import React, { useState, useEffect } from 'react';
import {
  View,
  Text,
  TouchableOpacity,
  Switch,
  StyleSheet,
  Alert,
  Share,
  ScrollView,
} from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { MaterialIcons } from '@expo/vector-icons';
import { kv } from '../../src/lib/kv';
import { useHouseholdStore } from '../../src/hooks/useHousehold';
import { regenerateInviteToken, buildInviteLink } from '../../src/services/household';
import { updateFcmToken, requestNotificationPermission } from '../../src/services/notifications';
import { COLORS } from '../../src/constants';
import Toast from 'react-native-toast-message';

const NOTIF_KEY = 'houseorg_notifications_enabled';

export default function SettingsScreen() {
  const household = useHouseholdStore((s) => s.household);
  const setHousehold = useHouseholdStore((s) => s.setHousehold);
  const [notificationsEnabled, setNotificationsEnabled] = useState<boolean | null>(null);

  useEffect(() => {
    kv.getItem(NOTIF_KEY).then((val) => {
      setNotificationsEnabled(val !== 'false');
    });
  }, []);

  const handleShareInvite = async () => {
    if (!household) return;
    const link = buildInviteLink(household.id, household.inviteToken);
    const text = `Tritt unserem Haushalt bei: ${link}`;
    if (typeof navigator !== 'undefined' && (navigator as any).share) {
      await (navigator as any).share({ text, title: 'HouseOrg Einladung' });
    } else if (typeof navigator !== 'undefined' && (navigator as any).clipboard) {
      await (navigator as any).clipboard.writeText(text);
      Toast.show({ type: 'success', text1: 'Link kopiert' });
    } else {
      await Share.share({ message: text, title: 'HouseOrg Einladung' });
    }
  };

  const handleRegenerateLink = async () => {
    if (!household) return;
    Alert.alert(
      'Link erneuern',
      'Der alte Link wird ungültig. Alle Mitglieder können sich damit nicht mehr neu anmelden.',
      [
        { text: 'Abbrechen', style: 'cancel' },
        {
          text: 'Erneuern',
          style: 'destructive',
          onPress: async () => {
            try {
              const newToken = await regenerateInviteToken(household.id);
              setHousehold({ ...household, inviteToken: newToken });
              Toast.show({ type: 'success', text1: 'Neuer Einladungslink erstellt' });
            } catch {
              Toast.show({ type: 'error', text1: 'Fehler beim Erneuern' });
            }
          },
        },
      ]
    );
  };

  const handleNotificationToggle = async (enabled: boolean) => {
    if (!household) return;
    if (enabled) {
      const granted = await requestNotificationPermission();
      if (!granted) {
        Toast.show({ type: 'error', text1: 'Benachrichtigungen nicht erlaubt' });
        return;
      }
    }
    setNotificationsEnabled(enabled);
    await kv.setItem(NOTIF_KEY, String(enabled));
    await updateFcmToken(household.id, enabled);
  };

  return (
    <SafeAreaView style={styles.container} edges={['top']}>
      <ScrollView showsVerticalScrollIndicator={false}>
        <View style={styles.section}>
          <Text style={styles.sectionTitle}>Haushalt</Text>
          <View style={styles.card}>
            <View style={styles.row}>
              <View style={[styles.iconWrap, { backgroundColor: '#E8F5E9' }]}>
                <MaterialIcons name="home" size={18} color={COLORS.primary} />
              </View>
              <View style={styles.rowContent}>
                <Text style={styles.rowLabel}>Name</Text>
                <Text style={styles.rowValue}>{household?.name}</Text>
              </View>
            </View>

            <View style={styles.divider} />

            <TouchableOpacity style={styles.row} onPress={handleShareInvite}>
              <View style={[styles.iconWrap, { backgroundColor: '#E3F2FD' }]}>
                <MaterialIcons name="share" size={18} color="#1E88E5" />
              </View>
              <View style={styles.rowContent}>
                <Text style={styles.rowLabel}>Einladungslink teilen</Text>
                <Text style={styles.rowHint}>Mitglieder einladen</Text>
              </View>
              <MaterialIcons name="chevron-right" size={20} color={COLORS.textSecondary} />
            </TouchableOpacity>

            <View style={styles.divider} />

            <TouchableOpacity style={styles.row} onPress={handleRegenerateLink}>
              <View style={[styles.iconWrap, { backgroundColor: '#FFF3E0' }]}>
                <MaterialIcons name="refresh" size={18} color={COLORS.warning} />
              </View>
              <View style={styles.rowContent}>
                <Text style={[styles.rowLabel, { color: COLORS.warning }]}>
                  Einladungslink erneuern
                </Text>
                <Text style={styles.rowHint}>Alter Link wird ungültig</Text>
              </View>
            </TouchableOpacity>
          </View>
        </View>

        <View style={styles.section}>
          <Text style={styles.sectionTitle}>Benachrichtigungen</Text>
          <View style={styles.card}>
            <View style={styles.row}>
              <View style={[styles.iconWrap, { backgroundColor: '#F3E5F5' }]}>
                <MaterialIcons name="notifications" size={18} color="#8E24AA" />
              </View>
              <View style={styles.rowContent}>
                <Text style={styles.rowLabel}>Push-Benachrichtigungen</Text>
                <Text style={styles.rowHint}>Einkaufsliste & MHD-Warnungen</Text>
              </View>
              <Switch
                value={notificationsEnabled ?? false}
                disabled={notificationsEnabled === null}
                onValueChange={handleNotificationToggle}
                trackColor={{ false: COLORS.border, true: COLORS.primaryLight }}
                thumbColor={notificationsEnabled ? COLORS.primary : COLORS.white}
              />
            </View>
          </View>
        </View>

        <View style={styles.section}>
          <Text style={styles.sectionTitle}>App</Text>
          <View style={styles.card}>
            <View style={styles.row}>
              <View style={[styles.iconWrap, { backgroundColor: COLORS.surface }]}>
                <MaterialIcons name="info-outline" size={18} color={COLORS.textSecondary} />
              </View>
              <View style={styles.rowContent}>
                <Text style={styles.rowLabel}>Version</Text>
                <Text style={styles.rowValue}>1.0.0</Text>
              </View>
            </View>
          </View>
        </View>
      </ScrollView>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: COLORS.surface },
  section: { marginTop: 28, paddingHorizontal: 16 },
  sectionTitle: {
    fontSize: 12,
    fontWeight: '600',
    color: COLORS.textSecondary,
    textTransform: 'uppercase',
    letterSpacing: 0.6,
    marginBottom: 10,
  },
  card: {
    backgroundColor: COLORS.white,
    borderRadius: 16,
    overflow: 'hidden',
    shadowColor: '#000',
    shadowOpacity: 0.05,
    shadowRadius: 8,
    elevation: 1,
  },
  row: {
    flexDirection: 'row',
    alignItems: 'center',
    padding: 14,
    gap: 12,
  },
  iconWrap: {
    width: 34,
    height: 34,
    borderRadius: 10,
    justifyContent: 'center',
    alignItems: 'center',
  },
  rowContent: { flex: 1 },
  rowLabel: { fontSize: 15, fontWeight: '500', color: COLORS.text },
  rowValue: { fontSize: 13, color: COLORS.textSecondary, marginTop: 2 },
  rowHint: { fontSize: 12, color: COLORS.textSecondary, marginTop: 1 },
  divider: { height: StyleSheet.hairlineWidth, backgroundColor: COLORS.border, marginLeft: 60 },
});