import { useEffect, useState } from 'react';
import {
  ActivityIndicator,
  ScrollView,
  Text,
  TextInput,
  TouchableOpacity,
  View,
} from 'react-native';
import { Image } from 'expo-image';
import { Ionicons } from '@expo/vector-icons';
import { useTranslation } from 'react-i18next';
import {
  isValidDomain,
  normalizeDomain,
  type AddDomainResult,
  type Tier,
} from '../../hooks/useCustomDomains';
import { useColors, type ColorScheme } from '../../lib/theme';
import { FormSheet } from '../FormSheet';

type Props = {
  visible: boolean;
  tier: Tier;
  onClose: () => void;
  onAdd: (
    pattern: string,
    kind?: 'web' | 'mail',
    opts?: { addToVip?: boolean },
  ) => Promise<AddDomainResult>;
};

function detectKind(input: string): 'web' | 'mail' | null {
  const raw = input.trim();
  if (!raw) return null;
  if (raw.includes('@')) return 'mail';
  if (raw.includes('.')) return 'web';
  return null;
}

function mailDomain(input: string): string {
  const raw = input.trim();
  const atIdx = raw.lastIndexOf('@');
  if (atIdx === -1) return raw.toLowerCase();
  return raw.slice(atIdx + 1).trim().toLowerCase();
}

export function AddDomainSheet({ visible, tier, onClose, onAdd }: Props) {
  const { t } = useTranslation();
  const colors = useColors();
  const [input, setInput] = useState('');
  const [confirmPermanent, setConfirmPermanent] = useState(false);
  const [adding, setAdding] = useState(false);
  const [error, setError] = useState<string | null>(null);
  // User-Override über den Auto-Detect. null = follow auto-detect, sonst forced.
  const [kindOverride, setKindOverride] = useState<'web' | 'mail' | null>(null);
  // Fall 3: Domain ist in Layer 1, aber nicht in der kuratierten VIP. Hält die
  // Domain fest, für die der User entscheiden soll, ob er sie zur VIP nimmt.
  const [vipPrompt, setVipPrompt] = useState<string | null>(null);

  const detected = detectKind(input);
  const kind: 'web' | 'mail' | null = kindOverride ?? detected;
  const normalizedWeb = kind === 'web' ? normalizeDomain(input) : '';
  const normalizedMail = kind === 'mail' ? mailDomain(input) : '';
  const inVipMode = vipPrompt !== null;

  // Reset override sobald User komplett neuen Input tippt
  useEffect(() => {
    if (!input) setKindOverride(null);
  }, [input]);

  function close() {
    setInput('');
    setKindOverride(null);
    setConfirmPermanent(false);
    setError(null);
    setVipPrompt(null);
    onClose();
  }

  function isInputValid(): boolean {
    if (kind === 'web') return isValidDomain(input);
    if (kind === 'mail') return normalizedMail.length > 0;
    return false;
  }

  async function handleAdd() {
    if (!isInputValid() || !confirmPermanent || adding) return;
    setAdding(true);
    setError(null);
    const pattern = kind === 'web' ? normalizeDomain(input) : normalizedMail;
    // Pass kind explicitly — we've already stripped the local-part for mail,
    // so the backend's auto-detect (which keys on the "@" character) can no
    // longer infer the type from the pattern alone.
    const result = await onAdd(pattern, kind === 'mail' ? 'mail' : 'web');
    setAdding(false);
    if (result.ok) {
      close();
      return;
    }
    // Fall 3: in Layer 1, nicht in kuratierter VIP → User entscheidet
    if (result.inGlobalNotVip) {
      setVipPrompt(pattern);
      return;
    }
    // Fall 2: schon voll geschützt (Layer 1 + kuratierte VIP)
    if (result.alreadyProtected) {
      setError(t('blocker.add_sheet_already_protected', { domain: pattern }));
      return;
    }
    if (result.alreadyGlobal) {
      setError(t('blocker.add_sheet_already_global', { domain: pattern }));
      return;
    }
    const raw = (result.error ?? '').toLowerCase();
    if (raw.includes('public_domain')) {
      setError(t('blocker.error_public_domain'));
    } else if (raw.includes('limit_reached')) {
      setError(t('blocker.error_limit_reached'));
    } else if (raw.includes('invalid_mail_domain') || raw.includes('display_name_not_supported')) {
      setError(t('blocker.error_invalid_mail'));
    } else if (raw.includes('invalid_domain') || raw.includes('invalid_pattern')) {
      setError(t('blocker.error_invalid_input'));
    } else if (raw.includes('eintrag bereits vorhanden') || raw.includes('duplicate')) {
      setError(t('blocker.error_duplicate'));
    } else {
      setError(t('blocker.add_sheet_add_failed'));
    }
  }

