prog1

/**********************************************************************
 * nurseprogram.c                                                     *
 * A program with intergrated login system that let's a nurse write   *
 * patient details to a file and has an option to change password.    *
 * Written details are then encrypted to a file.                      *
 * Candidate NO: 181452                                               *
 * December 2017                                                      *
 **********************************************************************/

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>

/*Function prototypes*/
int loginWindow();
int mainMenu();
void addPatient();
void changePassword(int nurse);
void createFileName(char pLastName[], char pDay[], char pMonth[],
                    char pYear[], char patientFileName[]);
void decryptString(char toDecrypt[], char toReturn[]);
void encryptString(char toEncrypt[], char toReturn[]);
void transformString(char toEncrypt[], char toReturn[], int toJump);
void showTopTitle(char header[]);
void equalsLine(void);
void waitForKey(void);
void emptyBuffer(void);

int main()
{
    int choice;
    int nurse = -1;

    /*Show the loginWindow and get the nurse login*/
    while(nurse == -1)
    {
        nurse = loginWindow();
    }

    /*Iterated switch selection used for calling a function using
    maineMenu function return value*/
    while(choice != 3)
    {   /*Display mainu menu screen and get choice made by the user*/
        choice = mainMenu();
        switch(choice)
        {
            case 1:
                /*Call addPatient function*/
                addPatient();
                break;
            case 2:
                /*Call changePassword function*/
                changePassword(nurse);
                break;
            case 3:
                /*Clear the contents and display a closing message*/
                printf("See you soon!");
                break;
        }
    }

    return 0;
}
/*A function which prompts for a user login and password, if the user
inputs matches the contents within a file the loop will end*/
int loginWindow()
{
    FILE *passwordFile;
    int i;
    int nurse;
    char nurseUsername[9];
    char nursePassword[9];
    char fileUsername[9];
    char filePassword[9];

    /*Displaying the header*/
    showTopTitle("\t\t      || LOGIN ||");

    puts("Enter your username and password:\n");

    /*Receiving user string inputs*/
    printf("Username: ");
    scanf("%9[^\n]", nurseUsername);
    emptyBuffer();
    printf("Password: ");
    scanf("%9[^\n]", nursePassword);
    emptyBuffer();

    /*Declare variables for encrypted username and password*/
    char encryptedNurseUsername[9];
    char encryptedNursePassword[9];

    /*Use encryptString to encrypt username and password*/
    encryptString(nurseUsername, encryptedNurseUsername);
    encryptString(nursePassword, encryptedNursePassword);


    /*Opening file for reading purposes*/
    passwordFile = fopen("passwords.txt", "r");

    /*Scanning for username and password within a file*/
    while(0<fscanf(passwordFile, " %[^\t] %[^\n]", fileUsername,
                   filePassword))
    {

        /*Comparing user input strings with file strings*/
        if((strcmp(fileUsername, encryptedNurseUsername) == 0)
           && (strcmp(filePassword, encryptedNursePassword) == 0))
        {
            /*Closing the file*/
            fclose(passwordFile);
            /*Returning a nurse address*/
            return i;
        }
        /*Adding one to i*/
        ++i;
    }
    /*Closing the file*/
    fclose(passwordFile);

    puts("\n!! Wrong username or password, please try again !!\n");
    waitForKey();

    return -1;
}
/*Main menu function which displays main menu contents including
a header and returns user's input*/
int mainMenu()
{
    int choice;
    /*Displaying menu list choices*/
    showTopTitle("\t\t    || NURSE MENU ||");
    puts("1) Add a patient");
    puts("2) Change password");
    puts("3) Exit");

    printf(">>> ");

    /*If the input is less than 1 or higher than 3 then
    display an error message*/
    while(((scanf(" %d", &choice)) == 0) ||
          (choice < 1) || (choice > 3))
    {
        emptyBuffer();
        puts("!! Please make a valid choice !!");
        printf(">>> ");
    }
    emptyBuffer();

    return choice;
}

void addPatient(void)
{
    /*Declaring variables for iteriation and patient details, using
    2d array to store date of birth*/
    FILE *patientDetails;
    char patientFileName[265];
    char pFirstName[256];
    char pLastName[256];
    char pDateOfBirth[3][256];
    char pHeight[256];
    char pWaistMeasurement[256];
    char pWeight[256];
    char pComment[512];


    /*Displaying the header*/
    showTopTitle("\t\t   || ADD A PATIENT ||");

