import { Ionicons } from '@expo/vector-icons';
import { LinearGradient } from 'expo-linear-gradient';
import { useRouter } from 'expo-router';
import { useEffect, useState } from 'react';
import {
  ActivityIndicator,
  Alert,
  Modal,
  Pressable,
  ScrollView,
  StyleSheet,
  Switch,
  Text,
  TextInput,
  View,
} from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { buildChecklistText } from '../src/api';
import { useOnboardingChecklist } from '../src/hooks';
import { shareText } from '../src/lib/shareFile';
import { colors, headerGradientShort } from '../src/theme';
import type { ChecklistGroup, OnboardingChecklist, OnboardingTip } from '../src/types';

/** 分组图标配色轮转（全部来自主题 token） */
const GROUP_ICON_THEME: Record<string, { bg: string; color: string }> = {
  material: { bg: colors.primaryLight, color: colors.primary },
  procedure: { bg: colors.infoLight, color: colors.info },
  study: { bg: colors.successLight, color: colors.success },
  life: { bg: colors.actionLight, color: colors.action },
  daily: { bg: colors.primaryLight, color: colors.primaryText },
};

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

function Header({ onBack, onShare }: { onBack: () => void; onShare: () => 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}>入职准备清单</Text>
      <Pressable style={styles.headerBtn} onPress={onShare} hitSlop={8}>
        <Ionicons name="share-outline" size={22} color={colors.textPrimary} />
      </Pressable>
    </View>
  );
}

/* ===================== 子组件：倒计时卡片 ===================== */

function CountdownCard({
  daysLeft,
  company,
  position,
  onboardingDate,
  completed,
  total,
}: {
  daysLeft: number;
  company: string;
  position: string;
  onboardingDate: string;
  completed: number;
  total: number;
}) {
  const percent = total > 0 ? Math.round((completed / total) * 100) : 0;
  return (
    <LinearGradient
      colors={headerGradientShort}
      start={{ x: 0, y: 0 }}
      end={{ x: 1, y: 1 }}
      style={styles.countdownCard}
    >
      <View style={styles.countdownTop}>
        <View>
          <Text style={styles.countdownLabel}>入职倒计时</Text>
          <View style={styles.countdownValueRow}>
            <Text style={styles.countdownValue}>{daysLeft}</Text>
            <Text style={styles.countdownUnit}>天</Text>
          </View>
          <Text style={styles.countdownCompany}>
            {company} · {position}
          </Text>
          <Text style={styles.countdownDate}>入职日期 {onboardingDate}</Text>
        </View>
        <View style={styles.countdownIcon}>
          <Ionicons name="briefcase" size={32} color={colors.primary} />
        </View>
      </View>
      <View style={styles.countdownProgress}>
        <View style={styles.countdownProgressHead}>
          <Text style={styles.countdownProgressLabel}>总体进度</Text>
          <Text style={styles.countdownProgressValue}>
            {completed}/{total}
          </Text>
        </View>
        <View style={styles.countdownTrack}>
          <View style={[styles.countdownFill, { width: `${percent}%` }]} />
        </View>
      </View>
    </LinearGradient>
  );
}

