/**********************************************************************************************************************
This is to certify that this project is my own work, based on my personal efforts in studying and applying the concepts
learned.  I have constructed the functions and their respective algorithms and corresponding code by myself.  The program
was run, tested, and debugged by my own efforts.  I further certify that I have not copied in part or whole or otherwise
plagiarized the work of other students and/or persons.

                                                            Alexandra Rotor Reyes, DLSU ID# 11622105
**********************************************************************************************************************/

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

#define MAX_ITEMS 100

typedef char string8[9];
typedef char string15[16];
typedef char string20[21];
typedef char string50[51];

/* structures needed for the program */
typedef struct
{
    string20    first,
                middle,
                last;
}   nameType;

typedef struct
{
    nameType    name;
    string50    address;
}   userInfoType;

typedef struct
{
    string8     code;
    int         qty;
} prodBoughtType;

typedef prodBoughtType arrBought[MAX_ITEMS];

/* linked list about the user */
typedef struct aboutUser
{
    string15        username,
                    password;
    userInfoType    info;
    int             type;           /* administrator or shopper? */
    float           creditLimit,
                    outstanding;
    arrBought       cart;
    int             nItems,
                    isLocked;
    struct          aboutUser *next;
}   userNode;

/* linked list about the stocks */
typedef struct aboutStock
{
    string8     pCode;
    string15    supplier,
                product;
    int         avbl,
                sold;
    float       purchasePrice,
                sellingPrice,
                discountRate;
    struct      aboutStock *next;
} stockNode;

/* linked list about the category */
typedef struct categ
{
    string15    category;
    stockNode   productInfo;
    struct      categ *next;
} categNode;

/*
FUNCTION: viewLocked allows the administrator to see all locked accounts
@param: userNode *user: structure with user information
@return: void
*/
void viewLocked (userNode *user)
{
    int ctr=1;
    userNode *temp=NULL;

    temp=user;

    printf("\nView Locked Accounts:\n");

    do
    {
        if (temp->isLocked==1 && temp->type==2)
        {
            printf("Account #%d: %s\n", ctr, temp->username);
            printf("Name: %s, %s %s\n", temp->info.name.last, temp->info.name.first, temp->info.name.middle);
        }
        else
        {
            printf("No locked accounts!\n");
            break;
        }
        temp=temp->next;
        ctr++;
    } while (temp!=NULL);
}

/*
FUNCTION: unlockSpecific allows the admin to unlock a specific account by selecting
          which account to unlock
@param: userNode *user: structure with user information
@return: void
*/
void unlockSpecific (userNode *user)
{
    string15 iUser;
    userNode *temp=NULL;
    int compare=2, choice=0, close=0;

    temp=user;

    printf("\nUnlock a specific account: \n");

    do
    {
        printf("Enter username of the account you wish to unlock: \n");
        scanf("%s", iUser);

        compare=strcmp(iUser, temp->username);

        do
        {
            if (temp->isLocked==1 && compare==0)
            {
                temp->isLocked=0;
                temp=temp->next;
            }
        } while (temp!=NULL);

        printf("Username: %s has been unlocked.\n");
        printf("Would you like to unlock another user? \n");
        printf("1. Yes\n");
        printf("2. No\n");

        do
        {
            switch (choice)
            {
                case 1: close=0;
                        break;
                case 2: close=1;
                        break;
                default: printf("Wrong input. Try again.\n");
            }
        } while (choice!=1 && choice!=2);

    } while (close==1);
}

/*
FUNCTION: unlockAll allows the admin to unlock all the accounts
@param: userNode *user: structure with user information
@return: void
*/
void unlockAll (userNode *user)
{
    userNode *temp=NULL;

    temp=user;

    printf("\nUnlock all accounts: \n");
    printf("Loading...\n");

    while (temp!=NULL)
    {
        if (temp->isLocked==1)
            temp->isLocked=0;

        temp=temp->next;
    }

    printf("All accounts have been unlocked!\n");
}

/*
FUNCTION: viewOutBal allows the admin to check which users have outstanding balance
@param: userNode *user: structure with user information
@return: void
*/
void viewOutBal (userNode *user)
{
    userNode *temp=NULL;

    temp=user;

    printf("\nViewAccounts With Outstanding Balance: \n");

    do
    {
        if (temp->outstanding <= 0.00)
            printf("Sorry, your outstanding balance is empty!\n");
        else if (temp->outstanding > 0.00)
        {
            printf("Username: %s", temp->username);
            printf("Outstanding Balance is: %.2f\n", temp->outstanding);
        }
        temp=temp->next;

