lnbits-legend/lnbits/extensions/watchonly/static/components/serial-signer/serial-signer.js

async function serialSigner(path) {
  const t = await loadTemplateAsync(path)
  Vue.component('serial-signer', {
    name: 'serial-signer',
    template: t,

    props: ['sats-denominated', 'network'],
    data: function () {
      return {
        selectedPort: null,
        writableStreamClosed: null,
        writer: null,
        readableStreamClosed: null,
        reader: null,
        receivedData: '',
        config: {},
        decryptionKey: null,
        sharedSecret: null,

        hww: {
          password: null,
          showPassword: false,
          mnemonic: null,
          showMnemonic: false,
          quickMnemonicInput: false,
          passphrase: null,
          showPassphrase: false,
          hasPassphrase: false,
          authenticated: false,
          showPasswordDialog: false,
          showConfigDialog: false,
          showWipeDialog: false,
          showRestoreDialog: false,
          showConfirmationDialog: false,
          showSignedPsbt: false,
          sendingPsbt: false,
          signingPsbt: false,
          loginResolve: null,
          psbtSentResolve: null,
          xpubResolve: null,
          seedWordPosition: 1,
          seedWord: null,
          showSeedWord: false,
          showSeedDialog: false,
          // config: null,

          confirm: {
            outputIndex: 0,
            showFee: false
          }
        },
        tx: null, // todo: move to hww

        showConsole: false,
        showPairedDevices: true
      }
    },

    computed: {
      pairedDevices: {
        cache: false,
        get: function () {
          return (
            JSON.parse(window.localStorage.getItem('lnbits-paired-devices')) ||
            []
          )
        },
        set: function (devices) {
          window.localStorage.setItem(
            'lnbits-paired-devices',
            JSON.stringify(devices)
          )
        }
      }
    },

    methods: {
      satBtc(val, showUnit = true) {
        return satOrBtc(val, showUnit, this.satsDenominated)
      },
      openSerialPortDialog: async function () {
        this.config = {...HWW_DEFAULT_CONFIG}
        await this.openSerialPort(this.config)
      },
      openSerialPort: async function (config = {baudRate: 9600}) {
        if (!this.checkSerialPortSupported()) return false
        if (this.selectedPort) {
          this.$q.notify({
            type: 'warning',
            message: 'Already connected. Disconnect first!',
            timeout: 10000
          })
          return true
        }

        try {
          this.selectedPort = await navigator.serial.requestPort()
          this.selectedPort.addEventListener('connect', event => {
            // do nothing
          })

          this.selectedPort.addEventListener('disconnect', () => {
            this.selectedPort = null
            this.hww.authenticated = false
            this.$q.notify({
              type: 'warning',
              message: 'Disconnected from Serial Port!',
              timeout: 10000
            })
          })

          // Wait for the serial port to open.
          await this.selectedPort.open(config)
          // do not await
          this.startSerialPortReading()
          // wait to init
          sleep(1000)

          const textEncoder = new TextEncoderStream()
          this.writableStreamClosed = textEncoder.readable.pipeTo(
            this.selectedPort.writable
          )

          this.writer = textEncoder.writable.getWriter()

          await this.hwwPing()

          return true
        } catch (error) {
          this.selectedPort = null
          this.$q.notify({
            type: 'warning',
            message: 'Cannot open serial port!',
            caption: `${error}`,
            timeout: 10000
          })
          return false
        }
      },
      openSerialPortConfig: async function (deviceId) {
        const device = this.getPairedDevice(deviceId)
        if (device) {
          this.config = device.config
        } else {
          this.config = {...HWW_DEFAULT_CONFIG}
        }
        this.hww.showConfigDialog = true
      },
      closeSerialPort: async function () {
        try {
          if (this.writer) this.writer.close()
          if (this.writableStreamClosed) await this.writableStreamClosed
          if (this.reader) this.reader.cancel()
          if (this.readableStreamClosed)
            await this.readableStreamClosed.catch(() => {
              /* Ignore the error */
            })
          if (this.selectedPort) await this.selectedPort.close()
          this.$q.notify({
            type: 'positive',
            message: 'Serial port disconnected!',
            timeout: 5000
          })
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Cannot close serial port!',
            caption: `${error}`,
            timeout: 10000
          })
        } finally {
          this.selectedPort = null
          this.hww.authenticated = false
        }
      },

