import { VersionParts } from './types';

export class Version {
  /**
   * comparators for version strings of the form
   * x.x.x[-beta.x]
   */

  static gte(a: string, b: string) {
    let valid = false;
    return compare(a, b, (c) => {
      if (c === 0) {
        return false;
      }

      valid ||= c > 0;
      return !valid;
    });
  }

  static lte(a: string, b: string) {
    return !Version.gt(a, b);
  }

  static eq(a: string, b: string) {
    return compare(a, b, (c) => c !== 0);
  }

  static gt(a: string, b: string) {
    return Version.gte(a, b) && !Version.eq(a, b);
  }

  static lt(a: string, b: string) {
    return Version.lte(a, b) && !Version.eq(a, b);
  }
}

const seq = ['major', 'minor', 'patch', 'beta'] as (keyof VersionParts)[];

function compare(a: string, b: string, isInvalid: (x: number) => boolean) {
  const partsA = parseVersionString(a);
  const partsB = parseVersionString(b);

  for (const p of seq) {
    const c = compareSingle(partsA, partsB, p);
    if (isInvalid(c)) {
      return false;
    }
  }

  return true;
}

function parseVersionString(a: string): VersionParts {
  const parts = a.split('-');
  const nonbeta = parts[0].split('.').map((n) => parseFloat(n));

  const versionParts: VersionParts = {
    major: nonbeta[0],
    minor: nonbeta[1],
    patch: nonbeta[2],
  };

  const beta = parseFloat(parts[1]?.split('.')?.[1]);
  if (!Number.isNaN(beta)) {
    versionParts.beta = beta;
  }

  if (Number.isNaN(beta) && parts[1]?.includes('beta')) {
    versionParts.beta = 0;
  }

  return versionParts;
}

function compareSingle(
  partsA: VersionParts,
  partsB: VersionParts,
  key: keyof VersionParts
): number {
  if (key !== 'beta') {
    return partsA[key] - partsB[key];
  }

  if (typeof partsA.beta === 'number' && typeof partsB.beta === 'number') {
    return partsA.beta - partsB.beta;
  }

  // A is not in beta
  if (partsA.beta === undefined && typeof partsB.beta === 'number') {
    return 1;
  }

  // B is not in beta
  if (typeof partsA.beta === 'number' && partsB.beta === undefined) {
    return -1;
  }

  // Both A and B are not in Beta
  return 0;
}