    } while (temp!=NULL);
}

/*
FUNCTION: manageAccounts displays the admin's options for Manage Account Menu
@param: userNode *user: structure with user information
@return: void
*/
void manageAccounts (userNode *user)
{
    int aChoice;
    userNode *temp=NULL;

    do
    {
        printf("\n === MANAGE ACCOUNTS MENU === \n");
        printf("1. View Locked Accounts\n");
        printf("2. Unlock Specific Account\n");
        printf("3. Unlock All Locked Accounts\n");
        printf("4. View Accounts with Outstanding Balance\n");
        printf("5. Return to Administrator Menu\n");
        printf("Enter choice: ");
        scanf("%d", &aChoice);

        switch (aChoice)
        {
            case 1: viewLocked (user);
                    break;
            case 2: unlockSpecific (user);
                    break;
            case 3: unlockAll (user);
                    break;
            case 4: viewOutBal (user);
                    break;
            case 5: break;
        }
    } while (aChoice!=5);
}

/*
FUNCTION: uniqueCateg checks if the category is unique or not
@param: string15 addCateg: string that contains the name of the new category
@param: categNode *temp: structure with the category information
@return: int
*/
int uniqueCateg (string15 addCateg, categNode *temp)
{
    int unique=1;
    categNode *check=NULL;

    check=temp;

    while(check!=NULL)
    {
        if (strcmp(check->category, addCateg)==0)
        {
            unique=0;
            check=NULL;
        }
        else
            check=check->next;
    }
    return unique;
}

/*
FUNCTION: uniqueProd checks if the product is unique or not
@param: string15 prod: string that contains the name of the new product
@param: categNode *temp: structure with the category information
@return: int
*/
int uniqueProd (string15 prod, categNode *temp)
{
    int unique=1;
    categNode *check=NULL;

    check=temp;

    while (check!=NULL)
    {
        if (strcmp(check->productInfo.product, prod)==0)
        {
            unique=0;
            check=NULL;
        }
        else
            check=check->next;
    }
    return unique;
}

/*
FUNCTION: addNewStock allows the admin to add a new stock to the current list of stocks
          and goes back to the Manage Stocks Menu after
@param: stockNode *stockInfo: structure with stock information
@param: int *stockctr: to check the number of categories, which but be max of 10
@param: categNode *stemp: structure with the category information
@return: categNode *
*/
categNode *addNewStock (stockNode *stockInfo, int *stockctr, categNode *stemp)
{
    string15 addCateg, supplier, prod, newcat, newsup, newprod;
    int cChoice=0, accept=0, compare=2, avbl=0, sold=0, i=0, add=0, rNum=0;
    float purchasePrice=0, sellingPrice=0, discountRate=0;
    categNode *stocktemp;
    srand(time(NULL));
    stocktemp = malloc(sizeof(categNode));
    printf("\nAdding New Stocks: \n");

    do
    {
        printf("Would you like to add a new category?\n");
        printf("1. Yes\n");
        printf("2. No\n");
        printf("Enter choice: ");
        fflush(stdin);
        scanf("%d", &cChoice);

        if (cChoice!=1 && cChoice!=2)
            printf("Invalid input. Try again\n");
        if ((*stockctr)==0 && cChoice==2)
            printf("\nNo categories yet!\n\n");
    } while (cChoice!=1 && (*stockctr)<11);

    while (cChoice==1 && accept!=1 && (*stockctr)<11)
    {
        do
        {
            printf("Enter Category: ");
            fflush(stdin);
            fgets(addCateg, 16, stdin);
            if(strlen(addCateg)>=3 && strlen(addCateg)<=15)
            {
                compare=uniqueCateg(addCateg, stocktemp);

