{ config, lib, pkgs, flakeRoot, ... }:
let
  # Where your numbered wallpapers live (1.*, 2.*, ... 9.*)
  userRelRoot = "nixos_conf/wallpaperstuff";
  userAbsRoot = "${config.home.homeDirectory}/${userRelRoot}";
  picturesDir = "${userAbsRoot}/pictures";
  # (Optional) still sync your repo wallpapers/scripts into ~/nixos_conf/wallpaperstuff
  repoWallpaperDir = flakeRoot + "/assets/conf/desktop/wallpaper";
  repoWallpapersOnly = lib.cleanSourceWith {
  src = repoWallpaperDir;
  filter = path: type: true;
  };
  daemonRel = "hypr/scripts/hyprpaper-ws-daemon.sh";
  setRel  = "hypr/scripts/set-wallpaper.sh";
in
{
  home.packages = [
  pkgs.hyprpaper
  pkgs.socat
  pkgs.jq
  pkgs.findutils
  pkgs.coreutils
  pkgs.gnused
  pkgs.gawk
  ];
  # Keep your existing "sync wallpapers into a writable dir" pattern
  home.file."${userRelRoot}" = {
  source = repoWallpapersOnly;
  recursive = true;
  };
  # Hyprpaper config (hyprpaper reads this; it does NOT need to write it)
  # `ipc = true` enables `hyprctl hyprpaper ...` commands. :contentReference[oaicite:0]{index=0}
  xdg.configFile."hypr/hyprpaper.conf".text = lib.mkForce ''
  ipc = true
  splash = false
  '';
  xdg.configFile."hypr/hyprpaper.conf".backup = lib.mkForce false;
  # Workspace wallpaper daemon: listens to socket2, applies w-<id>=... mapping
  # Uses workspacev2 to get numeric workspace id. :contentReference[oaicite:1]{index=1}
  xdg.configFile."${daemonRel}" = {
  executable = true;
  text = lib.mkForce ''
  #!/usr/bin/env bash
  set -euo pipefail
  : "''${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" ]] || { echo "Hyprland socket not found: $SOCK" >&2; exit 1; }
  PICTURES_DIR="''${1:-${picturesDir}}"
  FIT_MODE="fill" # hyprpaper fit_mode: contain|cover|tile|fill :contentReference[oaicite:2]{index=2}
  HYPR_DIR="''${XDG_CONFIG_HOME:-$HOME/.config}/hypr"
  MAP_ROOT="''${HYPR_DIR}/hyprpaper/config"
  focused_monitor() {
    hyprctl -j monitors | jq -r '.[] | select(.focused==true) | .name' | head -n 1
  }
  map_file_for_monitor() {
    local mon="''${1}"
    echo "''${MAP_ROOT}/''${mon}/defaults.conf"
  }
  ensure_map_file() {
    local mon="''${1}"
    local f
    f="$(map_file_for_monitor "''${mon}")"
    mkdir -p "$(dirname "''${f}")"
    if [[ ! -f "''${f}" ]]; then
    # Seed with 1..9 from picturesDir if present, else empty entries
    {
    for i in 1 2 3 4 5 6 7 8 9; do
      seed="$(ls -1 "''${PICTURES_DIR}/''${i}."* 2>/dev/null | head -n 1 || true)"
      echo "w-''${i}= ''${seed}"
    done
    } > "''${f}"
    fi
    echo "''${f}"
  }
  get_wall_for_ws() {
    local mon="''${1}"
    local wsid="''${2}"
    local f key val
    f="$(ensure_map_file "''${mon}")"
    key="w-''${wsid}"
    # accept "w-1=/path" or "w-1= /path"
    val="$(awk -F= -v k="''${key}" '$1==k {sub(/^[[:space:]]+/, "", $2); print $2; exit}' "''${f}" || true)"
    echo "''${val}"
  }
  apply_wallpaper() {
    local mon="''${1}"
    local wsid="''${2}"
    local file
    file="$(get_wall_for_ws "''${mon}" "''${wsid}")"
    [[ -n "''${file}" ]] || return 0
    [[ -f "''${file}" ]] || return 0
    # Apply via IPC
    # hyprpaper “wallpaper { monitor path fit_mode }” model is per monitor. :contentReference[oaicite:3]{index=3}
    hyprctl hyprpaper wallpaper "''${mon}, ''${file}, ''${FIT_MODE}" >/dev/null
  }
  # Initial apply on startup
  mon="$(focused_monitor || true)"
  wsid="$(hyprctl -j activeworkspace | jq -r '.id' | head -n 1 || true)"
  [[ -n "''${mon}" && -n "''${wsid}" ]] && apply_wallpaper "''${mon}" "''${wsid}"
  handle() {
    local line="''${1}"
    case "''${line}" in
    workspacev2* )
    # workspacev2>>ID,NAME  :contentReference[oaicite:4]{index=4}
    local payload wsid
    payload="''${line#*>>}"
    wsid="''${payload%%,*}"
    mon="$(focused_monitor || true)"
    [[ -n "''${mon}" && -n "''${wsid}" ]] && apply_wallpaper "''${mon}" "''${wsid}"
    ;;
    focusedmon* )
    # focusedmon>>MON,WORKSPACENAME :contentReference[oaicite:5]{index=5}
    # When monitor focus changes, re-apply for the active workspace id.
    mon="$(focused_monitor || true)"
    wsid="$(hyprctl -j activeworkspace | jq -r '.id' | head -n 1 || true)"
    [[ -n "''${mon}" && -n "''${wsid}" ]] && apply_wallpaper "''${mon}" "''${wsid}"
    ;;
    esac
  }
  socat -U - UNIX-CONNECT:"''${SOCK}" | while read -r line; do
    handle "''${line}" || true
  done
  '';
  backup = lib.mkForce false;
  };

