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

let
  username     = config.defaultUser or "henrov";
  homeDir      = "/home/${username}";
  wallpaperSrc = "${flakeRoot}/assets/Wallpapers";
  wallpaperDst = "${homeDir}/Wallpapers";

  script = pkgs.writeShellScript "wallpaper-sync-and-set.sh" ''
    #!/usr/bin/env bash
    set -euo pipefail

    SRC="${wallpaperSrc}"
    DST="${wallpaperDst}"

    mkdir -p "$SRC" "$DST"

    ########################################
    # 2-way sync (additive, newer wins)
    ########################################

    # SRC -> DST
    rsync -au "$SRC/" "$DST/"

    # DST -> SRC
    rsync -au "$DST/" "$SRC/"

    ########################################
    # Initialize swww (safe if already running)
    ########################################
    if ! pgrep -x swww-daemon >/dev/null; then
      swww init
      sleep 1
    fi

    ########################################
    # Get workspaces
    ########################################
    WORKSPACES=$(hyprctl workspaces -j | jq -r '.[].id')

    ########################################
    # Function: set random wallpaper for workspace
    ########################################
    set_wallpaper() {
      local WS="$1"

      WALL=$(find "$DST" -type f | shuf -n 1)

      if [ -n "$WALL" ]; then
        hyprctl dispatch workspace "$WS"
        swww img "$WALL" --transition-type any
      fi
    }

    ########################################
    # If workspace passed → only update that
    ########################################
    if [ "$#" -eq 1 ]; then
      set_wallpaper "$1"
      exit 0
    fi

    ########################################
    # Otherwise: update all workspaces
    ########################################
    for WS in $WORKSPACES; do
      set_wallpaper "$WS"
    done
  '';
in
{
  #################################
  # Packages
  #################################
  environment.systemPackages = with pkgs; [
    swww
    waypaper
    jq
    rsync
  ];

  #################################
  # Service: main worker
  #################################
  systemd.user.services.wallpaperSync = {
    description = "2-way sync wallpapers + set random per workspace";
    after = [ "graphical-session.target" ];

    serviceConfig = {
      Type = "oneshot";
      ExecStart = "${script}";
    };

    wantedBy = [ "default.target" ]; # run at login
  };

  #################################
  # Timer: every hour
  #################################
  systemd.user.timers.wallpaperSync = {
    description = "Run wallpaper sync hourly";

    wantedBy = [ "timers.target" ];

    timerConfig = {
      OnBootSec = "2min";
      OnUnitActiveSec = "1h";
      Persistent = true;
    };
  };

  #################################
  # Hyprland integration (new workspace)
  #################################
  # This assumes you manage Hyprland via Nix/Home Manager
  #################################
  environment.etc."hypr/hyprland.conf".text = lib.mkAfter ''
    # Run wallpaper script when workspace changes
    bind = SUPER, Return, exec, ${script}

    # Hook: when workspace is created/switched
    exec-once = hyprctl --batch "dispatch exec ${script}"
  '';
}