import { useEffect, useRef, useState } from 'react';
import { Animated, Easing, Text, TouchableOpacity, useWindowDimensions, View } from 'react-native';
import { useTranslation } from 'react-i18next';
import { Ionicons } from '@expo/vector-icons';
import { useColors } from '../../../lib/theme';
import { OnboardingShell } from '../OnboardingShell';
import { LyraBubble } from '../LyraBubble';
import { CTABar } from '../CTABar';

const FAQ_KEYS = ['faq_q1', 'faq_q2', 'faq_q3', 'faq_q4', 'faq_q5'] as const;

export function DoneSlide({
  onEnter,
  current,
  total,
}: {
  onEnter: () => void;
  current: number;
  total: number;
}) {
  const { t } = useTranslation();
  const colors = useColors();
  const scale = useRef(new Animated.Value(0.6)).current;
  const opacity = useRef(new Animated.Value(0)).current;

  useEffect(() => {
    Animated.parallel([
      Animated.spring(scale, { toValue: 1, useNativeDriver: true, friction: 5, tension: 90 }),
      Animated.timing(opacity, {
        toValue: 1,
        duration: 500,
        useNativeDriver: true,
        easing: Easing.out(Easing.cubic),
      }),
    ]).start();
  }, []);

  return (
    <OnboardingShell
      current={current}
      total={total}
      cta={<CTABar primaryLabel={t('onboarding.done.cta_primary')} onPrimary={onEnter} />}
    >
      <ConfettiOverlay />

      <LyraBubble text={t('onboarding.lyra.done.body')} emotion="happy" />

      <Animated.View
        style={{
          marginTop: 24,
          alignItems: 'center',
          opacity,
          transform: [{ scale }],
        }}
      >
        <View
          style={{
            width: 96,
            height: 96,
            borderRadius: 48,
            backgroundColor: 'rgba(34,197,94,0.14)',
            alignItems: 'center',
            justifyContent: 'center',
            borderWidth: 2,
            borderColor: 'rgba(34,197,94,0.40)',
          }}
        >
          <Ionicons name="checkmark" size={52} color={colors.success} />
        </View>

        <Text
          style={{
            marginTop: 18,
            fontFamily: 'Nunito_800ExtraBold',
            fontSize: 24,
            color: colors.text,
            textAlign: 'center',
            letterSpacing: -0.3,
          }}
        >
          {t('onboarding.done.headline')}
        </Text>
        <Text
          style={{
            marginTop: 6,
            fontFamily: 'Nunito_400Regular',
            fontSize: 14,
            lineHeight: 20,
            color: colors.textMuted,
            textAlign: 'center',
            paddingHorizontal: 16,
          }}
        >
          {t('onboarding.done.subhead')}
        </Text>
      </Animated.View>

      {/* Inline Top-5-FAQ Accordion */}
      <View style={{ marginTop: 28 }}>
        <Text
          style={{
            fontFamily: 'Nunito_700Bold',
            fontSize: 12,
            letterSpacing: 0.8,
            color: colors.textMuted,
            textTransform: 'uppercase',
            marginBottom: 10,
          }}
        >
          {t('onboarding.done.faq_section_title')}
        </Text>
        <View style={{ gap: 8 }}>
          {FAQ_KEYS.map((qkey) => (
            <FaqRow
              key={qkey}
              question={t(`help.${qkey}`)}
              answer={t(`help.${qkey.replace('q', 'a')}`)}
              colors={colors}
            />
          ))}
        </View>
      </View>
    </OnboardingShell>
  );
}

// ─── Confetti-Overlay (Reanimated Particles) ─────────────────────────────────

const CONFETTI_COUNT = 22;
const CONFETTI_COLORS = ['#fbbf24', '#34d399', '#60a5fa', '#a78bfa', '#f472b6'];

function ConfettiOverlay() {
  const { width: screenW } = useWindowDimensions();
  // Stabile Particle-Definitionen — Math.random nur einmal beim Mount
  const particles = useRef(
    Array.from({ length: CONFETTI_COUNT }).map((_, i) => ({
      key: i,
      anim: new Animated.Value(0),
      startX: Math.random() * screenW,
      drift: (Math.random() - 0.5) * 80,
      color: CONFETTI_COLORS[i % CONFETTI_COLORS.length],
      rotateStart: Math.random() * 360,
      size: 6 + Math.random() * 6,
      delay: Math.random() * 600,
      duration: 2200 + Math.random() * 1300,
    })),
  ).current;

  useEffect(() => {
    Animated.stagger(
      40,
      particles.map((p) =>
        Animated.timing(p.anim, {
          toValue: 1,
          duration: p.duration,
          delay: p.delay,
          useNativeDriver: true,
          easing: Easing.out(Easing.quad),
        }),
      ),
    ).start();
  }, []);

  return (
    <View
      pointerEvents="none"
      style={{ position: 'absolute', top: 0, left: 0, right: 0, height: 600, overflow: 'hidden' }}
    >
      {particles.map((p) => {
        const translateY = p.anim.interpolate({ inputRange: [0, 1], outputRange: [-30, 580] });
        const translateX = p.anim.interpolate({ inputRange: [0, 1], outputRange: [0, p.drift] });
        const rotate = p.anim.interpolate({
          inputRange: [0, 1],
          outputRange: [`${p.rotateStart}deg`, `${p.rotateStart + 540}deg`],
        });
        const opacity = p.anim.interpolate({ inputRange: [0, 0.85, 1], outputRange: [1, 1, 0] });
        return (
          <Animated.View
            key={p.key}
            style={{
              position: 'absolute',
              left: p.startX - p.size / 2,
              top: 0,
              width: p.size,
              height: p.size * 1.6,
              backgroundColor: p.color,
              borderRadius: 2,
              opacity,
              transform: [{ translateY }, { translateX }, { rotate }],
            }}
          />
        );
      })}
    </View>
  );
}

// ─── FAQ Accordion-Row ───────────────────────────────────────────────────────

function FaqRow({
  question,
  answer,
  colors,
}: {
  question: string;
  answer: string;
  colors: import('../../../lib/theme').ColorScheme;
}) {
  const [expanded, setExpanded] = useState(false);
  return (
    <View
      style={{
        backgroundColor: colors.surfaceElevated,
        borderRadius: 12,
        paddingVertical: 12,
        paddingHorizontal: 14,
      }}
    >
      <TouchableOpacity
        onPress={() => setExpanded((v) => !v)}
        activeOpacity={0.7}
        style={{ flexDirection: 'row', alignItems: 'center', gap: 10 }}
      >
        <Text
          style={{
            flex: 1,
            fontFamily: 'Nunito_600SemiBold',
            fontSize: 13,
            lineHeight: 19,
            color: colors.text,
          }}
        >
          {question}
        </Text>
        <Ionicons
          name={expanded ? 'chevron-up' : 'chevron-down'}
          size={16}
          color={colors.textMuted}
        />
      </TouchableOpacity>
      {expanded ? (
        <Text
          style={{
            marginTop: 8,
            paddingTop: 8,
            borderTopWidth: 1,
            borderTopColor: 'rgba(0,0,0,0.06)',
            fontFamily: 'Nunito_400Regular',
            fontSize: 13,
            lineHeight: 19,
            color: colors.textMuted,
          }}
        >
          {answer}
        </Text>
      ) : null}
    </View>
  );
}