    /*Storing non-encryped patient details into [0]*/
    printf("First Name: ");
    scanf("%[^\n]", &pFirstName);
    emptyBuffer();

    printf("Last Name: ");
    scanf("%[^\n]", &pLastName);
    emptyBuffer();

    printf("DOB Day [DD]: ");
    scanf("%[^\n]", &pDateOfBirth[0]);
    emptyBuffer();

    printf("DOB Month [MM]: ");
    scanf("%[^\n]", &pDateOfBirth[1]);
    emptyBuffer();

    printf("DOB Year [YYYY]: ");
    scanf("%[^\n]", &pDateOfBirth[2]);
    emptyBuffer();

    printf("Height [cm]: ");
    scanf("%[^\n]", &pHeight);
    emptyBuffer();

    printf("Waist measurement [inches]: ");
    scanf("%[^\n]", &pWaistMeasurement);
    emptyBuffer();

    printf("Weight [kg]: ");
    scanf("%[^\n]", &pWeight);
    emptyBuffer();

    printf("Comment: ");
    scanf("%[^\n]", &pComment);
    emptyBuffer();

    /*Creating file name using the createFileName function*/
    createFileName(pLastName, pDateOfBirth[0], pDateOfBirth[1],
                   pDateOfBirth[2], patientFileName);

    /*Encrypting patient's details*/
    encryptString(pFirstName, pFirstName);
    encryptString(pLastName, pLastName);
    encryptString(pDateOfBirth[0], pDateOfBirth[0]);
    encryptString(pDateOfBirth[1], pDateOfBirth[1]);
    encryptString(pDateOfBirth[2], pDateOfBirth[2]);
    encryptString(pHeight, pHeight);
    encryptString(pWaistMeasurement, pWaistMeasurement);
    encryptString(pWeight, pWeight);
    encryptString(pComment, pComment);

    /*Opening the file for writing purposes*/
    patientDetails = fopen(patientFileName, "w");

    /*Writing user to a file*/
    fprintf(patientDetails, "%s\n", pFirstName);
    fprintf(patientDetails, "%s\n", pLastName);

    fprintf(patientDetails, "%s/%s/%s\n", pDateOfBirth[0],
            pDateOfBirth[1], pDateOfBirth[2]);

    fprintf(patientDetails, "%s\n", pHeight);
    fprintf(patientDetails, "%s\n", pWaistMeasurement);
    fprintf(patientDetails, "%s\n", pWeight);
    fprintf(patientDetails, "%s\n", pComment);

    /*Closing the file*/
    fclose(patientDetails);

    equalsLine();
    puts("Patient has been added!");
    /*Display continue message using waitForKey function*/
    waitForKey();
}

/*Function that takes patient's last name and DOB input and returns
a file name for the patient*/
void createFileName(char pLastName[], char pDay[], char pMonth[],
                    char pYear[], char patientFileName[])
{
    int i;
    char pYearTwoDigits[3];

    strcpy(patientFileName, "Patients/");

    /*Adding last name, day and month to a file name*/
    strcat(patientFileName, pLastName);
    strcat(patientFileName, pDay);
    strcat(patientFileName, pMonth);

    /*Copy two last characters from the patient year of birth and store
    it to the variable*/
    memcpy(pYearTwoDigits, &pYear[2], 2);

    /*Adding \0 to the variable to make it a string*/
    pYearTwoDigits[2] = '\0';

    /*Adding last two DOB digits to the file name*/
    strcat(patientFileName, pYearTwoDigits);
    /*Add the .aow extension to the file name*/
    strcat(patientFileName, ".aow");

    /*Iterating trough a file name*/
    for(i = 0; patientFileName[i]; ++i)
    {
        /*Changing file first character to lowercase*/
        patientFileName[i] = tolower(patientFileName[i]);
    }

}
/*A function for encryption which uses transform function*/
void encryptString(char toEncrypt[], char toReturn[])
{
    /*Transforming character and moving it forwards by seven places*/
    transformString(toEncrypt, toReturn, +7);
}
/*A function for decryption which uses transform function*/
void decryptString(char toDecrypt[], char toReturn[])
{
    /*Transforming character and moving it backwards by seven places*/
    transformString(toDecrypt, toReturn, -7);
}
/*A function which takes a string and transforms it's characters*/
void transformString(char toEncrypt[], char toReturn[], int toJump)
{
    /*Declaring variables and storing length of the string to encrypt*/
    int strLen = strlen(toEncrypt);
    /*Declare variable that will hold the encrypted string*/
    char encrypted[strLen+1];

    int i;
    int character;

    /*Iterate trough the string*/
    for(i = 0; i < strLen; ++i)
    {
        /*Assign one character of the string to
        the character variable*/
        character = toEncrypt[i];

        /*If the character is between a and z*/
        if(character >= 'a' && character <= 'z')
        {
            /*Add toJump(7) to the character*/
            character += toJump;