  # CLI setter in the style of your inspiration script.
  # Usage: set-wallpaper.sh <workspace_id> <monitor> [wallpaper]
  xdg.configFile."${setRel}" = {
  executable = true;
  text = lib.mkForce ''
  #!/usr/bin/env bash
  set -euo pipefail

  HYPR_DIR="''${XDG_CONFIG_HOME:-$HOME/.config}/hypr"
  MAP_ROOT="''${HYPR_DIR}/hyprpaper/config"

  usage() {
    echo "Usage: set-wallpaper.sh <workspace_id> <monitor> [wallpaper_path]"
  }

  wsid="''${1:-}"
  mon="''${2:-}"
  wp="''${3:-}"

  [[ -n "''${wsid}" ]] || { usage; exit 1; }
  [[ -n "''${mon}"  ]] || { usage; exit 1; }

  cfg="''${MAP_ROOT}/''${mon}/defaults.conf"
  mkdir -p "$(dirname "''${cfg}")"
  [[ -f "''${cfg}" ]] || touch "''${cfg}"

  if [[ -z "''${wp}" ]]; then
    # Random pick from your defaults folder if you want; adjust path if needed:
    wp="$(find "$HOME/.config/wallpapers/defaults" -type f 2>/dev/null | shuf -n 1 || true)"
    [[ -n "''${wp}" ]] || { echo "No wallpaper found (random). Provide a path as arg 3."; exit 1; }
  fi

  # Ensure key exists; if not, append it
  key="w-''${wsid}"
  if ! grep -q "^''${key}=" "''${cfg}"; then
    echo "''${key}=" >> "''${cfg}"
  fi

  # Set mapping
  ${pkgs.gnused}/bin/sed -i "s|^''${key}=.*|''${key}= ''${wp}|g" "''${cfg}"

  # If this monitor is currently showing that workspace id, apply immediately
  curws="$(hyprctl -j monitors | jq -r --arg m "''${mon}" '.[] | select(.name==$m) | .activeWorkspace.id' | head -n 1 || true)"
  if [[ "''${curws}" == "''${wsid}" ]]; then
    hyprctl hyprpaper wallpaper "''${mon}, ''${wp}, fill" >/dev/null
  fi
  '';
  backup = lib.mkForce false;
  };

  # Services
  systemd.user.services.hyprpaper = {
  Unit = {
  Description = "hyprpaper wallpaper daemon";
  PartOf = [ "graphical-session.target" ];
  After  = [ "graphical-session.target" ];
  };
  Service = {
  ExecStart = "${pkgs.hyprpaper}/bin/hyprpaper";
  Restart = "on-failure";
  RestartSec = 1;
  };
  Install = { WantedBy = [ "graphical-session.target" ]; };
  };

  systemd.user.services.hyprpaper-ws-daemon = {
  Unit = {
  Description = "Workspace->wallpaper mapping daemon (hyprpaper + socket2)";
  PartOf = [ "graphical-session.target" ];
  After  = [ "graphical-session.target" "hyprpaper.service" ];
  };
  Service = {
  ExecStart = "${pkgs.bash}/bin/bash ${config.xdg.configHome}/${daemonRel} ${picturesDir}";
  Restart = "on-failure";
  RestartSec = 1;
  };
  Install = { WantedBy = [ "graphical-session.target" ]; };
  };
}