import { useState, useEffect, useCallback } from "react";

function getStorageKey(seasonId: string) {
  return `draftNotifications-${seasonId}`;
}

export function useDraftNotifications(seasonId: string) {
  const [isSupported, setIsSupported] = useState(false);
  const [permissionState, setPermissionState] = useState<
    NotificationPermission | "unsupported"
  >("unsupported");
  const [enabled, setEnabledState] = useState(false);

  // Check browser support, restore persisted preference, and watch for permission changes
  useEffect(() => {
    if (typeof window === "undefined" || !("Notification" in window)) {
      return;
    }

    setIsSupported(true);
    setPermissionState(Notification.permission);

    // Restore preference from localStorage only if permission is granted
    if (Notification.permission === "granted") {
      const stored = localStorage.getItem(getStorageKey(seasonId));
      if (stored === "true") {
        setEnabledState(true);
      }
    }

    // Watch for the user revoking/granting permission in browser settings
    let permissionStatus: PermissionStatus | null = null;
    navigator.permissions
      .query({ name: "notifications" })
      .then((status) => {
        permissionStatus = status;
        status.onchange = () => {
          setPermissionState(status.state as NotificationPermission);
          // If permission was revoked, disable notifications
          if (status.state !== "granted") {
            setEnabledState(false);
          }
        };
      })
      .catch(() => {
        // Permissions API not available in all environments; silently ignore
      });

    return () => {
      if (permissionStatus) {
        permissionStatus.onchange = null;
      }
    };
  }, [seasonId]);

  const setEnabled = useCallback(
    async (value: boolean) => {
      if (!isSupported) return;

      if (value) {
        // Request permission if not yet granted
        if (Notification.permission === "default") {
          const result = await Notification.requestPermission();
          setPermissionState(result);
          if (result !== "granted") {
            return;
          }
        } else if (Notification.permission === "denied") {
          return;
        }

        setEnabledState(true);
        localStorage.setItem(getStorageKey(seasonId), "true");
      } else {
        setEnabledState(false);
        localStorage.setItem(getStorageKey(seasonId), "false");
      }
    },
    [isSupported, seasonId]
  );

  const sendNotification = useCallback(
    (title: string, body: string) => {
      if (
        !enabled ||
        !isSupported ||
        Notification.permission !== "granted" ||
        typeof document === "undefined" ||
        !document.hidden
      ) {
        return;
      }

      new Notification(title, {
        body,
        tag: `draft-${seasonId}`,
      });
    },
    [enabled, isSupported, seasonId]
  );

  return {
    isSupported,
    permissionState,
    enabled,
    setEnabled,
    sendNotification,
  };
}