import { useState } from 'react';
import { Ionicons } from '@expo/vector-icons';
import { useRouter } from 'expo-router';
import {
  ActivityIndicator,
  Pressable,
  ScrollView,
  StyleSheet,
  Text,
  TextInput,
  View,
} from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { useDeleteAllData } from '../../src/hooks';
import { colors } from '../../src/theme';

/* ===================== 子组件：顶部导航 ===================== */

function Header({ onBack }: { onBack: () => void }) {
  return (
    <View style={styles.header}>
      <Pressable style={styles.headerBtn} onPress={onBack} hitSlop={8}>
        <Ionicons name="chevron-back" size={24} color={colors.textPrimary} />
      </Pressable>
      <Text style={styles.headerTitle}>删除数据</Text>
      <View style={styles.headerBtn} />
    </View>
  );
}

/* ===================== 子组件：勾选行 ===================== */

function CheckRow({
  title,
  desc,
  count,
  checked,
  onPress,
}: {
  title: string;
  desc?: string;
  count?: string;
  checked: boolean;
  onPress: () => void;
}) {
  return (
    <Pressable style={styles.row} onPress={onPress}>
      <View style={styles.rowBody}>
        <Text style={styles.rowTitle}>{title}</Text>
        {desc ? <Text style={styles.rowDesc}>{desc}</Text> : null}
      </View>
      <View style={[styles.checkbox, checked && styles.checkboxActive]}>
        {checked ? <Ionicons name="checkmark" size={14} color={colors.white} /> : null}
      </View>
      {count ? <Text style={styles.rowCount}>{count}</Text> : null}
    </Pressable>
  );
}

/* ===================== 页面 ===================== */

export default function DeleteAllDataScreen() {
  const router = useRouter();
  const { data, loading, error, refresh, submit } = useDeleteAllData();
  const [selected, setSelected] = useState<Set<string>>(new Set());
  const [confirmText, setConfirmText] = useState('');
  const [submitting, setSubmitting] = useState(false);
  const [done, setDone] = useState<{ success: boolean; message: string } | null>(null);

  const toggleCat = (id: string) => {
    setSelected((prev) => {
      const next = new Set(prev);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });
  };

  const handleSubmit = async () => {
    setSubmitting(true);
    try {
      const res = await submit(Array.from(selected));
      setDone(res);
    } finally {
      setSubmitting(false);
    }
  };

  if (loading) {
    return (
      <SafeAreaView style={styles.safeArea} edges={['top']}>
        <Header onBack={() => router.back()} />
        <View style={styles.stateBox}>
          <ActivityIndicator size="large" color={colors.primary} />
        </View>
      </SafeAreaView>
    );
  }

  if (error || !data) {
    return (
      <SafeAreaView style={styles.safeArea} edges={['top']}>
        <Header onBack={() => router.back()} />
        <View style={styles.stateBox}>
          <Ionicons name="alert-circle-outline" size={40} color={colors.danger} />
          <Text style={styles.stateText}>加载失败，请重试</Text>
          <Pressable style={styles.retryBtn} onPress={refresh}>
            <Text style={styles.retryText}>重试</Text>
          </Pressable>
        </View>
      </SafeAreaView>
    );
  }

  if (done?.success) {
    return (
      <SafeAreaView style={styles.safeArea} edges={['top']}>
        <Header onBack={() => router.back()} />
        <View style={styles.stateBox}>
          <Ionicons name="checkmark-circle" size={48} color={colors.success} />
          <Text style={styles.stateText}>{done.message}</Text>
          <Pressable style={styles.retryBtn} onPress={() => router.back()}>
            <Text style={styles.retryText}>返回</Text>
          </Pressable>
        </View>
      </SafeAreaView>
    );
  }

  const canSubmit = selected.size > 0 && confirmText === '删除全部数据' && !submitting;

  return (
    <SafeAreaView style={styles.safeArea} edges={['top', 'bottom']}>
      <Header onBack={() => router.back()} />
      <ScrollView
        style={styles.scroll}
        contentContainerStyle={styles.content}
        showsVerticalScrollIndicator={false}
      >
        <View style={styles.introCard}>
          <Text style={styles.introText}>{data.intro}</Text>
        </View>

        <View style={styles.section}>
          <Text style={styles.sectionTitle}>选择要删除的数据</Text>
          <View style={styles.card}>
            {data.categories.map((cat) => (
              <CheckRow
                key={cat.id}
                title={cat.label}
                desc={cat.description}
                count={cat.count}
                checked={selected.has(cat.id)}
                onPress={() => toggleCat(cat.id)}
              />
            ))}
          </View>
        </View>

        <View style={[styles.warnCard, { backgroundColor: colors.dangerLight }]}>
          <Ionicons name="warning-outline" size={18} color={colors.dangerText} />
          <Text style={[styles.warnText, { color: colors.dangerText }]}>{data.warning}</Text>
        </View>