  // Fall 3 bestätigt: Domain als VIP-Zweitschutz aufnehmen (Backend speichert
  // sie als 'approved' — kein Slot, erscheint nur in der VIP-Liste).
  async function handleConfirmVip() {
    if (!vipPrompt || adding) return;
    setAdding(true);
    setError(null);
    const result = await onAdd(vipPrompt, 'web', { addToVip: true });
    setAdding(false);
    if (result.ok) {
      close();
      return;
    }
    setVipPrompt(null);
    setError(t('blocker.add_sheet_add_failed'));
  }

  const warningText =
    tier.plan === 'free'
      ? t('blocker.add_sheet_warning_free')
      : t('blocker.add_sheet_warning_pro');

  const canSubmitNormal = isInputValid() && confirmPermanent && !adding;
  const ctaEnabled = inVipMode ? !adding : canSubmitNormal;
  const ctaColor = inVipMode
    ? colors.brandOrange
    : canSubmitNormal
      ? '#dc2626'
      : '#d4d4d4';

  return (
    <FormSheet
      visible={visible}
      onClose={close}
      title={t('blocker.add_sheet_title')}
      initialHeightPct={0.78}
      growWithKeyboard
    >
      <ScrollView
        keyboardShouldPersistTaps="handled"
        showsVerticalScrollIndicator={false}
        contentContainerStyle={{ padding: 16, gap: 12 }}
      >
        {/* Input field */}
        <View style={{ gap: 6 }}>
          <Text style={{ fontSize: 13, fontFamily: 'Nunito_600SemiBold', color: colors.text }}>
            {t('blocker.add_sheet_label')}
          </Text>
          <TextInput
            value={input}
            onChangeText={(v) => {
              setInput(v);
              setError(null);
              setVipPrompt(null);
            }}
            editable={!inVipMode}
            placeholder={t('blocker.add_sheet_placeholder')}
            placeholderTextColor={colors.textMuted}
            keyboardType="email-address"
            autoCapitalize="none"
            autoCorrect={false}
            style={{
              backgroundColor: colors.surfaceElevated,
              borderRadius: 10,
              padding: 12,
              fontSize: 14,
              fontFamily: 'Nunito_400Regular',
              color: colors.text,
              borderWidth: 1,
              borderColor: error ? '#dc2626' : colors.border,
              opacity: inVipMode ? 0.6 : 1,
            }}
          />
          {error && (
            <Text style={{ fontSize: 12, fontFamily: 'Nunito_400Regular', color: '#dc2626' }}>
              {error}
            </Text>
          )}
        </View>

        {inVipMode ? (
          /* Fall 3: Erklärungs-Karte — Domain ist in Layer 1, kann zusätzlich
             in den VIP-Zweitschutz aufgenommen werden. */
          <View
            style={{
              flexDirection: 'row',
              gap: 10,
              padding: 12,
              backgroundColor: '#eff6ff',
              borderRadius: 12,
              borderWidth: 1,
              borderColor: '#bfdbfe',
            }}
          >
            <Ionicons name="shield-half" size={18} color="#2563eb" style={{ marginTop: 1 }} />
            <Text
              style={{
                flex: 1,
                fontSize: 12,
                fontFamily: 'Nunito_400Regular',
                color: '#1e3a8a',
                lineHeight: 17,
              }}
            >
              {t('blocker.add_sheet_in_global_not_vip', { domain: vipPrompt ?? '' })}
            </Text>
          </View>
        ) : (
          <>
            {/* Help text */}
            <View
              style={{
                flexDirection: 'row',
                gap: 8,
                padding: 12,
                backgroundColor: colors.surfaceElevated,
                borderRadius: 12,
              }}
            >
              <Ionicons
                name="information-circle-outline"
                size={16}
                color={colors.textMuted}
                style={{ marginTop: 1 }}
              />
              <Text
                style={{
                  flex: 1,
                  fontSize: 12,
                  fontFamily: 'Nunito_400Regular',
                  color: colors.textMuted,
                  lineHeight: 17,
                }}
              >
                {t('blocker.add_sheet_help')}
              </Text>
            </View>

