import type { Request, Response } from "./http/types";
import type { Transport } from "@connectrpc/connect";
import type {TypedArray} from "@encore.dev/internal-runtime/compat/types";

/**
 * The runtime interface is used by this package to interact with the javascript runtime
 * we are running in.
 *
 * There are two implementations of this interface, one in `@encore.dev/bun-runtime` and one in
 * `@encore.dev/node-runtime`.
 */
export interface Runtime {
  /**
   * The name of the runtime
   */
  name: string;

  /**
   * Starts an HTTP server on the given port
   *
   * @param host The host to start the server on
   * @param port The port to start the server on
   * @param handler The handler to use for the server
   *
   * @returns The URL of the server
   */
  startHTTPServer(
    host: string,
    port: number,
    handler: (req: Request, res: Response) => void,
  ): URL;

  /**
   * Returns the value of the given environment variable
   *
   * @param {string} name
   * @returns {string | undefined}
   */
  env(name: string): string | undefined;

  /**
   * Creates a ConnectRPC transport for use by the sidecar-api package
   * @returns {Transport}
   */
  apiTransport(): Transport;

  /**
   * Writes the given object to stdout as a JSON line
   */
  objToStderr(obj: unknown): void;

  /**
   * Fills the array with cryptographically secure random values
   */
  getRandomValues<T extends TypedArray | DataView | ArrayBufferLike>(array: T): T;
}

/**
 * A singleton instance of the runtime object
 */
let runtimeObj: Runtime | null = null;

/**
 * Injects the runtime object
 */
export function inject(r: Runtime) {
  if (runtimeObj !== null) {
    throw new Error("The javascript runtime object has already been injected");
  }

  runtimeObj = r;
}

/**
 * Returns the runtime object for this javascript runtime
 */
export function runtime(): Runtime {
  if (runtimeObj === null) {
    throw new Error("The javascript runtime object has not been injected yet");
  }

  return runtimeObj;
}