import { useEffect, useMemo, useRef, useState } from 'react';
import {
  View,
  Text,
  Pressable,
  TextInput,
  Modal,
  LayoutAnimation,
  Platform,
  UIManager,
  ScrollView,
} from 'react-native';
import { Ionicons } from '@expo/vector-icons';
import { colors } from '../../lib/theme';
import type { Plan } from '../../hooks/useUserPlan';

if (Platform.OS === 'android' && UIManager.setLayoutAnimationEnabledExperimental) {
  UIManager.setLayoutAnimationEnabledExperimental(true);
}

export type Demographics = {
  birthYear: number | null;
  gender: string | null;
  maritalStatus: string | null;
  profession: string | null;
  bundesland: string | null;
  city: string | null;
};

type Props = {
  demographics: Demographics;
  plan: Plan;
  defaultExpanded?: boolean;
  onChange?: (next: Demographics) => void;
  onRevokeConsent?: () => void;
};

// Select-Optionen — Display-Label DE, value für DB-Persistenz
const GENDER_OPTIONS: Array<{ label: string; value: string }> = [
  { label: 'männlich', value: 'male' },
  { label: 'weiblich', value: 'female' },
  { label: 'divers', value: 'diverse' },
  { label: 'keine Angabe', value: 'none' },
];

const MARITAL_OPTIONS: Array<{ label: string; value: string }> = [
  { label: 'ledig', value: 'single' },
  { label: 'Partnerschaft', value: 'partnership' },
  { label: 'verheiratet', value: 'married' },
  { label: 'geschieden', value: 'divorced' },
  { label: 'verwitwet', value: 'widowed' },
  { label: 'keine Angabe', value: 'none' },
];

// ISO-3166-2:DE — value=ISO, label=DE-Display
const BUNDESLAND_OPTIONS: Array<{ label: string; value: string }> = [
  { label: 'Baden-Württemberg', value: 'BW' },
  { label: 'Bayern', value: 'BY' },
  { label: 'Berlin', value: 'BE' },
  { label: 'Brandenburg', value: 'BB' },
  { label: 'Bremen', value: 'HB' },
  { label: 'Hamburg', value: 'HH' },
  { label: 'Hessen', value: 'HE' },
  { label: 'Mecklenburg-Vorpommern', value: 'MV' },
  { label: 'Niedersachsen', value: 'NI' },
  { label: 'Nordrhein-Westfalen', value: 'NW' },
  { label: 'Rheinland-Pfalz', value: 'RP' },
  { label: 'Saarland', value: 'SL' },
  { label: 'Sachsen', value: 'SN' },
  { label: 'Sachsen-Anhalt', value: 'ST' },
  { label: 'Schleswig-Holstein', value: 'SH' },
  { label: 'Thüringen', value: 'TH' },
];

const FIELD_WHY: Record<keyof Demographics, string> = {
  birthYear:
    'Lyra spricht dich altersgerecht an, DiGA-Berichte erkennen Risiko nach Altersgruppe.',
  gender: 'Glücksspiel-Muster unterscheiden sich; Lyra coacht gendersensibel.',
  profession:
    'Schichtarbeit, Banking-Stress, Selbstständigkeit haben verschiedene Trigger — Lyra kennt deinen Kontext.',
  maritalStatus:
    'Trennung/Beziehungs-Konflikte sind klassische Trigger — Lyra erkennt sie früher in dir.',
  bundesland: 'Lokale Beratungsstellen + anonyme DiGA-Studien.',
  city: 'Lokale Beratungsstellen + anonyme DiGA-Studien.',
};

function lookupLabel(options: Array<{ label: string; value: string }>, v: string | null) {
  if (!v) return null;
  return options.find((o) => o.value === v)?.label ?? v;
}

function isComplete(d: Demographics) {
  return (
    d.birthYear !== null &&
    !!d.gender &&
    !!d.maritalStatus &&
    !!d.profession &&
    !!d.bundesland &&
    !!d.city
  );
}

// TODO Phase C: PATCH /api/profile/me/demographics — debounced auto-save (~500ms idle).
// Bis Endpoint live: lokaler State + onChange-Callback Richtung Parent.
function mockPersist(_next: Demographics) {
  // no-op placeholder — Parent ruft echten Endpoint
}

export function DemographicsAccordion({
  demographics,
  plan,
  defaultExpanded = false,
  onChange,
  onRevokeConsent,
}: Props) {
  const [expanded, setExpanded] = useState(defaultExpanded);
  const [local, setLocal] = useState<Demographics>(demographics);

  // Select-Sheet-State
  const [pickerField, setPickerField] = useState<keyof Demographics | null>(null);

