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

let
  moduleName = "hm-backgrounds";
  src = ../home-manager/conf/backgrounds;
  video = "${config.home.homeDirectory}/backgrounds/videos/191684-891315375.mp4";
  startWallpaper = pkgs.writeShellScript "start-video-wallpaper" ''
    set -euo pipefail

    VIDEO="${video}"
    MPVPAPER="${pkgs.mpvpaper}/bin/mpvpaper"
    HYPRCTL="${pkgs.hyprland}/bin/hyprctl"
    PKILL="${pkgs.procps}/bin/pkill"
    AWK="${pkgs.gawk}/bin/awk"

    # Avoid stacking multiple instances on rebuild / relogin
    $PKILL -x mpvpaper || true

    # Wait until Hyprland is ready
    for i in $(seq 1 30); do
      if $HYPRCTL monitors >/dev/null 2>&1; then
        break
      fi
      sleep 1
    done

    # If the file doesn't exist, don't crash-loop forever
    if [ ! -f "$VIDEO" ]; then
      echo "Wallpaper video not found: $VIDEO"
      exit 0
    fi

    # Detect monitors
    MONITORS="$($HYPRCTL monitors | $AWK '/^Monitor/ {print $2}')"
    if [ -z "$MONITORS" ]; then
      echo "No monitors detected by hyprctl."
      exit 0
    fi

    # Start mpvpaper per monitor
    for m in $MONITORS; do
      $MPVPAPER -o "--loop --no-audio --panscan=1.0 --video-aspect-override=yes" "$m" "$VIDEO" &
    done

    wait
  '';
in
{
  # 0) Make HM reliably manage/restart user services on switch
  # (prevents having to run systemctl --user daemon-reload manually)
  systemd.user.startServices = "sd-switch";

  # 1) Put the whole repo folder into ~/backgrounds
  home.file."backgrounds".source = src;

  # 2) Ensure dependencies exist
  home.packages = with pkgs; [
    mpv
    mpvpaper
    procps
    gawk
  ];

  # 3) Run video wallpaper on ALL monitors
  #
  # IMPORTANT:
  # - Do NOT tie to graphical-session.target / hyprland-session.target, because in your setup
  #   those targets were inactive/missing.
  # - Instead, start on user login via default.target, and the script itself waits for Hyprland.
  systemd.user.services.video-wallpaper = {
    Unit = {
      Description = "Video wallpaper (mpvpaper) on all Hyprland monitors";
    };

    Service = {
      Type = "simple";
      Restart = "on-failure";
      RestartSec = 2;

      ExecStart = startWallpaper;
    };

    Install = {
      WantedBy = [ "default.target" ];
    };
  };

  # 4) Restart on switch so new /nix/store script paths are picked up
  # (kept, but now it won’t break boot/login if the user bus isn’t ready)
  home.activation.restartVideoWallpaper =
    lib.hm.dag.entryAfter [ "writeBoundary" ] ''
      ${pkgs.systemd}/bin/systemctl --user daemon-reload || true
      ${pkgs.systemd}/bin/systemctl --user reset-failed video-wallpaper || true
      ${pkgs.systemd}/bin/systemctl --user restart video-wallpaper || true
    '';
  home.file.".nixlog/loaded.${moduleName}-module-loaded".text = "loaded\n";
}