'use strict'

const { Agent: HttpAgent } = require('bare-node-http')
const { Agent: HttpsAgent } = require('bare-node-https')
const { connect: tlsConnect } = require('bare-node-tls')

let Client

for (const ctor of [HttpAgent, HttpsAgent]) {
  class SSHAgent extends ctor {
    constructor(connectCfg, agentOptions) {
      super(agentOptions)

      this._connectCfg = connectCfg
      this._defaultSrcIP = (agentOptions && agentOptions.srcIP) || 'localhost'
    }

    createConnection(options, cb) {
      const srcIP = (options && options.localAddress) || this._defaultSrcIP
      const srcPort = (options && options.localPort) || 0
      const dstIP = options.host
      const dstPort = options.port

      if (Client === undefined) Client = require('./client.js')

      const client = new Client()
      let triedForward = false
      client
        .on('ready', () => {
          client.forwardOut(srcIP, srcPort, dstIP, dstPort, (err, stream) => {
            triedForward = true
            if (err) {
              client.end()
              return cb(err)
            }
            stream.once('close', () => client.end())
            cb(null, decorateStream(stream, ctor, options))
          })
        })
        .on('error', cb)
        .on('close', () => {
          if (!triedForward) cb(new Error('Unexpected connection close'))
        })
        .connect(this._connectCfg)
    }
  }

  exports[ctor === HttpAgent ? 'SSHTTPAgent' : 'SSHTTPSAgent'] = SSHAgent
}

function noop() {}

function decorateStream(stream, ctor, options) {
  if (ctor === HttpAgent) {
    // HTTP
    stream.setKeepAlive = noop
    stream.setNoDelay = noop
    stream.setTimeout = noop
    stream.ref = noop
    stream.unref = noop
    stream.destroySoon = stream.destroy
    return stream
  }

  // HTTPS
  options.socket = stream
  const wrapped = tlsConnect(options)

  // This is a workaround for a regression in node v12.16.3+
  // https://github.com/nodejs/node/issues/35904
  const onClose = (() => {
    let called = false
    return () => {
      if (called) return
      called = true
      if (stream.isPaused()) stream.resume()
    }
  })()
  // 'end' listener is needed because 'close' is not emitted in some scenarios
  // in node v12.x for some unknown reason
  wrapped.on('end', onClose).on('close', onClose)

  return wrapped
}