import React from 'react';
import { ImageBackground, ScrollView, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { useRouter } from 'expo-router';
import { Ionicons } from '@expo/vector-icons';
import { usePostHog } from 'posthog-react-native';
import { ThemeBackdrop } from '../../components/ThemeBackdrop';
import { useColors } from '../../constants/Colors';
import { useApp } from '../../context/AppContext';

const ONBOARDING_BACKGROUND = {
  light: '#fbfaf3',
  dark: '#0a110b',
};

const getHealthOnboardingCopy = (language: 'de' | 'en' | 'es') => {
  if (language === 'de') {
    return {
      step: 'Schritt 4 von 4',
      title: 'Wo ist der Health-Scan?',
      subtitle: 'Du findest ihn auf jeder gespeicherten Pflanze, direkt unter der Beschreibung.',
      buttonPreview: 'Health-Scan starten',
      cta: 'Weiter',
      skip: 'Spaeter',
      flow: ['Pflanze scannen', 'Speichern', 'Detailseite oeffnen', 'Health-Scan starten'],
      outputTitle: 'Was du danach bekommst',
      outputs: [
        'Gesundheits-Score mit Status: stabil, beobachten oder kritisch.',
        'Ausfuehrliche Analyse mit sichtbaren Hinweisen und Unsicherheit.',
        'Wahrscheinlichste Ursachen mit Confidence-Werten.',
        'Sofortmassnahmen plus konkreter 7-Tage-Pflegeplan.',
      ],
      guidanceNote: 'Tipp: Fotografiere die ganze Pflanze, die Blattunterseiten und die Erde. Je klarer das Foto, desto genauer wird der Plan.',
    };
  }

  if (language === 'es') {
    return {
      step: 'Paso 4 de 4',
      title: 'Donde esta el health-scan?',
      subtitle: 'Lo encuentras en cada planta guardada, justo debajo de la descripcion.',
      buttonPreview: 'Iniciar health-scan',
      cta: 'Continuar',
      skip: 'Mas tarde',
      flow: ['Escanear planta', 'Guardar', 'Abrir detalle', 'Iniciar health-scan'],
      outputTitle: 'Que recibes despues',
      outputs: [
        'Puntaje de salud con estado: estable, observar o critico.',
        'Analisis detallado con senales visibles e incertidumbre.',
        'Causas probables con valores de confianza.',
        'Acciones inmediatas y plan concreto de 7 dias.',
      ],
      guidanceNote: 'Consejo: fotografia la planta completa, el reverso de las hojas y el sustrato. Cuanto mas clara sea la foto, mas preciso sera el plan.',
    };
  }

  return {
    step: 'Step 4 of 4',
    title: 'Where is the health scan?',
    subtitle: 'It lives on every saved plant, directly below the plant description.',
    buttonPreview: 'Start health scan',
    cta: 'Continue',
    skip: 'Later',
    flow: ['Scan plant', 'Save', 'Open detail', 'Start health scan'],
    outputTitle: 'What you get after',
    outputs: [
      'Health score with stable, watch, or critical status.',
      'Detailed analysis with visible signals and uncertainty.',
      'Most likely causes with confidence values.',
      'Immediate actions plus a concrete 7-day care plan.',
    ],
    guidanceNote: 'Tip: photograph the full plant, leaf undersides, and the soil. The clearer the photo, the more precise the plan.',
  };
};

export default function HealthCheckOnboardingScreen() {
  const router = useRouter();
  const posthog = usePostHog();
  const { isDarkMode, colorPalette, language, billingSummary } = useApp();
  const colors = useColors(isDarkMode, colorPalette);
  const screenBackground = isDarkMode ? ONBOARDING_BACKGROUND.dark : ONBOARDING_BACKGROUND.light;
  const copy = getHealthOnboardingCopy(language);

  const finish = (skipped = false) => {
    posthog.capture('onboarding_health_check_explained', {
      skipped,
      plan: billingSummary?.entitlement?.plan ?? 'free',
    });
    const hasActiveEntitlement = billingSummary?.entitlement?.plan === 'pro'
      && billingSummary?.entitlement?.status === 'active';
    router.replace(hasActiveEntitlement ? '/(tabs)' : '/profile/billing');
  };

  return (
    <View style={[styles.container, { backgroundColor: screenBackground }]}>
      {isDarkMode ? <ThemeBackdrop colors={colors} /> : null}
      <SafeAreaView style={styles.safeArea} edges={['top', 'left', 'right', 'bottom']}>
        <View style={styles.header}>
          <View style={[styles.stepPill, { backgroundColor: colors.primarySoft, borderColor: colors.border }]}>
            <Text style={[styles.stepLabel, { color: colors.primaryDark }]}>{copy.step}</Text>
          </View>
          <Text style={[styles.title, { color: colors.text }]}>{copy.title}</Text>
          <Text style={[styles.subtitle, { color: colors.textSecondary }]}>{copy.subtitle}</Text>
        </View>

        <ScrollView contentContainerStyle={styles.content} showsVerticalScrollIndicator={false}>
          <ImageBackground
            source={require('../../assets/onboarding_health_scan_mockup.png')}
            style={[styles.illustration, { borderColor: colors.border }]}
            imageStyle={styles.illustrationImage}
            resizeMode="cover"
          >
            <View style={[styles.illustrationOverlay, { backgroundColor: isDarkMode ? 'rgba(8, 14, 9, 0.08)' : 'rgba(251, 250, 243, 0.04)' }]} />
          </ImageBackground>

