Fis-Retransmission/services/server-client.service.ts

import { BehaviorSubject, Subject } from 'rxjs';
import { ClientRequest, ConnectionAttribute, ConnectionRequest, ConnectionState, Message, ServerRequest, State } from '../interfaces/general.interface';
import { GrpcServiceMethod } from './grpc.service.method';
import { BufferService } from './buffer.service';
import * as dotenv from 'dotenv'
import * as _ from 'lodash'
dotenv.config()

export class ServerClientManager {
    private connectionAttributes: ConnectionAttribute[] = []
    private grpcService: GrpcServiceMethod = new GrpcServiceMethod()
    private defaultServerAttribute: ServerRequest = {
        name: 'Default - Server',
        serverUrl: "localhost:3000",
        connectionType: 'GRPC',
        messageToBePublishedFromApplication: new Subject<Message>()
    }
    private defaultClientAttribute: ClientRequest = {
        name: 'Default - Client',
        targetServer: "localhost:3001",
        connectionType: 'GRPC',
        messageToBeReceivedFromRemote: new Subject<Message>()
    }

    constructor() {
    }

    public async generateConnection(request: ConnectionRequest): Promise<any> {
        return new Promise(async (resolve, reject) => {
            let initialReport: ConnectionState
            let reportSubject: BehaviorSubject<ConnectionState>
            let retransmission: BufferService
            let errorString: string
            let originalRequest = _.cloneDeep(request)
            let database: string
            let response: any = { message: `Fail to complete connection generation` }
            let statusChain: State = 1
            let connectionAttribute: ConnectionAttribute

            if (statusChain == 1) {
                if (!request.server) {
                    request.server = this.defaultServerAttribute
                }
                if (!request.client) {
                    request.client = this.defaultClientAttribute
                }
                if (request.database) {
                    database = request.database
                } else {
                    database = request.server.name + request.client.name
                }
                /* Inject retransmission here */
                initialReport = { status: 'BUFFER' }
                reportSubject = new BehaviorSubject(initialReport)
                retransmission = new BufferService(request.server.messageToBePublishedFromApplication, reportSubject, database)
            }

            if (statusChain == 1) {
                // Connection Type checking
                if (request.server!.connectionType != request.client!.connectionType) {
                    statusChain = -1
                    errorString = "Connection Type DOES NOT MATCH!"
                } else {
                    statusChain = 1
                }
            }

            if (statusChain == 1) {
                connectionAttribute = {
                    ConnectionID: {
                        local: request.server!.name + request.client!.name,
                        remote: request.client!.name + request.server!.name
                    },
                    outGoing: {
                        StreamID: request.server!.name,
                        PublisherID: request.server!.name,
                        SubscriberID: request.server!.name,
                        serverUrl: request.server?.serverUrl,
                        connectionState: `OFF`,
                        MessageToBePublished: retransmission!.getMessages(),
                        MessageToBeReceived: null
                    },
                    inComing: {
                        StreamID: request.client!.name,
                        PublisherID: request.client!.name,
                        SubscriberID: request.client!.name,
                        serverUrl: request.client?.targetServer,
                        connectionState: `OFF`,
                        MessageToBePublished: null,
                        MessageToBeReceived: request.client!.messageToBeReceivedFromRemote
                    },
                    connectionStatus: reportSubject!
                }
            }

            if (statusChain == 1) {
                await this.checkConnectionAttribute(connectionAttribute!).then((res) => {
                    if (res == true) {
                        console.log(`Connection<${connectionAttribute.ConnectionID.local}> already exists `)
                    }
                    if (res == false) {
                        this.connectionAttributes.push(connectionAttribute)
                        console.log(`Connection ${connectionAttribute.ConnectionID.local} registered...`)
                    }
                    console.log(`There is now ${this.connectionAttributes.length} connection Attributes`)
                })
            }

            if (statusChain == 1) {
                // This is default connection`
                if (!request.client!.connectionType) {
                    request.client!.connectionType = 'GRPC'
                }
                // For each connection type:
                if (request.client!.connectionType == 'GRPC') {
                    this.grpcServerStatusHandler()
                    this.grpcClientStatusHandler()
                    this.grpcService.create(connectionAttribute!).then(() => {
                        // logic here
                    }).catch(() => {
                        errorString = `Something wrong with gRPC methods`
                        statusChain = -1
                    })
                }
            }

            if (statusChain == 1) {
                response = {
                    message: "Channel Response",
                    requestedTo: originalRequest,
                    data: connectionAttribute!
                }
                resolve(response);
            } else if (statusChain == -1) {
                response = {
                    message: "Channel Response Error",
                    requestedTo: originalRequest,
                    data: errorString! // put error string here
                }
                resolve(response);
            }
        })
    }

    private async checkConnectionAttribute(connectionAttribute: ConnectionAttribute): Promise<boolean> {
        return new Promise((resolve) => {
            let result: boolean = this.connectionAttributes.some(connection =>
                connection.ConnectionID.local === connectionAttribute.ConnectionID.local
            );
            resolve(result);
        });
    }

    private grpcServerStatusHandler() {
        this.grpcService.getLocalServerStatus().subscribe({
            next: (notification: any) => {
                if (notification.connectionStatus === `ON`) {
                    let connectionAttribute = this.connectionAttributes.find(connection => connection.ConnectionID.local == notification.connectionIDlocal)
                    if (connectionAttribute) {
                        connectionAttribute.outGoing.connectionState = 'ON'
                        console.log(`Connection ${notification.connectionIDlocal} updated`)
                    } else {
                        console.log(`Connection ${notification.connectionIDlocal} attribute is not found.`)
                    }
                }
            },
            error: err => console.error(err),
            complete: () => { }
        })
    }

    private grpcClientStatusHandler() {
        this.grpcService.getClientRequest().subscribe({
            next: (clientConnectionAttribute: ConnectionAttribute) => {
                console.log(`Received a request from ${clientConnectionAttribute.outGoing.serverUrl}`)
                let connectionAttribute = this.connectionAttributes.find(connection => connection.ConnectionID.remote == clientConnectionAttribute.ConnectionID.local)
                if (connectionAttribute) {
                    console.log(`Connection ${clientConnectionAttribute.ConnectionID.local} updated`)
                    connectionAttribute.inComing.connectionState = 'ON'
                } else {
                    console.log(`Connection Attribut ${clientConnectionAttribute.inComing.PublisherID} is not found`)
                }
            },
            error: err => console.error(err),
            complete: () => { }
        })
    }
}