enable = true;
    security.pam.services.greetd.enableGnomeKeyring = true;
    security.pam.services.login.enableGnomeKeyring = true;

    environment.systemPackages = with pkgs; [
      nemo                 # file manager
      gnome-themes-extra
      papirus-icon-theme
    ];

    # Cursor theme — stylix.cursor in settings/stylix.nix owns the choice.
    environment.sessionVariables = {
      XCURSOR_THEME = "Bibata-Modern-Ice";
      XCURSOR_SIZE = "24";
      XCURSOR_PATH = lib.mkForce [
        "${pkgs.bibata-cursors}/share/icons"
        "$HOME/.icons"
        "$HOME/.local/share/icons"
      ];
    };

    programs.xwayland.enable = true;
    programs.dconf.enable = true;

    home-manager.users.fred = { config, lib, pkgs, ... }: let
      # Scaling all three channels by the same factor is exactly what
      # Qt.lighter() does — hue and HSV saturation stay put, only value moves —
      # so this lands on the same surfaces as quickshell's Theme.base01/base02.
      # GTK's own shade() can't stand in: it multiplies saturation too.
      tint = f: let
        ch = k: toString (builtins.floor (builtins.fromJSON config.lib.stylix.colors."base00-rgb-${k}" * f));
      in "rgb(${ch "r"}, ${ch "g"}, ${ch "b"})";
    in {
      # Stylix's qt target only supports qtct; disable it to silence the warning.
      stylix.targets.qt.enable = false;
      # Minimal titlebars — stylix manages the GTK theme; we layer our
      # headerbar shrink on top via stylix.targets.gtk.extraCss.
      gtk.enable = true;

      dconf.settings."org/nemo/window-state".start-with-menu-bar = false;

      # GTK3 ignores dconf's color-scheme=prefer-dark — it only picks
      # adw-gtk3's gtk-dark.css when this setting is on. Without it GTK3 apps
      # (nemo) load the *light* sheet; stylix's @define-color overrides repaint
      # most of it, but colours sass baked in as literals survive — e.g.
      # `messagedialog.csd.background button { color: rgba(0,0,6,0.8); }`, which
      # is why nemo's delete confirmation had near-black buttons on dark bg.
      gtk.gtk3.extraConfig.gtk-application-prefer-dark-theme = true;

      stylix.targets.gtk.extraCss = ''
        /* Surfaces: one hue, three steps — the same ladder quickshell's Theme
           uses (settings/quickshell.nix, commit e2c413d). Stylix paints every
           raised surface with base01/base02, which come straight off the
           wallpaper and routinely land off-hue: base01 is #3f3fab purple over a
           slate #1c1f26 desktop, which is why nemo's delete dialog was blue. */
        @define-color headerbar_bg_color ${tint 1.7};
        @define-color sidebar_bg_color   ${tint 1.7};
        @define-color card_bg_color      ${tint 1.7};
        @define-color dialog_bg_color    ${tint 1.7};
        @define-color popover_bg_color   ${tint 1.7};
        @define-color scrollbar_outline_color ${tint 2.4};

        headerbar { min-height: 0; padding: 0; margin: 0; }
        headerbar .title { font-size: 0; }
        window:backdrop {
          background-color: @window_bg_color;
          color: @window_fg_color;
        }
        window:backdrop headerbar {
          background-color: @headerbar_bg_color;
          color: @headerbar_fg_color;
        }
      '';
    };
  };
}