import { useState, useRef, useEffect } from 'react'
import {
  View, Text, TextInput, TouchableOpacity, ScrollView,
  StyleSheet, KeyboardAvoidingView, Platform, ActivityIndicator,
} from 'react-native'
import { COLORS } from '../../constants/Config'
import { sendAIMessage } from '../../services/api'
import { useAuth } from '../../hooks/useAuth'

interface Msg { id: number; role: 'user' | 'ai'; text: string; time: string }

const QUICK = ['서버 상태 확인', 'SR 목록 보여줘', '최근 인시던트', '라이선스 현황']

export default function ChatScreen() {
  const { user } = useAuth()
  const [msgs,    setMsgs]    = useState<Msg[]>([
    { id: 0, role: 'ai', text: `안녕하세요 ${user?.display_name ?? ''}님! 👋\nGUARDiA AI 어시스턴트입니다.\n무엇을 도와드릴까요?`, time: now() },
  ])
  const [input,   setInput]   = useState('')
  const [loading, setLoading] = useState(false)
  const scrollRef = useRef<ScrollView>(null)

  function now() { return new Date().toLocaleTimeString('ko-KR', { hour: '2-digit', minute: '2-digit' }) }

  const send = async (text = input) => {
    if (!text.trim() || loading) return
    const userMsg: Msg = { id: Date.now(), role: 'user', text: text.trim(), time: now() }
    setMsgs(m => [...m, userMsg])
    setInput('')
    setLoading(true)
    try {
      const r = await sendAIMessage(text.trim())
      const reply = r.data?.reply ?? r.data?.message ?? r.data?.response ?? '응답을 받았습니다.'
      setMsgs(m => [...m, { id: Date.now()+1, role: 'ai', text: reply, time: now() }])
    } catch {
      setMsgs(m => [...m, { id: Date.now()+1, role: 'ai',
        text: '현재 AI 서버에 연결할 수 없습니다. Ollama 서버 상태를 확인해주세요.', time: now() }])
    } finally { setLoading(false) }
    setTimeout(() => scrollRef.current?.scrollToEnd({ animated: true }), 100)
  }

  useEffect(() => {
    setTimeout(() => scrollRef.current?.scrollToEnd({ animated: false }), 50)
  }, [msgs])

  return (
    <KeyboardAvoidingView style={{ flex:1 }} behavior={Platform.OS === 'ios' ? 'padding' : 'height'}>
      <View style={s.container}>
        {/* 메시지 목록 */}
        <ScrollView ref={scrollRef} style={s.messages} contentContainerStyle={{ padding: 16 }}>
          {msgs.map(m => (
            <View key={m.id} style={[s.msgRow, m.role === 'user' && s.userRow]}>
              {m.role === 'ai' && <Text style={s.avatar}>🤖</Text>}
              <View style={[s.bubble, m.role === 'user' ? s.userBubble : s.aiBubble]}>
                <Text style={[s.bubbleText, m.role === 'user' && s.userText]}>{m.text}</Text>
                <Text style={[s.timeText, m.role === 'user' && { color: 'rgba(255,255,255,.6)' }]}>{m.time}</Text>
              </View>
            </View>
          ))}
          {loading && (
            <View style={s.msgRow}>
              <Text style={s.avatar}>🤖</Text>
              <View style={s.aiBubble}>
                <ActivityIndicator size="small" color={COLORS.accent} />
              </View>
            </View>
          )}
        </ScrollView>

        {/* 빠른 질문 */}
        <ScrollView horizontal showsHorizontalScrollIndicator={false}
          style={s.quickScroll} contentContainerStyle={{ paddingHorizontal: 12, gap: 8 }}>
          {QUICK.map(q => (
            <TouchableOpacity key={q} style={s.quickChip} onPress={() => send(q)}>
              <Text style={s.quickChipText}>{q}</Text>
            </TouchableOpacity>
          ))}
        </ScrollView>

        {/* 입력창 */}
        <View style={s.inputRow}>
          <TextInput
            style={s.textInput}
            value={input}
            onChangeText={setInput}
            placeholder="GUARDiA AI에게 질문하세요..."
            placeholderTextColor={COLORS.muted}
            multiline
            maxLength={500}
            returnKeyType="send"
            onSubmitEditing={() => send()}
          />
          <TouchableOpacity style={[s.sendBtn, (!input.trim() || loading) && s.sendDisabled]}
            onPress={() => send()} disabled={!input.trim() || loading}>
            <Text style={s.sendIcon}>➤</Text>
          </TouchableOpacity>
        </View>
      </View>
    </KeyboardAvoidingView>
  )
}

const s = StyleSheet.create({
  container:   { flex:1, backgroundColor:COLORS.bg },
  messages:    { flex:1 },
  msgRow:      { flexDirection:'row', alignItems:'flex-end', marginBottom:12, gap:8 },
  userRow:     { flexDirection:'row-reverse' },
  avatar:      { fontSize:24, marginBottom:4 },
  bubble:      { maxWidth:'75%', borderRadius:16, padding:12 },
  aiBubble:    { backgroundColor:'#fff', borderBottomLeftRadius:4,
                 shadowColor:'#000', shadowOffset:{width:0,height:1}, shadowOpacity:.06, elevation:1 },
  userBubble:  { backgroundColor:COLORS.accent, borderBottomRightRadius:4 },
  bubbleText:  { fontSize:14, color:COLORS.text, lineHeight:20 },
  userText:    { color:'#fff' },
  timeText:    { fontSize:10, color:COLORS.muted, marginTop:4, textAlign:'right' },
  quickScroll: { maxHeight:44, borderTopWidth:1, borderTopColor:COLORS.border, backgroundColor:'#fff' },
  quickChip:   { alignSelf:'center', backgroundColor:COLORS.light, paddingHorizontal:12,
                 paddingVertical:6, borderRadius:20 },
  quickChipText: { fontSize:12, color:COLORS.accent, fontWeight:'500' },
  inputRow:    { flexDirection:'row', padding:12, backgroundColor:'#fff',
                 borderTopWidth:1, borderTopColor:COLORS.border, alignItems:'flex-end', gap:8 },
  textInput:   { flex:1, borderWidth:1.5, borderColor:COLORS.border, borderRadius:20,
                 paddingHorizontal:14, paddingVertical:10, fontSize:14, color:COLORS.text,
                 maxHeight:100, backgroundColor:'#fafafa' },
  sendBtn:     { width:42, height:42, borderRadius:21, backgroundColor:COLORS.accent,
                 justifyContent:'center', alignItems:'center' },
  sendDisabled:{ opacity:.4 },
  sendIcon:    { color:'#fff', fontSize:16, marginLeft:2 },
})