            /*If character is out of the range of z*/
            if(character > 'z')
            {
                /*Get the difference between the character a and z,
                subtract 1 and add it to the a value*/
                character = 'a' + (character - 'z') - 1;
            }
                /*If the character is out of the range of a*/
            else if(character < 'a')
            {
                /*Get the difference between the character z and a,
                add 1 and add it to the z value*/
                character = 'z' + (character - 'a') + 1;
            }
        }
            /*If the character is between A and Z*/
        else if(character >= 'A' && character <= 'Z')
        {
            /*Add toJump(7) to the character*/
            character += toJump;

            /*If character is out of the range of Z*/
            if(character > 'Z')
            {
                /*Get the difference between the character A and Z,
                subtract 1 and add it to the A value*/
                character = 'A' + (character - 'Z') - 1;
            }
                /*If the character is out of the range of A*/
            else if(character < 'A')
            {
                /*Get the difference between the character Z and A,
                add 1 and add it to the Z value*/
                character = 'Z' + (character - 'A') + 1;
            }
        }
            /*If the character is between 0 and 9*/
        else if(character >= '0' && character <= '9')
        {
            //Add toJump(7) to the character
            character += toJump;

            /*If character is out of the range of 9*/
            if(character > '9')
            {
                /*Get the difference between the character 0 and 9,
                subtract 1 and add it to the 9 value*/
                character = '0' + (character - '9') - 1;
            }
                /*If character is out of the range of 0*/
            else if(character < '0')
            {
                /*Get the difference between the character 9 and 0,
                add 1 and add it to the 0 value*/
                character = '9' + (character - '0') + 1;
            }
        }
        /*Store the encrypted character in the encrypted array*/
        encrypted[i] = character;
    }
    /*Add \0 to the encrypted array to make it a string*/
    encrypted[strLen] = '\0';

    /*Copy the encrypted string to the toReturn variable*/
    strcpy(toReturn, encrypted);
}
/*A function which allows a nurse to change a password within
a specified array location depending which nurse is logged in*/
void changePassword(int nurse)
{
    FILE *passwordFileRead;
    FILE *passwordFileWrite;

    char newPassword[10];
    char confirmPassword[10];

    /*Displaying the header*/
    showTopTitle("\t\t  || CHANGE PASSWORD ||");

    puts("Enter your new password:");
    printf(">>> ");
    /*Receiving user first password input*/
    scanf("%[^\n]", newPassword);
    emptyBuffer();
    /*If password string is not equal to 8 characters then display
    an an appropiate error*/
    if(strlen(newPassword) != 8)
    {
        puts("!! Password MUST be 8 characters long !!");
        waitForKey();
        return;
    }
    puts("Confirm your new password:");
    printf(">>> ");

    /*Receiving user second password input*/
    scanf("%[^\n]", confirmPassword);
    emptyBuffer();

    /*Compaing the two password strings to see if they match*/
    if(strcmp(newPassword, confirmPassword) == 0)
    {
        char encryptedPassword[10];

        /*Encrypting the new password*/
        encryptString(confirmPassword, encryptedPassword);

        char allPasswords[5][10];
        char allUsernames[5][10];

        /*Opening file for reading purposes*/
        passwordFileRead = fopen("passwords.txt", "r");
        int i = 0;

        /*Read all usernames and passwords*/
        while(2==fscanf(passwordFileRead, " %[^\t] %[^\n]",
                        allUsernames[i], allPasswords[i]))
        {
            i++;
        }

        /*Closing the file*/
        fclose(passwordFileRead);
        /*Opening the file for writing purposes*/
        passwordFileWrite = fopen("passwords.txt", "w");
        /*Overwriting an old password with a new password string*/
        strcpy(allPasswords[nurse], encryptedPassword);

        for (i = 0; i < 5; ++i)
        {
            /*Writing new strings to a file*/
            fprintf(passwordFileWrite, "%s\t%s\n", allUsernames[i],
                    allPasswords[i]);
        }
        /*Closing the file*/
        fclose(passwordFileWrite);

        equalsLine();
        puts("Password has been changed!");
        waitForKey();
        return;
    }
    else
    {
        puts("!! Your password did not match, please try again !!");
        waitForKey();
        return;
    }
}
/*Function that display the header*/
void showTopTitle(char header[])
{
    puts("*********************************************************");
    printf("\t\t    ACTION ON WEIGHT\n");
    puts("*********************************************************");
    equalsLine();
    printf(header);
    printf("\n");
    equalsLine();
    printf("\n");
}
/*Function that displays some ending text and waits for user
to press any key*/
void waitForKey(void)
{
    puts("=========================================================");
    printf("Press Any Key to Continue...\n");
    puts("=========================================================");
    getchar();

}
/*Function which displays a line*/
void equalsLine(void)
{
    puts("=========================================================");
}
/*Function that emptys the buffer*/
void emptyBuffer(void)
{
    while(getchar() != '\n')
    {
        ;
    }
}