          <View style={[styles.flowCard, { backgroundColor: colors.surface, borderColor: colors.border }]}>
            {copy.flow.map((item, index) => (
              <View key={item} style={styles.flowRow}>
                <View style={[styles.flowIndex, { backgroundColor: index === 3 ? colors.primary : colors.surfaceMuted }]}>
                  <Text style={[styles.flowIndexText, { color: index === 3 ? colors.onPrimary : colors.textMuted }]}>
                    {index + 1}
                  </Text>
                </View>
                <Text style={[styles.flowText, { color: colors.text }]}>{item}</Text>
              </View>
            ))}
          </View>

          <View style={[styles.outputCard, { backgroundColor: colors.surface, borderColor: colors.border }]}>
            <Text style={[styles.outputTitle, { color: colors.text }]}>{copy.outputTitle}</Text>
            {copy.outputs.map((item) => (
              <View key={item} style={styles.outputRow}>
                <Ionicons name="checkmark-circle" size={16} color={colors.success} />
                <Text style={[styles.outputText, { color: colors.textSecondary }]}>{item}</Text>
              </View>
            ))}
          </View>

          <View style={[styles.guidanceCard, { backgroundColor: colors.primarySoft, borderColor: colors.border }]}>
            <Ionicons name="camera-outline" size={18} color={colors.primaryDark} />
            <Text style={[styles.guidanceText, { color: colors.primaryDark }]}>{copy.guidanceNote}</Text>
          </View>
        </ScrollView>

        <View style={styles.footer}>
          <TouchableOpacity
            style={[styles.secondaryBtn, { borderColor: colors.borderStrong, backgroundColor: colors.surface }]}
            onPress={() => finish(true)}
          >
            <Text style={[styles.secondaryBtnText, { color: colors.text }]}>{copy.skip}</Text>
          </TouchableOpacity>
          <TouchableOpacity style={[styles.primaryBtn, { backgroundColor: colors.primary }]} onPress={() => finish(false)}>
            <Text style={[styles.primaryBtnText, { color: colors.onPrimary }]}>{copy.cta}</Text>
          </TouchableOpacity>
        </View>
      </SafeAreaView>
    </View>
  );
}

const styles = StyleSheet.create({
  container: { flex: 1 },
  safeArea: { flex: 1, paddingHorizontal: 20, paddingTop: 24, paddingBottom: 20 },
  header: { gap: 9, marginBottom: 18 },
  stepPill: { alignSelf: 'flex-start', borderWidth: 1, borderRadius: 999, paddingHorizontal: 12, paddingVertical: 7 },
  stepLabel: { fontSize: 12, fontWeight: '800', textTransform: 'uppercase', letterSpacing: 0.4 },
  title: { fontSize: 30, lineHeight: 34, fontWeight: '900' },
  subtitle: { fontSize: 14, lineHeight: 20 },
  content: { gap: 14, paddingBottom: 12 },
  illustration: { height: 230, borderRadius: 28, borderWidth: 1, justifyContent: 'center', overflow: 'hidden' },
  illustrationImage: { borderRadius: 28 },
  illustrationOverlay: { ...StyleSheet.absoluteFillObject },
  phone: { width: 178, minHeight: 156, borderRadius: 26, borderWidth: 1, padding: 12, gap: 10, marginLeft: 16 },
  phoneHeader: { height: 58, borderRadius: 18, justifyContent: 'flex-end', padding: 10 },
  phoneTitle: { fontSize: 13, fontWeight: '800' },
  phoneRows: { gap: 8 },
  phoneRowLong: { height: 8, borderRadius: 999 },
  phoneRowShort: { width: '66%', height: 8, borderRadius: 999 },
  healthButtonPreview: { height: 34, borderRadius: 14, borderWidth: 1, flexDirection: 'row', alignItems: 'center', justifyContent: 'center', gap: 5 },
  healthButtonText: { fontSize: 10, fontWeight: '800' },
  scanCard: { position: 'absolute', right: 16, bottom: 20, width: 136, borderRadius: 20, borderWidth: 1, padding: 14, gap: 7 },
  scanScore: { fontSize: 25, lineHeight: 29, fontWeight: '900' },
  scanLabel: { fontSize: 11, fontWeight: '800', textTransform: 'uppercase' },
  scanLine: { height: 8, borderRadius: 999 },
  scanLineShort: { width: '68%', height: 8, borderRadius: 999 },
  flowCard: { borderRadius: 18, borderWidth: 1, padding: 14, gap: 10 },
  flowRow: { flexDirection: 'row', alignItems: 'center', gap: 10 },
  flowIndex: { width: 26, height: 26, borderRadius: 13, alignItems: 'center', justifyContent: 'center' },
  flowIndexText: { fontSize: 12, fontWeight: '900' },
  flowText: { flex: 1, fontSize: 14, fontWeight: '700' },
  outputCard: { borderRadius: 18, borderWidth: 1, padding: 16, gap: 11 },
  outputTitle: { fontSize: 15, fontWeight: '800' },
  outputRow: { flexDirection: 'row', alignItems: 'flex-start', gap: 9 },
  outputText: { flex: 1, fontSize: 13, lineHeight: 18 },
  guidanceCard: { borderRadius: 18, borderWidth: 1, padding: 14, flexDirection: 'row', alignItems: 'flex-start', gap: 10 },
  guidanceText: { flex: 1, fontSize: 12, lineHeight: 18, fontWeight: '600' },
  footer: { flexDirection: 'row', gap: 12, marginTop: 12 },
  secondaryBtn: { flex: 1, height: 52, borderRadius: 16, borderWidth: 1.5, alignItems: 'center', justifyContent: 'center' },
  secondaryBtnText: { fontSize: 15, fontWeight: '600' },
  primaryBtn: { flex: 1.3, height: 52, borderRadius: 16, alignItems: 'center', justifyContent: 'center' },
  primaryBtnText: { fontSize: 15, fontWeight: '700' },
});