import type { DisplayUnit, UnitDim, UnitWeight } from "@/lib/frontend/types";
import {
  cmToIn,
  inToCm,
  kgToLb,
  lbToKg,
  toAxelWholeInches,
  toAxelWholePounds,
} from "@/modules/quote/unit-converter";

export function formatCargoInputNumber(value: number): string {
  if (!Number.isFinite(value)) {
    return "";
  }
  const rounded = Math.round(value * 100) / 100;
  return String(rounded);
}

export function parseCargoInputNumber(raw: string): number | null {
  const trimmed = raw.trim();
  if (!trimmed) {
    return null;
  }
  const value = Number(trimmed);
  return Number.isFinite(value) ? value : null;
}

/** 表单内单值重量换算（保持物理量不变） */
export function convertWeightInputValue(
  value: number,
  from: UnitWeight,
  to: UnitWeight,
): number {
  if (from === to) {
    return value;
  }
  const lb = from === "kg" ? kgToLb(value) : value;
  return to === "kg" ? lbToKg(lb) : lb;
}

/** 表单内尺寸换算（保持物理量不变） */
export function convertDimInputValue(
  value: number,
  from: UnitDim,
  to: UnitDim,
): number {
  if (from === to) {
    return value;
  }
  const inches = from === "cm" ? cmToIn(value) : value;
  return to === "cm" ? inToCm(inches) : inches;
}

export function displayUnitToCargoUnits(
  display: DisplayUnit,
): { weight: UnitWeight; dim: UnitDim } {
  return display === "metric"
    ? { weight: "kg", dim: "cm" }
    : { weight: "lb", dim: "in" };
}

/** 展示「询价将按 xxx lb」类提示（界面保留用户输入单位，后端向上取整） */
export function describeWeightEquivalent(
  value: number,
  unit: UnitWeight,
): string | null {
  if (!Number.isFinite(value) || value <= 0) {
    return null;
  }
  const rawLb = unit === "kg" ? kgToLb(value) : value;
  const queryLb = toAxelWholePounds(rawLb);
  if (unit === "kg") {
    return `询价将按 ${queryLb} lb（${formatCargoInputNumber(value)} kg 换算，小数进一）`;
  }
  if (queryLb !== rawLb) {
    return `询价将按 ${queryLb} lb（小数进一）`;
  }
  return null;
}

export function describeDimEquivalent(
  length: number,
  width: number,
  height: number,
  unit: UnitDim,
): string | null {
  if (
    !Number.isFinite(length) ||
    !Number.isFinite(width) ||
    !Number.isFinite(height) ||
    length <= 0 ||
    width <= 0 ||
    height <= 0
  ) {
    return null;
  }
  const toQueryIn = (v: number) =>
    toAxelWholeInches(unit === "cm" ? cmToIn(v) : v);
  const ql = toQueryIn(length);
  const qw = toQueryIn(width);
  const qh = toQueryIn(height);
  if (unit === "cm") {
    return `询价将按 ${ql} × ${qw} × ${qh} in（厘米换算，小数进一）`;
  }
  const rawL = length;
  const rawW = width;
  const rawH = height;
  if (ql !== rawL || qw !== rawW || qh !== rawH) {
    return `询价将按 ${ql} × ${qw} × ${qh} in（小数进一）`;
  }
  return null;
}