      isConnected: function () {
        return !!this.selectedPort
      },
      isAuthenticated: function () {
        return this.hww.authenticated
      },

      seedInputDone: function (mnemonic) {
        this.hww.mnemonic = mnemonic
      },
      isAuthenticating: function () {
        if (this.isAuthenticated()) return false
        return new Promise(resolve => {
          this.loginResolve = resolve
        })
      },

      isSendingPsbt: async function () {
        if (!this.hww.sendingPsbt) return false
        return new Promise(resolve => {
          this.psbtSentResolve = resolve
        })
      },

      isFetchingXpub: async function () {
        return new Promise(resolve => {
          this.xpubResolve = resolve
        })
      },

      checkSerialPortSupported: function () {
        if (!navigator.serial) {
          this.$q.notify({
            type: 'warning',
            message: 'Serial port communication not supported!',
            caption:
              'Make sure your browser supports Serial Port and that you are using HTTPS.',
            timeout: 10000
          })
          return false
        }
        return true
      },
      startSerialPortReading: async function () {
        const port = this.selectedPort

        while (port && port.readable) {
          const textDecoder = new TextDecoderStream()
          this.readableStreamClosed = port.readable.pipeTo(textDecoder.writable)
          this.reader = textDecoder.readable.getReader()
          const readStringUntil = readFromSerialPort(this.reader)

          try {
            while (true) {
              const {value, done} = await readStringUntil('\n')
              if (value) {
                const {command, commandData} = await this.extractCommand(value)
                this.handleSerialPortResponse(command, commandData)
                this.updateSerialPortConsole(command)
              }
              if (done) return
            }
          } catch (error) {
            this.$q.notify({
              type: 'warning',
              message: 'Serial port communication error!',
              caption: `${error}`,
              timeout: 10000
            })
          }
        }
      },
      handleSerialPortResponse: async function (command, commandData) {
        this.logPublicCommandsResponse(command, commandData)

        switch (command) {
          case COMMAND_PING:
            this.handlePingResponse(commandData)
            break
          case COMMAND_CHECK_PAIRING:
            this.handleCheckPairingResponse(commandData)
            break
          case COMMAND_SIGN_PSBT:
            this.handleSignResponse(commandData)
            break
          case COMMAND_PASSWORD:
            this.handleLoginResponse(commandData)
            break
          case COMMAND_PASSWORD_CLEAR:
            this.handleLogoutResponse(commandData)
            break
          case COMMAND_SEND_PSBT:
            this.handleSendPsbtResponse(commandData)
            break
          case COMMAND_WIPE:
            this.handleWipeResponse(commandData)
            break
          case COMMAND_XPUB:
            this.handleXpubResponse(commandData)
            break
          case COMMAND_SEED:
            this.handleShowSeedResponse(commandData)
            break
          case COMMAND_PAIR:
            this.handlePairResponse(commandData)
            break
          case COMMAND_LOG:
            console.log(
              `   %c${commandData}`,
              'background: #222; color: #bada55'
            )
            break
          default:
            console.log(`   %c${command}`, 'background: #222; color: red')
        }
      },
      logPublicCommandsResponse: function (command, commandData) {
        switch (command) {
          case COMMAND_SIGN_PSBT:
          case COMMAND_PASSWORD:
          case COMMAND_PASSWORD_CLEAR:
          case COMMAND_SEND_PSBT:
          case COMMAND_WIPE:
          case COMMAND_XPUB:
          case COMMAND_PAIR:
            console.log(
              `   %c${command} ${commandData}`,
              'background: #222; color: yellow'
            )
        }
      },
      updateSerialPortConsole: function (value) {
        this.receivedData += value + '\n'
        const textArea = document.getElementById('serial-port-console')
        if (textArea) textArea.scrollTop = textArea.scrollHeight
      },
      hwwPing: async function () {
        try {
          // Send an empty ping. The serial port buffer might have some jubk data. Flush it.
          await this.sendCommandClearText(COMMAND_PING)
          await this.sendCommandClearText(COMMAND_PING, [window.location.host])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to ping Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handlePingResponse: function (res = '') {
        const [status, deviceId] = res.split(' ')
        this.deviceId = deviceId