  // Debounce-Save Ref
  const saveTimer = useRef<ReturnType<typeof setTimeout> | null>(null);

  useEffect(() => {
    setLocal(demographics);
  }, [demographics]);

  function toggle() {
    LayoutAnimation.configureNext(LayoutAnimation.Presets.easeInEaseOut);
    setExpanded((v) => !v);
  }

  function persist(next: Demographics) {
    setLocal(next);
    if (saveTimer.current) clearTimeout(saveTimer.current);
    saveTimer.current = setTimeout(() => {
      mockPersist(next);
      onChange?.(next);
    }, 500);
  }

  function flushSave(next: Demographics) {
    if (saveTimer.current) clearTimeout(saveTimer.current);
    mockPersist(next);
    onChange?.(next);
    setLocal(next);
  }

  const completed = isComplete(local);
  const showProTrialBanner = plan === 'free' && completed;

  return (
    <View style={{ marginHorizontal: 16, marginTop: 24 }}>
      {/* Privacy-Header */}
      <Pressable
        onPress={toggle}
        style={({ pressed }) => ({
          opacity: pressed ? 0.7 : 1,
          backgroundColor: '#ffffff',
          borderWidth: 1,
          borderColor: '#e5e5e5',
          borderRadius: 14,
          padding: 16,
        })}
      >
        <View
          style={{
            flexDirection: 'row',
            alignItems: 'center',
            justifyContent: 'space-between',
          }}
        >
          <View style={{ flex: 1 }}>
            <Text
              style={{
                fontSize: 11,
                color: colors.textMuted,
                fontFamily: 'Nunito_700Bold',
                letterSpacing: 0.8,
              }}
            >
              ANONYMER BEITRAG ZUR FORSCHUNG
            </Text>
            <Text
              style={{
                marginTop: 6,
                fontSize: 13,
                color: colors.text,
                fontFamily: 'Nunito_600SemiBold',
              }}
            >
              Optional. Niemals mit Name oder Email verknüpft. Jederzeit löschbar.
            </Text>
          </View>
          <Ionicons
            name={expanded ? 'chevron-up' : 'chevron-down'}
            size={18}
            color={colors.textMuted}
          />
        </View>
      </Pressable>

      {expanded ? (
        <View
          style={{
            marginTop: 8,
            backgroundColor: '#ffffff',
            borderWidth: 1,
            borderColor: '#e5e5e5',
            borderRadius: 14,
            paddingVertical: 4,
          }}
        >
          {/* Pro-Trial-Reward-Banner — nur free + (idealerweise) nicht-vollständig.
              Wir zeigen ihn aber auch im "completed"-State als sanfte Bestätigung,
              tatsächliche Trial-Vergabe ist Backend-Sache (Phase C). */}
          {plan === 'free' ? (
            <View
              style={{
                marginHorizontal: 8,
                marginVertical: 8,
                backgroundColor: '#fff7ed',
                borderColor: '#fed7aa',
                borderWidth: 1,
                borderRadius: 12,
                padding: 12,
                flexDirection: 'row',
                gap: 10,
                alignItems: 'flex-start',
              }}
            >
              <Ionicons name="gift-outline" size={18} color="#c2410c" style={{ marginTop: 1 }} />
              <View style={{ flex: 1 }}>
                <Text
                  style={{
                    fontSize: 13,
                    color: '#7c2d12',
                    fontFamily: 'Nunito_700Bold',
                  }}
                >
                  {showProTrialBanner
                    ? 'Du bekommst 1 Woche Pro geschenkt'
                    : 'Vervollständige dein Profil — 1 Woche Pro geschenkt'}
                </Text>
                <Text
                  style={{
                    marginTop: 4,
                    fontSize: 11,
                    color: '#9a3412',
                    fontFamily: 'Nunito_400Regular',
                    lineHeight: 15,
                  }}
                >
                  Mit deinen anonymen Daten machen wir rebreak zur ersten DiGA-zertifizierten
                  Spielsucht-App. Als Dankeschön: 1 Woche Pro.
                </Text>
              </View>
            </View>
          ) : null}

          {/* Birth Year — Number-Input */}
          <FieldRow
            label="Geburtsjahr"
            why={FIELD_WHY.birthYear}
          >
            <TextInput
              value={local.birthYear !== null ? String(local.birthYear) : ''}
              onChangeText={(raw) => {
                const cleaned = raw.replace(/[^0-9]/g, '').slice(0, 4);
                if (cleaned === '') {
                  persist({ ...local, birthYear: null });
                  return;
                }
                const n = parseInt(cleaned, 10);
                // Erlaube tippen — Validierung beim Blur
                persist({ ...local, birthYear: Number.isNaN(n) ? null : n });
              }}
              onBlur={() => {
                const n = local.birthYear;
                if (n !== null && (n < 1920 || n > 2010)) {
                  // ungültig — auf null zurücksetzen
                  flushSave({ ...local, birthYear: null });
                }
              }}
              keyboardType="number-pad"
              maxLength={4}
              placeholder="z.B. 1989"
              placeholderTextColor={colors.textMuted}
              style={inputStyle}
            />
          </FieldRow>

