import { HTTPStatus } from 'deps';
import { isSuccessfulStatus } from 'deps';

import { Logger, logger as defaultLogger } from 'infra/logger.ts';

export interface ControllerOptions {
  status?: HTTPStatus;
  json?: boolean;
}

export type ControllerHandler = (
  req: Request,
  error?: string,
  headers?: Record<string, string>,
) => Response | Promise<Response>;

export type ControllerHandlers = Record<string, ControllerHandler>;

export default class Controller {
  constructor(
    private handlers: ControllerHandlers = {},
    private logger: Logger = defaultLogger,
  ) {}

  public setHandlers(handlers: ControllerHandlers): void {
    this.handlers = handlers;
  }

  public setHandler(
    path: string,
    method: string,
    handler: ControllerHandler,
  ): void {
    this.handlers[`${path}_${method}`] = handler;
  }

  public getHandlers(): ControllerHandlers {
    return this.handlers;
  }

  public getHandler(path: string, method: string): ControllerHandler {
    return this.handlers[`${path}_${method}`];
  }

  public hasHandler(path: string, method: string): boolean {
    return `${path}_${method}` in this.handlers;
  }

  public response = (
    req: Request,
    body: string,
    options: ControllerOptions = {},
  ) => {
    const url = new URL(req.url);
    const output = new TextEncoder().encode(body);
    const response = new Response(output, {
      status: options.status ?? HTTPStatus.OK,
    });
    const userName = Controller.getUser(req);

    if (options.json) {
      response.headers.set('Content-Type', 'application/json');
    }
    const userAgent = req.headers.get('User-Agent') ?? '-';
    const logMessage = Controller.getLogMessage(
      req.method,
      url.pathname,
      response.status,
      output.byteLength,
      userAgent,
      userName,
    );
    if (isSuccessfulStatus(response.status)) {
      if (Controller.isHealthCheck(userAgent)) {
        this.logger.debug(logMessage);
      } else {
        this.logger.info(logMessage);
      }
    } else {
      this.logger.error(logMessage);
    }

    return response;
  };

  public responseJSON = (
    req: Request,
    body: Record<string, unknown>,
    options: ControllerOptions = {},
  ) => {
    options.json = true;

    return this.response(req, JSON.stringify(body), options);
  };

  private static getUser = (req: Request): string | undefined => {
    const authHeader = req.headers.get('Authorization');

    if (authHeader && authHeader.startsWith('Basic ')) {
      const base64Credentials = authHeader.slice(6);
      const credentials = atob(base64Credentials);
      const [userName] = credentials.split(':');

      return userName;
    }

    return;
  };

  private static getLogMessage(
    method: string,
    path: string,
    status: number,
    length: number,
    userAgent: string,
    userName?: string,
  ) {
    const user = userName ? userName + ' ' : '';
    return `${method} ${path} ${user}${status} ${length} (${userAgent})`;
  }

  private static isHealthCheck(userAgent: string): boolean {
    return userAgent === Deno.env.get('DOCKER_USER_AGENT');
  }
}