/* ===================== 子组件：清单分组 ===================== */

function ChecklistGroupCard({
  group,
  onToggleItem,
  onRemoveItem,
  togglingId,
  expanded,
  onToggleExpand,
}: {
  group: ChecklistGroup;
  onToggleItem: (itemId: string, done: boolean) => void;
  onRemoveItem: (itemId: string) => void;
  togglingId: string | null;
  expanded: boolean;
  onToggleExpand: () => void;
}) {
  const theme = GROUP_ICON_THEME[group.id] ?? GROUP_ICON_THEME.material;
  const doneCount = group.items.filter((i) => i.done).length;
  // 只有「我的自定义待办」这一组可以删条目：模板待办删了下次进页面还会回来
  const removable = group.id === 'custom';
  return (
    <View style={styles.groupCard}>
      <Pressable style={styles.groupHead} onPress={onToggleExpand}>
        <View style={[styles.groupIcon, { backgroundColor: theme.bg }]}>
          <Ionicons name={group.icon as keyof typeof Ionicons.glyphMap} size={20} color={theme.color} />
        </View>
        <View style={styles.groupTitleWrap}>
          <Text style={styles.groupTitle}>{group.title}</Text>
          <Text style={styles.groupCount}>
            {doneCount}/{group.items.length}
          </Text>
        </View>
        <Ionicons
          name={expanded ? 'chevron-up' : 'chevron-down'}
          size={20}
          color={colors.textHint}
        />
      </Pressable>
      {expanded && (
        <View style={styles.groupBody}>
          {group.items.map((item) => (
            <Pressable
              key={item.id}
              style={styles.itemRow}
              onPress={() => onToggleItem(item.id, !item.done)}
              disabled={togglingId === item.id}
            >
              <Ionicons
                name={item.done ? 'checkbox' : 'square-outline'}
                size={20}
                color={item.done ? colors.success : colors.borderStrong}
              />
              <Text style={[styles.itemTitle, item.done && styles.itemTitleDone]}>
                {item.title}
              </Text>
              {item.required && !item.done && (
                <View style={styles.requiredTag}>
                  <Text style={styles.requiredText}>必填</Text>
                </View>
              )}
              {removable && (
                <Pressable onPress={() => onRemoveItem(item.id)} hitSlop={8}>
                  <Ionicons name="close-circle-outline" size={18} color={colors.textHint} />
                </Pressable>
              )}
            </Pressable>
          ))}
        </View>
      )}
    </View>
  );
}

/* ===================== 子组件：每日提醒 ===================== */

function DailyReminderCard({
  enabled,
  time,
  onToggle,
}: {
  enabled: boolean;
  time: string;
  onToggle: (v: boolean) => void;
}) {
  return (
    <View style={styles.card}>
      <View style={styles.reminderRow}>
        <View style={styles.reminderText}>
          <Text style={styles.reminderTitle}>入职每日提醒</Text>
          <Text style={styles.reminderDesc}>每天 {time} 提醒你完成待办</Text>
        </View>
        <Switch
          value={enabled}
          onValueChange={onToggle}
          trackColor={{ false: colors.border, true: colors.primaryBorder }}
          thumbColor={enabled ? colors.primary : colors.white}
        />
      </View>
    </View>
  );
}

/* ===================== 子组件：入职小贴士 ===================== */

function TipsCard({ tips }: { tips: OnboardingTip[] }) {
  return (
    <View style={styles.card}>
      <Text style={styles.cardTitle}>入职小贴士</Text>
      {tips.map((tip) => (
        <View key={tip.id} style={styles.tipRow}>
          <Ionicons name={tip.icon as keyof typeof Ionicons.glyphMap} size={18} color={colors.primary} />
          <View style={styles.tipBody}>
            <Text style={styles.tipTitle}>{tip.title}</Text>
            <Text style={styles.tipDesc}>{tip.desc}</Text>
          </View>
        </View>
      ))}
    </View>
  );
}

/* ===================== 子组件：四态 ===================== */

function Loading() {
  return (
    <View style={styles.center}>
      <ActivityIndicator size="large" color={colors.primary} />
      <Text style={styles.tip}>正在加载清单…</Text>
    </View>
  );
}

function ErrorState({ onRetry }: { onRetry: () => void }) {
  return (
    <View style={styles.center}>
      <Ionicons name="list-outline" size={40} color={colors.textHint} />
      <Text style={styles.tip}>清单加载失败</Text>
      <Pressable style={styles.retryBtn} onPress={onRetry} hitSlop={6}>
        <Text style={styles.retryText}>点击重试</Text>
      </Pressable>
    </View>
  );
}

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

export default function OnboardingScreen() {
  const router = useRouter();
  const { checklist, loading, error, refresh, toggle, togglingId, addItem, removeItem, mutating } =
    useOnboardingChecklist();