        if (!this.deviceId) {
          this.$q.notify({
            type: 'warning',
            message: 'Missing device ID for Hardware Wallet',
            timeout: 10000
          })
          return
        }

        const device = this.getPairedDevice(deviceId)

        if (device) {
          this.sharedSecret = nobleSecp256k1.utils.hexToBytes(
            device.sharedSecretHex
          )
          this.hwwCheckPairing()
        } else {
          this.hwwPair()
        }
      },
      hwwShowPasswordDialog: async function () {
        try {
          this.hww.showPasswordDialog = true
          await this.sendCommandSecure(COMMAND_PASSWORD)
        } catch (error) {
          console.log(error)
          this.$q.notify({
            type: 'warning',
            message: 'Failed to connect to Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwShowWipeDialog: async function () {
        try {
          this.hww.showWipeDialog = true
          await this.sendCommandSecure(COMMAND_WIPE)
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to connect to Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwShowRestoreDialog: async function () {
        try {
          this.hww.showRestoreDialog = true
          await this.sendCommandSecure(COMMAND_RESTORE)
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to connect to Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      closeSeedDialog: function () {
        this.hww.seedWord = null
        this.hww.showSeedWord = false
      },
      hwwConfirmNext: async function () {
        this.hww.confirm.outputIndex += 1
        if (this.hww.confirm.outputIndex >= this.tx.outputs.length) {
          this.hww.confirm.showFee = true
        }
        await this.sendCommandSecure(COMMAND_CONFIRM_NEXT)
      },
      cancelOperation: async function () {
        try {
          await this.sendCommandSecure(COMMAND_CANCEL)
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to send cancel!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwConfigAndConnect: async function () {
        this.hww.showConfigDialog = false
        if (this.config.deviceId) {
          this.updatePairedDeviceConfig(this.config.deviceId, this.config)
        }
        await this.openSerialPort(this.config)
        return true
      },
      hwwLogin: async function () {
        try {
          await this.sendCommandSecure(COMMAND_PASSWORD, [
            this.hww.password,
            this.hww.passphrase
          ])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to send password to Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        } finally {
          this.hww.showPasswordDialog = false
          this.hww.password = null
          this.hww.passphrase = null
          this.hww.showPassword = false
          this.hww.showPassphrase = false
        }
      },
      handleLoginResponse: function (res = '') {
        this.hww.authenticated = res.trim() === '1'
        if (this.loginResolve) {
          this.loginResolve(this.hww.authenticated)
        }

        if (this.hww.authenticated) {
          this.$q.notify({
            type: 'positive',
            message: 'Login successfull!',
            timeout: 10000
          })
        } else {
          this.$q.notify({
            type: 'warning',
            message: 'Wrong password, try again!',
            timeout: 10000
          })
        }
      },
      hwwLogout: async function () {
        try {
          await this.sendCommandSecure(COMMAND_PASSWORD_CLEAR)
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to logout from Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwShowAddress: async function (path, address) {
        try {
          await this.sendCommandSecure(COMMAND_ADDRESS, [
            this.network,
            path,
            address
          ])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to logout from Hardware Wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handleLogoutResponse: function (res = '') {
        const authenticated = !(res.trim() === '1')
        if (this.hww.authenticated && !authenticated) {
          this.$q.notify({
            type: 'positive',
            message: 'Logged Out',
            timeout: 10000
          })
        }
        this.hww.authenticated = authenticated
      },
      hwwSendPsbt: async function (psbtBase64, tx) {
        try {
          this.tx = tx
          this.hww.sendingPsbt = true
          await this.sendCommandSecure(COMMAND_SEND_PSBT, [
            this.network,
            psbtBase64
          ])
          this.$q.notify({
            type: 'positive',
            message: 'Data sent to serial port device!',
            timeout: 5000
          })
        } catch (error) {
          this.hww.sendingPsbt = false
          this.$q.notify({
            type: 'warning',
            message: 'Failed to send data to serial port!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handleSendPsbtResponse: function (res = '') {
        try {
          const psbtOK = res.trim() === '1'
          if (!psbtOK) {
            this.$q.notify({
              type: 'warning',
              message: 'Failed to send PSBT!',
              caption: `${res}`,
              timeout: 10000
            })
            return
          }
          this.hww.confirm.outputIndex = 0
          this.hww.showConfirmationDialog = true
          this.hww.confirm = {
            outputIndex: 0,
            showFee: false
          }
          this.hww.sendingPsbt = false
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to send PSBT!',
            caption: `${error}`,
            timeout: 10000
          })
        } finally {
          this.psbtSentResolve()
        }
      },
      hwwSignPsbt: async function () {
        try {
          this.hww.showConfirmationDialog = false
          this.hww.signingPsbt = true
          await this.sendCommandSecure(COMMAND_SIGN_PSBT)
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to sign PSBT!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handleSignResponse: function (res = '') {
        this.hww.signingPsbt = false
        const [count, psbt] = res.trim().split(' ')
        if (!psbt || !count || count.trim() === '0') {
          this.$q.notify({
            type: 'warning',
            message: 'No input signed!',
            caption: 'Are you using the right seed?',
            timeout: 10000
          })
          return
        }
        this.updateSignedPsbt(psbt)
        this.$q.notify({
          type: 'positive',
          message: 'Transaction Signed',
          message: `Inputs signed: ${count}`,
          timeout: 10000
        })
      },
      hwwCheckPairing: async function () {
        const iv = window.crypto.getRandomValues(new Uint8Array(16))
        const encrypted = await this.encryptMessage(
          this.sharedSecret, // todo: revisit
          iv,
          PAIRING_CONTROL_TEXT.length + ' ' + PAIRING_CONTROL_TEXT
        )

