import { EbacPassportManagerSettingsInterface } from '../../interfaces/ebac-passport-manager-settings.interface';
import * as session from 'express-session';
import { DynamoDB } from 'aws-sdk';
import { ConfigService } from '@nestjs/config';
import {
  AWS_EBAC_PASSPORT_REGION,
  AWS_EBAC_PASSPORT_USER_ACCESS_KEY,
  AWS_EBAC_PASSPORT_USER_SECRET_KEY,
  DEFAULT_AWS_REGION,
  DEFAULT_SESSION_TABLE_NAME,
  SESSION_SECRET,
  SESSION_TABLE_NAME,
} from '../../constants';
import { Store } from 'express-session';
import { SessionManagerInterface } from './session-manager.interface';
import { SessionPassportInterface } from './interfaces/session-passport.interface';
import { MiddlewareInterface } from '../../interfaces/middleware.interface';

const DynamoDBStore = require('connect-dynamodb')({ session });

export class SessionManager implements SessionManagerInterface {
  configService: ConfigService;

  constructor(params: EbacPassportManagerSettingsInterface) {
    this.configService = params.configService;
    this.init(params);
  }

  init(params: EbacPassportManagerSettingsInterface): void {
    if (!params.app) {
      throw new Error('App not set');
    }

    const secret: string = this.getSecret(params);
    const store: Store = this.initDynamoDbStore(params);

    params.app.use(
      session({
        ...params.sessionSettings,
        store,
        secret,
      }),
    );
  }

  getSessionPassport(params: MiddlewareInterface): SessionPassportInterface {
    const req = params.req;
    let passport: SessionPassportInterface = req?.session?.passport;
    if (passport) {
      return passport;
    }
    passport = this.initSessionPassportData(req);
    return passport;
  }

  clearSession(params: MiddlewareInterface): void {
    const req = params.req;
    const passport: SessionPassportInterface = req?.session?.passport;
    passport.users = [];
    delete passport.activeUser;
    delete passport.auth;
  }

  destroySession(params: MiddlewareInterface): void {
    const session = params?.req?.session;
    if(session) {
      session.destroy();
    }
  }

  private initSessionPassportData(req): SessionPassportInterface {
    req.session.passport = {};
    return req.session.passport;
  }

  private initDynamoDbStore(
    params: EbacPassportManagerSettingsInterface,
  ): Store {
    const table: string = this.getTableName(params);
    const region: string = this.getAwsRegion();
    const accessKeyId: string = this.getAwsAccessKeyId();
    const secretAccessKey: string = this.getAwsSecretAccessKey();
    const client: DynamoDB = this.getDynamoDbClient(params);

    const dynamoDbStore: Store = new DynamoDBStore({
      table,
      AWSConfigJSON: {
        region,
        accessKeyId,
        secretAccessKey,
      },
      client,
    });

    return dynamoDbStore;
  }

  private getDynamoDbClient(
    params: EbacPassportManagerSettingsInterface,
  ): DynamoDB {
    const region: string = this.getAwsRegion();
    const accessKeyId: string = this.getAwsAccessKeyId();
    const secretAccessKey: string = this.getAwsSecretAccessKey();

    const client: DynamoDB = new DynamoDB({
      region,
      credentials: {
        accessKeyId,
        secretAccessKey,
      },
    });

    return client;
  }

  private getSecret(params: EbacPassportManagerSettingsInterface): string {
    const secret: string =
      <string>params?.sessionSettings?.secret ||
      this.configService.get<string>(SESSION_SECRET);
    if (!secret) {
      throw new Error(`${SESSION_SECRET} not set`);
    }
    return secret;
  }

  private getTableName(params: EbacPassportManagerSettingsInterface): string {
    const tableName: string =
      params?.sessionSettings?.tableName ||
      this.configService.get<string>(SESSION_TABLE_NAME) ||
      DEFAULT_SESSION_TABLE_NAME;
    return tableName;
  }

  private getAwsRegion(): string {
    const region: string =
      this.configService.get<string>(AWS_EBAC_PASSPORT_REGION) ||
      DEFAULT_AWS_REGION;
    return region;
  }

  private getAwsSecretAccessKey(): string {
    const secretAccessKey: string = this.configService.get<string>(
      AWS_EBAC_PASSPORT_USER_SECRET_KEY,
    );
    return secretAccessKey;
  }

  private getAwsAccessKeyId(): string {
    const accessKeyId: string = this.configService.get<string>(
      AWS_EBAC_PASSPORT_USER_ACCESS_KEY,
    );
    return accessKeyId;
  }
}