        <View style={styles.card}>
          <Text style={styles.confirmTitle}>确认删除</Text>
          <Text style={styles.confirmHint}>
            请输入「{data.confirmPlaceholder.replace('请输入「', '').replace('」以确认', '')}」以确认操作
          </Text>
          <TextInput
            style={styles.confirmInput}
            value={confirmText}
            onChangeText={setConfirmText}
            placeholder={data.confirmPlaceholder}
            placeholderTextColor={colors.textHint}
          />
        </View>

        <Pressable
          style={[styles.submitBtn, !canSubmit && styles.submitDisabled]}
          disabled={!canSubmit}
          onPress={handleSubmit}
        >
          <Text style={styles.submitText}>
            {submitting ? '提交中…' : `删除选中数据（${selected.size} 项）`}
          </Text>
        </Pressable>
      </ScrollView>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  safeArea: {
    flex: 1,
    backgroundColor: colors.pageBg,
  },
  header: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: 8,
    height: 48,
    backgroundColor: colors.white,
    borderBottomWidth: 1,
    borderBottomColor: colors.borderLight,
  },
  headerBtn: {
    width: 40,
    height: 40,
    alignItems: 'center',
    justifyContent: 'center',
  },
  headerTitle: {
    flex: 1,
    textAlign: 'center',
    fontSize: 17,
    fontWeight: '700',
    color: colors.textPrimary,
  },
  scroll: {
    flex: 1,
  },
  content: {
    padding: 8,
    paddingBottom: 24,
  },
  stateBox: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    gap: 12,
  },
  stateText: {
    marginTop: 12,
    fontSize: 14,
    color: colors.textSecondary,
    paddingHorizontal: 32,
    textAlign: 'center',
  },
  retryBtn: {
    marginTop: 16,
    paddingHorizontal: 24,
    paddingVertical: 8,
    borderRadius: 18,
    backgroundColor: colors.primaryBtn,
  },
  retryText: {
    fontSize: 13,
    fontWeight: '600',
    color: colors.white,
  },
  introCard: {
    backgroundColor: colors.infoLight,
    borderRadius: 8,
    padding: 8,
    marginBottom: 8,
  },
  introText: {
    fontSize: 13,
    lineHeight: 19,
    color: colors.textSecondary,
  },
  section: {
    marginBottom: 16,
  },
  sectionTitle: {
    fontSize: 14,
    fontWeight: '700',
    color: colors.textPrimary,
    marginBottom: 10,
  },
  card: {
    backgroundColor: colors.white,
    borderRadius: 8,
    overflow: 'hidden',
    padding: 8,
  },
  row: {
    flexDirection: 'row',
    alignItems: 'center',
    paddingHorizontal: 14,
    paddingVertical: 14,
    gap: 12,
  },
  rowBody: {
    flex: 1,
  },
  rowTitle: {
    fontSize: 15,
    fontWeight: '600',
    color: colors.textPrimary,
  },
  rowDesc: {
    marginTop: 3,
    fontSize: 12,
    lineHeight: 16,
    color: colors.textSecondary,
  },
  rowCount: {
    fontSize: 12,
    color: colors.textHint,
    marginLeft: 4,
  },
  checkbox: {
    width: 22,
    height: 22,
    borderRadius: 6,
    borderWidth: 1.5,
    borderColor: colors.border,
    alignItems: 'center',
    justifyContent: 'center',
  },
  checkboxActive: {
    backgroundColor: colors.primary,
    borderColor: colors.primary,
  },
  warnCard: {
    flexDirection: 'row',
    alignItems: 'flex-start',
    gap: 8,
    borderRadius: 8,
    padding: 8,
    marginBottom: 8,
  },
  warnText: {
    flex: 1,
    fontSize: 13,
    fontWeight: '600',
    lineHeight: 18,
  },
  confirmTitle: {
    fontSize: 15,
    fontWeight: '700',
    color: colors.textPrimary,
    paddingHorizontal: 14,
    paddingTop: 12,
  },
  confirmHint: {
    fontSize: 12,
    color: colors.textSecondary,
    paddingHorizontal: 14,
    marginTop: 4,
    marginBottom: 10,
  },
  confirmInput: {
    marginHorizontal: 14,
    marginBottom: 14,
    height: 42,
    borderRadius: 10,
    borderWidth: 1,
    borderColor: colors.border,
    paddingHorizontal: 12,
    fontSize: 14,
    color: colors.textPrimary,
  },
  submitBtn: {
    marginTop: 8,
    height: 48,
    borderRadius: 24,
    backgroundColor: colors.danger,
    alignItems: 'center',
    justifyContent: 'center',
  },
  submitDisabled: {
    backgroundColor: colors.border,
  },
  submitText: {
    fontSize: 15,
    fontWeight: '700',
    color: colors.white,
  },
});