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

let
  # Repo inputs
  repoWallpaperDir = flakeRoot + "/assets/conf/desktop/wallpaper";

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

  picturesDir = "${userAbsRoot}/pictures";

  # Writable runtime TOML (NOT under ~/.config)
  runtimeConf = "${userAbsRoot}/wpaperd-runtime.toml";

  # Your generator script (synced from repo into userAbsRoot)
  wsScript = "${userAbsRoot}/wpaperd-workspace-1to9.sh";

  # Sync everything in repoWallpaperDir to ~/nixos_conf/wallpaperstuff,
  # but keep it simple: we exclude no files here unless you want to.
  repoWallpapersOnly = lib.cleanSourceWith {
    src = repoWallpaperDir;
    filter = path: type: true;
  };
in
{
  home.packages = [
    pkgs.wpaperd
  ];

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

  # 2) Ensure we have a writable runtime config (created if missing)
  #
  # NOTE: We intentionally do NOT create ~/.config/wpaperd/config.toml via HM,
  # because HM places managed files in /nix/store and symlinks them (read-only),
  # which breaks apps/scripts that want to write there.
  home.activation.ensureWpaperdRuntimeConf =
    lib.hm.dag.entryAfter [ "writeBoundary" ] ''
      mkdir -p "${userAbsRoot}"
      mkdir -p "${picturesDir}"

      if [ ! -f "${runtimeConf}" ]; then
        cat > "${runtimeConf}" <<'EOF'
[default]
mode = "stretch"

# Fallback for outputs not explicitly listed:
[any]
path = "__WALLPAPER_DIR__"
EOF
        # default: point [any].path at your pictures dir
        ${pkgs.gnused}/bin/sed -i "s|__WALLPAPER_DIR__|${picturesDir}|g" "${runtimeConf}"
      fi
    '';

  # 3) wpaperd user service: always use the writable runtime config
  systemd.user.services.wpaperd = {
    Unit = {
      Description = "wpaperd wallpaper daemon (runtime config)";
      PartOf = [ "graphical-session.target" ];
      After  = [ "graphical-session.target" ];
    };

    Service = {
      ExecStart = "${pkgs.wpaperd}/bin/wpaperd --config ${runtimeConf}";
      Restart = "on-failure";
      RestartSec = 1;
    };

    Install = {
      WantedBy = [ "graphical-session.target" ];
    };
  };

  # 4) Optional: run your workspace generator once per login, then restart wpaperd
  systemd.user.services.wpaperd-workspaces-init = {
    Unit = {
      Description = "Generate workspace wallpapers (wpaperd runtime config)";
      PartOf = [ "graphical-session.target" ];
      After  = [ "graphical-session.target" ];
    };

    Service = {
      Type = "oneshot";
      ExecStart = "${pkgs.bash}/bin/bash ${wsScript} ${picturesDir}";
      ExecStartPost = "${pkgs.systemd}/bin/systemctl --user restart wpaperd";
    };

    Install = {
      WantedBy = [ "graphical-session.target" ];
    };
  };
}