  /** 本地清单状态（勾选后即时更新，避免等待接口往返） */
  const [localChecklist, setLocalChecklist] = useState<OnboardingChecklist | null>(null);
  const [expandedIds, setExpandedIds] = useState<string[]>([]);
  const [reminderEnabled, setReminderEnabled] = useState(false);
  /** 「添加自定义待办」弹窗 */
  const [addVisible, setAddVisible] = useState(false);
  const [draftTitle, setDraftTitle] = useState('');

  useEffect(() => {
    if (checklist && !localChecklist) {
      setLocalChecklist(checklist);
      setExpandedIds(checklist.groups.filter((g) => g.expanded).map((g) => g.id));
      setReminderEnabled(checklist.dailyReminder.enabled);
    }
  }, [checklist, localChecklist]);

  const display = localChecklist ?? checklist;

  const handleToggleItem = async (itemId: string, done: boolean) => {
    setLocalChecklist((prev) => {
      if (!prev) return prev;
      const groups = prev.groups.map((g) => ({
        ...g,
        items: g.items.map((item) => (item.id === itemId ? { ...item, done } : item)),
      }));
      const completed = groups.reduce((sum, g) => sum + g.items.filter((i) => i.done).length, 0);
      return { ...prev, groups, completed };
    });
    await toggle(itemId, done);
  };

  /** 添加自定义待办：接口层负责落库并返回新清单，页面直接换成返回值 */
  const handleAddItem = async () => {
    try {
      const updated = await addItem(draftTitle);
      setLocalChecklist(updated);
      setDraftTitle('');
      setAddVisible(false);
    } catch (e) {
      Alert.alert('添加失败', e instanceof Error ? e.message : '请稍后重试');
    }
  };

  /** 删除自定义待办（模板条目接口层会拒绝） */
  const handleRemoveItem = async (itemId: string) => {
    try {
      const updated = await removeItem(itemId);
      setLocalChecklist(updated);
    } catch (e) {
      Alert.alert('删除失败', e instanceof Error ? e.message : '请稍后重试');
    }
  };

  /**
   * 导出 / 分享清单：把清单拼成文本交给系统分享面板。
   * `ok` 只代表面板已拉起，不能据此提示「分享成功」（见 lib/shareFile 的说明）。
   */
  const handleExport = async () => {
    if (!display) return;
    const outcome = await shareText(buildChecklistText(display), '入职准备清单');
    if (!outcome.ok) Alert.alert('无法导出', outcome.message);
  };

  if (loading) {
    return (
      <SafeAreaView style={styles.container} edges={['top']}>
        <Header onBack={() => router.back()} onShare={() => void handleExport()} />
        <Loading />
      </SafeAreaView>
    );
  }

  if (error || !display) {
    return (
      <SafeAreaView style={styles.container} edges={['top']}>
        <Header onBack={() => router.back()} onShare={() => void handleExport()} />
        <ErrorState onRetry={refresh} />
      </SafeAreaView>
    );
  }

  return (
    <SafeAreaView style={styles.container} edges={['top']}>
      <Header onBack={() => router.back()} onShare={() => void handleExport()} />
      <ScrollView contentContainerStyle={styles.body} showsVerticalScrollIndicator={false}>
        <CountdownCard
          daysLeft={display.daysLeft}
          company={display.company}
          position={display.position}
          onboardingDate={display.onboardingDate}
          completed={display.completed}
          total={display.total}
        />

        {display.groups.map((group) => (
          <ChecklistGroupCard
            key={group.id}
            group={group}
            onToggleItem={handleToggleItem}
            onRemoveItem={handleRemoveItem}
            togglingId={togglingId}
            expanded={expandedIds.includes(group.id)}
            onToggleExpand={() =>
              setExpandedIds((prev) =>
                prev.includes(group.id)
                  ? prev.filter((id) => id !== group.id)
                  : [...prev, group.id],
              )
            }
          />
        ))}

        <DailyReminderCard
          enabled={reminderEnabled}
          time={display.dailyReminder.time}
          onToggle={setReminderEnabled}
        />

        <TipsCard tips={display.tips} />
      </ScrollView>

      <View style={styles.footer}>
        <Pressable
          style={[styles.addBtn, mutating && styles.footerBtnDisabled]}
          onPress={() => setAddVisible(true)}
          disabled={mutating}
        >
          <Ionicons name="add" size={20} color={colors.primary} />
          <Text style={styles.addBtnText}>添加自定义待办</Text>
        </Pressable>
        <Pressable style={styles.exportBtn} onPress={() => void handleExport()}>
          <Text style={styles.exportBtnText}>导出清单</Text>
        </Pressable>
      </View>

