import { effect, signal, batch } from '@preact/signals-core'
import { runCommand } from './runner.mjs'
import serial from '../serial/serial.mjs'

class EncoderManager {
  constructor() {
    this.encoder = signal(null)
    this.frameMatcher = new RegExp('frame= *(\\d+\\.?\\d*).*fps= *(\\d+\\.?\\d*).*bitrate= *(\\d+\\.?\\d*).*speed= *(\\d+\\.?\\d*)')
    this.repeatedMatcher = new RegExp('repeated (\\d+) time')

    this.stopError = null
    this.attempting = signal(false)
    this.encoderStatus = signal(null)
    this.data = ''
    this.failues = 0
    this.logHistory = []
    this.setup()
  }

  updateSmartMonitor(status) {
    if (status.errors) {
      if ((new Date() - status.lastError) > 1000 * 60 * 60) {
        status.errors = status.repeated = 0
        status.lastError = null
      }
    }
    if (status.speed < 1) {
      status.showSlowSpeed = new Date()
    } else if (status.speed > 1 || (status.showSlowSpeed && new Date() - status.showSlowSpeed > 1000 * 60 * 60 * 2)) {
      status.showSlowSpeed = null
    }
    if (status.errors && status.errors > 100) {
      this.stopError = new Error('Too many errors')
      this.safeStop()
      return true
    }
    return false
  }

  setup() {
    effect(() => {
      let attempting = this.attempting.value
      let status = this.encoderStatus.value
      let encoder = this.encoder.value

      if (this.stopError) {
        this.io?.io.emit('encoder.stats', null)
        this.io?.io.emit('encoder.status', this.status())
        return serial.updateDisplay(
          'Stream was stopped:',
          this.stopError.message,
        )
      }
      if (attempting || (encoder && !status)) {
        this.io?.io.emit('encoder.status', this.status())
        return serial.updateDisplay(
          'Filadelfia streamer',
          'Starting [         ]',
        )
      }
      if (!encoder && status) {
        this.io?.io.emit('encoder.stats', null)
        this.io?.io.emit('encoder.status', this.status())
        return serial.updateDisplay(
          'Error, no encoder',
          'but there was status',
        )
      }
      if (!encoder) {
        this.io?.io.emit('encoder.stats', null)
        this.io?.io.emit('encoder.status', this.status())
        return serial.updateDisplay(
          'Filadelfia streamer',
          'Status: Offline.',
        )
      }
      if (this.updateSmartMonitor(status)) {
        return
      }
      if (status.lastPrint && (new Date() - status.lastPrint) < 1000) {
        return
      }
      this.io?.io.emit('encoder.stats', status)
      status.lastPrint = new Date()
      let prefix = 'LIVE'
      if (status.showSlowSpeed) {
        prefix = 'SLOW SPEED'
      }
      if (status.errors) {
        prefix = `${status.errors} ERRORS`
      }
      let fps = `fps=${status.fps.toFixed(1)}`
      return serial.updateDisplay(
        prefix + (` spd=${status.speed % 1 === 0 ? status.speed : status.speed.toFixed(3)}x`).padStart(20 - prefix.length),
        fps + (` kbps=${Math.round(status.bitrate)}`.padStart(20 - fps.length)),
      )
    })
  }

  init(core, io) {
    this.core = core
    this.io = io
    if (!this.core.db.data.encoder_settings) {
      this.core.db.data.encoder_settings = {
        device: '',
        format_code: '',
        command: 'ffmpeg.exe -f decklink -pix_fmt yuv420p -vcodec libx264 -vf yadif=1 -b:v 8000k -maxrate 8000k -minrate 8000k -bufsize 8000k -x264-params "nal-hrd=cbr" -preset faster -tune zerolatency -g 100 -keyint_min 100 -force_key_frames "expr:gte(t,n_forced*2)" -profile:v main -r 50 -ac 2 -c:a libfdk_aac -b:a 164k -ar 44100 -f mp4 test.mp4'
      }
      this.core.db.write()
    }
    this.safeStart()
  }

