//pirooz vahedian



#include <iostream>
using namespace std;
#include <fstream>
#include <string>
#include <cctype>
#include <algorithm>

class toLower {public: char operator() (char c) const {return tolower(c) ;}};

bool isValidLocalEmailCharacter(char c) {

  bool validCheck = false;
  if ((c>='A' && c<='Z') || (c>='a' && c<='z') || (c>='0' && c<='9') || (c=='.') || (c=='!') || (c=='#') || (c=='$') || (c=='%') || (c=='&') || (c==39) || (c=='*') || (c=='+') || (c=='-') || (c=='/') || (c=='=') || (c=='?') || (c=='^') || (c=='_') || (c=='`') || (c=='{') || (c=='|') || (c=='}') || (c=='~'))
    {
    validCheck = true;
    }
  return validCheck;
}

bool isValidDomainEmailCharacter(char c) {

  bool validCheck = false;
  if ((c>='A' && c<='Z') || (c>='a' && c<='z') || (c>='0' && c<='9') || (c=='.') || (c=='-') || (c=='+'))
    {
    validCheck = true;
    }
  return validCheck;
}
 
bool isDuplicate(string theAddress, string* address, int SIZE) {
  bool checkDuplicate = false;
  for (int i = 0; i < SIZE; i++)
    {
	string convertedAddress1 = address[i];
    transform(convertedAddress1.begin(), convertedAddress1.end(), convertedAddress1.begin(), toLower());
	  
    string convertedAddress2 = theAddress;
    transform(convertedAddress2.begin(), convertedAddress2.end(), convertedAddress2.begin(), toLower());
	  
    if (convertedAddress1 == convertedAddress2) checkDuplicate = true;
    }
  return checkDuplicate;
}

int main() { // Entry point

  ifstream fin;
  ofstream fout;

  // input file
  string inputFile; 
  cout << "Enter input file: [ blank for default] ";
  getline(cin, inputFile);
  if (inputFile.length() == 0)
    {
	inputFile = "fileContainingEmails.txt";
	cout << "fileContainingEmails.txt has been set as input" << endl;
	}
  
  // output file
  string outputFile; 
  cout << "Enter output file: [blank for default] ";
  getline(cin, outputFile);
    if (outputFile.length() == 0)
    {
	 cout << "copyPasteMyEmails.txt has been set as output file." << endl;
	outputFile = "copyPasteMyEmails.txt";
	}
  
  // Read input file
  fin.open(inputFile.c_str());
  if (!fin.good()) throw "I/O error";

  // make list
  const int MAX_ADDRESSES = 1000; // capacity
  int numAddresses = 0; // start empty
  string address[MAX_ADDRESSES];
  
  cout << endl;
  
  while(fin.good()) // loop till end of text file is reached
  {
  
  string line;
  getline(fin, line);
  
  int startPosition = 0; 
  int endPosition = 0;
  int numberOfPeriods = 0;
  bool doublePeriod = false;
  bool periodEndofSentence = false;
  
  for(int i = 0; i < line.length(); i++) // check lines
    {
	if(line[i] == '@') // check characters to locate position of @ symbol
	  {
	  int atSym = i;
	  for(int m = atSym-1; m >= 0; m--) // go back from position of @ to beginning if needed
	    {
		if(line[m] == '.') // count periods
		  {
		  
		  if(line[m+1] == '.')
		    {
			doublePeriod = true;
		    }
		  numberOfPeriods = numberOfPeriods + 1;
	      }
		if(isValidLocalEmailCharacter(line[m]) == false) // check till invalid character is found
	      {
		    startPosition = m+1; // start point of the next string
		    break;
		  } 
        }
		

		
	  for(int p = atSym+1; p <= line.length(); p++) // start from position of @ to end
	    {
		if(line[p] == '.') // count periods
		  {
		  if(line[p+1] == '.') // break if period is after @ symbol
		  	{
			  doublePeriod = true;
			  
		    }
		  numberOfPeriods = numberOfPeriods + 1;
	      }
	    if(isValidDomainEmailCharacter(line[p]) == false) // check till invalid character is found
	      {
		    endPosition = p;
			break;
		  }
        
		}
		int addressLength = endPosition - startPosition; // Calculate length of address
	    string theAddress = line.substr (startPosition,addressLength); // Capture substring
        cout << theAddress << endl;
	
		
		// check emails, if valid add to list.
        if (numAddresses < MAX_ADDRESSES) // check the list
	      {
		  if (numberOfPeriods > 0)  // Check if enough periods exist
		    {
			if ((line[startPosition] !='.') && (line[endPosition-1] !='.') || (line[endPosition] == ' ') && (line[endPosition-1] == '.')) // Does not start or end with period
		      {
			  if ((doublePeriod == false) && ( line[atSym+1] !='.')) // Does not have consecutive periods
			    {
			    if (addressLength < 254 && atSym - startPosition < 64 && endPosition - atSym < 253 ) // Restrict length
		   	      {
		          if (isDuplicate(theAddress,address,numAddresses) == false) // Skip duplicate addresses
		            {
		            address[numAddresses++] = theAddress; // Add to list
		   	        cout << " VALID" << endl;
		            }// if skip duplicate
		          else
		            {
		            cout << " INVALID! Duplicate." << endl;
		            }
		          } // if restrict length
		        else
		          {
		          cout << " INVALID! Max/min length expectation fail." << endl;
	              }
			    } // if double period
			  else
		        {
		          cout << " INVALID! Consecutive periods or period after @ symbol." << endl;
	            }
			  } // if start or end with period
			else
			  {
		      cout << " INVALID! Starts or ends with a period." << endl;
			  }
			}// if enough periods
		  else
		    {
		    cout << " INVALID! Not enough periods or email address incomplete." << endl;
		    }
			numberOfPeriods = 0; 
			 cout << endl;
		  } 
		 
      }
	} 
  } // While
  fin.close();
  
  if (numAddresses != 0) // open and write to the file if emails are found
  {
    fout.open(outputFile.c_str());
	cout << "Addresses Saved"<< endl;
    for (int i = 0; i < numAddresses; i++)
      { 
        cout << address[i] << endl;
        fout << address[i] << endl;
      }
	  
    cout << endl;
    cout << numAddresses << " emails were found and copied to the file " << outputFile << "." << endl;
	cout << endl;
	cout << "Open " << outputFile << " and copy its contents into the " << endl;
	cout << "'to', 'cc', or 'bcc' field of any email message." << endl;
	cout << endl;
	cout << "please use the 'bcc' field to keep the emails private." << endl;
	fout.close();
  }
  else // if no emails are in the file
    {
    cout << "The file doesnt have any emails. " << inputFile << endl;
    }

  return 0;
} // End Main