include <string>
  include <Logger.h>
  
  using namespace std;
  
  const string Logger::kLogLevelDebug = "DEBUG";
  const string Logger::kLogLevelInfo = "INFO";
  const string Logger::kLogLevelError = "ERROR";
  
  const char* const Logger::kLogFileName = "log.out";
  
  bool Logger::sInitialized = false;
  ofstream Logger::sOutputStream;
  
  void Logger::log(const string& inMessage, const string& inLogLevel)
  {
    if (!sInitialized) {
      init();
    }
    // print Print the message and flush the stream with endl.
    sOutputStream << inLogLevel << ": " << inMessage << endl;
  
  }
  
  void Logger::log(const vector<string>& inMessages, const string& inLogLevel)
  {
    for (size_t i = 0; i < inMessages.size(); i++) {
  
      log(inMessages[i], inLogLevel);
    }
  }
  
  void Logger::teardown()
  {
    if (sInitialized) {
      sOutputStream.close();
      sInitialized = false;
    }
  }
  
  void Logger::init()
  {
    if (!sInitialized) {
      sOutputStream.open(kLogFileName, ios_base::app);
      if (!sOutputStream.good()) {
        cerr << "Unable to initialize the Logger!" << endl;
        return;
      }
      sInitialized = true;
    }
  }
  
  int main(int argc, char** argv)
  {
    Logger::log("test message", Logger::kLogLevelDebug);
  
    vector<string> items;
    items.push_back("item1");
    items.push_back("item2");
  
    Logger::log(items, Logger::kLogLevelError);
  
    Logger::teardown();
  }