var decodeValueFns = {
  group: decodeSet,
  pairwise: decodeSet,
  key_mgmt: decodeSet,
  proto: decodeSet,
  eap: decodeSet,
  ctrl_interface: decodeObj,
  driver_param: decodeObj,
}

function defaultDecodeValue(value) {
  try {
    return JSON.parse(value)
  } catch(e) {}
  var m = /^"(.*)"$/.exec(value)
  if (m) return m[1]
  return value
}

function decodeSet(value) {
  return value.split(' ')
}

function decodeObj(str) {
  var obj = {}
  str.split(' ').map(decodeProperty).forEach(function (prop) {
    obj[prop.name] = prop.value
  })
  return obj
}

function decodeProperty(line) {
  var m = /^([^=]*)=(.*)$/.exec(line)
  if (!m) return
  var name = m[1]
  var decodeValue = decodeValueFns[name] || defaultDecodeValue
  return {name: name, value: decodeValue(m[2])}
}

module.exports = function decodeConfig(txt) {
  var lines = txt.split(/\s*[\n\r]+\s*/g)
  var state = 'begin'
  var preNetworkComments = []
  var prop
  var network
  var conf = {
    networks: []
  }
  lines.forEach(function (line) {
    line = line.trim()
    switch (state) {
      case 'begin':
        if (line[0] === '#') {
          preNetworkComments.push(line.substr(1))
        } else if (/^network={/.test(line)) {
          state = 'network'
          network = {}
          conf.networks.push(network)
          if (preNetworkComments.length > 0) {
            network._comment = preNetworkComments.join('\n')
            preNetworkComments = []
          }
        } else if (prop = decodeProperty(line)) {
          conf[prop.name] = prop.value
          if (preNetworkComments.length > 0) {
            // should comments before global config items be handled?
            preNetworkComments = []
          }
        }
        break
      case 'network':
        if (line[0] === '#') {
          // should comments in network blocks be handled?
        } else if (line === '}') {
          state = 'begin'
        } else if (prop = decodeProperty(line)) {
          network[prop.name] = prop.value
        } else {
          throw new Error('unexpected line in network block: ' + line)
        }
        break
    }
  })
  return conf
}