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

let
  # Repo inputs (same as you had)
  repoWallpaperDir = flakeRoot + "/assets/conf/desktop/wallpaper";

  # Where we sync assets to (writable)
  userRelRoot = "nixos_conf/wallpaperstuff";
  userAbsRoot = "${config.home.homeDirectory}/${userRelRoot}";
  picturesDir = "${userAbsRoot}/pictures";

  # Sync everything in repoWallpaperDir to ~/nixos_conf/wallpaperstuff
  repoWallpapersOnly = lib.cleanSourceWith {
    src = repoWallpaperDir;
    filter = path: type: true;
  };

  # Workspace→wallpaper listener script
  wsScriptRel = "hypr/scripts/hyprpaper-workspace-1to9.sh";
in
{
  home.packages = [
    pkgs.hyprpaper
    pkgs.socat
    pkgs.jq
  ];

  # 1) Sync your wallpaper assets + scripts into a writable location
  home.file."${userRelRoot}" = {
    source = repoWallpapersOnly;
    recursive = true;
  };

  # 2) hyprpaper config (read-only is fine; hyprpaper doesn't need to write it)
  #    Location per wiki: ~/.config/hypr/hyprpaper.conf :contentReference[oaicite:1]{index=1}
  xdg.configFile."hypr/hyprpaper.conf".text = ''
    # Managed by Home Manager
    ipc = true
    splash = false

    # Fallback wallpaper (only used for monitors that never got a specific one yet)
    wallpaper {
      monitor =
      path = ${picturesDir}
      fit_mode = fill
      timeout = 3600
    }
  '';

  # 3) Install the listener script at ~/.config/hypr/scripts/...
  xdg.configFile."${wsScriptRel}".executable = true;
  xdg.configFile."${wsScriptRel}".text = ''
    #!/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  (fill ≈ stretch) :contentReference[oaicite:2]{index=2}

    # Track focused monitor (workspace events do not include monitor name) :contentReference[oaicite:3]{index=3}
    FOCUSED_MON=""

    pick_wall_for_ws() {
      local ws="$1"
      # Prefer exact matches like 1.png / 1.jpg / 1.webp / 1.jxl etc.
      # Pick first match; if none, return empty.
      local f
      f="$(ls -1 "${PICTURES_DIR}/${ws}."* 2>/dev/null | head -n 1 || true)"
      echo "$f"
    }

    apply_wallpaper() {
      local mon="$1"
      local ws="$2"

      local file
      file="$(pick_wall_for_ws "$ws")"
      [[ -n "$file" ]] || return 0

      # hyprpaper IPC via hyprctl: hyprctl hyprpaper wallpaper '[mon], [path], [fit_mode]' :contentReference[oaicite:4]{index=4}
      # Note: wiki shows commas + optional fit_mode; keep it explicit.
      hyprctl hyprpaper wallpaper "${mon}, ${file}, ${FIT_MODE}" >/dev/null
    }

    # Initial state
    # focused monitor from hyprctl monitors
    FOCUSED_MON="$(hyprctl -j monitors | jq -r '.[] | select(.focused==true) | .name' | head -n 1)"
    # workspace name (may be "1" or "1:something")
    CUR_WS="$(hyprctl -j activeworkspace | jq -r '.name' | head -n 1)"
    CUR_WS="''${CUR_WS%%:*}"

    [[ -n "$FOCUSED_MON" && -n "$CUR_WS" ]] && apply_wallpaper "$FOCUSED_MON" "$CUR_WS"

    handle() {
      case "$1" in
        focusedmon* )
          # format: focusedmon>>MONNAME,WORKSPACENAME :contentReference[oaicite:5]{index=5}
          local payload="''${1#*>>}"
          FOCUSED_MON="''${payload%%,*}"
          ;;
        workspace* )
          # format: workspace>>WORKSPACENAME :contentReference[oaicite:6]{index=6}
          local ws="''${1#*>>}"
          ws="''${ws%%:*}"
          ws="''${ws%% *}"   # trim trailing space if present
          [[ -n "$FOCUSED_MON" && -n "$ws" ]] && apply_wallpaper "$FOCUSED_MON" "$ws"
          ;;
      esac
    }

    # Listen to socket2 events via socat (wiki example) :contentReference[oaicite:7]{index=7}
    socat -U - UNIX-CONNECT:"$SOCK" | while read -r line; do
      handle "$line" || true
    done
  '';

  # 4) Start hyprpaper + the workspace listener as user 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-workspace-wallpapers = {
    Unit = {
      Description = "Hyprpaper workspace wallpapers (socket2 listener)";
      PartOf = [ "graphical-session.target" ];
      After = [ "graphical-session.target" "hyprpaper.service" ];
    };
    Service = {
      ExecStart = "${pkgs.bash}/bin/bash ${config.xdg.configHome}/${wsScriptRel} ${picturesDir}";
      Restart = "on-failure";
      RestartSec = 1;
    };
    Install = { WantedBy = [ "graphical-session.target" ]; };
  };
}