MAIN.H

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>

struct currentValidID{
    int year;
    char branch[6];
    int totalVoters;
};
typedef struct candidate{
    int cid;
    char cname[20];
    int votes;
}CANDIDATE;

//GLOBALS --------------------------------------------------------
struct currentValidID currentValidID; //stores current Valid user ID parameters
CANDIDATE candidateArray[20]; //to store information all candidates
int numberOfCandidates; //Total number of candidates standing for election
char studentVotes[200]; //to store information of votes given by each student
//----------------------------------------------------------------

//To extract year from userID -- For example, userID:2018btecs00064 year:2018 
int extractYear(char userID[15])
{
    int year=0;
    char tmp;
    for(int i=0;i<4;i++){
        tmp=userID[i];
		year=(year*10)+(tmp-48);
    }
    return year;
}

int extractRollNo(char userID[15])
{
    int rollno=0;
    char tmp;
    for(int i=9;i<14;i++){
        tmp=userID[i];
		rollno=(rollno*10)+(tmp-48);
    }
    return rollno;
}

//Will check whether the global branch code and inputed branch code is matching or not
int checkBranchCode(char userID[15])
{
    char branchCode[6];
    for(int i=4;i<9;i++){
        branchCode[i-4]=userID[i];
    }
    branchCode[5]='\0';
    if(strcmp(branchCode,currentValidID.branch)==0)
        return 1;
    else
        return 0;
}

int authenticateAdmin(){
    char username[15], password[6];
    
    printf("\nEnter username: ");
    scanf("%s",username);
    if((strcmp(username,"Admin"))!=0)
        return 0;
    else
    {
        printf("Enter Password: ");
        int i=0;
        for(i=0;i<5;i++)
        {
            password[i]=getch();
            printf("%c",'*');
        }
        password[i]='\0';
        if((strcmp(password,"admiN"))!=0)
            return 0;
    }
    return 1;
}

void banID(){
    printf("\nCreating Banned.txt...\n");
    FILE *fp=fopen("Banned.txt", "w");
    if(fp==NULL){
        printf("Error: Banned.txt not created.\n");
        fclose(fp);
        return;
    }
    printf("Just Enter last roll no to ban\nPress 0 to exit... ");
    int input;
    while(1){
        printf("\nEnter Number: ");
        scanf("%d",&input);
        if(input==0)
            break;
        studentVotes[input-1]='$';
        fprintf(fp,"%d\n",input);
    }
    fclose(fp);
    printf("Created Successfully\n");
}

void createCandidateFiles(){
    printf("\nCreating candidate files...\n");
    FILE *fp;
	char filename[20];
    for(int i = 1;i <= numberOfCandidates; i++){
        sprintf(filename,"candidate%d.txt",i);
		fp=fopen(filename,"w");
        fprintf(
            fp,"0\n%s",
            candidateArray[i-1].cname
        );
		fclose(fp);
    }
    printf("Created Files successfully\n");
}

void deleteIllegalVote(char userID[15])
{
    FILE *fp,*fcp;
    char filename[20];
    char line[20];

    int location = extractRollNo(userID);
    sprintf(filename,"candidate%d.txt",candidateArray[studentVotes[location-1]-49].cid);
    candidateArray[studentVotes[location-1]-49].votes--;
    studentVotes[location-1]='0';
    if ((fp = fopen(filename,"r")) == NULL)    
    {    
        printf("\nFile cannot be opened...Operation Failed");
        return;
    }
    printf("\nDeleting in process...\n ");    
    if ((fcp = fopen("tmp.txt","w")) == NULL)    
    {    
        printf("\nFile cannot be opened...Operation Failed");
        return;
    }
    
    while (!feof(fp))
    {
        fscanf(fp,"%s",line);
        fprintf(fcp,"%s\n",line);
    }
    fclose(fp);
    fclose(fcp);
    if ((fp = fopen(filename,"w")) == NULL)    
    {    
        printf("\nFile cannot be opened...Operation Failed");
        return;
    }
    int numFromFile;
    char cnameFromFile[20];
    fcp = fopen("tmp.txt","r");  
    fscanf(fcp,"%d",&numFromFile);
    fprintf(fp,"%d",numFromFile-1);
    fscanf(fcp,"%s",cnameFromFile);
    fprintf(fp,"\n%s",cnameFromFile);
    while(!feof(fcp)){
        fscanf(fcp,"%d",&numFromFile);
        if(numFromFile!=location)
            fprintf(fp,"\n%d",numFromFile);
    }
    fclose(fp);
    fclose(fcp);
    remove("tmp.txt");
    printf("\nVote deleted successfully\nPress any key to continue...");
    getch();
}

