import { Ionicons } from '@expo/vector-icons';
import { useRouter } from 'expo-router';
import { Alert, Pressable, ScrollView, StyleSheet, Switch, Text, View } from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { usePrivacyCenter } from '../../src/hooks';
import { buildPrivacySummaryText } from '../../src/api';
import { shareText } from '../../src/lib/shareFile';
import { ErrorState, LoadingState } from '../../src/components/StateView';
import { colors } from '../../src/theme';
import type { PrivacyLevelInfo, PrivacySettingItem, PrivacySection } from '../../src/types';

/* ===================== 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}>隐私设置</Text>
      <View style={styles.headerBtn} />
    </View>
  );
}

/* ===================== 子组件：隐私等级卡 ===================== */

function PrivacyLevelCard({ level, onExport }: { level: PrivacyLevelInfo; onExport: () => void }) {
  const theme = {
    high: { bg: colors.successLight, text: colors.successText, icon: 'shield-checkmark' },
    medium: { bg: colors.actionLight, text: colors.actionText, icon: 'shield' },
    low: { bg: colors.infoLight, text: colors.infoText, icon: 'shield-outline' },
  }[level.level];

  return (
    <View style={[styles.levelCard, { backgroundColor: theme.bg }]}>
      <View style={styles.levelRow}>
        <Ionicons name={theme.icon as keyof typeof Ionicons.glyphMap} size={24} color={theme.text} />
        <View style={styles.levelText}>
          <Text style={[styles.levelLabel, { color: theme.text }]}>
            当前隐私等级：{level.label}
          </Text>
          <Text style={styles.levelDesc}>{level.description}</Text>
        </View>
      </View>
      {/* 这里原先叫「查看隐私报告」并弹「功能开发中」。语义上「隐私报告」= 谁访问了我的数据，
          需要后端访问日志，本机给不出；能如实做到的是导出「我的隐私设置现状」，故改名并真实现。 */}
      <Pressable style={styles.levelBtn} onPress={onExport}>
        <Text style={[styles.levelBtnText, { color: theme.text }]}>导出隐私设置摘要</Text>
        <Ionicons name="share-outline" size={14} color={theme.text} />
      </Pressable>
    </View>
  );
}

/* ===================== 子组件：设置项行 ===================== */

function SettingRow({
  item,
  isLast,
  onToggle,
}: {
  item: PrivacySettingItem;
  isLast: boolean;
  onToggle?: (id: string, enabled: boolean) => void;
}) {
  const router = useRouter();
  const isDanger = item.type === 'danger-link';
  const titleColor = isDanger ? colors.dangerText : colors.textPrimary;

  const handlePress = () => {
    if (item.route) router.push(item.route);
  };

  const rowBody = (
    <View style={styles.rowBody}>
      <Text style={styles.rowTitle}>{item.title}</Text>
      {item.description ? <Text style={styles.rowDesc}>{item.description}</Text> : null}
    </View>
  );

  // 开关型条目：带 route 的（如「勿扰模式」「真实姓名可见性」）点击左侧文字区进详情页，
  // 右侧 Switch 保持独立可切换，两者互不干扰。
  if (item.type === 'switch') {
    return (
      <View style={[styles.row, !isLast && styles.rowBorder]}>
        {item.route ? (
          <Pressable style={styles.rowTapArea} onPress={handlePress} hitSlop={4}>
            {rowBody}
            <Ionicons name="chevron-forward" size={18} color={colors.textHint} />
          </Pressable>
        ) : (
          rowBody
        )}
        <Switch
          value={item.enabled}
          onValueChange={(next) => onToggle?.(item.id, next)}
          trackColor={{ false: colors.border, true: colors.primaryBorder }}
          thumbColor={item.enabled ? colors.primary : colors.white}
        />
      </View>
    );
  }

  return (
    <Pressable style={[styles.row, !isLast && styles.rowBorder]} onPress={handlePress}>
      <View style={styles.rowBody}>
        <Text style={[styles.rowTitle, { color: titleColor }]}>{item.title}</Text>
        {item.description ? <Text style={styles.rowDesc}>{item.description}</Text> : null}
      </View>
      <View style={styles.rowRight}>
        {item.value ? <Text style={styles.rowValue}>{item.value}</Text> : null}
        <Ionicons
          name="chevron-forward"
          size={18}
          color={isDanger ? colors.dangerText : colors.textHint}
        />
      </View>
    </Pressable>
  );
}

