import React, { useEffect, useState } from 'react'
import {
  View, Text, FlatList, StyleSheet, TouchableOpacity, SafeAreaView,
  TextInput, Alert,
} from 'react-native'
import { useNavigation } from '@react-navigation/native'
import type { NativeStackNavigationProp } from '@react-navigation/native-stack'
import type { RootStackParams } from '../../navigation/types'
import { demoApi, type UserProfile } from '../../api/demo'
import { load, save, K } from '../../utils/storage'

type Nav = NativeStackNavigationProp<RootStackParams>

function ContactRow({ user, onPress }: { user: UserProfile; onPress(): void }) {
  const letter = (user.nickname || user.userId).charAt(0).toUpperCase()
  return (
    <TouchableOpacity style={styles.row} onPress={onPress} activeOpacity={0.7}>
      <View style={styles.avatar}><Text style={styles.avatarText}>{letter}</Text></View>
      <View style={styles.body}>
        <Text style={styles.name}>{user.nickname}</Text>
        <Text style={styles.uid}>@{user.userId}</Text>
      </View>
      <Text style={styles.arrow}>›</Text>
    </TouchableOpacity>
  )
}

export default function ContactsScreen() {
  const navigation = useNavigation<Nav>()
  const [contacts, setContacts] = useState<UserProfile[]>([])

  useEffect(() => {
    load<UserProfile[]>(K.CONTACTS).then(c => { if (c) setContacts(c) })
  }, [])

  const openChat = (user: UserProfile) => {
    navigation.navigate('SingleChat', { targetId: user.userId, targetName: user.nickname, targetAvatar: user.avatar })
  }

  return (
    <SafeAreaView style={styles.root}>
      <View style={styles.header}>
        <Text style={styles.title}>通讯录</Text>
        <View style={styles.headerActions}>
          <TouchableOpacity onPress={() => navigation.navigate('GroupList')} style={styles.headerBtn}>
            <Text style={styles.headerBtnText}>群聊</Text>
          </TouchableOpacity>
          <TouchableOpacity onPress={() => navigation.navigate('UserSearch')} style={styles.headerBtn}>
            <Text style={styles.headerBtnText}>添加</Text>
          </TouchableOpacity>
        </View>
      </View>
      <FlatList
        data={contacts}
        keyExtractor={u => u.userId}
        renderItem={({ item }) => <ContactRow user={item} onPress={() => openChat(item)} />}
        ItemSeparatorComponent={() => <View style={styles.sep} />}
        ListEmptyComponent={
          <View style={styles.empty}>
            <Text style={styles.emptyText}>还没有联系人</Text>
            <TouchableOpacity onPress={() => navigation.navigate('UserSearch')}>
              <Text style={styles.emptyLink}>搜索添加</Text>
            </TouchableOpacity>
          </View>
        }
      />
    </SafeAreaView>
  )
}

const styles = StyleSheet.create({
  root: { flex: 1, backgroundColor: '#f5f5f5' },
  header: { flexDirection: 'row', justifyContent: 'space-between', alignItems: 'center', padding: 16, backgroundColor: '#fff', borderBottomWidth: StyleSheet.hairlineWidth, borderBottomColor: '#e0e0e0' },
  title: { fontSize: 20, fontWeight: '700', color: '#111' },
  headerActions: { flexDirection: 'row', gap: 12 },
  headerBtn: { paddingHorizontal: 12, paddingVertical: 6, backgroundColor: '#07C160', borderRadius: 6 },
  headerBtnText: { color: '#fff', fontSize: 13, fontWeight: '600' },
  row: { flexDirection: 'row', alignItems: 'center', padding: 12, backgroundColor: '#fff' },
  avatar: { width: 46, height: 46, borderRadius: 8, backgroundColor: '#07C160', alignItems: 'center', justifyContent: 'center', marginRight: 12 },
  avatarText: { color: '#fff', fontSize: 18, fontWeight: '600' },
  body: { flex: 1 },
  name: { fontSize: 16, fontWeight: '500', color: '#111' },
  uid: { fontSize: 13, color: '#888', marginTop: 2 },
  arrow: { color: '#ccc', fontSize: 20 },
  sep: { height: StyleSheet.hairlineWidth, backgroundColor: '#e0e0e0', marginLeft: 70 },
  empty: { alignItems: 'center', paddingTop: 80 },
  emptyText: { color: '#bbb', fontSize: 15 },
  emptyLink: { color: '#07C160', fontSize: 14, marginTop: 12 },
})