var http = require('http')

var constant = require('./constants')
var helper = require('./helper')
var cfg = require('./config')

var parseExitCode = function (buffer, defaultCode) {
  var tailPos = buffer.length - Buffer.byteLength(constant.EXIT_CODE) - 1

  if (tailPos < 0) {
    return defaultCode
  }

  // tail buffer which might contain the message
  var tail = buffer.slice(tailPos)
  var tailStr = tail.toString()
  if (tailStr.substr(0, tailStr.length - 1) === constant.EXIT_CODE) {
    tail.fill('\x00')
    return parseInt(tailStr.substr(-1), 10)
  }

  return defaultCode
}

// TODO(vojta): read config file (port, host, urlRoot)
exports.run = function (config, done) {
  done = helper.isFunction(done) ? done : process.exit
  config = cfg.parseConfig(config.configFile, config)

  var exitCode = 1
  var options = {
    hostname: config.hostname,
    path: config.urlRoot + 'run',
    port: config.port,
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    }
  }

  var request = http.request(options, function (response) {
    response.on('data', function (buffer) {
      exitCode = parseExitCode(buffer, exitCode)
      process.stdout.write(buffer)
    })

    response.on('end', function () {
      done(exitCode)
    })
  })

  request.on('error', function (e) {
    if (e.code === 'ECONNREFUSED') {
      console.error('There is no server listening on port %d', options.port)
      done(1, e.code)
    } else {
      throw e
    }
  })

  request.end(JSON.stringify({
    args: config.clientArgs,
    removedFiles: config.removedFiles,
    changedFiles: config.changedFiles,
    addedFiles: config.addedFiles,
    refresh: config.refresh
  }))
}