/* ===================== 子组件：设置分组 ===================== */

function Section({ section, onToggle }: { section: PrivacySection; onToggle?: (id: string, enabled: boolean) => void }) {
  return (
    <View style={styles.section}>
      <Text style={styles.sectionTitle}>{section.title}</Text>
      <View style={styles.card}>
        {section.items.map((item, index) => (
          <SettingRow
            key={item.id}
            item={item}
            isLast={index === section.items.length - 1}
            onToggle={onToggle}
          />
        ))}
      </View>
    </View>
  );
}

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

export default function PrivacyCenterScreen() {
  const router = useRouter();
  const { privacyCenter, loading, error, refresh, toggle } = usePrivacyCenter();

  /**
   * 导出隐私设置摘要：拼成文本经系统分享面板发出。
   * `ok` 只代表面板已拉起，不能据此提示「导出成功」，只在失败时说明原因（见 lib/shareFile）。
   */
  const handleExport = async () => {
    if (!privacyCenter) return;
    const outcome = await shareText(buildPrivacySummaryText(privacyCenter), '我的隐私设置摘要');
    if (!outcome.ok) Alert.alert('无法导出', outcome.message);
  };

  if (loading) {
    return (
      <SafeAreaView style={styles.safeArea} edges={['top']}>
        <Header onBack={() => router.back()} />
        <LoadingState />
      </SafeAreaView>
    );
  }

  if (error || !privacyCenter) {
    return (
      <SafeAreaView style={styles.safeArea} edges={['top']}>
        <Header onBack={() => router.back()} />
        <ErrorState message="加载失败，请重试" onRetry={refresh} />
      </SafeAreaView>
    );
  }

  return (
    <SafeAreaView style={styles.safeArea} edges={['top', 'bottom']}>
      <Header onBack={() => router.back()} />
      <ScrollView
        style={styles.scroll}
        contentContainerStyle={styles.content}
        showsVerticalScrollIndicator={false}
      >
        <PrivacyLevelCard level={privacyCenter.privacyLevel} onExport={handleExport} />

        {privacyCenter.sections.map((section) => (
          <Section key={section.id} section={section} onToggle={toggle} />
        ))}

        <View style={styles.explanationCard}>
          <Text style={styles.explanationTitle}>权限说明</Text>
          <Text style={styles.explanationText}>{privacyCenter.explanation}</Text>
        </View>
      </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: {
    fontSize: 17,
    fontWeight: '700',
    color: colors.textPrimary,
  },
  scroll: {
    flex: 1,
  },
  content: {
    padding: 12,
    paddingBottom: 24,
  },
  levelCard: {
    borderRadius: 8,
    padding: 16,
    marginBottom: 16,
  },
  levelRow: {
    flexDirection: 'row',
    alignItems: 'flex-start',
  },
  levelText: {
    flex: 1,
    marginLeft: 12,
  },
  levelLabel: {
    fontSize: 16,
    fontWeight: '700',
    marginBottom: 4,
  },
  levelDesc: {
    fontSize: 13,
    lineHeight: 18,
    color: colors.textSecondary,
  },
  levelBtn: {
    flexDirection: 'row',
    alignItems: 'center',
    alignSelf: 'flex-start',
    marginTop: 12,
    paddingVertical: 4,
  },
  levelBtnText: {
    fontSize: 13,
    fontWeight: '600',
    marginRight: 2,
  },
  section: {
    marginBottom: 16,
  },
  sectionTitle: {
    fontSize: 14,
    fontWeight: '700',
    color: colors.textPrimary,
    marginBottom: 10,
  },
  card: {
    backgroundColor: colors.white,
    borderRadius: 8,
    overflow: 'hidden',
  },
  row: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: 14,
    paddingVertical: 14,
  },
  rowBorder: {
    borderBottomWidth: 1,
    borderBottomColor: colors.borderLight,
  },
  rowBody: {
    flex: 1,
    marginRight: 12,
  },
  rowTapArea: {
    flex: 1,
    flexDirection: 'row',
    alignItems: 'center',
  },
  rowTitle: {
    fontSize: 15,
    fontWeight: '600',
    color: colors.textPrimary,
  },
  rowDesc: {
    marginTop: 3,
    fontSize: 12,
    lineHeight: 16,
    color: colors.textSecondary,
  },
  rowRight: {
    flexDirection: 'row',
    alignItems: 'center',
  },
  rowValue: {
    fontSize: 13,
    color: colors.textHint,
    marginRight: 4,
  },
  explanationCard: {
    backgroundColor: colors.white,
    borderRadius: 8,
    padding: 16,
    marginBottom: 8,
  },
  explanationTitle: {
    fontSize: 15,
    fontWeight: '700',
    color: colors.textPrimary,
    marginBottom: 8,
  },
  explanationText: {
    fontSize: 13,
    lineHeight: 20,
    color: colors.textSecondary,
  },
});