church_streamer/api/serial/serial.mjs

import { SerialPort  } from 'serialport'
import { autoDetect } from '@serialport/bindings-cpp'
import { effect, signal } from '@preact/signals-core'

class SerialManager {
  constructor() {
    this.serial = signal(null)
    this.currentDisplay = signal({
      first: 'Filadelfia streamer ',
      second: '                    ',
    })
    this.queue = null
    this.attempting = null
    this.data = ''
    this.failues = 0
    // this.serial = null
    this.gotPing = false
    this.logHistory = []
    this.setup()
  }

  setup() {
    this.binding = autoDetect()
    setInterval(() => {
      if (!this.serial.value) return
      this.serial.value.write('~')
    }, 15000)

    effect(() => {
      if (!this.serial.value) {
        this.gotPing = false
        this.displayUpdated = false
        this.safeStartDelay(5)
        return
      }

      this.log('info', `Connection with display established.`)
      this.updateDisplay(
        'Filadelfia streamer',
        'Version ' + this.core.version,
        true
      )

      if (this.queue) {
        setTimeout(() => {
          this.updateDisplay(
            this.queue[0],
            this.queue[1],
          )
        }, 1000)
      }
    })

    effect(() => {
      let display = this.currentDisplay.value
      this.io?.io.emit('serial.display', display)
    })
  }

  init(core, io) {
    this.core = core
    this.io = io
    this.safeStartDelay(1)
  }

  log(level, message) {
    this.logHistory.unshift(`[${(new Date()).toISOString().replace('T', ' ').split('.')[0]}] ${message}`)
    this.logHistory = this.logHistory.slice(0, 40)
    this.core.log[level]('DISPLAY: ' + message)
    this.io.io.emit('serial.status', this.status())
  }

  bufferToString(buf) {
    if (typeof buf === 'string') return buf
    let out = Buffer.from(buf)
    for (let i = 0; i < out.length; i++) {
      if (out[i] === 255) {
        out.writeUInt8('#'.charCodeAt(0), i)
      }
    }
    return out.toString().replace(/#/g, '█')
  }

  updateDisplay(firstLine, secondLine, local = false) {
    if (!local) {
      this.queue = [firstLine, secondLine]
    }
    if (!this.serial.value) return
    let first = Buffer.from(firstLine)
    let second = Buffer.from(secondLine)
    if (first.length > 20) {
      first = first.subarray(0, 20)
    } else if (first.length < 20) {
      first = Buffer.concat([first, Buffer.from(new Array(20 - first.length).fill(32))])
    }
    if (second.length > 20) {
      second = second.subarray(0, 20)
    } else if (second.length < 20) {
      second = Buffer.concat([second, Buffer.from(new Array(20 - second.length).fill(32))])
    }

    this.serial.value.write(Buffer.concat([
      Buffer.from('^'),
      first,
      second,
    ]))
    this.currentDisplay.value = {
      first: this.bufferToString(firstLine).slice(0, 20),
      second: this.bufferToString(secondLine).slice(0, 20),
    }
  }

  safeStartDelay(sec) {
    if (this.attempting || !this.core) return

    this.log('info', `Attempting to connect with display in ${sec} second${sec > 1 ? 's': ''}.`)
    this.attempting = setTimeout(this.safeStart.bind(this), sec * 1000)
  }

  safeStart() {
    this.start()
    .then(
      serial => {
        this.attempting = null
        this.failues = 0
        this.serial.value = serial
      },
      err => {
        this.attempting = null
        this.failues = Math.min(this.failues + 1, 4)
        this.log('error', err.message)
        this.safeStartDelay(this.failues * 15)
      }
    )
  }

  async start() {
    let list = await this.binding.list()
    if (!list.length) {
      throw new Error('No com ports were found')
    }
    for (let item of list) {
      this.log('info', `Found ${item.path} (${item.friendlyName})`)
    }
    for (let item of list) {
      this.log('info', `Testing out ${item.path} (${item.friendlyName})`)
      let serial = new SerialPort({
        path: item.path,
        baudRate: 9600,
        autoOpen: false,
      })

      await this.openSerial(serial)
      if (!serial.port) continue

      this.listen(serial)
      let index = 0
      while (index < 50 && !this.gotPing) {
        if (index % 10 === 0) serial.write('~')
        await new Promise(res => setTimeout(res, 100))
        index++
      }
      if (this.gotPing) return serial
      serial.destroy()
    }
    throw new Error('Failed to find display device')
  }

  listen(serial) {
    serial.on('data', this.onData.bind(this))
    serial.on('error', err => {
      this.log('error', 'serial on error: ' + err.message)
    })
    serial.once('close', () => {
      serial.destroy()
      if (serial === this.serial.value) {
        this.log('warn', 'Serial was closed')
        this.serial.value = null
      }
    })
  }

  onData(data) {
    this.data = (this.data + data).slice(-1000)

    if (this.data.indexOf('^') < 0) return

    let split = this.data.split('^')
    this.data = split[split.length - 1]
    this.gotPing = this.gotPing || split.includes('pong')
  }

  openSerial(serial) {
    return new Promise(res => {
      serial.open(err => {
        if (err) {
          this.log('error', 'Failed to open serial connection: ' + err.message)
          serial.destroy()
        }
        res()
      })
    })
  }

  getDisplay() {
    return this.currentDisplay.value
  }

  status() {
    return {
      running: Boolean(this.serial.value),
      log: this.logHistory.join('\n'),
    }
  }
}

const serial = new SerialManager()
export default serial;