import { randomBytes, createHash } from "node:crypto";

const ALPHABET = "0123456789abcdefghijkmnpqrstuvwxyz"; // no l/o to avoid confusion

export const ID_PREFIXES = {
  facility: "fac",
  campus: "cmp",
  operator: "op",
  cloud_region: "cr",
  metro: "met",
  ixp: "ix",
  project: "prj",
  event: "evt",
  document: "doc",
  source: "src",
  news: "nws",
  run: "run",
  match: "mtc",
  provenance: "prv",
  ranking: "rnk",
  claim: "clm",
  flag: "flg",
  constraint: "grd",
  watch: "wtc",
  cluster: "cls",
} as const;
export type IdKind = keyof typeof ID_PREFIXES;

export function newId(kind: IdKind, len = 12): string {
  const bytes = randomBytes(len);
  let out = "";
  for (let i = 0; i < len; i++) out += ALPHABET[bytes[i]! % ALPHABET.length];
  return `${ID_PREFIXES[kind]}_${out}`;
}

/** Deterministic id from a stable key (used for documents/provenance so re-runs are idempotent). */
export function stableId(kind: IdKind, key: string, len = 16): string {
  const h = createHash("sha256").update(key).digest("hex").slice(0, len);
  return `${ID_PREFIXES[kind]}_${h}`;
}

export function kindOfId(id: string): IdKind | null {
  const p = id.split("_")[0];
  for (const [k, v] of Object.entries(ID_PREFIXES)) if (v === p) return k as IdKind;
  return null;
}