const VERSION_REGEX = /^\d+\.\d+\.\d+$/;

export function bumpVersion(current: string, command: "major" | "minor" | "patch" | "set", target?: string): string {
  validateVersion(current);
  const [major, minor, patch] = parseVersion(current);

  switch (command) {
    case "major":
      return formatVersion(major + 1, 0, 0);
    case "minor":
      return formatVersion(major, minor + 1, 0);
    case "patch":
      return formatVersion(major, minor, patch + 1);
    case "set": {
      if (!target) {
        throw new Error("set command requires a target version");
      }
      validateVersion(target);
      return target;
    }
  }
}

export function formatVersion(major: number, minor: number, patch: number): string {
  return `${major}.${minor}.${patch}`;
}

export function parseVersion(version: string): [number, number, number] {
  const parts = version.split(".").map((p) => parseInt(p, 10));
  if (parts.length !== 3 || parts.some(isNaN)) {
    throw new Error(`Invalid version format: ${version}`);
  }
  return [parts[0]!, parts[1]!, parts[2]!];
}

export function validateVersion(version: string): void {
  if (!VERSION_REGEX.test(version)) {
    throw new Error(`Invalid version format: ${version}. Expected MAJOR.MINOR.PATCH (e.g., 0.1.0)`);
  }
}