          {/* Gender — Select */}
          <FieldRow label="Geschlecht" why={FIELD_WHY.gender}>
            <SelectButton
              value={lookupLabel(GENDER_OPTIONS, local.gender)}
              onPress={() => setPickerField('gender')}
            />
          </FieldRow>

          {/* Profession — TextInput */}
          <FieldRow label="Beruf" why={FIELD_WHY.profession}>
            <TextInput
              value={local.profession ?? ''}
              onChangeText={(t) => persist({ ...local, profession: t })}
              onBlur={() => {
                const trimmed = (local.profession ?? '').trim();
                flushSave({ ...local, profession: trimmed === '' ? null : trimmed });
              }}
              maxLength={80}
              placeholder="z.B. Pflege, IT, Schichtarbeit"
              placeholderTextColor={colors.textMuted}
              style={inputStyle}
            />
          </FieldRow>

          {/* Marital — Select */}
          <FieldRow label="Familienstand" why={FIELD_WHY.maritalStatus}>
            <SelectButton
              value={lookupLabel(MARITAL_OPTIONS, local.maritalStatus)}
              onPress={() => setPickerField('maritalStatus')}
            />
          </FieldRow>

          {/* Bundesland — Select */}
          <FieldRow label="Bundesland" why={FIELD_WHY.bundesland}>
            <SelectButton
              value={lookupLabel(BUNDESLAND_OPTIONS, local.bundesland)}
              onPress={() => setPickerField('bundesland')}
            />
          </FieldRow>

          {/* City — TextInput */}
          <FieldRow label="Stadt" why={FIELD_WHY.city} isLast>
            <TextInput
              value={local.city ?? ''}
              onChangeText={(t) => persist({ ...local, city: t })}
              onBlur={() => {
                const trimmed = (local.city ?? '').trim();
                flushSave({ ...local, city: trimmed === '' ? null : trimmed });
              }}
              maxLength={60}
              placeholder="z.B. München"
              placeholderTextColor={colors.textMuted}
              style={inputStyle}
            />
          </FieldRow>

          {/* Revoke Consent */}
          <Pressable
            onPress={onRevokeConsent}
            style={({ pressed }) => ({
              opacity: pressed ? 0.7 : 1,
              marginTop: 4,
              paddingHorizontal: 14,
              paddingVertical: 12,
              borderTopWidth: 1,
              borderTopColor: 'rgba(0,0,0,0.06)',
            })}
          >
            <Text
              style={{
                fontSize: 12,
                color: colors.error,
                fontFamily: 'Nunito_600SemiBold',
                textAlign: 'center',
              }}
            >
              Einwilligung widerrufen
            </Text>
          </Pressable>
        </View>
      ) : null}

      <SelectSheet
        visible={pickerField === 'gender'}
        title="Geschlecht"
        options={GENDER_OPTIONS}
        selectedValue={local.gender}
        onClose={() => setPickerField(null)}
        onSelect={(v) => {
          flushSave({ ...local, gender: v });
          setPickerField(null);
        }}
      />
      <SelectSheet
        visible={pickerField === 'maritalStatus'}
        title="Familienstand"
        options={MARITAL_OPTIONS}
        selectedValue={local.maritalStatus}
        onClose={() => setPickerField(null)}
        onSelect={(v) => {
          flushSave({ ...local, maritalStatus: v });
          setPickerField(null);
        }}
      />
      <SelectSheet
        visible={pickerField === 'bundesland'}
        title="Bundesland"
        options={BUNDESLAND_OPTIONS}
        selectedValue={local.bundesland}
        onClose={() => setPickerField(null)}
        onSelect={(v) => {
          flushSave({ ...local, bundesland: v });
          setPickerField(null);
        }}
      />
    </View>
  );
}

const inputStyle = {
  fontSize: 14,
  color: colors.text,
  fontFamily: 'Nunito_600SemiBold',
  paddingVertical: 8,
  paddingHorizontal: 10,
  backgroundColor: '#fafafa',
  borderRadius: 8,
  borderWidth: 1,
  borderColor: '#ececec',
  minWidth: 140,
  textAlign: 'right' as const,
};

