/** Application-facing Automerge heads. Head order is not significant. */
export type Heads = readonly string[]

/** Return a defensive, canonical copy for unordered-head comparisons. */
export function normalizeHeads(heads: Heads): string[] {
  return [...heads].sort()
}

export function headsEqual(a: Heads, b: Heads): boolean {
  const left = normalizeHeads(a)
  const right = normalizeHeads(b)
  return left.length === right.length && left.every((head, index) => head === right[index])
}

export function headsKey(heads: Heads): string {
  return JSON.stringify(normalizeHeads(heads))
}