// This code is a simplified and typed version adapted from the 'node-record-lpcm16' project by Gilles De Mey.
// Original source code: https://github.com/gillesdemey/node-record-lpcm16

import { ok as assert } from "assert"
import { ChildProcess, spawn } from "child_process"
import { Readable } from "stream"
import { ReadableStream } from "stream/web"

export type SoxRecordingOptions = {
  sampleRate: number
  channels: number
  compress: boolean
  threshold: number
  silence: string
  endOnSilence: boolean
  audioType: string
}

const debug =
  !!process.env.DEBUG && process.env.DEBUG.indexOf("record") !== -1
    ? console.debug
    : () => {}

export class SoxRecording {
  private options: SoxRecordingOptions
  private process: ChildProcess | undefined
  private soxStream: Readable | null | undefined

  constructor(options = {}) {
    const defaults = {
      sampleRate: 16000,
      channels: 1,
      compress: false,
      threshold: 0.5,
      silence: "1.0",
      recorder: "sox",
      endOnSilence: false,
      audioType: "wav",
    }

    this.options = Object.assign(defaults, options)

    debug("Started recording")
    debug(this.options)

    return this.start()
  }

  start() {
    const cmd = "sox"
    const args = [
      "--default-device",
      "--no-show-progress", // show no progress
      "--rate",
      this.options.sampleRate.toString(), // sample rate
      "--channels",
      this.options.channels.toString(), // channels
      "--encoding",
      "signed-integer", // sample encoding
      "--bits",
      "16", // precision (bits)
      "--type",
      this.options.audioType, // audio type
      "-", // pipe
    ]
    debug(` ${cmd} ${args.join(" ")}`)

    const cp = spawn(cmd, args, {
      stdio: "pipe",
    })
    const rec = cp.stdout
    const err = cp.stderr

    this.process = cp // expose child process
    this.soxStream = cp.stdout // expose output stream

    cp.on("close", (code) => {
      if (code === 0) return
      rec?.emit(
        "error",
        `${cmd} has exited with error code ${code}.

Enable debugging with the environment variable debug=record.`,
      )
    })

    err?.on("data", (chunk) => {
      debug(`STDERR: ${chunk}`)
    })

    rec?.on("data", (chunk) => {
      debug(`Recording ${chunk.length} bytes`)
    })

    rec?.on("end", () => {
      debug("Recording ended")
    })

    return this
  }

  stop() {
    assert(this.process, "Recording not yet started")
    this.process.kill()
  }

  pause() {
    assert(this.process, "Recording not yet started")

    this.process.kill("SIGSTOP")
    this.soxStream?.pause()
    debug("Paused recording")
  }

  resume() {
    assert(this.process, "Recording not yet started")

    this.process.kill("SIGCONT")
    this.soxStream?.resume()
    debug("Resumed recording")
  }

  isPaused() {
    assert(this.process, "Recording not yet started")

    return this.soxStream?.isPaused()
  }

  stream(): ReadableStream<Buffer> {
    assert(this?.soxStream, "Recording not yet started")
    return Readable.toWeb(this?.soxStream)
  }
}