function FieldRow({
  label,
  why,
  isLast,
  children,
}: {
  label: string;
  why: string;
  isLast?: boolean;
  children: React.ReactNode;
}) {
  return (
    <View
      style={{
        paddingHorizontal: 14,
        paddingVertical: 12,
        borderBottomWidth: isLast ? 0 : 1,
        borderBottomColor: 'rgba(0,0,0,0.06)',
      }}
    >
      <View
        style={{
          flexDirection: 'row',
          alignItems: 'center',
          justifyContent: 'space-between',
          gap: 12,
        }}
      >
        <Text
          style={{
            fontSize: 13,
            color: colors.text,
            fontFamily: 'Nunito_600SemiBold',
          }}
        >
          {label}
        </Text>
        <View style={{ flexShrink: 1 }}>{children}</View>
      </View>
      <Text
        style={{
          marginTop: 6,
          fontSize: 11,
          color: colors.textMuted,
          fontFamily: 'Nunito_400Regular',
          lineHeight: 15,
        }}
      >
        {why}
      </Text>
    </View>
  );
}

function SelectButton({ value, onPress }: { value: string | null; onPress: () => void }) {
  return (
    <Pressable
      onPress={onPress}
      style={({ pressed }) => ({
        opacity: pressed ? 0.6 : 1,
        flexDirection: 'row',
        alignItems: 'center',
        gap: 6,
        paddingVertical: 8,
        paddingHorizontal: 10,
        backgroundColor: '#fafafa',
        borderRadius: 8,
        borderWidth: 1,
        borderColor: '#ececec',
        minWidth: 140,
        justifyContent: 'flex-end',
      })}
    >
      <Text
        style={{
          fontSize: 14,
          color: value ? colors.text : colors.textMuted,
          fontFamily: value ? 'Nunito_600SemiBold' : 'Nunito_400Regular',
          textAlign: 'right',
        }}
      >
        {value ?? 'auswählen'}
      </Text>
      <Ionicons name="chevron-down" size={14} color={colors.textMuted} />
    </Pressable>
  );
}

function SelectSheet({
  visible,
  title,
  options,
  selectedValue,
  onClose,
  onSelect,
}: {
  visible: boolean;
  title: string;
  options: Array<{ label: string; value: string }>;
  selectedValue: string | null;
  onClose: () => void;
  onSelect: (v: string) => void;
}) {
  const sortedOptions = useMemo(() => options, [options]);

  return (
    <Modal
      visible={visible}
      transparent
      animationType="slide"
      onRequestClose={onClose}
    >
      <Pressable
        onPress={onClose}
        style={{
          flex: 1,
          backgroundColor: 'rgba(0,0,0,0.4)',
          justifyContent: 'flex-end',
        }}
      >
        <Pressable
          onPress={() => {
            /* swallow */
          }}
          style={{
            backgroundColor: '#ffffff',
            borderTopLeftRadius: 18,
            borderTopRightRadius: 18,
            paddingHorizontal: 8,
            paddingTop: 12,
            paddingBottom: 24,
            maxHeight: '70%',
          }}
        >
          <View
            style={{
              flexDirection: 'row',
              alignItems: 'center',
              justifyContent: 'space-between',
              paddingHorizontal: 12,
              paddingBottom: 8,
            }}
          >
            <Text
              style={{
                fontSize: 15,
                color: colors.text,
                fontFamily: 'Nunito_700Bold',
              }}
            >
              {title}
            </Text>
            <Pressable onPress={onClose} hitSlop={10}>
              <Ionicons name="close" size={22} color={colors.textMuted} />
            </Pressable>
          </View>
          <ScrollView style={{ maxHeight: 380 }}>
            {sortedOptions.map((opt) => {
              const isSelected = opt.value === selectedValue;
              return (
                <Pressable
                  key={opt.value}
                  onPress={() => onSelect(opt.value)}
                  style={({ pressed }) => ({
                    opacity: pressed ? 0.6 : 1,
                    flexDirection: 'row',
                    alignItems: 'center',
                    justifyContent: 'space-between',
                    paddingHorizontal: 14,
                    paddingVertical: 14,
                    borderRadius: 10,
                    backgroundColor: isSelected ? '#f5f8ff' : 'transparent',
                  })}
                >
                  <Text
                    style={{
                      fontSize: 14,
                      color: colors.text,
                      fontFamily: isSelected ? 'Nunito_700Bold' : 'Nunito_400Regular',
                    }}
                  >
                    {opt.label}
                  </Text>
                  {isSelected ? (
                    <Ionicons name="checkmark" size={18} color={colors.brandOrange} />
                  ) : null}
                </Pressable>
              );
            })}
          </ScrollView>
        </Pressable>
      </Pressable>
    </Modal>
  );
}