/**
 * Shared grouping for the versioned libraries (skills and agent profiles). Both pages show one card
 * per key with a version picker, and both must collapse a builtin that an org has forked at the same
 * version — the org's own copy shadows the builtin (it's the one that resolves at run time and the
 * one you can edit), keeping the picker unambiguous. Kept in one place so the two libraries can't drift.
 */
export interface VersionedItem {
  version: string
  origin: string
}

/** Group items by key, dedupe per version (org-owned shadows builtin), and sort keys alphabetically. */
export function groupVersions<T extends VersionedItem>(
  items: T[],
  keyOf: (item: T) => string,
): [string, T[]][] {
  const byKey = new Map<string, T[]>()
  for (const item of items) {
    const key = keyOf(item)
    const list = byKey.get(key) ?? []
    list.push(item)
    byKey.set(key, list)
  }

  for (const [key, list] of byKey) {
    const perVersion = new Map<string, T>()
    for (const item of list) {
      const existing = perVersion.get(item.version)
      if (!existing || (existing.origin === 'Builtin' && item.origin !== 'Builtin')) {
        perVersion.set(item.version, item)
      }
    }
    byKey.set(key, [...perVersion.values()])
  }

  return [...byKey.entries()].sort((a, b) => a[0].localeCompare(b[0]))
}