import type { Key } from "./index.js";

const codes = [
  "storage", "transport", "validation", "record", "blob", "discovery",
  "conflict", "resolution", "unconfirmed-write", "stale",
  "unsupported", "collection-not-loaded", "protocol",
  "binding", "initialization", "closed", "cancelled",
] as const;

export type FolioErrorCode = typeof codes[number];

/** Rust and host failures share these classifications at the JavaScript boundary. */
export interface FolioError extends Error {
  readonly name: "FolioError";
  readonly code: FolioErrorCode;
  readonly key?: Key;
}

export function isFolioError(value: unknown): value is FolioError {
  return value instanceof Error && value.name === "FolioError"
    && "code" in value && codes.some((code) => code === value.code);
}

export function failure(code: FolioErrorCode, cause: unknown): FolioError {
  if (code === "binding" && isFolioError(cause)) return cause;
  return Object.assign(new Error(cause instanceof Error ? cause.message : String(cause), { cause }), {
    name: "FolioError" as const, code,
  });
}