                if (compare==1)
                {
                    accept=1;
                    strcpy (stocktemp->category, addCateg);
                    stocktemp->category[strlen(stocktemp->category)-1]='\0';
                    (*stockctr)++;
                    printf("You have created a new category! Category #%d\n", *stockctr);
                }
                if (compare!=1)
                    printf("Choose a unique category!\n");
            }
            else
                printf("Enter another category that contains 3-15 characters\n");
            if (*stockctr==10)
                printf("You have reached the maximum amout of categories!\n");
        } while ((strlen(addCateg)<3 && strlen(addCateg)>15) && accept!=1 && (*stockctr)<11);
    }

    accept=0;
    compare=2;

    if (cChoice==1 && accept!=1)
    {
        do
        {
            printf("Enter Supplier: ");
            fflush(stdin);
            fgets(supplier, 16, stdin);

            if (strlen(supplier)<16)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1);

        if (accept==1)
        {
            strcpy(stocktemp->productInfo.supplier, supplier);
            stocktemp->productInfo.supplier[strlen(stocktemp->productInfo.supplier)-1]='\0';
            accept=0;
        }

        do
        {
            printf("Enter Product: ");
            fflush(stdin);
            fgets(prod, 16, stdin);

            compare=uniqueProd(prod, stocktemp);

            if (strlen(prod)<16 && compare==1)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1 && compare!=1);

        if (accept==1)
        {
            strcpy(stocktemp->productInfo.product, prod);
            stocktemp->productInfo.product[strlen(stocktemp->productInfo.product)-1]='\0';
            accept=0;
        }

        do
        {
            printf("Enter Quantity Available: ");
            fflush(stdin);
            scanf("%d", &avbl);
            if (avbl>0)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1);

        if (accept==1)
        {
            stocktemp->productInfo.avbl=avbl;
            accept=0;
        }

        do
        {
            printf("Enter Purchase Price: ");
            fflush(stdin);
            scanf("%f", &purchasePrice);
            if (purchasePrice>0)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1);

        if (accept==1)
        {
            stocktemp->productInfo.purchasePrice=purchasePrice;
            accept=0;
        }

        do
        {
            printf("Enter Unit Selling Price: ");
            fflush(stdin);
            scanf("%f", &sellingPrice);
            if (sellingPrice>0)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1);

        if (accept==1)
        {
            stocktemp->productInfo.sellingPrice=sellingPrice;
            accept=0;
        }

        do
        {
            printf("Enter Discount Rate: ");
            fflush(stdin);
            scanf("%f", &discountRate);
            if (discountRate>0)
                accept=1;
            else
                printf("Invalid input. Try again!\n");
        } while (accept!=1);

        if (accept==1)
        {
            stocktemp->productInfo.discountRate=discountRate;
            accept=0;
        }
    }

    strcpy(newcat, addCateg);
    for(i=0; i<strlen(newcat); i++)
    {
        if (newcat[i]>='a' && newcat[i]<='z')
            newcat[i]-=32;
    }

    strcpy(newsup, supplier);
    for(i=0; i<strlen(newsup); i++)
    {
        if (newsup[i]>='a' && newsup[i]<='z')
            newsup[i]-=32;
    }

    strcpy(newprod, prod);
    for(i=0; i<strlen(newprod); i++)
    {
        if (newprod[i]>='a' && newprod[i]<='z')
            newprod[i]-=32;
    }

    stocktemp->productInfo.sold=0;
    stocktemp->productInfo.pCode[0]=newcat[0];
    stocktemp->productInfo.pCode[1]=newsup[0];
    stocktemp->productInfo.pCode[2]=newprod[0];

    i=0;

    while (i<5)
    {
        rNum=rand()%58;
        if(rNum>47 && rNum<57)
        {
            stocktemp->productInfo.pCode[(i+3)]=rNum;
            i++;
        }
        stocktemp->productInfo.pCode[8]='\0';
    }

