import React, { useState } from 'react';
import {
  IonButton,
  IonButtons,
  IonContent,
  IonHeader,
  IonIcon,
  IonPage,
  IonSkeletonText,
  IonTitle,
  IonToolbar,
  useIonViewWillEnter,
} from '@ionic/react';
import {
  alertCircleOutline,
  chevronBackOutline,
  chevronForwardOutline,
  notificationsOutline,
} from 'ionicons/icons';
import { useHistory } from 'react-router-dom';
import { supabase } from '../supabase';
import { useAuth } from '../contexts/AuthContext';
import '../styles/activity.css';
import '../styles/recipients.css';

type NotificationRow = {
  id: string;
  title: string;
  body: string;
  priority: string;
  type: string;
  read_at: string | null;
  created_at: string;
  order_id: string | null;
  voucher_id: string | null;
};

const NotificationsPage: React.FC = () => {
  const history = useHistory();
  const { user } = useAuth();
  const [notifications, setNotifications] = useState<NotificationRow[]>([]);
  const [loading, setLoading] = useState(true);
  const [markingAll, setMarkingAll] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useIonViewWillEnter(() => {
    void loadNotifications();
  });

  const showError = (message: string) => {
    setError(message);
    setTimeout(() => setError(null), 4000);
  };

  const loadNotifications = async () => {
    if (!user) return;
    setLoading(true);
    setError(null);

    const { data, error: loadError } = await supabase
      .from('notifications')
      .select(
        'id,title,body,priority,type,read_at,created_at,order_id,voucher_id'
      )
      .eq('user_id', user.id)
      .order('created_at', { ascending: false });

    if (loadError) {
      showError(loadError.message);
      setLoading(false);
      return;
    }

    setNotifications((data ?? []) as NotificationRow[]);
    setLoading(false);
  };

  const markRead = async (notificationId: string) => {
    const readAt = new Date().toISOString();
    setNotifications((current) =>
      current.map((item) =>
        item.id === notificationId ? { ...item, read_at: readAt } : item
      )
    );
    await supabase.functions.invoke('mark-notification-read', {
      body: { notificationId },
    });
  };

  const handleOpenNotification = async (notification: NotificationRow) => {
    if (!notification.read_at) {
      await markRead(notification.id);
    }
    if (notification.voucher_id) {
      history.push(`/voucher/${notification.voucher_id}`);
    } else if (notification.order_id) {
      history.push(`/activity/${notification.order_id}`);
    }
  };

  const handleMarkAllRead = async () => {
    if (!user) return;
    setMarkingAll(true);
    const readAt = new Date().toISOString();
    const { error: updateError } = await supabase
      .from('notifications')
      .update({ read_at: readAt })
      .eq('user_id', user.id)
      .is('read_at', null);

    if (updateError) {
      showError(updateError.message);
    } else {
      setNotifications((current) =>
        current.map((item) => ({ ...item, read_at: item.read_at ?? readAt }))
      );
    }
    setMarkingAll(false);
  };

  return (
    <IonPage style={{ backgroundColor: '#fafafa' }}>
      <IonHeader className="ion-no-border">
        <IonToolbar
          style={
            {
              '--background': '#fafafa',
              '--border-width': '0px',
            } as React.CSSProperties
          }
        >
          <IonButtons slot="start">
            <IonButton
              fill="clear"
              onClick={() =>
                history.length > 1
                  ? history.goBack()
                  : history.replace('/profile')
              }
              aria-label="Go back"
            >
              <IonIcon icon={chevronBackOutline} slot="icon-only" />
            </IonButton>
          </IonButtons>
          <IonTitle style={{ fontSize: 18, fontWeight: 700 }}>
            Notifications
          </IonTitle>
          <IonButtons slot="end">
            <IonButton
              className="notifications-header-btn"
              fill="clear"
              disabled={markingAll}
              onClick={handleMarkAllRead}
            >
              Mark all
            </IonButton>
          </IonButtons>
        </IonToolbar>
      </IonHeader>

      <IonContent style={{ '--background': '#fafafa' } as React.CSSProperties}>
        {error && (
          <p style={{ margin: '12px 20px', color: '#dc2626', fontSize: 13 }}>
            {error}
          </p>
        )}

        {loading ? (
          <div className="notifications-list-card">
            {[1, 2, 3].map((item) => (
              <div className="notification-row" key={item}>
                <IonSkeletonText
                  animated
                  style={{
                    width: 44,
                    height: 44,
                    borderRadius: 12,
                    flexShrink: 0,
                  }}
                />
                <div style={{ flex: 1 }}>
                  <IonSkeletonText
                    animated
                    style={{ width: '65%', height: 15 }}
                  />
                  <IonSkeletonText
                    animated
                    style={{ width: '90%', height: 12 }}
                  />
                </div>
              </div>
            ))}
          </div>
        ) : notifications.length === 0 ? (
          <div className="empty-state-card" style={{ marginTop: 20 }}>
            <IonIcon icon={notificationsOutline} className="esc-icon" />
            <h2 className="esc-title">No notifications yet</h2>
            <p className="esc-msg">
              Important payment and voucher updates will appear here.
            </p>
          </div>
        ) : (
          <div className="notifications-list-card">
            {notifications.map((notification) => (
              <button
                key={notification.id}
                type="button"
                className="notification-row"
                onClick={() => handleOpenNotification(notification)}
                style={{
                  width: '100%',
                  border: 'none',
                  background: 'transparent',
                  textAlign: 'left',
                }}
              >
                {!notification.read_at && <span className="nr-unread-dot" />}
                <div className={`nr-icon-box ${notification.priority}`}>
                  <IonIcon icon={alertCircleOutline} />
                </div>
                <div className="nr-content">
                  <h3 className="nr-title">{notification.title}</h3>
                  <p className="nr-body">{notification.body}</p>
                  <span className="nr-time">
                    {new Date(notification.created_at).toLocaleString()}
                  </span>
                </div>
                <IonIcon
                  icon={chevronForwardOutline}
                  className="nr-link-icon"
                />
              </button>
            ))}
          </div>
        )}
      </IonContent>
    </IonPage>
  );
};

export default NotificationsPage;