/*********************************************************
*Patient Data Management System                         *
*Developed for Dr. Grace-Ann Cooper                     *
*Jonathan Cooper                                        *
*13-1                                                   *
*Ms Jones                                               *
*Computer Science                                       *
/*********************************************************/


//header files
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include <string.h>
#include <time.h>

//inline functions
#define TIME() time_t rawtime; time(&rawtime); printf("The current local time is: %s\n\n", ctime(&rawtime));

//Data structure to hold Patient Data
typedef struct {
        int patientID; //Unique Patient ID
        char fname[40]; //First Name
        char lname[40]; //Last Name
        float price; //Price of Services
        float paid; //Amount Paid
        float owing; //Amount Owing
}pData;

//Function prototype declarations
void login(void);
void header(char *text);
void menu(void);
void config(void);
void manageData(int opt);
pData saveData(pData Info, char *filename);
pData printData(pData Info);
void readData(char *filename);
pData appendData(pData Info, char *filename);

//Global Variables
int option;
pData Patient;

int main (void) {
    login();
}


void login(void) {

    char valid[20], vpass[20];

    FILE *info;

    if((info = fopen("login.txt","r"))) {  // Check if file exists / is valid
             fscanf(info,"%s",&valid); //Get the Username and Password
             fscanf(info,"%s",&vpass);
             fclose(info);
    }

    else {
         header("E R R O R!");
         printf("Program not configured!\nPress Enter to begin configuration . . .");
         getch();
         system("cls");
         config();
    }


    int i = 0;

    char user[7], pass[6];
    header("L O G I N");

    printf("Welcome to the Cooper Patient Data Payment Management System\n\nPlease enter your credentials:\n\n");

    printf("User Name:\t");
    scanf("%s",&user);

    printf("\n\nPassword:\t");

    scanf("%s",&pass);

    if(strcmp(user,valid)==0 && strcmp(pass,vpass)==0 ) { //ensure validity of username AND password
                                system("cls");
                                header("S U C C E S S");
                                printf("\n\n\n\n\n\n\t\tPress Enter To Continue to Menu. . . ");
                                getch();
                                system("cls");
                                menu();
    }

    /* Create a proper error message here */
    else { //If User info is invalid
         system("cls");
         header("E R R O R ");
         printf("Invalid username or password.  Press Enter to try again . . . ");
         getch();
         system("cls");
         login();
    }
}

/* Menu function */
void menu(void) {
     system("cls");
     header("M E N U");
     printf("Options:\n\
     [1]\tNew Patient\n\
     [2]\tExisting Patient\n\
     [3]\tCurrent Patient Information\n\
     [4]\tExit Program\n\
     [5]\tSettings\n");

     scanf("%d",&option);
     fflush(stdin); //flush input stream to avoid fatal error if user enters a character
     system("cls");

     manageData(option); //passes the user selection to this function

}

//header for menus, etc
void header(char *text) {
     printf("\t\t====================================================\n");
     printf("\t\t\t\t\t%s\n\n\t\t", text);
     TIME()
     printf("\t\t====================================================\n\n\n\n");
}

//allows for setup of user data
void config(void) {

     char username[20], password[20], confirm[20];
     FILE *config, *pID;

     header("C O N F I G");
     printf("Enter Desired Username:\t");
     scanf("%s",&username);
     printf("\nEnter Desired Password:\t");
     scanf("%s",&password);
     printf("\nEnter Password Again:\t");
     scanf("%s",&confirm);

     if(strcmp(confirm, password)==0) {

                        if(config = fopen("login.txt","w")) {
                                  if(pID = fopen("ID.txt","w")) {
                                         fprintf(config,"%s\t%s",username,password);
                                         fprintf(pID,"1");
                                         fclose(pID);
                                         fclose(config);

                                         system("cls");
                                         header("S U C C E S S");
                                         printf("\n\n\nFile Write Successful!\n\nPress enter to access the menu . . .");
                                         getch();
                                         system("cls");
                                         menu();
                                  }
                        }

                        else {
                             system("cls");
                             header("F A I L U R E");
                             printf("\n\nID File Write Failed\n");
                             getch();
                             system("cls");
                             login();
                        }
     }


     else {
          system("cls");
          header("F A I L U R E");
          printf("Passwords do not match!\nPress enter to try again . . .");
          getch();
          system("cls");
          login();
     }
}

void manageData(int opt) {

     char patient[50];
     int ID;
     FILE *pID, *IDWrite;
     if(pID = fopen("ID.txt","r")) {
            fscanf(pID,"%d",&ID);
            fclose(pID);
     }

     if(IDWrite = fopen("ID.txt","w")) {
                ID++;
                fprintf(IDWrite,"%d",ID);
                fclose(IDWrite);
     }

     else {
          system("cls");
          header("F A I L U R E");
          printf("\n\nFile read operation failed\n");
          getch();
          menu();
     }

     switch(opt) {
                 case 1: header("N E W  D A T A");
                         printf("\n\n\nEnter your first name:\t");
                         scanf("%s",&Patient.fname);
                         printf("\nEnter your last name:\t");
                         scanf("%s",&Patient.lname);