        const encryptedHex = nobleSecp256k1.utils.bytesToHex(encrypted)
        const encryptedIvHex = nobleSecp256k1.utils.bytesToHex(iv)
        try {
          await this.sendCommandClearText(COMMAND_CHECK_PAIRING, [
            encryptedHex + encryptedIvHex
          ])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to check secure connection!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handleCheckPairingResponse: async function (res = '') {
        const [statusCode, message] = res.split(' ')
        switch (statusCode) {
          case '0':
            const controlText = await this.decryptData(message)
            if (controlText == PAIRING_CONTROL_TEXT) {
              this.$q.notify({
                type: 'positive',
                message: 'Re-paired with success!',
                timeout: 10000
              })
            } else {
              this.$q.notify({
                type: 'warning',
                message: 'Re-pairing failed!',
                caption: 'Remove (forget) device and try again!',
                timeout: 10000
              })
            }
            break
          case '1':
            this.closeSerialPort()
            this.$q.notify({
              type: 'warning',
              message:
                'Re-pairing failed. Remove (forget) device and try again!',
              caption: `Error: ${message}`,
              timeout: 10000
            })
            break
          default:
            // noting to do here yet
            break
        }
      },
      hwwPair: async function () {
        try {
          this.decryptionKey = nobleSecp256k1.utils.randomPrivateKey()
          const publicKey = nobleSecp256k1.Point.fromPrivateKey(
            this.decryptionKey
          )
          const publicKeyHex = publicKey.toHex().slice(2)

          const args = [publicKeyHex]
          if (Number.isInteger(+this.config.buttonOnePin)) {
            args.push(this.config.buttonOnePin)
          }
          if (Number.isInteger(+this.config.buttonTwoPin)) {
            args.push(this.config.buttonTwoPin)
          }
          await this.sendCommandClearText(COMMAND_PAIR, args)
          this.$q.notify({
            type: 'positive',
            message: 'Pairing started!',
            timeout: 5000
          })
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to pair with device!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handlePairResponse: async function (res = '') {
        const [statusCode, data] = res.trim().split(' ')
        let pubKeyHex, errorMessage, captionMessage
        switch (statusCode) {
          case '0':
            pubKeyHex = data
            if (!data) errorMessage = 'Failed to exchange DH secret!'
            break
          case '1':
            errorMessage =
              'Device pairing only possible in the first 10 seconds after start-up!'
            captionMessage = 'Restart and try again'
            break

          default:
            errorMessage = 'Unexpected error code'
            break
        }

        if (errorMessage) {
          this.$q.notify({
            type: 'warning',
            message: errorMessage,
            caption: captionMessage || '',
            timeout: 10000
          })
          this.closeSerialPort()
          return
        }
        const hwwPublicKey = nobleSecp256k1.Point.fromHex('04' + pubKeyHex)

