/**
 * MotherShip 结账选价 / FreightProtect 货值校验
 */

export type MsCoverageKind = "basic" | "freight_protect";

export type MsCheckoutSelection = {
  preferredCarrier: string;
  coverage: MsCoverageKind;
  cargoValueUsd?: number;
};

/** 返回中文错误；null = 通过 */
export function validateMsCheckoutSelection(
  input: MsCheckoutSelection,
): string | null {
  const carrier = input.preferredCarrier?.trim();
  if (!carrier) return "请选择承运商";
  if (carrier.length > 128) return "承运商名称过长";
  if (input.coverage !== "basic" && input.coverage !== "freight_protect") {
    return "保障方案无效";
  }
  if (input.coverage === "freight_protect") {
    const v = Number(input.cargoValueUsd);
    if (!Number.isFinite(v) || v <= 0) {
      return "选择 FreightProtect 时请填写大于 0 的货物价值（美元）";
    }
    if (v > 1_000_000) {
      return "货物价值超出允许范围";
    }
  }
  return null;
}

/** 输入框清洗：允许美元小数（最多两位），并兼容输入过程中的尾随小数点 */
export function sanitizeCargoValueUsdInput(raw: string): string {
  let cleaned = raw.replace(/[$,\s]/g, "").replace(/[^\d.]/g, "");
  const firstDot = cleaned.indexOf(".");
  if (firstDot >= 0) {
    cleaned =
      cleaned.slice(0, firstDot + 1) +
      cleaned.slice(firstDot + 1).replace(/\./g, "");
  }
  const m = cleaned.match(/^(\d*)(\.?)(\d{0,2})/);
  if (!m) return "";
  return `${m[1] ?? ""}${m[2] ?? ""}${m[3] ?? ""}`;
}

/** 解析货值（美元）；支持小数，四舍五入到分 */
export function parseCargoValueUsd(raw: string): number | null {
  const cleaned = raw.replace(/[$,\s]/g, "").trim();
  if (!cleaned || cleaned === ".") return null;
  const n = Number(cleaned);
  if (!Number.isFinite(n) || n <= 0) return null;
  const cents = Math.round(n * 100) / 100;
  if (!Number.isFinite(cents) || cents <= 0) return null;
  return cents;
}