{ config, pkgs, lib, flakeRoot, ... }:
let
  repoWallpaperDir = flakeRoot + "/assets/conf/desktop/wallpaper";
  userRelRoot = "nixos_conf/wallpaperstuff";
  userAbsRoot = "${config.home.homeDirectory}/${userRelRoot}";
  scriptRel = "hypr/scripts/wpaperd-workspace-1to9.sh";
in
{
  home.packages = [
    pkgs.wpaperd
    pkgs.socat
    pkgs.jq
  ];
  # Copy wallpapers from repo → ~/nixos_conf/wallpaperstuff
  home.file."${userRelRoot}" = {
    source = repoWallpaperDir;
    recursive = true;
  };
  # Workspace listener script (no wpaperd config needed)
  xdg.configFile."${scriptRel}".text = ''
    #!/usr/bin/env bash
    set -euo pipefail
    ROOT="${userAbsRoot}"
    : "''${XDG_RUNTIME_DIR:?XDG_RUNTIME_DIR not set}"
    : "''${HYPRLAND_INSTANCE_SIGNATURE:?HYPRLAND_INSTANCE_SIGNATURE not set}"
    SOCK="''${XDG_RUNTIME_DIR}/hypr/''${HYPRLAND_INSTANCE_SIGNATURE}/.socket2.sock"
    [[ -S "$SOCK" ]] || exit 0
    # Extract numeric workspace prefix from "1" or "1:foo"
    ws_num() {
      local w="''${1%%:*}"
      [[ "$w" =~ ^[0-9]+$ ]] || return 1
      printf '%s\n' "$w"
    }
    img_for_ws() {
      local n="$1"
      case "$n" in
        1|2|3|4|5|6|7|8|9) printf '%s/wallpaper%s.jpg\n' "$ROOT" "$n" ;;
        *) return 1 ;;
      esac
    }
    apply_for() {
      local mon="$1"
      local ws="$2"
      local n
      n="$(ws_num "$ws")" || return 0
      local img
      img="$(img_for_ws "$n")" || return 0
      [[ -f "$img" ]] || return 0
      # Set wallpaper for specific monitor (supported by wpaperctl)
      ${pkgs.wpaperd}/bin/wpaperctl set "$img" "$mon" >/dev/null 2>&1 || true
    }
    apply_initial() {
      # For each monitor, read its activeWorkspace.name and apply once at startup
      ${pkgs.hyprland}/bin/hyprctl -j monitors \
        | ${pkgs.jq}/bin/jq -r '.[] | "\(.name)\t\(.activeWorkspace.name)"' \
        | while IFS=$'\t' read -r mon ws; do
            [[ -n "$mon" && -n "$ws" ]] || continue
            apply_for "$mon" "$ws"
          done
    }
    handle_line() {
      case "$1" in
        focusedmon\>\>*)
          # focusedmon>>MONNAME,WORKSPACENAME
          local payload="''${1#focusedmon>>}"
          local mon="''${payload%%,*}"
          local ws="''${payload#*,}"
          apply_for "$mon" "$ws"
          ;;
        workspace\>\>*)
          # workspace>>WORKSPACENAME (no monitor info) — ignore
          ;;
        workspacev2\>\>*)
          # workspacev2>>ID,NAME (no monitor info) — ignore
          ;;
      esac
    }
    apply_initial
    exec ${pkgs.socat}/bin/socat -U - "UNIX-CONNECT:$SOCK" \
      | while IFS= read -r line; do
          handle_line "$line" || true
        done
  '';
  xdg.configFile."${scriptRel}".executable = true;
  # Start wpaperd
  systemd.user.services.wpaperd = {
    Unit = {
      Description = "wpaperd wallpaper daemon";
      After = [ "graphical-session.target" ];
      PartOf = [ "graphical-session.target" ];
    };
    Service = {
      ExecStart = "${pkgs.wpaperd}/bin/wpaperd";
      Restart = "on-failure";
    };
    Install.WantedBy = [ "graphical-session.target" ];
  };
  # Listen to Hyprland workspace/monitor focus and set wallpapers accordingly
  systemd.user.services.wpaperd-workspace-wallpapers = {
    Unit = {
      Description = "Set wallpaper based on workspace number (1..9)";
      After = [ "graphical-session.target" "wpaperd.service" ];
      PartOf = [ "graphical-session.target" ];
    };
    Service = {
      ExecStart = "${pkgs.bash}/bin/bash ${config.xdg.configHome}/${scriptRel}";
      Restart = "on-failure";
    };
    Install.WantedBy = [ "graphical-session.target" ];
  };
}