/** 门店筛选用伪区县，禁止写入收货地址 */
export const PSEUDO_SHIPPING_DISTRICTS = ['全市', '全部'] as const;

export const SHIPPING_DETAIL_MIN_LEN = 8;

export const SHIPPING_REGION_REQUIRED_MSG = '请选择具体区县';
export const SHIPPING_DETAIL_REQUIRED_MSG = '请填写详细地址';
export const SHIPPING_DETAIL_TOO_SHORT_MSG = '请填写更详细的收货地址（含街道门牌）';

export type ShippingAddressFields = {
  province?: string | null;
  city?: string | null;
  district?: string | null;
  detail?: string | null;
};

export type ShippingAddressValidation = {
  ok: boolean;
  message?: string;
};

function trim(v: string | null | undefined): string {
  return String(v ?? '').trim();
}

export function isPseudoShippingDistrict(district: string | null | undefined): boolean {
  const d = trim(district);
  if (!d) return true;
  return (PSEUDO_SHIPPING_DISTRICTS as readonly string[]).includes(d);
}

/** 区县是否可作为收货地址（非空且非全市/全部） */
export function isConcreteShippingDistrict(district: string | null | undefined): boolean {
  return !isPseudoShippingDistrict(district);
}

/**
 * 校验收货省市区 + 详细地址。
 * - 现场取货等特殊值请勿调用本函数
 * - 不依赖完整省市区树；前端另做树内白名单
 */
export function validateShippingAddress(
  input: ShippingAddressFields,
  options?: { requireDetail?: boolean },
): ShippingAddressValidation {
  const province = trim(input.province);
  const city = trim(input.city);
  const district = trim(input.district);
  const detail = trim(input.detail);
  const requireDetail = options?.requireDetail !== false;

  if (!province || !city) {
    return { ok: false, message: '请选择所在地区' };
  }
  if (!isConcreteShippingDistrict(district)) {
    return { ok: false, message: SHIPPING_REGION_REQUIRED_MSG };
  }
  if (requireDetail) {
    if (!detail) {
      return { ok: false, message: SHIPPING_DETAIL_REQUIRED_MSG };
    }
    if (detail.length < SHIPPING_DETAIL_MIN_LEN) {
      return { ok: false, message: SHIPPING_DETAIL_TOO_SHORT_MSG };
    }
  }
  return { ok: true };
}

/** 详细地址含「全市」时的软提示（不单独作为硬失败条件） */
export function shippingDetailCityWideHint(detail: string | null | undefined): string | null {
  const d = trim(detail);
  if (!d.includes('全市')) return null;
  if (/路|街|巷|号|大厦|广场|小区|村|镇|乡/.test(d)) return null;
  return '详细地址含「全市」，建议改为具体街道门牌，以免配送拒单';
}