int getWinner(){
    int maxV = -1;
    int winnerCid;
    for(int i = 0;i < numberOfCandidates; i++){
        if(candidateArray[i].votes > maxV) {
            winnerCid = candidateArray[i].cid;
            maxV = candidateArray[i].votes;      
        }
        else if(candidateArray[i].votes == maxV) {
            return -1;
        }
    }
    return winnerCid;
}

void initiateNewElection()
{
    printf("\nNew Election Initiation:\n");
    
    printf("\nElections for which Year: ");
    scanf("%d",&currentValidID.year);
    printf("Enter branch code:");
    scanf("%s",currentValidID.branch);
    printf("Enter max roll no.:");
    scanf("%d",&currentValidID.totalVoters);
    printf("Enter the no. of candidates:");
    scanf("%d",&numberOfCandidates);

   for (int i = 0; i < currentValidID.totalVoters; i++)
    {
        studentVotes[i] = '0';
    }

    for (int i = 0;i < numberOfCandidates; i++)
    {
        candidateArray[i].cid=i+1;
        printf("Enter name of candidate %d: ",i+1);
        scanf(" %s",candidateArray[i].cname);
        candidateArray[i].votes=0;
    }
    return;
}

void saveElectionInfoInFile(){
    printf("Saving Election Info in File...\n");
    FILE *fp = fopen("ElectionInfo.txt", "w");
    if(fp==NULL)
    {
        printf("\nError in file creation\n");
        fclose(fp);
        return;
    }
    fprintf(
        fp,"%d\n%s\n%d\n%d",
        currentValidID.year,
        currentValidID.branch,
        currentValidID.totalVoters,
        numberOfCandidates
    );
    fclose(fp);
    printf("Saved Successfully : )");
}

void loadElectionInfoFromFile()
{
    FILE *f1,*f2,*f3;
    f1=fopen("ElectionInfo.txt","r");
    if(f1==NULL)
        printf("Not Exist");
    fscanf(f1,"%d",&currentValidID.year);
    fseek(f1,2,SEEK_CUR);
    fscanf(f1,"%s",currentValidID.branch);
    fseek(f1,2,SEEK_CUR);
    fscanf(f1,"%d",&currentValidID.totalVoters);
    fseek(f1,2,SEEK_CUR);
    fscanf(f1,"%d",&numberOfCandidates);
    fclose(f1);
   
    //load candidates info and student votes
    for (int i = 0; i < currentValidID.totalVoters; i++)
    {
        studentVotes[i] = '0';
    }
    for(int i=1;i<=numberOfCandidates;i++)
    {
        int location;
        char filename[20];
        sprintf(filename,"candidate%d.txt",i);
        f2=fopen(filename,"r+");
        candidateArray[i-1].cid=i;
        fscanf(f2,"%d",&candidateArray[i-1].votes);
        fscanf(f2,"%s",candidateArray[i-1].cname);
        while(!feof(f2)){
            fscanf(f2,"%d",&location);
            studentVotes[location-1] = i+48;
        }
        fclose(f2);
    }

    //load banned votes
    int location;
    f3=fopen("banned.txt","r+");
    while(!feof(f3)){
        fscanf(f3,"%d",&location);
        studentVotes[location-1] = '$';
    }
    fclose(f3);
    