            {/* Preview card — only when user has typed something */}
            {input.trim().length > 0 && (
              <PreviewCard
                kind={kind}
                normalizedWeb={normalizedWeb}
                normalizedMail={normalizedMail}
                placeholder={t('blocker.add_sheet_placeholder')}
                colors={colors}
                t={t}
              />
            )}

            {/* Override toggle — User kann Auto-Detect korrigieren falls falsch erkannt */}
            {detected !== null && (
              <TouchableOpacity
                onPress={() => setKindOverride(kind === 'mail' ? 'web' : 'mail')}
                activeOpacity={0.7}
                style={{
                  flexDirection: 'row',
                  alignItems: 'center',
                  gap: 10,
                  paddingHorizontal: 12,
                  paddingVertical: 10,
                  borderRadius: 12,
                  borderWidth: 1,
                  borderColor: colors.border,
                  backgroundColor: colors.surface,
                }}
              >
                <Ionicons
                  name={kind === 'mail' ? 'checkbox' : 'square-outline'}
                  size={20}
                  color={kind === 'mail' ? colors.brandOrange : colors.textMuted}
                />
                <Text
                  style={{
                    flex: 1,
                    fontSize: 13,
                    fontFamily: 'Nunito_600SemiBold',
                    color: colors.text,
                  }}
                >
                  {t('blocker.kind_override_label')}
                </Text>
              </TouchableOpacity>
            )}

            {/* Warning card */}
            <View
              style={{
                flexDirection: 'row',
                gap: 10,
                padding: 12,
                backgroundColor: '#fef3c7',
                borderRadius: 12,
                borderWidth: 1,
                borderColor: '#fcd34d',
              }}
            >
              <Ionicons name="lock-closed" size={18} color="#92400e" style={{ marginTop: 1 }} />
              <Text
                style={{
                  flex: 1,
                  fontSize: 12,
                  fontFamily: 'Nunito_400Regular',
                  color: '#92400e',
                  lineHeight: 17,
                }}
              >
                {warningText}
              </Text>
            </View>

            {/* Confirm checkbox */}
            <TouchableOpacity
              onPress={() => setConfirmPermanent((v) => !v)}
              activeOpacity={0.7}
              style={{
                flexDirection: 'row',
                alignItems: 'flex-start',
                gap: 10,
                paddingVertical: 4,
              }}
            >
              <View
                style={{
                  width: 22,
                  height: 22,
                  borderRadius: 6,
                  borderWidth: 1.5,
                  borderColor: confirmPermanent ? colors.success : colors.border,
                  backgroundColor: confirmPermanent ? colors.success : colors.bg,
                  alignItems: 'center',
                  justifyContent: 'center',
                  marginTop: 1,
                }}
              >
                {confirmPermanent && <Ionicons name="checkmark" size={16} color="#fff" />}
              </View>
              <Text
                style={{
                  flex: 1,
                  fontSize: 13,
                  fontFamily: 'Nunito_400Regular',
                  color: colors.text,
                  lineHeight: 18,
                }}
              >
                {t('blocker.add_sheet_confirm_permanent')}
              </Text>
            </TouchableOpacity>
          </>
        )}

