pull

#!/usr/bin/env node

// Parse the arguments from the command as parameters for the pull function.
var params = parseArgv(process.argv)

// Log to the screen. Will only log if --verbose flag is added to the command.
log(params)

if (params.hasOwnProperty('help')) {
  var thermometers=require("temper1x");
  var devices = thermometers.getDevices();
  console.log('./pull')
  console.log('  --path [path] The system path to the device. This can change over time so leave blank for the command to use the first device detected.')
  devices.forEach(function(device) {
    console.log('      ' + device)
  })
  console.log('  --timeout [timeout] How long before trying the `try` command again. If you are on a slow system you may need to increase this.')
  console.log('  --scale [scale] Choose which scale you would like to use. Default is celsius.')
  console.log('    celsius')
  console.log('    farenheit')
  console.log('  --verbose', 'Turn on verbose mode')
}
else {
  // For arguments not set, apply defaults.
  if (!params.hasOwnProperty('timeout')) params.timeout = 3000
  if (!params.hasOwnProperty('scale')) params.scale = 'celsius'
  // Run the pull command!
  pull(params)
}

/*
 * Functions
 */

// This pull command features timeout. That means it will run a try command
// that if it does not hear back from, it will kill the child process and
// run it again. That darn temper1 sensor is finicky, sometimes returning
// a value in 200 milliseconds, sometimes never.
function pull(params) {
  var exec = require('child_process').exec;
  log('trying...')
  function go() {
    var cmd =
      __dirname +
      '/try' +
        ' --path ' + params.path +
        ' --scale ' + params.scale
    if (params.verbose) cmd += ' --verbose'
    log(cmd)
    var child = exec(cmd, function(err, stdout, stderr) {
      if (stdout) {
        var value = stdout.replace(/[\n\r]+/g, '')
        if (params.hasOwnProperty('json')) {
          process.stdout.write('{"' + params.json + '":' + value + '}')
        }
        else {
          process.stdout.write(value)
        }
        process.exit(0)
      }
    })
    setTimeout(function() {
      child.kill('SIGKILL')
      pull(params)
    }, params.timeout)
  }
  if(params.hasOwnProperty('path')) {
    go()
  }
  else {
    var thermometers=require("temper1x");
    var devices = thermometers.getDevices();
    devices.forEach(function(device) {
      params.path = device
    })
    go()
  }
}

// This is the standard function for parsing process.argv. It will return
// an object that where `--argumentName` is a property name and the
// proceding argument is the value. If there is no proceeding value then
// it will be interpreted as a boolean true.
function parseArgv(argv) {
  params = {}
  argv.forEach(function(arg, i) {
    if (arg.substr(0, 2) == '--') {
      paramName = arg.substr(2, arg.length)
      nextArg = argv[i+1]
      if (typeof nextArg == 'string' && nextArg.substr(0, 2) == '--') {
        params[paramName] = true
      }
      else {
        params[paramName] = nextArg
      }
    }
  })
  return params
}

// A log function that will only log if the --verbose flag is set
function log(msg) {
  if (params.hasOwnProperty('verbose')) {
    console.log(msg)
  }
}