import fs from 'fs'
import path from 'path'
import { FileEncryptor } from './file_encryptor'
import { TcpCommunicator } from './tcp_communicator'
import { operationCodes } from '../network/operation_codes'
import { ParsedMessage } from '../network/message_handler'
import { Database } from '../database/database'
import { NetworkUserScheme } from '../database/schemes/network_scheme'

export class BackupManager {
  private fileEncryptor: FileEncryptor | null = null
  private readonly db: Database
  private readonly clientPort: number
  private isBusy: boolean = false
  private intervalId: NodeJS.Timeout | null = null
  private stopRequested: boolean = false

  constructor(pathToDatabaseFile: string, clientPort: number) {
    this.db = new Database(pathToDatabaseFile)
    this.clientPort = clientPort
  }

  async start(): Promise<void> {
    this.intervalId = setInterval(async () => {
      if (!this.isBusy || !this.stopRequested) {
        this.isBusy = true
        this.log('Start successfully. Backup files to users.')
        await this.initialize()
      }

      if (global.gc) {
        global.gc()
      }
    }, 10000) // 10-second interval for testing
  }

  private async initialize(): Promise<void> {
    this.isBusy = true
    try {
      const data = await this.db.read()
      const userInfo = data.app_config.user_info
      const encryptionKey = data.app_config.encryption_key
      const usersIp = data.network.usersInLan.map((user: NetworkUserScheme) => user.ip)
      const backupDirectoryData = data.local_resources.directory_schemes.backup

      this.fileEncryptor = new FileEncryptor(encryptionKey.key, encryptionKey.iv)

      await this.sendFilesToUsers(
        userInfo.name,
        usersIp,
        backupDirectoryData.structure,
        backupDirectoryData.path,
      )
    } catch (error: any) {
      this.log(`Error in initialize process: ${error.message}`, 'error')
    } finally {
      this.log('Backup process completed.')
      this.isBusy = false
    }
  }

  private encryptFile(filePath: string): string {
    if (!this.fileEncryptor) {
      return filePath
    }

    if (!fs.existsSync(filePath)) {
      this.log(`File not found: ${filePath}`, 'error')
      return ''
    }

    return this.fileEncryptor.encryptFileToBase64(filePath)
  }

  private async sendFilesToUsers(
    userName: string,
    usersIp: string[],
    fileStructure: { [key: string]: string },
    backupDirectoryPath: string,
  ): Promise<void> {
    let unsentFiles = Object.keys(fileStructure)

    for (const fileName of unsentFiles) {
      const filePath = fileStructure[fileName]
      const encryptedFileContent = this.encryptFile(filePath)

      if (!encryptedFileContent) {
        this.log(`Failed to encrypt file: ${fileName}`, 'error')
        continue
      }

      const relativeFilePath = path.relative(backupDirectoryPath, filePath)
      const metaInfo = { userName, relativeFilePath }

      for (const ip of usersIp) {
        const tcpCommunicator = new TcpCommunicator(ip, this.clientPort)

        try {
          await tcpCommunicator.connect()
          this.log(`Connected to ${ip}`)

          const sendSuccess = await tcpCommunicator.sendMessage(
            operationCodes.BACKUP_FILE,
            metaInfo,
            Buffer.from(encryptedFileContent, 'base64'),
          )
          if (!sendSuccess) {
            throw new Error('Failed to send file content.')
          }

          const responseReceived = await this.waitForResponse(tcpCommunicator)
          if (!responseReceived) {
            throw new Error('Timeout waiting for the message response.')
          }

          this.log(`Successfully sent file: ${fileName} to ${ip}`)
          unsentFiles = unsentFiles.filter((f) => f !== fileName)
          break
        } catch (error) {
          this.log(`Failed to send file: ${fileName} to ${ip}. Error: ${error}`, 'error')
        } finally {
          await tcpCommunicator.disconnect()
          this.log(`Disconnected from ${ip}`)
        }
      }
    }

    if (unsentFiles.length > 0) {
      process.send?.({ type: 'log', message: 'Backup could not be completed for all files' })
    } else {
      process.send?.({ type: 'log', message: 'Backup completed successfully' })
    }
  }

  private async waitForResponse(tcpCommunicator: TcpCommunicator): Promise<ParsedMessage | null> {
    return new Promise((resolve) => {
      const idResponseCheck = setInterval(() => {
        if (!tcpCommunicator) return null
        if (tcpCommunicator.hasResponseArrived()) {
          clearInterval(idResponseCheck)
          resolve(tcpCommunicator.getLastResult())
        }
      }, 100)
    })
  }

  async stop(): Promise<void> {
    this.stopRequested = true // Signal that stop is requested

    if (this.intervalId) {
      clearInterval(this.intervalId)
      this.intervalId = null
    }

    // Wait for any ongoing process to complete if busy
    while (this.isBusy) {
      await new Promise((resolve) => setTimeout(resolve, 100))
    }

    console.log('[BackupManager] Stopped successfully.')
  }

  // Unified logging function
  private log(message: string, level: 'log' | 'error' | 'warn' = 'log'): void {
    const prefix = '[BackupManager]'
    if (level === 'error') {
      console.error(`${prefix} ${message}`)
    } else if (level === 'warn') {
      console.warn(`${prefix} ${message}`)
    } else {
      console.log(`${prefix} ${message}`)
    }
  }
}