import { Injectable, inject } from 'injection-js';
import { BehaviorSubject, Observable, throwError } from 'rxjs';
import { distinctUntilChanged } from 'rxjs/operators';
import { OpenIdConfiguration } from '../config/openid-configuration';
import { AuthResult } from '../flows/callback-context';
import { LoggerService } from '../logging/logger.service';
import { EventTypes } from '../public-events/event-types';
import { PublicEventsService } from '../public-events/public-events.service';
import { StoragePersistenceService } from '../storage/storage-persistence.service';
import { TokenValidationService } from '../validation/token-validation.service';
import { AuthenticatedResult } from './auth-result';
import { AuthStateResult } from './auth-state';

const DEFAULT_AUTHRESULT = {
  isAuthenticated: false,
  allConfigsAuthenticated: [],
};

@Injectable()
export class AuthStateService {
  private readonly storagePersistenceService = inject(
    StoragePersistenceService
  );

  private readonly loggerService = inject(LoggerService);

  private readonly publicEventsService = inject(PublicEventsService);

  private readonly tokenValidationService = inject(TokenValidationService);

  private readonly authenticatedInternal$ =
    new BehaviorSubject<AuthenticatedResult>(DEFAULT_AUTHRESULT);

  get authenticated$(): Observable<AuthenticatedResult> {
    return this.authenticatedInternal$
      .asObservable()
      .pipe(distinctUntilChanged());
  }

  setAuthenticatedAndFireEvent(allConfigs: OpenIdConfiguration[]): void {
    const result = this.composeAuthenticatedResult(allConfigs);

    this.authenticatedInternal$.next(result);
  }

  setUnauthenticatedAndFireEvent(
    currentConfig: OpenIdConfiguration,
    allConfigs: OpenIdConfiguration[]
  ): void {
    this.storagePersistenceService.resetAuthStateInStorage(currentConfig);

    const result = this.composeUnAuthenticatedResult(allConfigs);

    this.authenticatedInternal$.next(result);
  }

  updateAndPublishAuthState(authenticationResult: AuthStateResult): void {
    this.publicEventsService.fireEvent<AuthStateResult>(
      EventTypes.NewAuthenticationResult,
      authenticationResult
    );
  }

  setAuthorizationData(
    accessToken: string,
    authResult: AuthResult | null,
    currentConfig: OpenIdConfiguration,
    allConfigs: OpenIdConfiguration[]
  ): void {
    this.loggerService.logDebug(
      currentConfig,
      `storing the accessToken '${accessToken}'`
    );

    this.storagePersistenceService.write(
      'authzData',
      accessToken,
      currentConfig
    );
    this.persistAccessTokenExpirationTime(authResult, currentConfig);
    this.setAuthenticatedAndFireEvent(allConfigs);
  }

  getAccessToken(configuration: OpenIdConfiguration | null): string {
    if (!configuration) {
      return '';
    }

    if (!this.isAuthenticated(configuration)) {
      return '';
    }

    const token = this.storagePersistenceService.getAccessToken(configuration);

    return this.decodeURIComponentSafely(token);
  }

  getIdToken(configuration: OpenIdConfiguration | null): string {
    if (!configuration) {
      return '';
    }

    if (!this.isAuthenticated(configuration)) {
      return '';
    }

    const token = this.storagePersistenceService.getIdToken(configuration);

    return this.decodeURIComponentSafely(token);
  }

  getRefreshToken(configuration: OpenIdConfiguration | null): string {
    if (!configuration) {
      return '';
    }

    if (!this.isAuthenticated(configuration)) {
      return '';
    }

    const token = this.storagePersistenceService.getRefreshToken(configuration);

    return this.decodeURIComponentSafely(token);
  }

  getAuthenticationResult(
    configuration: OpenIdConfiguration | null
  ): AuthResult | null {
    if (!configuration) {
      return null;
    }

    if (!this.isAuthenticated(configuration)) {
      return null;
    }

    return this.storagePersistenceService.getAuthenticationResult(
      configuration
    );
  }

  areAuthStorageTokensValid(
    configuration: OpenIdConfiguration | null
  ): boolean {
    if (!configuration) {
      return false;
    }

    if (!this.isAuthenticated(configuration)) {
      return false;
    }

    if (this.hasIdTokenExpiredAndRenewCheckIsEnabled(configuration)) {
      this.loggerService.logDebug(
        configuration,
        'persisted idToken is expired'
      );