        this.sharedSecret = nobleSecp256k1
          .getSharedSecret(this.decryptionKey, hwwPublicKey)
          .slice(1, 33)

        const sharedSecretHex = nobleSecp256k1.utils.bytesToHex(
          this.sharedSecret
        )
        const sharedSecredHash = await nobleSecp256k1.utils.sha256(
          asciiToUint8Array(sharedSecretHex)
        )
        const fingerprint = nobleSecp256k1.utils
          .bytesToHex(sharedSecredHash)
          .substring(0, 5)
          .toUpperCase()

        LNbits.utils
          .confirmDialog('Confirm code from display: ' + fingerprint)
          .onOk(() => {
            this.addPairedDevice(
              this.deviceId,
              nobleSecp256k1.utils.bytesToHex(this.sharedSecret),
              this.config
            )

            this.$q.notify({
              type: 'positive',
              message: 'Paired with device!',
              timeout: 5000
            })
          })
          .onCancel(() => {
            this.closeSerialPort()
          })
      },
      hwwHelp: async function () {
        try {
          await this.sendCommandSecure(COMMAND_HELP)
          this.$q.notify({
            type: 'positive',
            message: 'Check display or console for details!',
            timeout: 5000
          })
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to ask for help!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwWipe: async function () {
        try {
          this.hww.showWipeDialog = false
          await this.sendCommandSecure(COMMAND_WIPE, [this.hww.password])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to wipe!',
            caption: `${error}`,
            timeout: 10000
          })
        } finally {
          this.hww.password = null
          this.hww.confirmedPassword = null
          this.hww.showPassword = false
        }
      },
      handleWipeResponse: function (res = '') {
        const wiped = res.trim() === '1'
        if (wiped) {
          this.$q.notify({
            type: 'positive',
            message: 'Wallet wiped!',
            timeout: 10000
          })
        } else {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to wipe wallet!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      hwwXpub: async function (path) {
        try {
          await this.sendCommandSecure(COMMAND_XPUB, [this.network, path])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to fetch XPub!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      handleXpubResponse: function (res = '') {
        const args = res.trim().split(' ')
        if (args.length < 3 || args[0].trim() !== '1') {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to fetch XPub!',
            caption: `${res}`,
            timeout: 10000
          })
          this.xpubResolve({})
          return
        }
        const xpub = args[1].trim()
        const fingerprint = args[2].trim()
        this.xpubResolve({xpub, fingerprint})
      },

      hwwShowSeed: async function () {
        try {
          this.hww.showSeedDialog = true
          this.hww.seedWordPosition = 1

          await this.sendCommandSecure(COMMAND_SEED, [
            this.hww.seedWordPosition
          ])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to show seed!',
            caption: `${error}`,
            timeout: 10000
          })
        }
      },
      showNextSeedWord: async function () {
        this.hww.seedWordPosition++
        await this.sendCommandSecure(COMMAND_SEED, [this.hww.seedWordPosition])
      },
      showPrevSeedWord: async function () {
        this.hww.seedWordPosition = Math.max(1, this.hww.seedWordPosition - 1)
        await this.sendCommandSecure(COMMAND_SEED, [this.hww.seedWordPosition])
      },
      handleShowSeedResponse: function (res = '') {
        const [pos, word] = res.trim().split(' ')
        this.hww.seedWord = `${pos}. ${word}`
        this.hww.seedWordPosition = pos
      },
      hwwRestore: async function () {
        try {
          await this.sendCommandSecure(COMMAND_RESTORE, [
            this.hww.password,
            this.hww.mnemonic
          ])
        } catch (error) {
          this.$q.notify({
            type: 'warning',
            message: 'Failed to restore from seed!',
            caption: `${error}`,
            timeout: 10000
          })
        } finally {
          this.hww.showRestoreDialog = false
          this.hww.mnemonic = null
          this.hww.showMnemonic = false
          this.hww.password = null
          this.hww.confirmedPassword = null
          this.hww.showPassword = false
        }
      },

      updateSignedPsbt: async function (value) {
        this.$emit('signed:psbt', value)
      },

