// MT1Q2.cpp - Message Logger

#include <string>
#include <iostream>
#include <vector>
#include <utility>
#include <ctime>
#include <time.h>
#include <fstream>
#include "../Utilities/Utilities.h"

std::string getTimeDate()
{
  //http://stackoverflow.com/questions/997946/how-to-get-current-time-and-date-in-c
  time_t     now = time(0);
  struct tm  tstruct;
  char       buf[80];
  errno_t  err = localtime_s(&tstruct, &now);
  // Visit http://en.cppreference.com/w/cpp/chrono/c/strftime
  // for more information about date/time format
  strftime(buf, sizeof(buf), "%Y-%m-%d %X", &tstruct);
  return buf;
}

struct ILog
{
  using Msg = std::pair < std::string, std::string > ;
  using iterator = std::vector<Msg>::iterator;
  virtual ~ILog() {}
  virtual void message(const std::string& time, const std::string& text)=0;
  virtual iterator begin()=0;
  virtual iterator end()=0;
  virtual void show()=0;
  virtual bool save()=0;
};

struct factory
{
  ILog* create();
};

class Log : public ILog
{
public:
  using Msg = std::pair < std::string, std::string >;
  using iterator = std::vector<Msg>::iterator;
  void message(const std::string& time, const std::string& text);
  virtual iterator begin() { return log_.begin(); }
  virtual iterator end() { return log_.end(); }
  void show();
  bool save();
  // compiler generated methods are correct
private:
  using Msg = std::pair < std::string, std::string >;
  std::vector<Msg> log_;  // stores in arrival order
};                        // std::list<Msg> may have better performance

ILog* factory::create() { return new Log(); }

void Log::message(const std::string& time, const std::string& text)
{
  Msg msg;
  msg.first = time; 
  msg.second = text;
  log_.push_back(msg);
}

void Log::show()
{
  std::cout << "\n  Message Log";
  std::cout << "\n -------------";
  for (auto msg : log_)
  {
    std::cout << "\n  " << msg.first << " " << msg.second;
  }
  std::cout << "\n";
}

bool Log::save()
{
  std::ofstream out("logfile.txt", std::ios::app);
  if (out.good())
  {
    for (auto msg : log_)
    {
      out << "\n  " << msg.first << " " << msg.second;
    }
    out.close();
    log_.clear();
    return true;
  }
  return false;
}

int main()
{
  title("MT1Q2 and MT1Q4 - Message Logger", '=');

  title("testing message logging");
  Log log;
  log.message(getTimeDate(), "first message");
  log.message(getTimeDate(), "second message");
  log.message(getTimeDate(), "third message");

  log.show();
  log.save();
  log.show();

  title("testing interface");
  factory fact;
  ILog* pLog = fact.create();
  pLog->message(getTimeDate(), "fourth message");
  pLog->message(getTimeDate(), "fifth message");
  pLog->message(getTimeDate(), "sixth message");
  pLog->show();
  pLog->save();

  title("testing iterators");
  for (auto item : *pLog)
  {
    std::cout << "\n  " << item.first << " " << item.second;
  }
  std::cout << "\n\n";
}