import { useState } from 'react';
import {
  ActivityIndicator,
  Alert,
  Pressable,
  ScrollView,
  Text,
  View,
} from 'react-native';
import { useBottomTabBarHeight } from 'react-native-bottom-tabs';
import { useTranslation } from 'react-i18next';
import { Ionicons } from '@expo/vector-icons';
import { AppHeader } from '../../components/AppHeader';
import { MailStatsRow } from '../../components/mail/MailStatsRow';
import { MailAccountCard } from '../../components/mail/MailAccountCard';
import { MailEmptyState } from '../../components/mail/MailEmptyState';
import { MailActivityLog } from '../../components/mail/MailActivityLog';
import { ConnectMailSheet } from '../../components/mail/ConnectMailSheet';
import { SuccessAlert } from '../../components/SuccessAlert';
import { useMailStatus } from '../../hooks/useMailStatus';
import { useMailDisconnect } from '../../hooks/useMailDisconnect';
import { useUserPlan } from '../../hooks/useUserPlan';
import { useColors } from '../../lib/theme';

export default function MailScreen() {
  const { t } = useTranslation();
  const tabBarHeight = useBottomTabBarHeight();
  const colors = useColors();

  const { plan } = useUserPlan();

  const { connected, accounts, totalBlocked, maxAccounts, loading, refresh } =
    useMailStatus(plan);
  const { disconnect, disconnecting } = useMailDisconnect();

  const [sheetVisible, setSheetVisible] = useState(false);
  const [successVisible, setSuccessVisible] = useState(false);
  const [disconnectingId, setDisconnectingId] = useState<string | null>(null);
  const [expandedAccount, setExpandedAccount] = useState<string | null>(null);
  const [activityLogExpanded, setActivityLogExpanded] = useState(false);

  const nextScanAt =
    accounts
      .map((a) => a.nextScanAt)
      .filter((v): v is string => v !== null)
      .sort()[0] ?? null;

  const limitReached = accounts.length >= maxAccounts;

  function handleAddPress() {
    if (limitReached) {
      Alert.alert(t('mail.upgrade_alert_title'), t('mail.upgrade_alert_desc'));
      return;
    }
    setSheetVisible(true);
  }

  async function handleDisconnect(id: string) {
    setDisconnectingId(id);
    await disconnect(id);
    setDisconnectingId(null);
    if (expandedAccount === id) setExpandedAccount(null);
    refresh();
  }

  function handleConnectSuccess() {
    setSuccessVisible(true);
    refresh();
  }

  function toggleAccount(id: string) {
    setExpandedAccount((prev) => (prev === id ? null : id));
  }

  if (loading) {
    return (
      <View style={{ flex: 1, backgroundColor: colors.bg }}>
        <AppHeader />
        <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
          <ActivityIndicator size="large" color="#007AFF" />
        </View>
      </View>
    );
  }

  return (
    <View style={{ flex: 1, backgroundColor: colors.bg }}>
      <AppHeader />

      <ScrollView
        contentContainerStyle={{
          paddingHorizontal: 16,
          paddingTop: 16,
          paddingBottom: tabBarHeight + 24,
        }}
        showsVerticalScrollIndicator={false}
      >
        {/* Stats card */}
        {accounts.length > 0 && (
          <View style={{ marginBottom: 14 }}>
            <MailStatsRow
              totalBlocked={totalBlocked}
              accountCount={accounts.length}
              isLegend={plan === 'legend'}
            />
          </View>
        )}

        {/* Section header with prominent + button */}
        <View
          style={{
            flexDirection: 'row',
            alignItems: 'center',
            marginBottom: 10,
            paddingHorizontal: 2,
          }}
        >
          <View style={{ flex: 1, marginRight: 10 }}>
            <Text
              style={{
                fontSize: 11,
                fontFamily: 'Nunito_700Bold',
                color: colors.textMuted,
                textTransform: 'uppercase',
                letterSpacing: 0.8,
              }}
            >
              {t('mail.section_accounts')}
            </Text>
            <Text
              style={{
                fontSize: 11,
                fontFamily: 'Nunito_400Regular',
                color: colors.textMuted,
                marginTop: 2,
              }}
            >
              {maxAccounts === Infinity
                ? t('mail.section_accounts_count_unlimited', { used: accounts.length })
                : t('mail.section_accounts_count', {
                    used: accounts.length,
                    max: maxAccounts,
                  })}
            </Text>
          </View>

          <Pressable
            onPress={handleAddPress}
            disabled={limitReached}
            android_ripple={{ color: '#0066cc' }}
            style={{
              backgroundColor: limitReached ? colors.surfaceElevated : '#007AFF',
              borderRadius: 12,
              opacity: limitReached ? 0.7 : 1,
              shadowColor: '#007AFF',
              shadowOffset: { width: 0, height: 4 },
              shadowOpacity: limitReached ? 0 : 0.25,
              shadowRadius: 8,
              elevation: limitReached ? 0 : 4,
            }}
            accessibilityLabel={t('mail.add_account_a11y')}
          >
            <View
              style={{
                flexDirection: 'row',
                alignItems: 'center',
                paddingHorizontal: 14,
                paddingVertical: 10,
              }}
            >
              <Ionicons
                name="add"
                size={18}
                color={limitReached ? colors.textMuted : '#fff'}
                style={{ marginRight: 6 }}
              />
              <Text
                style={{
                  fontSize: 13,
                  fontFamily: 'Nunito_700Bold',
                  color: limitReached ? colors.textMuted : '#fff',
                }}
              >
                {t('mail.add_account')}
              </Text>
            </View>
          </Pressable>
        </View>

        {/* Account cards or empty */}
        {accounts.length === 0 ? (
          <MailEmptyState onConnectPress={handleAddPress} />
        ) : (
          <View>
            {accounts.map((account, idx) => (
              <View key={account.id} style={{ marginTop: idx === 0 ? 0 : 10 }}>
                <MailAccountCard
                  account={account}
                  plan={plan}
                  expanded={expandedAccount === account.id}
                  onToggle={() => toggleAccount(account.id)}
                  onDisconnect={handleDisconnect}
                  onIntervalChanged={refresh}
                  onEditSuccess={handleConnectSuccess}
                  disconnecting={disconnectingId === account.id && disconnecting}
                />
              </View>
            ))}
          </View>
        )}

        {/* Activity log */}
        {accounts.length > 0 && (
          <View style={{ marginTop: 14 }}>
            <MailActivityLog
              expanded={activityLogExpanded}
              onToggle={() => setActivityLogExpanded((p) => !p)}
            />
          </View>
        )}
      </ScrollView>

      <ConnectMailSheet
        visible={sheetVisible}
        onClose={() => setSheetVisible(false)}
        onSuccess={handleConnectSuccess}
      />

      <SuccessAlert
        visible={successVisible}
        title={t('mail.connect_success_title')}
        message={t('mail.connect_success_message')}
        onClose={() => setSuccessVisible(false)}
      />
    </View>
  );
}