        {/* Buttons */}
        <View style={{ flexDirection: 'row', gap: 10, marginTop: 4 }}>
          <TouchableOpacity onPress={close} activeOpacity={0.8} style={{ flex: 1 }}>
            <View
              style={{
                borderRadius: 14,
                paddingVertical: 14,
                alignItems: 'center',
                backgroundColor: colors.surfaceElevated,
                borderWidth: 1,
                borderColor: colors.border,
              }}
            >
              <Text style={{ fontSize: 15, fontFamily: 'Nunito_600SemiBold', color: colors.textMuted }}>
                {t('common.cancel')}
              </Text>
            </View>
          </TouchableOpacity>

          <TouchableOpacity
            onPress={inVipMode ? handleConfirmVip : handleAdd}
            disabled={!ctaEnabled}
            activeOpacity={0.85}
            style={{ flex: 2 }}
          >
            <View
              style={{
                backgroundColor: ctaColor,
                borderRadius: 14,
                paddingVertical: 14,
                alignItems: 'center',
              }}
            >
              {adding ? (
                <ActivityIndicator color="#fff" />
              ) : (
                <Text style={{ fontSize: 15, fontFamily: 'Nunito_700Bold', color: '#fff' }}>
                  {inVipMode
                    ? t('blocker.add_sheet_add_to_vip_cta')
                    : t('blocker.add_sheet_cta')}
                </Text>
              )}
            </View>
          </TouchableOpacity>
        </View>
      </ScrollView>
    </FormSheet>
  );
}

// ─── PreviewCard ──────────────────────────────────────────────────────────────

function PreviewCard({
  kind,
  normalizedWeb,
  normalizedMail,
  placeholder,
  colors,
  t,
}: {
  kind: 'web' | 'mail' | null;
  normalizedWeb: string;
  normalizedMail: string;
  placeholder: string;
  colors: ColorScheme;
  t: (key: string, opts?: Record<string, unknown>) => string;
}) {
  if (kind === 'web') {
    return (
      <View
        style={{
          flexDirection: 'row',
          alignItems: 'center',
          gap: 10,
          padding: 12,
          backgroundColor: colors.surfaceElevated,
          borderRadius: 12,
        }}
      >
        <Image
          source={{ uri: `https://www.google.com/s2/favicons?domain=${normalizedWeb || 'example.com'}&sz=64` }}
          style={{ width: 24, height: 24, borderRadius: 4 }}
        />
        <View style={{ flex: 1 }}>
          <Text style={{ fontSize: 11, fontFamily: 'Nunito_400Regular', color: colors.textMuted }}>
            {t('blocker.preview_web', { value: normalizedWeb || '…' })}
          </Text>
        </View>
        <Ionicons name="globe-outline" size={16} color={colors.textMuted} />
      </View>
    );
  }

  if (kind === 'mail') {
    return (
      <View
        style={{
          flexDirection: 'row',
          alignItems: 'center',
          gap: 10,
          padding: 12,
          backgroundColor: colors.surfaceElevated,
          borderRadius: 12,
        }}
      >
        <View
          style={{
            width: 24,
            height: 24,
            borderRadius: 4,
            backgroundColor: '#dbeafe',
            alignItems: 'center',
            justifyContent: 'center',
          }}
        >
          <Ionicons name="mail-outline" size={14} color="#2563eb" />
        </View>
        <View style={{ flex: 1 }}>
          <Text style={{ fontSize: 11, fontFamily: 'Nunito_400Regular', color: colors.textMuted }}>
            {t('blocker.preview_mail', { value: normalizedMail || '…' })}
          </Text>
        </View>
        <Ionicons name="mail-outline" size={16} color={colors.textMuted} />
      </View>
    );
  }

  return (
    <View
      style={{
        flexDirection: 'row',
        alignItems: 'center',
        gap: 10,
        padding: 12,
        backgroundColor: colors.surfaceElevated,
        borderRadius: 12,
      }}
    >
      <Ionicons name="warning-outline" size={20} color="#dc2626" />
      <Text style={{ flex: 1, fontSize: 11, fontFamily: 'Nunito_400Regular', color: '#dc2626' }}>
        {t('blocker.preview_invalid')}
      </Text>
    </View>
  );
}