import React, { useState } from 'react';
import {
  Alert,
  KeyboardAvoidingView,
  Platform,
  Pressable,
  ScrollView,
  StyleSheet,
  Text,
  View,
} from 'react-native';
import { useSafeAreaInsets } from 'react-native-safe-area-context';
import type { NativeStackScreenProps } from '@react-navigation/native-stack';
import type { AttendanceCheckInResult } from '../api/types';
import { CheckInResultModal } from '../components/CheckInResultModal';
import type { RootStackParamList } from '../navigation/types';
import { performAppAssignBlank, performAppUndoCheckIn } from '../offline/checkInService';
import { useOffline } from '../offline/OfflineContext';
import { colors, spacing, typography } from '../theme';
import { AppIcon, PrimaryButton, TextField } from '../components/ui';

type Props = NativeStackScreenProps<RootStackParamList, 'AssignBlank'>;

export function AssignBlankScreen({ navigation, route }: Props) {
  const {
    eventId,
    eventName,
    attendanceId,
    attendanceName,
    participantId,
    firstName: initialFirst,
    lastName: initialLast,
    email: initialEmail,
    phone: initialPhone,
  } = route.params;
  const insets = useSafeAreaInsets();
  const { refreshStatuses } = useOffline();

  const [firstName, setFirstName] = useState(initialFirst || '');
  const [lastName, setLastName] = useState(initialLast || '');
  const [email, setEmail] = useState(initialEmail || '');
  const [phone, setPhone] = useState(initialPhone || '');
  const [saving, setSaving] = useState(false);
  const [result, setResult] = useState<AttendanceCheckInResult | null>(null);
  const [resultError, setResultError] = useState<string | null>(null);
  const [pendingSync, setPendingSync] = useState(false);
  const [modalVisible, setModalVisible] = useState(false);
  const [undoLoading, setUndoLoading] = useState(false);

  const save = async () => {
    if (!firstName.trim()) {
      setResult(null);
      setResultError('First name is required');
      setPendingSync(false);
      setModalVisible(true);
      return;
    }
    setSaving(true);
    const outcome = await performAppAssignBlank({
      eventId,
      attendanceId,
      attendanceName,
      participantId,
      profile: { firstName, lastName, email, phone },
    });
    setSaving(false);
    if (!outcome.ok) {
      setResult(null);
      setResultError(outcome.error);
      setPendingSync(false);
    } else {
      setResult(outcome.result);
      setResultError(null);
      setPendingSync(outcome.pendingSync);
      refreshStatuses().catch(() => undefined);
    }
    setModalVisible(true);
  };

  const closeModal = () => {
    if (undoLoading) return;
    setModalVisible(false);
    if (result && !resultError) {
      navigation.goBack();
      return;
    }
    setResult(null);
    setResultError(null);
    setPendingSync(false);
  };

  const handleUndo = async () => {
    if (!result) return;
    setUndoLoading(true);
    const outcome = await performAppUndoCheckIn({
      eventId,
      attendanceId,
      attendanceName,
      participantId: result.participantId,
    });
    setUndoLoading(false);
    if (!outcome.ok) {
      Alert.alert('Undo failed', outcome.error);
      return;
    }
    setModalVisible(false);
    setResult(null);
    setResultError(null);
    setPendingSync(false);
    refreshStatuses().catch(() => undefined);
    navigation.goBack();
  };

  return (
    <View style={styles.wrap}>
      <View style={[styles.header, { paddingTop: insets.top + spacing.md }]}>
        <View style={styles.headerBg} />
        <Pressable onPress={() => navigation.goBack()} hitSlop={10} style={styles.backBtn}>
          <AppIcon name="arrow-back" size={18} color="rgba(255,255,255,0.85)" />
          <Text style={styles.backLabel} numberOfLines={1}>
            {eventName}
          </Text>
        </Pressable>
        <Text style={styles.headerTitle}>Assign a Blank</Text>
        <Text style={styles.headerSubtitle}>{attendanceName}</Text>
      </View>

      <KeyboardAvoidingView
        style={styles.flex}
        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
      >
        <ScrollView
          contentContainerStyle={[
            styles.form,
            { paddingBottom: Math.max(insets.bottom, 16) + 24 },
          ]}
          keyboardShouldPersistTaps="handled"
        >
          <Text style={styles.lead}>
            Update this spare badge’s details, then save to check the person in.
          </Text>
          <TextField
            label="First name"
            value={firstName}
            onChangeText={setFirstName}
            autoCapitalize="words"
            autoCorrect={false}
          />
          <TextField
            label="Last name"
            value={lastName}
            onChangeText={setLastName}
            autoCapitalize="words"
            autoCorrect={false}
          />
          <TextField
            label="Email"
            value={email}
            onChangeText={setEmail}
            keyboardType="email-address"
            autoCapitalize="none"
            autoCorrect={false}
          />
          <TextField
            label="Phone"
            value={phone}
            onChangeText={setPhone}
            keyboardType="phone-pad"
            autoCorrect={false}
          />
          <PrimaryButton
            title="Save and check in"
            loading={saving}
            onPress={() => {
              void save();
            }}
          />
        </ScrollView>
      </KeyboardAvoidingView>

      <CheckInResultModal
        visible={modalVisible}
        result={result}
        error={resultError}
        pendingSync={pendingSync}
        onClose={closeModal}
        onUndo={result ? handleUndo : undefined}
        undoLoading={undoLoading}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  wrap: { flex: 1, backgroundColor: colors.background },
  flex: { flex: 1 },
  header: {
    paddingHorizontal: spacing.xl,
    paddingBottom: spacing.lg,
    overflow: 'hidden',
  },
  headerBg: {
    ...StyleSheet.absoluteFill,
    backgroundColor: colors.primary,
    zIndex: 0,
  },
  backBtn: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: 8,
    marginBottom: spacing.md,
    alignSelf: 'flex-start',
    zIndex: 1,
  },
  backLabel: {
    color: 'rgba(255,255,255,0.85)',
    fontSize: 14,
    fontWeight: '500',
  },
  headerTitle: {
    color: '#fff',
    fontSize: 20,
    fontWeight: '700',
    marginBottom: 4,
    zIndex: 1,
  },
  headerSubtitle: {
    color: 'rgba(255,255,255,0.90)',
    fontSize: 14,
    zIndex: 1,
  },
  form: {
    paddingHorizontal: spacing.lg,
    paddingTop: spacing.lg,
    gap: 16,
  },
  lead: {
    ...typography.small,
    color: colors.muted,
    marginBottom: 4,
  },
});