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

  safeStart() {
    this.stopError = null
    if (this.attempting.value) return

    batch(() => {
      this.encoderStatus.value = null
      this.attempting.value = true
    })

    this.start()
    .then(
      encoder => {
        this.encoder.value = encoder
      },
      err => {
        this.log('error', err.message)
      }
    )
    .then(() => {
      this.attempting.value = false
    })
  }

  safeStop(process) {
    let encoder = process || this.encoder.value || this.attempting.value
    if (!encoder || encoder === true) return
    try {
      encoder.stdin.write('q')
    } catch {
      encoder.kill()
    }

    setTimeout(() => {
      if (encoder.exitCode === null) {
        encoder.kill()
      }
    }, 1000)
  }

  async start() {
    let settings = this.core.db.data.encoder_settings
    let command = settings.command
    if (settings.command.indexOf('-f decklink')) {
      if ((settings.command.indexOf('-i ') < 0 && !settings.device)
          || (settings.command.indexOf('-format_code') < 0 && !settings.format_code)) {
        throw new Error('Missing deckling device or format_code')
      }
      command = command.replace('-f decklink ', `${settings.format_code} -f decklink ${settings.device} `)
    }
    command = command.replace('$date$', new Date().toISOString().replace('T','_').replace(/:/g,'').split('.')[0])

    let process = await runCommand('', command, this.fromEncoder.bind(this), true)
    this.attempting.value = process
    let index = 0
    while (index < 100 && process.exitCode === null && !process.killed && !this.encoderStatus.value) {
      if (index > 0 && index % 10 === 0) {
        let bars = Buffer.from(new Array(Math.min(index / 10, 9)).fill(255))
        serial.updateDisplay(
          'Filadelfia streamer',
          Buffer.concat([
            Buffer.from('Starting ['),
            bars,
            Buffer.from(']'.padStart(10 - bars.length))
          ]),
        )
      }
      await new Promise(res => setTimeout(res, 100))
      index++
    }
    if (process.exitCode !== null) {
      throw new Error('Failed to start encoder, exit code: ' + process.exitCode)
    }
    if (!this.encoderStatus.value) {
      this.safeStop(process)
      throw new Error('Encoder did not start successfully, shutting down')
    }
    this.listen(process)

    return process
  }

  fromEncoder(message, source) {
    let lowered = message.toLocaleLowerCase()
    let status = this.encoderStatus.value

    // Limit normal logging to log file a little bit from the encoder, just to not cause a massive spam in our log file
    let allowNormalLogging = !status || !status.lastLog
    let allowWarnLogging = allowNormalLogging
    if (status?.lastLog && new Date() - status.lastLog > 1000 * 57) {
      allowWarnLogging = true
      if (new Date() - status.lastLog > 1000 * 60) {
        allowNormalLogging = true
        status.lastLog = new Date()
      }
    }

    // Handle buffered overrun detection
    if (lowered.indexOf('decklink') > 0 && lowered.indexOf('buffer overrun') > 0 && status) {
      status.errors += 1
      status.lastError = new Date()
      this.encoderStatus.value = status
      return this.log('warn', message, allowWarnLogging)
    }

    // Handle repeated error detection
    let repeated = this.repeatedMatcher.exec(lowered)
    if (repeated && status) {
      let newRepeated = Number(repeated[1])
      if (status.repeated > newRepeated) {
        status.errors += newRepeated
      } else {
        status.errors += (newRepeated - status.repeated)
      }
      status.repeated = newRepeated
      return this.log('warn', message, allowWarnLogging)
    }

    // Handle anything that is not a frame progress
    if (message.indexOf('frame=') < 0) {
      if (status) {
        status.errors += 1
        status.lastError = new Date()
      }
      return this.log('info', message, allowNormalLogging)
    }
    let groups = this.frameMatcher.exec(lowered)
    if (!groups) {
      return this.log('warn', message)
    }
    status = status || {
      errors: 0,
      repeated: 0,
      lastError: null,
      lastLog: new Date()
    }
    this.encoderStatus.value = {
      ...status,
      frame: Number(groups[1]),
      fps: Number(groups[2]),
      bitrate: Number(groups[3]),
      speed: Number(groups[4]),
    }
  }

  listen(process) {
    process.on('error', function(err) {
      this.log('error', 'Encode process encountered an error: ' + err.message)
    })
    process.once('exit', (code) => {
      if (code !== 0) {
        this.log('error', 'Encoder returned error code: ' + code)
      } else {
        this.log('warn', 'Encoder closed normally')
      }
      batch(() => {
        this.encoder.value = this.encoderStatus.value = null
      })
    })
  }

  status() {
    return {
      status: this.encoderStatus.value,
      stopError: this.stopError?.message,
      starting: Boolean(this.attempting.value),
      running: Boolean(this.encoder.value),
      log: this.logHistory.join('\n'),
      settings: this.core.db.data.encoder_settings,
    }
  }
}

const encoder = new EncoderManager()
export default encoder;