/**
 * FlashcardSheet — génère et sauvegarde des flashcards depuis une note
 */
import { useState } from 'react'
import { View, Text, StyleSheet, TouchableOpacity, ActivityIndicator, ScrollView } from 'react-native'
import { GraduationCap, Check, RefreshCw } from 'lucide-react-native'
import { BottomSheet } from './BottomSheet'
import { C } from '@/lib/theme'
import { apiFetch } from '@/lib/api'
import { ENDPOINTS } from '@/lib/config'
import { useRouter } from 'expo-router'

const STYLES = [
  { key: 'qa', label: 'Q&A', desc: 'Questions / Réponses' },
  { key: 'concept', label: 'Concept', desc: 'Terme / Définition' },
  { key: 'cloze', label: 'Cloze', desc: 'Texte à trous' },
] as const

const COUNTS = [5, 10, 15, 20]

interface Props {
  visible: boolean
  onClose: () => void
  noteId: string
  noteTitle: string
}

export function FlashcardSheet({ visible, onClose, noteId, noteTitle }: Props) {
  const router = useRouter()
  const [style, setStyle] = useState<'qa' | 'concept' | 'cloze'>('qa')
  const [count, setCount] = useState(10)
  const [loading, setLoading] = useState(false)
  const [result, setResult] = useState<{ deckId: string; count: number } | null>(null)
  const [error, setError] = useState<string | null>(null)

  const generate = async () => {
    setLoading(true)
    setError(null)
    setResult(null)
    try {
      const res = await apiFetch(ENDPOINTS.flashcardGenerate, {
        method: 'POST',
        body: JSON.stringify({ noteId, style, count }),
      })
      const data = await res.json()
      if (!res.ok) throw new Error(data.error ?? `Erreur ${res.status}`)
      setResult({ deckId: data.deckId, count: data.count })
    } catch (e: any) {
      setError(e.message ?? 'Erreur de génération')
    } finally {
      setLoading(false)
    }
  }

  const goRevise = () => {
    onClose()
    router.push({ pathname: '/(tabs)/revision' })
  }

  const reset = () => { setResult(null); setError(null) }

  return (
    <BottomSheet visible={visible} onClose={onClose}>
      <View style={s.header}>
        <GraduationCap size={20} color={C.brand} />
        <Text style={s.title}>Générer des flashcards</Text>
      </View>
      <Text style={s.noteTitle} numberOfLines={1}>📝 {noteTitle}</Text>

      {!result && !loading && (
        <ScrollView showsVerticalScrollIndicator={false}>
          {/* Style */}
          <Text style={s.sectionLabel}>Type de cartes</Text>
          <View style={s.pills}>
            {STYLES.map((st) => (
              <TouchableOpacity
                key={st.key}
                style={[s.pill, style === st.key && s.pillActive]}
                onPress={() => setStyle(st.key)}
                activeOpacity={0.8}
              >
                <Text style={[s.pillLabel, style === st.key && s.pillLabelActive]}>{st.label}</Text>
                <Text style={[s.pillDesc, style === st.key && s.pillDescActive]}>{st.desc}</Text>
              </TouchableOpacity>
            ))}
          </View>

          {/* Nombre */}
          <Text style={s.sectionLabel}>Nombre de cartes</Text>
          <View style={s.countRow}>
            {COUNTS.map((n) => (
              <TouchableOpacity
                key={n}
                style={[s.countBtn, count === n && s.countBtnActive]}
                onPress={() => setCount(n)}
                activeOpacity={0.8}
              >
                <Text style={[s.countTxt, count === n && s.countTxtActive]}>{n}</Text>
              </TouchableOpacity>
            ))}
          </View>

          {error && <Text style={s.error}>{error}</Text>}

          <TouchableOpacity style={s.generateBtn} onPress={generate} activeOpacity={0.85}>
            <GraduationCap size={16} color="#fff" />
            <Text style={s.generateTxt}>Générer {count} cartes</Text>
          </TouchableOpacity>
        </ScrollView>
      )}

      {loading && (
        <View style={s.center}>
          <ActivityIndicator color={C.brand} size="large" />
          <Text style={s.loadingTxt}>Génération en cours…</Text>
        </View>
      )}