      return false;
    }

    if (this.hasAccessTokenExpiredIfExpiryExists(configuration)) {
      this.loggerService.logDebug(
        configuration,
        'persisted accessToken is expired'
      );

      return false;
    }

    this.loggerService.logDebug(
      configuration,
      'persisted idToken and accessToken are valid'
    );

    return true;
  }

  hasIdTokenExpiredAndRenewCheckIsEnabled(
    configuration: OpenIdConfiguration
  ): boolean {
    const {
      renewTimeBeforeTokenExpiresInSeconds,
      triggerRefreshWhenIdTokenExpired,
      disableIdTokenValidation,
    } = configuration;

    if (!triggerRefreshWhenIdTokenExpired || disableIdTokenValidation) {
      return false;
    }
    const tokenToCheck =
      this.storagePersistenceService.getIdToken(configuration);

    const idTokenExpired = this.tokenValidationService.hasIdTokenExpired(
      tokenToCheck,
      configuration,
      renewTimeBeforeTokenExpiresInSeconds
    );

    if (idTokenExpired) {
      this.publicEventsService.fireEvent<boolean>(
        EventTypes.IdTokenExpired,
        idTokenExpired
      );
    }

    return idTokenExpired;
  }

  hasAccessTokenExpiredIfExpiryExists(
    configuration: OpenIdConfiguration
  ): boolean {
    const { renewTimeBeforeTokenExpiresInSeconds } = configuration;
    const accessTokenExpiresIn = this.storagePersistenceService.read(
      'access_token_expires_at',
      configuration
    );
    const accessTokenHasNotExpired =
      this.tokenValidationService.validateAccessTokenNotExpired(
        accessTokenExpiresIn,
        configuration,
        renewTimeBeforeTokenExpiresInSeconds
      );

    const hasExpired = !accessTokenHasNotExpired;

    if (hasExpired) {
      this.publicEventsService.fireEvent<boolean>(
        EventTypes.TokenExpired,
        hasExpired
      );
    }

    return hasExpired;
  }

  isAuthenticated(configuration: OpenIdConfiguration | null): boolean {
    if (!configuration) {
      throwError(
        () =>
          new Error(
            'Please provide a configuration before setting up the module'
          )
      );

      return false;
    }

    const hasAccessToken =
      !!this.storagePersistenceService.getAccessToken(configuration);
    const hasIdToken =
      !!this.storagePersistenceService.getIdToken(configuration);

    return hasAccessToken && hasIdToken;
  }

  private decodeURIComponentSafely(token: string): string {
    if (token) {
      return decodeURIComponent(token);
    } else {
      return '';
    }
  }

  private persistAccessTokenExpirationTime(
    authResult: AuthResult | null,
    configuration: OpenIdConfiguration
  ): void {
    if (authResult?.expires_in) {
      const accessTokenExpiryTime =
        new Date(new Date().toUTCString()).valueOf() +
        authResult.expires_in * 1000;

      this.storagePersistenceService.write(
        'access_token_expires_at',
        accessTokenExpiryTime,
        configuration
      );
    }
  }

  private composeAuthenticatedResult(
    allConfigs: OpenIdConfiguration[]
  ): AuthenticatedResult {
    if (allConfigs.length === 1) {
      const { configId } = allConfigs[0];

      return {
        isAuthenticated: true,
        allConfigsAuthenticated: [
          { configId: configId ?? '', isAuthenticated: true },
        ],
      };
    }

    return this.checkAllConfigsIfTheyAreAuthenticated(allConfigs);
  }

  private composeUnAuthenticatedResult(
    allConfigs: OpenIdConfiguration[]
  ): AuthenticatedResult {
    if (allConfigs.length === 1) {
      const { configId } = allConfigs[0];

      return {
        isAuthenticated: false,
        allConfigsAuthenticated: [
          { configId: configId ?? '', isAuthenticated: false },
        ],
      };
    }

    return this.checkAllConfigsIfTheyAreAuthenticated(allConfigs);
  }

  private checkAllConfigsIfTheyAreAuthenticated(
    allConfigs: OpenIdConfiguration[]
  ): AuthenticatedResult {
    const allConfigsAuthenticated = allConfigs.map((config) => ({
      configId: config.configId ?? '',
      isAuthenticated: this.isAuthenticated(config),
    }));

    const isAuthenticated = allConfigsAuthenticated.every(
      (x) => !!x.isAuthenticated
    );

    return { allConfigsAuthenticated, isAuthenticated };
  }
}