      {/* 添加自定义待办：Alert.prompt 只有 iOS 有，这里用自绘弹窗（与岗位评价回复一致） */}
      <Modal visible={addVisible} transparent animationType="fade" onRequestClose={() => setAddVisible(false)}>
        <View style={styles.modalMask}>
          <View style={styles.modalCard}>
            <Text style={styles.modalTitle}>添加自定义待办</Text>
            <TextInput
              style={styles.modalInput}
              value={draftTitle}
              onChangeText={setDraftTitle}
              placeholder="例如：办理落户材料"
              placeholderTextColor={colors.textHint}
              maxLength={30}
              autoFocus
            />
            <View style={styles.modalActions}>
              <Pressable style={styles.modalCancel} onPress={() => setAddVisible(false)}>
                <Text style={styles.modalCancelText}>取消</Text>
              </Pressable>
              <Pressable
                style={[styles.modalConfirm, (draftTitle.trim() === '' || mutating) && styles.footerBtnDisabled]}
                onPress={() => void handleAddItem()}
                disabled={draftTitle.trim() === '' || mutating}
              >
                <Text style={styles.modalConfirmText}>{mutating ? '添加中…' : '添加'}</Text>
              </Pressable>
            </View>
          </View>
        </View>
      </Modal>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: colors.pageBg },
  header: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingHorizontal: 12,
    paddingVertical: 12,
    backgroundColor: colors.white,
  },
  headerBtn: { width: 40, alignItems: 'center' },
  headerTitle: { fontSize: 17, fontWeight: '700', color: colors.textPrimary },
  body: { paddingHorizontal: 16, paddingBottom: 100, paddingTop: 12 },
  center: { flex: 1, alignItems: 'center', justifyContent: 'center', paddingHorizontal: 40, gap: 12 },
  tip: { fontSize: 14, color: colors.textSecondary },
  retryBtn: {
    paddingHorizontal: 18,
    paddingVertical: 8,
    borderRadius: 16,
    backgroundColor: colors.primaryLight,
  },
  retryText: { fontSize: 13, fontWeight: '600', color: colors.primaryText },
  countdownCard: { borderRadius: 16, padding: 18, marginBottom: 12 },
  countdownTop: { flexDirection: 'row', justifyContent: 'space-between', alignItems: 'center' },
  countdownLabel: { fontSize: 13, color: colors.textInverse, opacity: 0.9 },
  countdownValueRow: { flexDirection: 'row', alignItems: 'baseline', marginTop: 6 },
  countdownValue: { fontSize: 44, fontWeight: '800', color: colors.textInverse },
  countdownUnit: { fontSize: 15, color: colors.textInverse, marginLeft: 4 },
  countdownCompany: { fontSize: 14, color: colors.textInverse, marginTop: 8, fontWeight: '600' },
  countdownDate: { fontSize: 12, color: colors.textInverse, opacity: 0.85, marginTop: 2 },
  countdownIcon: {
    width: 60,
    height: 60,
    borderRadius: 30,
    backgroundColor: colors.white,
    alignItems: 'center',
    justifyContent: 'center',
  },
  countdownProgress: { marginTop: 18 },
  countdownProgressHead: {
    flexDirection: 'row',
    justifyContent: 'space-between',
    marginBottom: 8,
  },
  countdownProgressLabel: { fontSize: 13, color: colors.textInverse, opacity: 0.9 },
  countdownProgressValue: { fontSize: 13, fontWeight: '700', color: colors.textInverse },
  countdownTrack: {
    height: 8,
    borderRadius: 4,
    backgroundColor: colors.onBrandTrack,
    overflow: 'hidden',
  },
  countdownFill: { height: 8, borderRadius: 4, backgroundColor: colors.white },
  groupCard: {
    backgroundColor: colors.white,
    borderRadius: 12,
    marginBottom: 10,
    borderWidth: 1,
    borderColor: colors.borderLight,
    overflow: 'hidden',
  },
  groupHead: {