      sendCommandSecure: async function (command, attrs = []) {
        const message = [command].concat(attrs).join(' ')
        const iv = window.crypto.getRandomValues(new Uint8Array(16))
        if (!this.sharedSecret || !this.sharedSecret.length) {
          throw new Error(
            `Secure connection not estabileshed. Tried to run command: ${command}`
          )
        }
        const encrypted = await this.encryptMessage(
          this.sharedSecret,
          iv,
          message.length + ' ' + message
        )

        const encryptedHex = nobleSecp256k1.utils.bytesToHex(encrypted)
        const encryptedIvHex = nobleSecp256k1.utils.bytesToHex(iv)
        await this.writer.write(encryptedHex + encryptedIvHex + '\n')
      },
      sendCommandClearText: async function (command, attrs = []) {
        const message = [command].concat(attrs).join(' ')
        await this.writer.write(message + '\n')
      },
      extractCommand: async function (value) {
        const command = value.split(' ')[0]
        const commandData = value.substring(command.length).trim()

        if (
          command === COMMAND_PAIR ||
          command === COMMAND_LOG ||
          command === COMMAND_PASSWORD_CLEAR ||
          command === COMMAND_PING ||
          command === COMMAND_CHECK_PAIRING
        )
          return {command, commandData}

        const decryptedValue = await this.decryptData(value)
        const decryptedCommand = decryptedValue.split(' ')[0]
        const decryptedCommandData = decryptedValue
          .substring(decryptedCommand.length)
          .trim()
        return {
          command: decryptedCommand,
          commandData: decryptedCommandData
        }
      },
      decryptData: async function (value) {
        if (!this.sharedSecret) {
          return '/error Secure session not established!'
        }
        try {
          const ivSize = 32
          const messageHex = value.substring(0, value.length - ivSize)
          const ivHex = value.substring(value.length - ivSize)
          const messageBytes = nobleSecp256k1.utils.hexToBytes(messageHex)
          const iv = nobleSecp256k1.utils.hexToBytes(ivHex)
          const decrypted1 = await this.decryptMessage(
            this.sharedSecret,
            iv,
            messageBytes
          )
          const data = new TextDecoder().decode(decrypted1)
          const [len] = data.split(' ')
          const command = data
            .substring(len.length + 1, +len + len.length + 1)
            .trim()
          return command
        } catch (error) {
          return '/error Failed to decrypt message from device!'
        }
      },
      encryptMessage: async function (key, iv, message) {
        while (message.length % 16 !== 0) message += ' '
        const encodedMessage = asciiToUint8Array(message)

        const aesCbc = new aesjs.ModeOfOperation.cbc(key, iv)
        const encryptedBytes = aesCbc.encrypt(encodedMessage)

        return encryptedBytes
      },
      decryptMessage: async function (key, iv, encryptedBytes) {
        const aesCbc = new aesjs.ModeOfOperation.cbc(key, iv)
        const decryptedBytes = aesCbc.decrypt(encryptedBytes)
        return decryptedBytes
      },

      getPairedDevice: function (deviceId) {
        return this.pairedDevices.find(d => d.id === deviceId)
      },
      removePairedDevice: function (deviceId) {
        const devices = this.pairedDevices
        const deviceIndex = devices.findIndex(d => d.id === deviceId)
        if (deviceIndex !== -1) {
          devices.splice(deviceIndex, 1)
        }
        this.pairedDevices = devices
        this.showPairedDevices = false
        setTimeout(() => {
          // force UI refresh
          this.showPairedDevices = true
        })
      },
      addPairedDevice: function (deviceId, sharedSecretHex, config) {
        const devices = this.pairedDevices
        config.deviceId = deviceId
        devices.unshift({
          id: deviceId,
          sharedSecretHex: sharedSecretHex,
          pairingDate: new Date().toISOString(),
          config
        })
        this.pairedDevices = devices
        this.showPairedDevices = false
        setTimeout(() => {
          // force UI refresh
          this.showPairedDevices = true
        })
      },
      updatePairedDeviceConfig(deviceId, config) {
        const device = this.getPairedDevice(deviceId)
        if (device) {
          this.removePairedDevice(deviceId)
          this.addPairedDevice(deviceId, device.sharedSecretHex, config)
        }
      }
    },
    created: async function () {}
  })
}