import { useEffect, useRef, useState } from 'react';
import { View, Text, TouchableOpacity, Animated } from 'react-native';
import AsyncStorage from '@react-native-async-storage/async-storage';
import { useRouter } from 'expo-router';
import { Ionicons } from '@expo/vector-icons';
import { useQuery } from '@tanstack/react-query';
import { useTranslation } from 'react-i18next';
import { useMe } from '../hooks/useMe';
import { useProtectionCoverage } from '../hooks/useProfileData';
import { apiFetch } from '../lib/api';
import { FormSheet } from './FormSheet';
import { useColors } from '../lib/theme';

const MILESTONES = [3, 7, 10] as const;

function storageKey(userId: string, days: number) {
  return `@rebreak/diga_milestone_${userId}_${days}`;
}

type DemographicsResp = { birthYear: number | null } & Record<string, unknown>;

export function DiGaMilestoneModal() {
  const { t } = useTranslation();
  const colors = useColors();
  const router = useRouter();
  const { me } = useMe();
  const { coverage } = useProtectionCoverage();
  const [milestone, setMilestone] = useState<number | null>(null);
  const scaleAnim = useRef(new Animated.Value(0.8)).current;

  // Lean demographics check — only birthYear needed to determine completeness
  const { data: demo } = useQuery<DemographicsResp>({
    queryKey: ['diga-demo-check'],
    queryFn: () => apiFetch('/api/profile/me/demographics'),
    enabled: !!me,
    staleTime: 60_000,
  });

  useEffect(() => {
    if (!me || demo === undefined) return;
    // Kumulative Schutz-Tage (fällt NIE auf 0 zurück, anders als die
    // zusammenhängende Streak-Phase). So erreicht jeder engagierte User
    // irgendwann einen Milestone — auch rückfall-anfällige, deren DiGA-Daten
    // am wertvollsten sind.
    const protectedDays = coverage?.protectedDays ?? 0;
    const demographicsComplete = !!(demo?.birthYear);
    if (demographicsComplete) return; // already filled → never show

    (async () => {
      // Find highest milestone reached and not yet shown
      for (let i = MILESTONES.length - 1; i >= 0; i--) {
        const m = MILESTONES[i];
        if (protectedDays < m) continue;
        const shown = await AsyncStorage.getItem(storageKey(me.id, m));
        if (!shown) {
          setMilestone(m);
          return;
        }
      }
    })();
  }, [me?.id, coverage?.protectedDays, demo]);

  useEffect(() => {
    if (milestone !== null) {
      Animated.spring(scaleAnim, { toValue: 1, useNativeDriver: true, damping: 14 }).start();
    } else {
      scaleAnim.setValue(0.8);
    }
  }, [milestone]);

  async function dismiss() {
    if (!me || !milestone) return;
    await AsyncStorage.setItem(storageKey(me.id, milestone), '1');
    setMilestone(null);
  }

  async function openProfile() {
    await dismiss();
    router.push('/profile?openDemo=1' as any);
  }

  if (!milestone) return null;

  const badgeColor = milestone >= 10 ? '#f59e0b' : milestone >= 7 ? '#8b5cf6' : colors.brandOrange;

  return (
    <FormSheet
      visible={true}
      onClose={dismiss}
      title=""
      initialHeightPct={0.52}
      dismissOnBackdrop
    >
      <Animated.View style={{ transform: [{ scale: scaleAnim }], paddingHorizontal: 24, paddingTop: 8, paddingBottom: 32, alignItems: 'center', gap: 0 }}>
        {/* Milestone badge */}
        <View style={{
          width: 80, height: 80, borderRadius: 40,
          backgroundColor: badgeColor + '18',
          alignItems: 'center', justifyContent: 'center',
          marginBottom: 16,
        }}>
          <Text style={{ fontSize: 40 }}>
            {milestone >= 10 ? '🏆' : milestone >= 7 ? '🌟' : '🎉'}
          </Text>
        </View>

        <View style={{
          backgroundColor: badgeColor + '18',
          borderRadius: 20,
          paddingHorizontal: 14,
          paddingVertical: 5,
          marginBottom: 14,
        }}>
          <Text style={{ fontSize: 13, fontFamily: 'Nunito_700Bold', color: badgeColor }}>
            {t('diga_milestone.badge', { days: milestone })}
          </Text>
        </View>

        <Text style={{ fontSize: 22, fontFamily: 'Nunito_800ExtraBold', color: colors.text, textAlign: 'center', marginBottom: 10 }}>
          {t('diga_milestone.title', { days: milestone })}
        </Text>

        <Text style={{ fontSize: 14, fontFamily: 'Nunito_400Regular', color: colors.textMuted, textAlign: 'center', lineHeight: 21, marginBottom: 28 }}>
          {t('diga_milestone.body')}
        </Text>

        {/* Primary CTA */}
        <TouchableOpacity
          onPress={openProfile}
          activeOpacity={0.85}
          style={{
            width: '100%',
            backgroundColor: badgeColor,
            borderRadius: 14,
            paddingVertical: 15,
            alignItems: 'center',
            flexDirection: 'row',
            justifyContent: 'center',
            gap: 8,
            marginBottom: 10,
          }}
        >
          <Ionicons name="person-outline" size={17} color="#fff" />
          <Text style={{ fontSize: 15, fontFamily: 'Nunito_700Bold', color: '#fff' }}>
            {t('diga_milestone.cta')}
          </Text>
        </TouchableOpacity>

        {/* Dismiss */}
        <TouchableOpacity onPress={dismiss} activeOpacity={0.7} hitSlop={12}>
          <Text style={{ fontSize: 13, fontFamily: 'Nunito_600SemiBold', color: colors.textMuted }}>
            {t('diga_milestone.later')}
          </Text>
        </TouchableOpacity>
      </Animated.View>
    </FormSheet>
  );
}