}

void adminPanel()
{
    while(1){
        
        if(authenticateAdmin()!=1){
            printf("\n Wrong Username or Password \n");            
            break;
        }

        printf("\n\nLOGGED IN SUCCESSFULLY (Press Enter)");
		getch();

        while(1)
        {
            char inputID[15];
            char input;char banInp;
            int WinnerCid, totalVotedNow=0;
            printf("\n1.New Election\n2.Continue Previous Election\n3.Delete Illegal Vote\n4.Ban User IDs\n5.Result\n6.Logout\nOption:");
			scanf(" %c",&input);

            switch(input)
            {
                case '1':
                    initiateNewElection();
                    saveElectionInfoInFile();
                    createCandidateFiles();
                    break;
                case '2':
                    loadElectionInfoFromFile();
                    break;
                case '3':
                    printf("\nEnter user ID to delete its vote: ");
                    scanf("%s",inputID);
                    deleteIllegalVote(inputID);
                    break;
                case '4':
                    printf("Do you want to ban particular ID's?\nPress 1 if yes or any other key to continue...");
                    scanf(" %c",&banInp);
                    if(banInp=='1'){
                        banID();
                    }
                    break;
                case '5':
                    WinnerCid = getWinner();
                    if(WinnerCid != -1){
                        printf("\nWinner is %s with %d votes\n",candidateArray[WinnerCid-1].cname,candidateArray[WinnerCid-1].votes);
                    }
                    else{
                        printf("\nIts A TIE");
                    }
                    printf("\nFull Result\n");
                    for(int i=0;i<numberOfCandidates;i++){
                        totalVotedNow+=candidateArray[i].votes;
                        printf("%d. %s -> %d votes\n",candidateArray[i].cid,candidateArray[i].cname,candidateArray[i].votes);
                    }
                    printf("\nVoting Percentage: %d %%\n\n",(totalVotedNow*100)/currentValidID.totalVoters);
                    break;
                case '6':
                    return;
                default:
                    printf("Invalid Option");
					getch();
            }
			
        }
    }

};


int isValid(char userID[15])
{
    if(strlen(userID)!=14)
        return 0;
    
    int inputedYear=extractYear(userID);
    int inputedRollNo = extractRollNo(userID);
    
    if(inputedYear!=currentValidID.year || checkBranchCode(userID)!=1 || inputedRollNo>currentValidID.totalVoters)
        return 0;

    return 1;
}

int isVoted(char userID[15])
{
    int location=extractRollNo(userID);
    if(studentVotes[location-1]=='0')
        return 0;
    else
        return 1;
}

int isBanned(char userID[15]){
    int location=extractRollNo(userID);
    if(studentVotes[location-1]=='$')
        return 1;
    else
        return 0;
}

void saveVote(char userID[15],char voteInput)
{
    char filename[20];
    sprintf(filename,"candidate%d.txt",voteInput-48);
    FILE *fp = fopen(filename,"r+");
    int location=extractRollNo(userID);
    studentVotes[location-1]=voteInput;
    candidateArray[voteInput-49].votes++;
    fseek(fp, 0, SEEK_SET);
    fprintf(fp,"%d\n",candidateArray[voteInput-49].votes);
    fseek(fp, 0, SEEK_END);
    fprintf(fp,"\n%d",location);
    fclose(fp);
}


void studentPanel()
{
    char userID[15];
    char voteInput;
    while(1)
	{
		printf("\n\n  To exit press 0");
        printf("\n  Enter user ID:");
        scanf("%s",userID);
        if(strcmp(userID, "0")==0)
				return;
        if(isValid(userID)!=1)
        {
            printf("\n  Invalid User ID(Press Enter)");
            getch();
            continue;
        }
        if(isBanned(userID)!=0)
        {
            printf("\nThis User ID is currently banned...\nContact Admin for the reason...(Press Enter to continue)");
            getch();
            continue;
        }
        if(isVoted(userID)!=0)
        {
            printf("\n  Your PRN entered is already voted\n  Contact Admin for furthur query");
            getch();
            continue;
        }
        printf("\n\n  Candidates for election:");
		for (int i = 0; i < numberOfCandidates; i++)
        {
            printf("\n  %d. %s",i+1,candidateArray[i].cname);
        }
        printf("\n\n  Your Vote(Enter Number):");
        voteInput=getch();
        printf("*");
        if(voteInput-48 < 1 || voteInput-48 > numberOfCandidates)
        {
            printf("\nInvalid Vote\nTry Again...");
            getch();
            continue;
        }
        saveVote(userID,voteInput);
        printf("\n\nThanks for your precious vote(Press Enter)");
        getch();
    }
};