var EventEmitter = require('events').EventEmitter
  
  exports = module.exports = function (wrapper) {
  
    if('function' == typeof wrapper)
      return wrapper
    
    return exports[wrapper] || exports.json
  }
  
  exports.json = function (stream, _JSON) {
    _JSON = _JSON || JSON
  
    var write = stream.write
    var soFar = ''
  
    function parse (line) {
      var js
      try {
        js = _JSON.parse(line)
        //ignore lines of whitespace...
      } catch (err) { 
        err.line = line
        return stream.emit('error', err)
        //return console.error('invalid JSON', line)
      }
      if(js !== undefined)
        write.call(stream, js)
    }
  
    function onData (data) {
      var lines = (soFar + data).split('
  ')
      soFar = lines.pop()
      while(lines.length) {
        parse(lines.shift())
      }
    }
  
    stream.write = onData
    
    var end = stream.end
  
    stream.end = function (data) {
      if(data)
        stream.write(data)
      //if there is any left over...
      if(soFar) {
        parse(soFar)
      }
      return end.call(stream)
    }
  
    stream.emit = function (event, data) {
  
      if(event == 'data') {
        data = _JSON.stringify(data) + '
  '
      }
      //since all stream events only use one argument, this is okay...
      EventEmitter.prototype.emit.call(stream, event, data)
    }
  
    return stream
  }
  
  exports.raw = function (stream) {
    return stream
  }