import { Tabs, Redirect } from 'expo-router'
import { Platform, View, Text, StyleSheet, TextInput, TouchableOpacity, ActivityIndicator, Alert, ScrollView } from 'react-native'
import { useEffect, useState } from 'react'
import { Ionicons } from '@expo/vector-icons'
import { SafeAreaView } from 'react-native-safe-area-context'
import { useAuthStore } from '@/store/auth.store'
import { trpc } from '@/lib/trpc'
import { setupPushNotifications } from '@/lib/notifications'
import { authClient } from '@/lib/auth-client'

function UnreadBadge({ count }: { count: number }) {
  if (count === 0) return null
  return (
    <View style={badge.dot}>
      <Text style={badge.text}>{count > 9 ? '9+' : count}</Text>
    </View>
  )
}

const badge = StyleSheet.create({
  dot: {
    position: 'absolute',
    top: -4,
    right: -8,
    minWidth: 17,
    height: 17,
    borderRadius: 9,
    backgroundColor: '#DC2626',
    justifyContent: 'center',
    alignItems: 'center',
    paddingHorizontal: 4,
    borderWidth: 2,
    borderColor: '#FFFFFF',
  },
  text: {
    fontSize: 10,
    fontWeight: '700',
    color: '#FFFFFF',
    lineHeight: 13,
  },
})

function ChatTabIcon({ color, focused }: { color: string; focused: boolean }) {
  const { data: unreadCount } = trpc.messages.getConversations.useQuery(undefined, {
    refetchInterval: 15_000,
    staleTime: 10_000,
    select: (data) => data.filter((c) => c.hasUnread).length,
  })

  return (
    <View>
      <Ionicons name={focused ? 'chatbubbles' : 'chatbubbles-outline'} size={23} color={color} />
      <UnreadBadge count={unreadCount ?? 0} />
    </View>
  )
}

function ForcePasswordChangeScreen() {
  const { setSession, signOut } = useAuthStore()
  const [current, setCurrent] = useState('')
  const [next, setNext] = useState('')
  const [confirm, setConfirm] = useState('')
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState('')

  async function handleSubmit() {
    setError('')
    if (!current) { setError('Bitte temporäres Passwort eingeben.'); return }
    if (next.length < 8) { setError('Das neue Passwort muss mindestens 8 Zeichen haben.'); return }
    if (next !== confirm) { setError('Die Passwörter stimmen nicht überein.'); return }

    setLoading(true)
    const result = await authClient.changePassword({ currentPassword: current, newPassword: next })
    setLoading(false)

    if (result.error) {
      setError(result.error.message ?? 'Passwort konnte nicht geändert werden.')
      return
    }

    // Refresh session — mustChangePassword is now false
    const sessionResult = await authClient.getSession()
    if (sessionResult?.data?.user) {
      const u = sessionResult.data.user as any
      await setSession({
        user: {
          id: u.id,
          email: u.email,
          name: u.name,
          mustChangePassword: false,
        },
      })
    }
  }

  return (
    <SafeAreaView style={fpc.safe}>
      <ScrollView contentContainerStyle={fpc.content} keyboardShouldPersistTaps="handled">
        <View style={fpc.card}>
          <View style={fpc.iconWrap}>
            <Ionicons name="lock-closed-outline" size={32} color="#003B7E" />
          </View>
          <Text style={fpc.title}>Passwort ändern</Text>
          <Text style={fpc.subtitle}>
            Ihr Administrator hat ein temporäres Passwort vergeben. Bitte legen Sie jetzt Ihr persönliches Passwort fest.
          </Text>

          <View style={fpc.field}>
            <Text style={fpc.label}>Temporäres Passwort</Text>
            <TextInput
              style={fpc.input}
              value={current}
              onChangeText={setCurrent}
              secureTextEntry
              placeholder="••••••••"
              placeholderTextColor="#CBD5E1"
              autoCapitalize="none"
            />
          </View>
          <View style={fpc.field}>
            <Text style={fpc.label}>Neues Passwort</Text>
            <TextInput
              style={fpc.input}
              value={next}
              onChangeText={setNext}
              secureTextEntry
              placeholder="Mindestens 8 Zeichen"
              placeholderTextColor="#CBD5E1"
              autoCapitalize="none"
            />
          </View>
          <View style={fpc.field}>
            <Text style={fpc.label}>Neues Passwort wiederholen</Text>
            <TextInput
              style={fpc.input}
              value={confirm}
              onChangeText={setConfirm}
              secureTextEntry
              placeholder="Neues Passwort wiederholen"
              placeholderTextColor="#CBD5E1"
              autoCapitalize="none"
            />
          </View>

          {!!error && (
            <View style={fpc.errorBox}>
              <Text style={fpc.errorText}>{error}</Text>
            </View>
          )}

          <TouchableOpacity style={fpc.btn} onPress={handleSubmit} disabled={loading}>
            {loading
              ? <ActivityIndicator color="#fff" />
              : <Text style={fpc.btnText}>Passwort festlegen</Text>
            }
          </TouchableOpacity>

