//A program to manage a dictionary
#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
using namespace std;

#define inFile "/Users/me/Documents/diction.txt"          //Main dictionary file
#define outFile "/Users/me/Documents/diction.txt"         //for both reading and writing
#define tempInFile "/Users/me/Documents/tempDict.txt"     //Temporary dictionary file
#define tempOutFile "/Users/me/Documents/tempDict.txt"    //for both reading and writing

//Function prototypes
void checkEqual (ifstream&, const string);
void replaceWord (ifstream&, const string);

int main () {

    string nextWord;                                //input - new word
    ifstream ins;                                   //create ifstream object ins
    ins.open(inFile);                               //associate ins with inFile (main dictionary)
    if (ins.fail()) {                               //error check
        cerr << "Error opening input file." << endl;
        return EXIT_FAILURE;
    }
    cout << "Enter text.  If the dictionary finds a word, you will be informed."
         << endl << "If the dictionary does not find a word, the nearest words will"
         << endl << "be displayed and you will be asked if you want to add the word"
         << endl << "to the dictionary. Enter 'Q' to quit." << endl;
    cin >> nextWord;                                //Get new word
    while (nextWord != "Q") {                       //while user doesn't enter 'Q'
        checkEqual (ins, nextWord);                 //call function checkEqual
        cout << "Enter next word" << endl;          //on return of function,
        cin >> nextWord;                            //enter next word
    }                                               //end while loop
    //Assertion: user has entered 'Q'
    ins.close();                                    //close inFile

    return 0;
}

//Check new word for match in dictionary file
//Pre: new word has been entered
void checkEqual (ifstream& ins, const string nextWord)
{
    string savedWord;                               //input - words in dictionary
    bool wordFound = false;                         //Is there a match?
    ins.clear();                                    //Reset eof flag and failbit
    ins.seekg(0);                                   //Reset pointer to start of ins
    while (ins >> savedWord) {                      //While there are words in ins, get the next word
        if (nextWord == savedWord) {                //If there is a match
            wordFound = true;                       //set wordFound to true
            cout << "Word " << nextWord << " found in dictionary." << endl;
            break;                                  //break out of loop - word has been found
        }
    }                                               //end of while loop - no more words in dictionary
    if (wordFound == false) {                       //If word is not found
        replaceWord(ins, nextWord);                 //call replaceWord function
    }
}   //End of function checkEqual, return control to main

//Find nearest words, ask user whether to add word, replace word if answer is yes
//Pre: new word has not been found in dictionary
void replaceWord (ifstream& ins, const string newWord)
{
    string preWord = "aaaaa", postWord;             //Temporary variables to hold closest words to new word
    ins.clear();                                    //Reset eof flag and failbit in ins
    ins.seekg(0);                                   //Reset pointer to start of ins
    
    while (ins >> postWord) {                       //While words are in dictionary stream, get the next
        if (newWord < postWord) {                   //If new word smaller than first word in dictionary
            break;                                  //break out of loop - position has been found
        }
        else {                                      //If new word not smaller than first word
            preWord = postWord;                     //put first word in preWord
        }                                           //get another word and compare new word to it
    }                                               //end of while
    //Assertion: no more words in dictionary stream to be compared
    //Ask user if he wants to add new word to dictionary
    //if new word is either before or after last word in dictionary
    if (preWord == "aaaaa" || preWord == postWord) {
        cout << "Word not found.  Nearest word is " 
             << postWord << ". Add " << newWord << " to dictionary?" << endl;
    }
    else {                                          //Otherwise
        cout << "Word not found. Nearest words are "
             << preWord << " and " << postWord << ". Add "
             << newWord << " to dictionary?" << endl;
    }
    
    char agree;                                     //Input
    cin >> agree;                                   //Get character 
    agree = toupper(agree);                         // 'y' or 'Y'
    
    if (agree == 'Y') {                             //If answer is yes
        ofstream tempDict;                          //create output file stream object tempDict
        tempDict.open(tempOutFile);                 //associate tempDict with tempOutFile
        
        if (tempDict.fail()) {                      //error check
            cerr << "Error opening temporary Dictionary file" << endl;
        }
                    
        string tempString;                          //Temporary storage of string
        ins.clear();                                //Reset eof flag and failbit of insstream
        ins.seekg(0);                               //Reset pointer to start of ins
        ins >> postWord;                            //Get first word of dictionary, assign to postWord
        do
        {
            if (newWord < postWord) {               //If the new word is less than first word
                tempDict << newWord;                //Insert new word into temp dictionary file
                tempDict << '\r';                   //Insert newline character
                tempDict << postWord;               //Insert previous first word into temp dictionary
                getline (ins, tempString, '\0');    //Get the rest of the dictionary file
                tempDict << tempString;             //Insert the rest of the file into the temp dictionary
                break;                              //Break out of loop - entire file has been copied
            }                                       
            else {                                  //If new word is not less than first word compared,
                //preWord = postWord;               //put first word in preWord
                tempDict << postWord;               //Insert first word in temp dictionary
                tempDict << '\r';                   //Insert newline character in temp dictionary
            }                                       //Get next word in dictionary, assign to postWord
        } while (ins >> postWord);                  //end do-while loop
        //special case -
        if (newWord > postWord) {                   //if the new word is greater than the last word in dictionary
            tempDict << newWord;                    //add new word to end of dictionary
            tempDict << '\r';                       //add new line char (not sure if necessary)
            cout << newWord << " is new last word in dictionary." << endl;
        }
        //Assertion: all files have been copied to temp dictionary file,
        //new word has been inserted at its proper place alphabetically
        tempDict.close();                           //Close the temporary file for output
        ifstream tempDictionary(tempInFile);        //Reopen temp file for input
        
        if (tempDictionary.fail()) {                //Error check
            cerr << "Error opening temporary Dictionary file" << endl;
        }
        
        ins.close();                                //Close main dictionary file for input
        ofstream outs(outFile);                     //Reopen main file for output
        
        if (outs.fail()) {                          //Error check
            cerr << "Error opening output file." << endl;
        }
                    
        //copy temp dictionary to main dictionary
        getline (tempDictionary, tempString, '\0'); //Get all contents of temp dictionary file, assign to temp string
        outs << tempString;                         //Insert contents of string into main dictionary file
        
        //Assertion: contents of temp dictionary have been copied to main dictionary file
        tempDictionary.close();                     //Close temp dictionary file for input
        outs.close();                               //Close main dictionary file for output
        ins.open(inFile);                           //reopen main dictionary file for input
        
        if (ins.fail()) {                           //error check
            cerr << "<Error re-opening input file>" << endl;
        }
        else {
            cout << "<input file re-opened>" << endl;
        }
    }                                               //end if 
    //Assertion: either new word has been inserted into main dictionary file
    //or user entered any character other than 'y' or 'Y'
}   //End of function replaceWord - return control to function checkEqual