import {CommandHandler, EventBus, ICommandHandler} from '@nestjs/cqrs';
import {Inject} from "@nestjs/common";
import {CreateClientCommand} from "./create-client.command";
import {
    ClientEntity,
    ClientRepositoryInterface,
} from "../../domain";
import { v4 as uuidv4 } from 'uuid'
import * as crypto from "crypto";
import * as selfsigned from 'selfsigned';
import {ClientCreatedEvent} from "../event";

@CommandHandler(CreateClientCommand)
export class CreateClientHandler implements ICommandHandler<CreateClientCommand> {
    constructor(
        @Inject('ClientRepositoryInterface')
        private readonly clientRepository: ClientRepositoryInterface,
        private readonly eventBus: EventBus
    ) {
    }

    /**
     * Execute the create Client Command
     *
     * @param command
     */
    async execute(command: CreateClientCommand) {
        const client = new ClientEntity();
        client.name = command.name;
        client.clientId = command.clientId || uuidv4();
        if (!command.noSecret) {
            client.clientSecret = crypto.randomBytes(32).toString('hex');
        }

        client.scope = command.scope;
        client.accessTokenLifetime = command.accessTokenLifetime || 3600;
        client.refreshTokenLifetime = command.refreshTokenLifetime || 7200;
        client.grants = command.grants || ['client_credentials', 'refresh_token'];

        // generate keys
        const attrs = [{ name: 'commonName', value: command.name }];
        const pem = selfsigned.generate(attrs, { days: 365 });

        client.privateKey = pem.private;
        client.publicKey = pem.public;
        client.cert = pem.cert;

        const exp = new Date();
        exp.setDate(exp.getDate() + 365);
        client.certExpiresAt = exp;

        const createdClient = await this.clientRepository.create(client);

        // emit an access token created event
        this.eventBus.publish(new ClientCreatedEvent(
            createdClient.id,
            createdClient.name,
            createdClient.clientId,
            createdClient.certExpiresAt
        ));

        return createdClient;
    }
}