# LXQt Desktop Environment with Niri Window Manager
#
# This module provides LXQt desktop environment components running with
# Niri as the Wayland compositor instead of the default window manager.
#
# Features:
# - LXQt panel, settings, file manager, and utilities
# - Niri as the tiling Wayland compositor
# - Proper Qt theming with LXQt themes and Kvantum
# - XDG portals for screen sharing and file dialogs
# - Audio, network, and power management integration
#
# Usage:
# Add this to your host configuration:
#   imports = lib.flatten [
#     # ... other imports ...
#     "hosts/common/optional/lxqt-niri.nix"
#     "hosts/common/optional/gdm.nix"  # or sddm.nix for display manager
#   ];
#
# The session will appear as "LXQt (Niri)" in the session list.
#
{
  pkgs,
  inputs,
  lib,
  ...
}: {
  imports = [
    inputs.niri.nixosModules.niri
  ];

  # Enable Niri as the window manager
  programs.niri.enable = true;

  # Enable LXQt desktop environment components
  # Note: We don't enable services.xserver.desktopManager.lxqt.enable = true
  # because it would conflict with our custom display manager configuration
  services.xserver = {
    enable = true;
  };

  # Install additional LXQt components and utilities
  environment.systemPackages = with pkgs; [
    # Core LXQt components that work well with other window managers
    lxqt.lxqt-panel
    lxqt.lxqt-session
    lxqt.lxqt-config
    lxqt.lxqt-themes
    lxqt.lxqt-notificationd
    lxqt.lxqt-powermanagement
    lxqt.lxqt-policykit
    lxqt.lxqt-archiver
    lxqt.qterminal
    lxqt.pcmanfm-qt
    lxqt.lximage-qt
    lxqt.qps

    # Theme engines and styling
    libsForQt5.qtstyleplugins
    libsForQt5.qt5ct

    # System tools that integrate well with LXQt
    lxqt.pavucontrol-qt
    qpwgraph

    # Network management
    libsForQt5.networkmanager-qt

    # Custom session script
    (writeScriptBin "niri-session" ''
      #!/bin/sh

      # Set up environment
      export XDG_CURRENT_DESKTOP=LXQt
      export XDG_SESSION_DESKTOP=lxqt-niri
      export DESKTOP_SESSION=lxqt-niri

      # Start LXQt session components in background
      ${lxqt.lxqt-session}/bin/lxqt-session &

      # Start Niri as the main session
      exec ${niri}/bin/niri
    '')
  ];

  # Configure XDG portals for better integration
  xdg.portal = {
    enable = true;
    extraPortals = with pkgs; [
      xdg-desktop-portal-gtk
      xdg-desktop-portal-wlr
    ];
    config = {
      common = {
        default = ["gtk"];
        "org.freedesktop.impl.portal.Screenshot" = ["wlr"];
        "org.freedesktop.impl.portal.Screencast" = ["wlr"];
      };
    };
  };

  # Use LXQt's polkit agent
  security.polkit.enable = true;
  systemd.user.services.lxqt-policykit-agent = {
    description = "LXQt PolicyKit Agent";
    wantedBy = ["graphical-session.target"];
    wants = ["graphical-session.target"];
    after = ["graphical-session.target"];
    serviceConfig = {
      Type = "simple";
      ExecStart = "${pkgs.lxqt.lxqt-policykit}/bin/lxqt-policykit-agent";
      Restart = "on-failure";
      RestartSec = 1;
      TimeoutStopSec = 10;
    };
  };

  # Configure Qt theming (basic settings)
  # Note: More specific Qt theming may be handled by system-wide theming modules

  # Configure Qt theming to use LXQt
  qt = {
    platformTheme = lib.mkForce "lxqt";
  };

  # Environment variables for proper integration
  environment.sessionVariables = {
    NIXOS_OZONE_WL = "1";
    QT_QPA_PLATFORM = "wayland;xcb";
    QT_WAYLAND_DISABLE_WINDOWDECORATION = "1";
    QT_AUTO_SCREEN_SCALE_FACTOR = "1";
    QT_QPA_PLATFORMTHEME = lib.mkForce "lxqt";
    QT_STYLE_OVERRIDE = "kvantum";
    DESKTOP_SESSION = "lxqt-niri";
    XDG_CURRENT_DESKTOP = "LXQt";
    XDG_SESSION_DESKTOP = "lxqt-niri";
  };

  # Enable necessary services for LXQt functionality
  services = {
    # Power management
    upower.enable = true;
  };

  # Create a custom session file for LXQt + Niri
  environment.etc."xdg/lxqt/session.conf".text = ''
    [General]
    __userfile__=true
    window_manager=niri
  '';

  # Create desktop entry for the session
  environment.etc."wayland-sessions/lxqt-niri.desktop".text = ''
    [Desktop Entry]
    Name=LXQt (Niri)
    Comment=LXQt Desktop with Niri Window Manager
    Exec=niri-session
    Type=Application
    Keywords=niri;lxqt;wayland;
  '';
}