                         printf("\nEnter price of services:\t$");
                         scanf("%f",&Patient.price);

                         printf("\nEnter amount paid:\t$");
                         scanf("%f",&Patient.paid);

                         Patient.owing = Patient.price - Patient.paid;

                         Patient.patientID = ID--;
                         getch();

                         printData(Patient);
                 break;
                 case 2: header("E X I S T I N G");

                         printf("Enter the last name of the patient who's record you wish to update:\t");
                         scanf("%s",&patient);

                         appendData(Patient, patient);

                         getch();
                 break;
                 case 3: header("V I E W");
                         printf("Enter the last name of the patient who's record you wish to view:\t");
                         scanf("%s",&patient);
                         readData(patient);
                         getch();
                 break;

                 case 4: printf("Are you sure you wish to exit?\n[1]\tYes\n[2]\tNo\nEnter Option:\t");
                         scanf("%d",&option);
                         switch(option) {
                                        case 1: exit(0);
                                        break;
                                        case 2: system("cls");
                                                menu();
                                        break;
                                        default: system("cls");
                                                 header("E R R O R");
                                                 printf("Invalid Input.\nPress Enter to continue . . .");
                                                 getch();
                                                 manageData(4);
                                        break;
                         }
                 case 5: config();
                 break;
                 default: system("cls");
                          header("E R R O R");
                          printf("Invalid Input.\nPress Enter to try again . . . ");
                          getch();
                          menu(); //back to menu() function if input was invalid
                 break;
     }
}

//output data
pData printData(pData Info)
{
     system("cls");
     header("D A T A");
     printf("Name:\t%s %s\n",Info.fname,Info.lname);
     printf("ID Number:\t%d\n",Info.patientID);
     printf("Cost of Services:\t%.2f\n",Info.price);
     printf("Amount Paid:\t%.2f\n",Info.paid);
     printf("Amount Owing:\t%.2f\n",Info.owing);

     getch();

     saveData(Info, Info.lname);
}

//save data to a file
pData saveData(pData Info, char *filename) {
      FILE *data;
      if(data = fopen(filename,"w")) {
              fprintf(data,"ID Number:\t%d\n\n\n",Info.patientID);
              fprintf(data,"Name:\t%s %s\n",Info.fname,Info.lname);
              fprintf(data,"Cost of Services:\t%.2f\n",Info.price);
              fprintf(data,"Amount Paid:\t%.2f\n",Info.paid);
              fprintf(data,"Amount Owing:\t%.2f\n",Info.owing);
              fclose(data);
              menu();
      }

      else {
           printf("ERROR SAVING DATA TO FILE!  Try Again!");
           getch();
           menu();
      }
}

//read all data stored in a file
void readData(char *filename) {

     FILE *data;

     long lSize; //size of file
     char *buffer; //pointer to store file contents
     size_t result; //buffer to check consistiency of file

     if(data = fopen(filename,"rb")) { //open file for reading in binary mode
             fseek (data , 0 , SEEK_END); //set pointer to end of file
             lSize = ftell (data); //tell position, therefore passing file size
             rewind (data);  //set pointer to beginning of file
             buffer = (char*) malloc (sizeof(char)*lSize); //allocate the memory

             if (buffer == NULL) { // ensure validity of pointer
                        printf("MEMORY ERROR\nPress Enter to return to menu . . .");
                        getch();
                        menu();
             }

             result = fread (buffer,1,lSize,data); //read all the data

             if (result != lSize) { //ensure validity
                        printf("File Read Error!\nPress Enter to return to menu . . .");
                        getch();
                        menu();
             }

             printf("%s",buffer); //output data
             printf("\n\nPress Enter to return to menu . . .");
             fclose (data);
             free (buffer); //free memory allocated to avoid a leak

             getch();
             menu();

     }
}

//append existing patient data to data file
pData appendData(pData Info, char *filename) {
      system("cls");

      header("U P D A T E");
      printf("\n\n\nEnter your first name:\t");
      scanf("%s",&Info.fname);
      printf("\nEnter your last name:\t");
      scanf("%s",&Info.lname);

      printf("\nEnter price of services:\t$");
      scanf("%f",&Info.price);

      printf("\nEnter amount paid:\t$");
      scanf("%f",&Info.paid);

      Info.owing = Info.price - Info.paid;


      FILE *data;
      if(data = fopen(filename,"a")) {
              fprintf(data,"Name:\t%s %s\n",Info.fname,Info.lname);
              fprintf(data,"Cost of Services:\t%.2f\n",Info.price);
              fprintf(data,"Amount Paid:\t%.2f\n",Info.paid);
              fprintf(data,"Amount Owing:\t%.2f\n",Info.owing);
              fclose(data);
              menu();
      }

      else {
           printf("ERROR SAVING DATA TO FILE!  Try Again!");
           getch();
           menu();
      }
}