/**
 * #34 보안 이벤트 로그
 * GET /api/auth/events
 * 이벤트: 날짜, 유형(로그인성공/실패/디바이스등록), IP(마스킹 *.*.*.xxx)
 * FlatList, 날짜순 내림차순
 */
import { useCallback, useEffect, useState } from 'react'
import {
  View, Text, FlatList, StyleSheet, RefreshControl, ActivityIndicator,
} from 'react-native'
import { COLORS } from '../../constants/Config'
import { getSecurityEvents } from '../../services/api'

interface SecEvent {
  id?: string | number
  type?: string
  event_type?: string
  ip?: string
  ip_addr?: string
  created_at?: string
  timestamp?: string
  detail?: string
}

const TYPE_META: Record<string, { label: string; color: string; bg: string; icon: string }> = {
  login_success:   { label: '로그인 성공',   color: '#15803d', bg: '#dcfce7', icon: '✓' },
  login_failed:    { label: '로그인 실패',   color: '#b91c1c', bg: '#fee2e2', icon: '✕' },
  login_fail:      { label: '로그인 실패',   color: '#b91c1c', bg: '#fee2e2', icon: '✕' },
  device_register: { label: '디바이스 등록', color: '#a16207', bg: '#fef9c3', icon: '＋' },
  device_removed:  { label: '디바이스 해제', color: '#c2410c', bg: '#ffedd5', icon: '－' },
  logout:          { label: '로그아웃',     color: '#475569', bg: '#f1f5f9', icon: '↩' },
  tenant_switch:   { label: '기관 전환',     color: '#1d4ed8', bg: '#dbeafe', icon: '⇄' },
}

/** IP 마스킹: 앞 3옥텟 가림 → *.*.*.xxx */
function maskIp(ip?: string): string {
  if (!ip) return '*.*.*.***'
  const parts = ip.split('.')
  if (parts.length === 4) return `*.*.*.${parts[3]}`
  // IPv6 등은 끝 4자리만
  return `*.*.*.${ip.slice(-4)}`
}

function fmt(d?: string): string {
  if (!d) return '-'
  try {
    const dt = new Date(d)
    if (isNaN(dt.getTime())) return d
    return dt.toLocaleString('ko-KR', { dateStyle: 'medium', timeStyle: 'short' })
  } catch {
    return d
  }
}

function ts(e: SecEvent): number {
  const d = e.created_at ?? e.timestamp
  const t = d ? new Date(d).getTime() : 0
  return isNaN(t) ? 0 : t
}

export default function SecurityLogScreen() {
  const [events, setEvents] = useState<SecEvent[]>([])
  const [loading, setLoading] = useState(true)
  const [refresh, setRefresh] = useState(false)

  const load = useCallback(async (isRefresh = false) => {
    isRefresh ? setRefresh(true) : setLoading(true)
    try {
      const r = await getSecurityEvents()
      const list: SecEvent[] = Array.isArray(r.data) ? r.data : r.data?.items ?? []
      list.sort((a, b) => ts(b) - ts(a)) // 날짜 내림차순
      setEvents(list)
    } catch {
      setEvents([])
    } finally {
      setLoading(false)
      setRefresh(false)
    }
  }, [])

  useEffect(() => { load() }, [load])

  if (loading) {
    return (
      <View style={s.center}>
        <ActivityIndicator color={COLORS.accent} size="large" />
      </View>
    )
  }

  return (
    <FlatList
      style={{ flex: 1, backgroundColor: COLORS.bg }}
      data={events}
      keyExtractor={(e, i) => String(e.id ?? i)}
      refreshControl={<RefreshControl refreshing={refresh} onRefresh={() => load(true)} tintColor={COLORS.accent} />}
      ListHeaderComponent={
        <View style={s.header}>
          <Text style={s.headerTitle}>보안 이벤트 로그</Text>
          <Text style={s.headerSub}>최근 인증·기기 활동 {events.length}건 · IP는 마스킹 표시</Text>
        </View>
      }
      ListEmptyComponent={
        <View style={s.empty}><Text style={s.emptyText}>보안 이벤트가 없습니다.</Text></View>
      }
      contentContainerStyle={events.length === 0 ? { flexGrow: 1 } : undefined}
      renderItem={({ item }) => {
        const key = (item.type ?? item.event_type ?? '').toLowerCase()
        const meta = TYPE_META[key] ?? { label: item.type ?? item.event_type ?? '이벤트', color: COLORS.muted, bg: '#f1f5f9', icon: '•' }
        return (
          <View style={s.row}>
            <View style={[s.iconBox, { backgroundColor: meta.bg }]}>
              <Text style={[s.icon, { color: meta.color }]}>{meta.icon}</Text>
            </View>
            <View style={{ flex: 1 }}>
              <Text style={[s.type, { color: meta.color }]}>{meta.label}</Text>
              {!!item.detail && <Text style={s.detail}>{item.detail}</Text>}
              <Text style={s.date}>{fmt(item.created_at ?? item.timestamp)}</Text>
            </View>
            <Text style={s.ip}>{maskIp(item.ip ?? item.ip_addr)}</Text>
          </View>
        )
      }}
    />
  )
}

const s = StyleSheet.create({
  center: { flex: 1, alignItems: 'center', justifyContent: 'center', backgroundColor: COLORS.bg },
  header: { padding: 20, paddingBottom: 8 },
  headerTitle: { fontSize: 18, fontWeight: '800', color: COLORS.text },
  headerSub: { fontSize: 12, color: COLORS.muted, marginTop: 4 },
  row: {
    flexDirection: 'row', alignItems: 'center', gap: 12,
    backgroundColor: '#fff', marginHorizontal: 16, marginTop: 10,
    borderRadius: 14, padding: 14,
    borderWidth: 1, borderColor: COLORS.border,
  },
  iconBox: { width: 36, height: 36, borderRadius: 18, alignItems: 'center', justifyContent: 'center' },
  icon: { fontSize: 16, fontWeight: '800' },
  type: { fontSize: 14, fontWeight: '700' },
  detail: { fontSize: 12, color: COLORS.text, marginTop: 2 },
  date: { fontSize: 12, color: COLORS.muted, marginTop: 2 },
  ip: { fontSize: 12, color: COLORS.muted, fontWeight: '600', fontVariant: ['tabular-nums'] },
  empty: { flex: 1, alignItems: 'center', justifyContent: 'center' },
  emptyText: { color: COLORS.muted, fontSize: 14 },
})