import {BehaviorSubject, catchError, of, Subject} from "rxjs";
import {Injectable} from "@angular/core";
import {AuthService} from "@service/auth.service";
import {environment} from "@environment";
import ApiService from "@api/api.service";

@Injectable({
  providedIn: 'root',
})
export class TokenRefreshService {
  private tokenRefreshing$ = new BehaviorSubject<boolean>(false);
  private refreshTokenTimeout: any;
  private refreshTokenExpireMs: number = environment.retryDelay;

  constructor(private authService: AuthService) {
    this.setRefreshTokenExpireMs(AuthService.tokenExpiresIn);
  }

  private startTokenRefresh(): void {
    this.refreshTokenTimeout = setTimeout(() => {
      this.refreshToken();
    }, this.refreshTokenExpireMs);
  }

  private refreshToken(): void {
    if (this.tokenRefreshing$.value)
      return;

    this.tokenRefreshing$.next(true);

    this.authService.refreshToken()
      .pipe(
        catchError(error => {
          if (error.status === 403 || error.status === 401 || !localStorage.getItem(ApiService.tokenKey)) {
            localStorage.removeItem(ApiService.tokenKey);
            return of(undefined);
          }

          let retryTime = this.refreshTokenExpireMs;

          if (retryTime < environment.retryDelay)
            retryTime = environment.retryDelay;

          // 15 minutes
          if (retryTime * 2 <= 900_000)
            retryTime *= 2;
          else
            retryTime = 900_000;

          return of(retryTime);
        }))
      .subscribe(data => {
        if (data)
          this.setRefreshTokenExpireMs(data);

        this.tokenRefreshing$.next(false);
      });
  }

  public getTokenRefreshing$(): Subject<boolean> {
    return this.tokenRefreshing$;
  }

  public setRefreshTokenExpireMs(expireMs: number | string | Date | null = null): void {
    let expireMsNumber: number;
    if (expireMs === null)
      expireMsNumber = -1;
    else if (expireMs instanceof Date || typeof expireMs === 'string')
      expireMsNumber = new Date(expireMs).getTime() - 1000 - Date.now();
    else
      expireMsNumber = expireMs;

    if (expireMsNumber < environment.retryDelay)
      expireMsNumber = environment.retryDelay;

    this.refreshTokenExpireMs = expireMsNumber;
    console.log('New refresh token interval:', this.refreshTokenExpireMs);

    clearTimeout(this.refreshTokenTimeout);
    this.startTokenRefresh();
  }
}