      {result && (
        <View style={s.resultWrap}>
          <View style={s.checkCircle}>
            <Check size={28} color="#16a34a" />
          </View>
          <Text style={s.resultTitle}>{result.count} cartes créées !</Text>
          <Text style={s.resultSub}>Votre paquet est prêt pour la révision.</Text>
          <View style={s.resultActions}>
            <TouchableOpacity style={s.reviseBtn} onPress={goRevise} activeOpacity={0.85}>
              <GraduationCap size={16} color="#fff" />
              <Text style={s.reviseTxt}>Réviser maintenant</Text>
            </TouchableOpacity>
            <TouchableOpacity style={s.retryBtn} onPress={reset} activeOpacity={0.8}>
              <RefreshCw size={14} color={C.concrete} />
              <Text style={s.retryTxt}>Regénérer</Text>
            </TouchableOpacity>
          </View>
        </View>
      )}
    </BottomSheet>
  )
}

const s = StyleSheet.create({
  header: { flexDirection: 'row', alignItems: 'center', gap: 8, marginBottom: 4 },
  title: { fontSize: 17, fontWeight: '700', color: C.ink },
  noteTitle: { fontSize: 13, color: C.concrete, marginBottom: 20 },
  sectionLabel: { fontSize: 11, fontWeight: '700', color: C.concrete, letterSpacing: 0.8, textTransform: 'uppercase', marginBottom: 10 },
  pills: { flexDirection: 'row', gap: 8, marginBottom: 20 },
  pill: { flex: 1, padding: 12, borderRadius: 12, borderWidth: 1.5, borderColor: C.border, backgroundColor: C.paper },
  pillActive: { borderColor: C.brand, backgroundColor: 'rgba(164,113,72,0.08)' },
  pillLabel: { fontSize: 13, fontWeight: '700', color: C.ink, marginBottom: 2 },
  pillLabelActive: { color: C.brand },
  pillDesc: { fontSize: 10, color: C.concrete },
  pillDescActive: { color: C.brand },
  countRow: { flexDirection: 'row', gap: 8, marginBottom: 24 },
  countBtn: { flex: 1, paddingVertical: 12, borderRadius: 12, borderWidth: 1.5, borderColor: C.border, alignItems: 'center', backgroundColor: C.paper },
  countBtnActive: { borderColor: C.brand, backgroundColor: 'rgba(164,113,72,0.08)' },
  countTxt: { fontSize: 15, fontWeight: '700', color: C.ink },
  countTxtActive: { color: C.brand },
  error: { color: '#e11d48', fontSize: 13, marginBottom: 12, textAlign: 'center' },
  generateBtn: { backgroundColor: C.brand, borderRadius: 14, paddingVertical: 14, flexDirection: 'row', alignItems: 'center', justifyContent: 'center', gap: 8 },
  generateTxt: { color: '#fff', fontWeight: '700', fontSize: 15 },
  center: { alignItems: 'center', justifyContent: 'center', paddingVertical: 40 },
  loadingTxt: { marginTop: 16, color: C.concrete, fontSize: 14 },
  resultWrap: { alignItems: 'center', paddingVertical: 20 },
  checkCircle: { width: 64, height: 64, borderRadius: 32, backgroundColor: '#dcfce7', alignItems: 'center', justifyContent: 'center', marginBottom: 16 },
  resultTitle: { fontSize: 20, fontWeight: '800', color: C.ink, marginBottom: 8 },
  resultSub: { fontSize: 14, color: C.concrete, marginBottom: 28 },
  resultActions: { width: '100%', gap: 10 },
  reviseBtn: { backgroundColor: C.brand, borderRadius: 14, paddingVertical: 14, flexDirection: 'row', alignItems: 'center', justifyContent: 'center', gap: 8 },
  reviseTxt: { color: '#fff', fontWeight: '700', fontSize: 15 },
  retryBtn: { borderRadius: 14, paddingVertical: 12, flexDirection: 'row', alignItems: 'center', justifyContent: 'center', gap: 6, borderWidth: 1, borderColor: C.border },
  retryTxt: { color: C.concrete, fontWeight: '600', fontSize: 13 },
})