/**
 * Version comparison for plugin manifests. Versions are validated by the
 * manifest schema as `MAJOR.MINOR.PATCH`, so a numeric three-part compare is
 * exact — no pre-release/build metadata to reason about in v1. The install flow
 * (#71) uses this to accept an update only when the uploaded version is higher
 * than the installed one.
 */

/** Splits a validated `x.y.z` string into its three numeric parts. */
function parts(version: string): [number, number, number] {
  const [major = 0, minor = 0, patch = 0] = version.split('.').map((n) => Number.parseInt(n, 10));
  return [major, minor, patch];
}

/** Returns -1 if `a` < `b`, 1 if `a` > `b`, 0 if equal. */
export function compareVersions(a: string, b: string): -1 | 0 | 1 {
  const pa = parts(a);
  const pb = parts(b);
  for (let i = 0; i < 3; i += 1) {
    const left = pa[i] ?? 0;
    const right = pb[i] ?? 0;
    if (left < right) return -1;
    if (left > right) return 1;
  }
  return 0;
}

/** Whether `candidate` is a strictly higher version than `current`. */
export function isHigherVersion(candidate: string, current: string): boolean {
  return compareVersions(candidate, current) > 0;
}