import { Request, Response } from 'express';

type Authorization = {
  (req: Request, res: Response, next: Function);
  (req: Request, res: Response): Promise<boolean>;
}

type AuthRunner = {
  (req: Request, res: Response): Promise<boolean>;
}

export class KnexCrudOptions {
  private _general_authorization?: Authorization;
  private _create_authorization?: Authorization;
  private _read_authorization?: Authorization;
  private _update_authorization?: Authorization;
  private _delete_authorization?: Authorization;

  public optional_columns?: Array<string>;

  private get_auth_runner (
    auth?: Authorization
  ): AuthRunner {
    if (typeof auth === 'undefined')
      return (): Promise<boolean> => new Promise ((r) => r (true));
    return (): Promise<boolean> => new Promise ((resolve) => {
      const result = auth (req, res, resolve);
      if (typeof result !== 'undefined')
        resolve (result);
    });
  }

  public set general_authorization (value: Authorization): void{
    this._general_authorization = value;
  }

  public get create_authorization (): AuthRunner {
    const general = this.get_auth_runner (this._general_authorization);
    const specific = this.get_auth_runner (this._create_authorization);
    return async (req, res): Promise<boolean> => {
      const res = (await general (req, res)) && (await specific (req, res));
      return res;
    };
  }

  public set create_authorization (value: Authorization): void{
    this._create_authorization = value;
  }

  public get read_authorization (): AuthRunner {
    const general = this.get_auth_runner (this._general_authorization);
    const specific = this.get_auth_runner (this._read_authorization);
    return async (req, res): Promise<boolean> => {
      const res = (await general (req, res)) && (await specific (req, res));
      return res;
    };
  }

  public set read_authorization (value: Authorization): void{
    this._read_authorization = value;
  }

  public get update_authorization (): AuthRunner {
    const general = this.get_auth_runner (this._general_authorization);
    const specific = this.get_auth_runner (this._update_authorization);
    return async (req, res): Promise<boolean> => {
      const res = (await general (req, res)) && (await specific (req, res));
      return res;
    };
  }

  public set update_authorization (value: Authorization): void{
    this._update_authorization = value;
  }

  public get delete_authorization (): AuthRunner {
    const general = this.get_auth_runner (this._general_authorization);
    const specific = this.get_auth_runner (this._delete_authorization);
    return async (req, res): Promise<boolean> => {
      const res = (await general (req, res)) && (await specific (req, res));
      return res;
    };
  }

  public set delete_authorization (value: Authorization): void{
    this._delete_authorization = value;
  }
}