import { IEncryptionPassword } from "@nestia/fetcher";
import { Module } from "@nestjs/common";

import { Creator } from "../typings/Creator";
import { ENCRYPTION_METADATA_KEY } from "./internal/EncryptedConstant";
import { load_controllers } from "./internal/load_controller";

/**
 * Encrypted module.
 *
 * `EncryptedModule` is an extension of the {@link Module} class decorator
 * function who configures encryption password of the AES-128/256 algorithm. The
 * encryption algorithm and password would be used by {@link EncryptedRoute} and
 * {@link EncryptedBody} to encrypt the request and response bod of the HTTP
 * protocol.
 *
 * By using this `EncryptedModule` decorator function, all of the
 * {@link Controller controllers} configured in the _metadata_ would be
 * automatically changed to the {@link EncryptedController} with the _password_.
 * If there're some original {@link EncryptedController} decorated classes in the
 * _metadata_, their encryption password would be kept.
 *
 * Therefore, if you're planning to place original {@link EncryptedController}
 * decorated classes in the _metadata_, I hope them to have different encryption
 * password from the module level. If not, I recommend you use the
 * {@link Controller} decorator function instead.
 *
 * In addition, the `EncryptedModule` supports a convenient dynamic controller
 * importing function, {@link EncryptedModule.dynamic}. If you utilize the
 * function with directory path of the controller classes, it imports and
 * configures the controller classes into the `Module`, automatically.
 *
 * @author Jeongho Nam - https://github.com/samchon
 * @param metadata Module configuration metadata
 * @param password Encryption password or its getter function
 * @returns Class decorator
 */
export function EncryptedModule(
  metadata: Parameters<typeof Module>[0],
  password: IEncryptionPassword.Closure,
): ClassDecorator {
  return function (target: any) {
    Module(metadata)(target);
    iterate(password)(target);
  };
}

export namespace EncryptedModule {
  /**
   * Dynamic encrypted module.
   *
   * `EncryptedModule.dynamic` is an extension of the {@link EncryptedModule}
   * function who configures controller classes by the dynamic importing. By
   * specifying directory path of the controller classes, those controllers
   * would be automatically imported and configured.
   *
   * @param path Directory path of the controller classes
   * @param password Encryption password or its getter function
   * @param options Additional options except controller
   * @returns Class decorated module instance
   */
  export async function dynamic(
    path: string | string[] | { include: string[]; exclude?: string[] },
    password: IEncryptionPassword | IEncryptionPassword.Closure,
    options: Omit<Parameters<typeof Module>[0], "controllers"> = {},
    isTsNode?: boolean,
  ) {
    // LOAD CONTROLLERS
    const controllers: Creator<object>[] = await load_controllers(
      path,
      isTsNode,
    );

    // RETURNS WITH DECORATING
    @EncryptedModule(
      { ...options, controllers },
      typeof password === "object" ? () => password : password,
    )
    class NestiaModule {}
    return NestiaModule;
  }
}

/** @internal */
const iterate =
  (password: IEncryptionPassword.Closure) =>
  (modulo: any): void => {
    const imports = Reflect.getMetadata("imports", modulo);
    if (Array.isArray(imports))
      for (const imp of imports)
        if (typeof imp === "function") iterate(password)(imp);

    const controllers = Reflect.getMetadata("controllers", modulo);
    if (Array.isArray(controllers))
      for (const c of controllers)
        if (typeof c === "function")
          Reflect.defineMetadata(ENCRYPTION_METADATA_KEY, password, c);
  };