    flexDirection: 'row',
    alignItems: 'center',
    padding: 14,
  },
  groupIcon: {
    width: 36,
    height: 36,
    borderRadius: 18,
    alignItems: 'center',
    justifyContent: 'center',
  },
  groupTitleWrap: { flex: 1, marginLeft: 12 },
  groupTitle: { fontSize: 15, fontWeight: '700', color: colors.textPrimary },
  groupCount: { fontSize: 12, color: colors.textHint, marginTop: 2 },
  groupBody: { paddingHorizontal: 14, paddingBottom: 12 },
  itemRow: {
    flexDirection: 'row',
    alignItems: 'center',
    paddingVertical: 10,
    borderTopWidth: 1,
    borderTopColor: colors.borderLight,
  },
  itemTitle: { flex: 1, fontSize: 14, color: colors.textPrimary, marginLeft: 10 },
  itemTitleDone: { textDecorationLine: 'line-through', color: colors.textHint },
  requiredTag: {
    backgroundColor: colors.dangerLight,
    borderRadius: 8,
    paddingHorizontal: 6,
    paddingVertical: 2,
  },
  requiredText: { fontSize: 10, color: colors.dangerText, fontWeight: '600' },
  card: {
    backgroundColor: colors.white,
    borderRadius: 12,
    padding: 16,
    marginTop: 8,
    borderWidth: 1,
    borderColor: colors.borderLight,
  },
  cardTitle: { fontSize: 15, fontWeight: '700', color: colors.textPrimary, marginBottom: 12 },
  reminderRow: { flexDirection: 'row', alignItems: 'center', justifyContent: 'space-between' },
  reminderText: { flex: 1 },
  reminderTitle: { fontSize: 15, fontWeight: '700', color: colors.textPrimary },
  reminderDesc: { fontSize: 12, color: colors.textHint, marginTop: 2 },
  tipRow: {
    flexDirection: 'row',
    paddingVertical: 10,
    borderTopWidth: 1,
    borderTopColor: colors.borderLight,
  },
  tipBody: { flex: 1, marginLeft: 10 },
  tipTitle: { fontSize: 14, fontWeight: '600', color: colors.textPrimary },
  tipDesc: { fontSize: 12, color: colors.textSecondary, marginTop: 2, lineHeight: 18 },
  footer: {
    position: 'absolute',
    left: 0,
    right: 0,
    bottom: 0,
    flexDirection: 'row',
    paddingHorizontal: 16,
    paddingVertical: 12,
    backgroundColor: colors.white,
    borderTopWidth: 1,
    borderTopColor: colors.borderLight,
  },
  addBtn: {
    flex: 1,
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'center',
    backgroundColor: colors.white,
    borderRadius: 24,
    paddingVertical: 14,
    borderWidth: 1,
    borderColor: colors.border,
    marginRight: 12,
  },
  addBtnText: { fontSize: 14, fontWeight: '700', color: colors.primary, marginLeft: 4 },
  exportBtn: {
    flex: 1,
    backgroundColor: colors.primaryBtn,
    borderRadius: 24,
    paddingVertical: 14,
    alignItems: 'center',
  },
  exportBtnText: { fontSize: 15, fontWeight: '700', color: colors.white },
  footerBtnDisabled: { opacity: 0.5 },
  modalMask: {
    flex: 1,
    backgroundColor: colors.scrim,
    justifyContent: 'center',
    paddingHorizontal: 32,
  },
  modalCard: { backgroundColor: colors.white, borderRadius: 16, padding: 20 },
  modalTitle: { fontSize: 16, fontWeight: '700', color: colors.textPrimary },
  modalInput: {
    marginTop: 14,
    borderWidth: 1,
    borderColor: colors.border,
    borderRadius: 10,
    paddingHorizontal: 12,
    paddingVertical: 10,
    fontSize: 14,
    color: colors.textPrimary,
  },
  modalActions: { flexDirection: 'row', justifyContent: 'flex-end', gap: 12, marginTop: 18 },
  modalCancel: { paddingHorizontal: 16, paddingVertical: 8 },
  modalCancelText: { fontSize: 14, color: colors.textSecondary },
  modalConfirm: {
    backgroundColor: colors.primaryBtn,
    borderRadius: 18,
    paddingHorizontal: 20,
    paddingVertical: 8,
  },
  modalConfirmText: { fontSize: 14, fontWeight: '700', color: colors.white },
});