import {
  ArrayPrototypePush,
  Error,
  ObjectSetPrototypeOf,
  TypeError,
} from "ext:core/primordials";

// Keep live initializers in the JS heap, but do not run them when building a snapshot.
let initializers = ObjectSetPrototypeOf([], null);

export function onRuntimeStart(callback) {
  if (initializers === undefined) throw new Error("Runtime already started");
  if (typeof callback !== "function") {
    throw new TypeError("Expected a runtime initializer");
  }
  ArrayPrototypePush(initializers, callback);
}

export function startRuntime() {
  if (initializers === undefined) throw new Error("Runtime already started");
  const pending = initializers;
  initializers = undefined;
  for (let i = 0; i < pending.length; i++) {
    const initialize = pending[i];
    if (initialize() !== undefined) {
      throw new TypeError("Runtime initializers must return undefined");
    }
  }
}