import { Request, Response } from 'express';
import { http } from '@scode/consts';
import { try_parse_json } from '@scode/utilities';
import { KnexCrudOptions } from './KnexCrudOptions';
import { CrudHandler } from './CrudHandler';

export class KnexCrudHandler implements CrudHandler {
  protected table: string;
  protected columns: Array<string>;
  protected options: KnexCrudOptions;

  public constructor (
    table: string,
    columns: Array<string>,
    options: KnexCrudOptions = {}
  ) {
    this.table = table;
    this.columns = columns;
    this.options = options;
  }

  private call_auth (
    auth?: Function,
    req: Request,
    res: Response
  ): Promise<boolean> {
    if (typeof auth === 'undefined')
      return true;

    const promise = new Promise ((resolve) => {
      const result = auth (req, res, resolve);
      if (typeof result !== 'undefined')
        resolve (result);
    });

    return promise;
  }

  protected validate_body (
    req: Request,
    res: Response
  ): Promise<object> | object {
    if (typeof req.body === 'undefined') {
      res.status (http.status_bad_request);
      res.end ();
      return null;
    }
    return try_parse_json (req.body);
  }

  public async create (req: Request, res: Response): Promise<void> {
    if (!await this.call_auth (this.options.create_authentication, req, res))
      return;
    if (!await this.call_auth (this.options.create_authorization, req, res))
      return;

    const body_data = await this.validate_body (req, res);
    if (body_data === null)
      return;
  }

  public async read (req: Request, res: Response): Promise<void> {

  }

  public async update (req: Request, res: Response): Promise<void> {

  }

  public async delete (req: Request, res: Response): Promise<void> {

  }
}