refactor: consolidate default values handling

[e-mobility-charging-stations-simulator.git] / src / charging-station / ui-server / AbstractUIServer.ts

import { type IncomingMessage, Server, type ServerResponse } from 'node:http'
import { type Http2Server, createServer } from 'node:http2'

import type { WebSocket } from 'ws'

import type { AbstractUIService } from './ui-services/AbstractUIService.js'
import { UIServiceFactory } from './ui-services/UIServiceFactory.js'
import { BaseError } from '../../exception/index.js'
import {
  ApplicationProtocolVersion,
  AuthenticationType,
  type ChargingStationData,
  type ProcedureName,
  type ProtocolRequest,
  type ProtocolResponse,
  ProtocolVersion,
  type RequestPayload,
  type ResponsePayload,
  type UIServerConfiguration
} from '../../types/index.js'

export abstract class AbstractUIServer {
  public readonly chargingStations: Map<string, ChargingStationData>
  public readonly chargingStationTemplates: Set<string>
  protected readonly httpServer: Server | Http2Server
  protected readonly responseHandlers: Map<string, ServerResponse | WebSocket>
  protected readonly uiServices: Map<ProtocolVersion, AbstractUIService>

  public constructor (protected readonly uiServerConfiguration: UIServerConfiguration) {
    this.chargingStations = new Map<string, ChargingStationData>()
    this.chargingStationTemplates = new Set<string>()
    switch (this.uiServerConfiguration.version) {
      case ApplicationProtocolVersion.VERSION_11:
        this.httpServer = new Server()
        break
      case ApplicationProtocolVersion.VERSION_20:
        this.httpServer = createServer()
        break
      default:
        throw new BaseError(
          `Unsupported application protocol version ${this.uiServerConfiguration.version}`
        )
    }
    this.responseHandlers = new Map<string, ServerResponse | WebSocket>()
    this.uiServices = new Map<ProtocolVersion, AbstractUIService>()
  }

  public buildProtocolRequest (
    id: string,
    procedureName: ProcedureName,
    requestPayload: RequestPayload
  ): ProtocolRequest {
    return [id, procedureName, requestPayload]
  }

  public buildProtocolResponse (id: string, responsePayload: ResponsePayload): ProtocolResponse {
    return [id, responsePayload]
  }

  public stop (): void {
    this.stopHttpServer()
    this.chargingStations.clear()
    this.chargingStationTemplates.clear()
  }

  public async sendInternalRequest (request: ProtocolRequest): Promise<ProtocolResponse> {
    const protocolVersion = ProtocolVersion['0.0.1']
    this.registerProtocolVersionUIService(protocolVersion)
    return await (this.uiServices
      .get(protocolVersion)
      ?.requestHandler(request) as Promise<ProtocolResponse>)
  }

  public hasResponseHandler (id: string): boolean {
    return this.responseHandlers.has(id)
  }

  protected startHttpServer (): void {
    if (!this.httpServer.listening) {
      this.httpServer.listen(this.uiServerConfiguration.options)
    }
  }

  protected registerProtocolVersionUIService (version: ProtocolVersion): void {
    if (!this.uiServices.has(version)) {
      this.uiServices.set(version, UIServiceFactory.getUIServiceImplementation(version, this))
    }
  }

  protected authenticate (req: IncomingMessage, next: (err?: Error) => void): void {
    if (this.isBasicAuthEnabled()) {
      if (!this.isValidBasicAuth(req)) {
        next(new BaseError('Unauthorized'))
      }
      next()
    }
    next()
  }

  private stopHttpServer (): void {
    if (this.httpServer.listening) {
      this.httpServer.close()
    }
  }

  private isBasicAuthEnabled (): boolean {
    return (
      this.uiServerConfiguration.authentication?.enabled === true &&
      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
      this.uiServerConfiguration.authentication.type === AuthenticationType.BASIC_AUTH
    )
  }

  private isValidBasicAuth (req: IncomingMessage): boolean {
    const authorizationHeader = req.headers.authorization ?? ''
    const authorizationToken = authorizationHeader.split(/\s+/).pop() ?? ''
    const authentication = Buffer.from(authorizationToken, 'base64').toString()
    const authenticationParts = authentication.split(/:/)
    const username = authenticationParts.shift()
    const password = authenticationParts.join(':')
    return (
      this.uiServerConfiguration.authentication?.username === username &&
      this.uiServerConfiguration.authentication?.password === password
    )
  }

  public abstract start (): void
  public abstract sendRequest (request: ProtocolRequest): void
  public abstract sendResponse (response: ProtocolResponse): void
  public abstract logPrefix (moduleName?: string, methodName?: string, prefixSuffix?: string): string
}