function normalizeCustomerKey(value) {
  return String(value || '')
    .replace(/[（]/g, '(')
    .replace(/[）]/g, ')')
    .replace(/[，,。.;；、\s]/g, '')
    .toLowerCase()
    .trim();
}

function customerDisplayName(value = {}, fallback = '') {
  return value.erpName || value.name || fallback;
}

function candidateFor(key, value, keyword) {
  return {
    key,
    id: String(value && value.id || ''),
    name: customerDisplayName(value, key),
    value,
    matchedBy: keyword,
  };
}

function matchesCustomer(candidateKey, customer, keyword) {
  const wanted = normalizeCustomerKey(keyword);
  const haystacks = [
    candidateKey,
    customer && customer.erpName,
    customer && customer.name,
    customer && customer.searchName,
  ].map(normalizeCustomerKey).filter(Boolean);
  return haystacks.some((value) => value === wanted || value.includes(wanted) || wanted.includes(value));
}

function resolveCustomerKeyword(map, keyword, kind = 'customer') {
  const source = map || {};
  const rawKeyword = String(keyword || '').trim();
  if (!rawKeyword) {
    return {
      status: 'not_found',
      reason: 'customer_keyword_empty',
      keyword: rawKeyword,
      candidates: [],
      customerMessage: `请补充${kind}关键词。`,
    };
  }
  if (source[rawKeyword]) {
    return {
      status: 'matched',
      reason: '',
      keyword: rawKeyword,
      key: rawKeyword,
      value: source[rawKeyword],
      candidates: [candidateFor(rawKeyword, source[rawKeyword], rawKeyword)],
    };
  }

  const matches = Object.entries(source)
    .filter(([key, value]) => matchesCustomer(key, value, rawKeyword))
    .map(([key, value]) => candidateFor(key, value, rawKeyword));

  if (matches.length === 1) {
    return {
      status: 'matched',
      reason: '',
      keyword: rawKeyword,
      key: matches[0].key,
      value: matches[0].value,
      candidates: matches,
    };
  }
  if (matches.length > 1) {
    return {
      status: 'ambiguous',
      reason: 'customer_keyword_ambiguous',
      keyword: rawKeyword,
      candidates: matches,
      customerMessage: `${kind}关键词“${rawKeyword}”匹配到多个客户，请确认：${matches.map((item) => item.name).join('、')}`,
    };
  }
  return {
    status: 'not_found',
    reason: 'customer_keyword_not_found',
    keyword: rawKeyword,
    candidates: [],
    customerMessage: `${kind}关键词“${rawKeyword}”没有匹配到 ERP 客户，请补充更完整名称。`,
  };
}

function resolveCustomerOrThrow(map, keyword, kind = 'customer', options = {}) {
  const result = resolveCustomerKeyword(map, keyword, kind);
  if (result.status === 'matched') return result.value;
  if (result.status === 'not_found' && options.allowPlainName) return {};
  const error = new Error(result.status === 'ambiguous'
    ? `customer keyword ambiguous for ${kind}: ${keyword}`
    : `customer keyword not found for ${kind}: ${keyword}`);
  error.code = result.reason;
  error.customerMessage = result.customerMessage;
  error.candidates = result.candidates;
  throw error;
}

module.exports = {
  normalizeCustomerKey,
  resolveCustomerKeyword,
  resolveCustomerOrThrow,
};