// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
import { ANY } from "./constants.ts";
import type { SemVer } from "./types.ts";

function formatNumber(value: number) {
  if (value === Number.POSITIVE_INFINITY) {
    return "∞";
  } else if (value === Number.NEGATIVE_INFINITY) {
    return "⧞";
  } else {
    return value.toFixed(0);
  }
}

/**
 * Format a SemVer object into a string.
 *
 * If any number is NaN then NaN will be printed.
 *
 * If any number is positive or negative infinity then '∞' or '⧞' will be printed instead.
 *
 * @param semver The semantic version to format
 * @returns The string representation of a semantic version.
 */
export function format(semver: SemVer): string {
  if (semver === ANY) {
    return "*";
  }

  const major = formatNumber(semver.major);
  const minor = formatNumber(semver.minor);
  const patch = formatNumber(semver.patch);
  const pre = semver.prerelease?.join(".") ?? "";
  const build = semver.build?.join(".") ?? "";

  const primary = `${major}.${minor}.${patch}`;
  const release = [primary, pre].filter((v) => v).join("-");
  return [release, build].filter((v) => v).join("+");
}