          <TouchableOpacity style={fpc.logoutBtn} onPress={() => void signOut()}>
            <Text style={fpc.logoutText}>Abmelden</Text>
          </TouchableOpacity>
        </View>
      </ScrollView>
    </SafeAreaView>
  )
}

const fpc = StyleSheet.create({
  safe: { flex: 1, backgroundColor: '#F8FAFC' },
  content: { flex: 1, justifyContent: 'center', padding: 24 },
  card: {
    backgroundColor: '#FFFFFF', borderRadius: 20,
    borderWidth: 1, borderColor: '#E2E8F0',
    padding: 24, gap: 12,
  },
  iconWrap: {
    width: 60, height: 60, borderRadius: 16,
    backgroundColor: '#EFF6FF', alignItems: 'center', justifyContent: 'center',
    alignSelf: 'center', marginBottom: 4,
  },
  title: { fontSize: 22, fontWeight: '800', color: '#0F172A', textAlign: 'center' },
  subtitle: { fontSize: 13, color: '#64748B', textAlign: 'center', lineHeight: 19 },
  field: { gap: 4 },
  label: { fontSize: 12, fontWeight: '700', color: '#475569', textTransform: 'uppercase', letterSpacing: 0.5 },
  input: {
    borderWidth: 1, borderColor: '#E2E8F0', borderRadius: 10,
    paddingHorizontal: 12, paddingVertical: 11,
    fontSize: 14, color: '#0F172A', backgroundColor: '#F8FAFC',
  },
  errorBox: {
    backgroundColor: '#FEF2F2', borderWidth: 1,
    borderColor: '#FECACA', borderRadius: 10,
    paddingHorizontal: 12, paddingVertical: 10,
  },
  errorText: { color: '#B91C1C', fontSize: 13 },
  btn: {
    backgroundColor: '#003B7E', borderRadius: 12,
    paddingVertical: 13, alignItems: 'center', marginTop: 4,
  },
  btnText: { color: '#FFFFFF', fontWeight: '700', fontSize: 15 },
  logoutBtn: { alignItems: 'center', paddingVertical: 8 },
  logoutText: { color: '#94A3B8', fontSize: 13 },
})

export default function AppLayout() {
  const session = useAuthStore((s) => s.session)

  useEffect(() => {
    if (!session?.user) return
    setupPushNotifications().catch(() => {})
  }, [session?.user?.id])

  if (!session) {
    return <Redirect href="/(auth)/login" />
  }

  if (session.user.mustChangePassword) {
    return <ForcePasswordChangeScreen />
  }

  return (
    <Tabs
      screenOptions={{
        tabBarActiveTintColor: '#003B7E',
        tabBarInactiveTintColor: '#64748B',
        tabBarStyle: {
          borderTopWidth: 1,
          borderTopColor: '#E2E8F0',
          backgroundColor: '#FFFFFF',
          height: Platform.OS === 'ios' ? 88 : 64,
          paddingBottom: Platform.OS === 'ios' ? 28 : 8,
          paddingTop: 8,
        },
        tabBarLabelStyle: {
          fontSize: 11,
          fontWeight: '600',
          letterSpacing: 0.1,
        },
        headerShown: false,
      }}
    >
      <Tabs.Screen
        name="home/index"
        options={{
          title: 'Start',
          tabBarIcon: ({ color, focused }) => (
            <Ionicons name={focused ? 'home' : 'home-outline'} size={23} color={color} />
          ),
        }}
      />
      <Tabs.Screen
        name="news/index"
        options={{
          title: 'Aktuelles',
          tabBarIcon: ({ color, focused }) => (
            <Ionicons name={focused ? 'newspaper' : 'newspaper-outline'} size={23} color={color} />
          ),
        }}
      />
      <Tabs.Screen
        name="termine/index"
        options={{
          title: 'Termine',
          tabBarIcon: ({ color, focused }) => (
            <Ionicons name={focused ? 'calendar' : 'calendar-outline'} size={23} color={color} />
          ),
        }}
      />
      <Tabs.Screen
        name="stellen/index"
        options={{
          title: 'Stellen',
          tabBarIcon: ({ color, focused }) => (
            <Ionicons name={focused ? 'briefcase' : 'briefcase-outline'} size={23} color={color} />
          ),
        }}
      />
      <Tabs.Screen
        name="chat/index"
        options={{
          title: 'Nachrichten',
          tabBarIcon: ({ color, focused }) => (
            <ChatTabIcon color={color} focused={focused} />
          ),
        }}
      />
      <Tabs.Screen
        name="profil/index"
        options={{
          title: 'Profil',
          tabBarIcon: ({ color, focused }) => (
            <Ionicons name={focused ? 'person' : 'person-outline'} size={23} color={color} />
          ),
        }}
      />

      <Tabs.Screen name="members/index" options={{ href: null }} />
      <Tabs.Screen name="news/[id]" options={{ href: null }} />
      <Tabs.Screen name="members/[id]" options={{ href: null }} />
      <Tabs.Screen name="termine/[id]" options={{ href: null }} />
      <Tabs.Screen name="stellen/[id]" options={{ href: null }} />
      <Tabs.Screen name="chat/[id]" options={{ href: null }} />
    </Tabs>
  )
}