    printf("Product code: %s\n", stocktemp->productInfo.pCode);
        stocktemp->next = stemp;
        stemp = stocktemp;
        return stemp;
}


void viewAllStocks (stockNode *stockInfo, int *stockctr, categNode *stemp)
{
    int i;
    int ctr=0;
      printf("\nCATEGORY       |SUPPLIER       |  PROD  |PRODUCT   |QTY |QTY |BUY  |SELL |DISC|\n");
        printf("               |               |  CODE  |          |AVBL|SOLD|PRICE|PRICE|RATE|\n");
    while (stemp!=NULL)
    {
        if(ctr!=20)
        {
            printf("\n");
            printf("%s", stemp->category);
            if(strlen(stemp->category)<15)
                for(i=strlen(stemp->category);i<15;i++)
                    printf(" ");
            printf("|%s", stemp->productInfo.supplier);
            if(strlen(stemp->productInfo.supplier)<15)
                for(i=strlen(stemp->productInfo.supplier);i<15;i++)
                    printf(" ");
            printf("|%s", stemp->productInfo.pCode);
            printf("|%s", stemp->productInfo.product);
            if(strlen(stemp->productInfo.product)<10)
                for(i=strlen(stemp->productInfo.product);i<10;i++)
                    printf(" ");
            printf("|%d", stemp->productInfo.avbl);
            if(stemp->productInfo.avbl<1000)
                for(i=stemp->productInfo.avbl;i<10;i++)
                    printf(" ");
            printf("|%d", stemp->productInfo.sold);
            if(strlen(stemp->productInfo.product)<10)
                for(i=strlen(stemp->productInfo.product);i<10;i++)
                    printf(" ");
            printf("|%.2f", stemp->productInfo.purchasePrice);
            printf("|%.2f", stemp->productInfo.sellingPrice);
            printf("|%.2f", stemp->productInfo.discountRate);
            printf("\n");
            ctr++;
        }else{
            printf("\nPress Enter to continue...\n");
            getch();
        }
        stemp = stemp->next;
    }
    printf("\nPress Enter to continue...\n");
    getch();
}
/*
void modStockInfo ()
{

}

void restock ()
{

}*/


/*
FUNCTION: manageStocks asks the admin what they want to do with all the stock information
@param: stockNode *stockInfo: structure with stock information
@param: int *stockctr: to check the number of categories, which but be max of 10
@param: categNode *stemp: structure with the category information
@return: void
*/
void manageStocks (stockNode *stockInfo, int *stockctr,categNode *stemp)
{
    int aChoice=0;
    do
    {
        printf("\n === MANAGE STOCKS MENU === \n");
        printf("1. Add New Stock\n");
        printf("2. View All Stocks\n");
        printf("3. View Stocks by Category (PHASE 2)\n");
        printf("4. View Stocks to Reorder (PHASE 2)\n");
        printf("5. Modify Stock Info\n");
        printf("6. Restock\n");
        printf("7. Save Inventory (PHASE 2)\n");
        printf("8. Update Inventory from File (PHASE 2)\n");
        printf("Enter choice: ");
        fflush(stdin);
        scanf("%d", &aChoice);

        switch (aChoice)
        {
            case 1: stemp = addNewStock (stockInfo, stockctr, stemp);
                    break;
            case 2: viewAllStocks (stockInfo, stockctr, stemp);
                    break;
            case 3: break;
            case 4: break;
        //  case 5: modStockInfo ();
                    break;
        //  case 6: restock ();
                    break;
            case 7: break;
            case 8: break;
        }
    } while (aChoice>0 && aChoice<9);
}

/*
FUNCTION: adminMenu displays only when an administrator is able to log in successfully
          It then asks the admin what (s)he wants to do
@param: userNode *user: structure with the user information
@param: int *close: option to exit
@param: stockNode *stockInfo: structure with stock information
@param: int *stockctr: to check the number of categories, which but be max of 10
@param: categNode *stemp: structure with the category information
@return: void
*/
void adminMenu (userNode *user, int *close, stockNode *stockInfo, int *stockctr, categNode *stemp)
{
    int adChoice=0;

    do
    {
        printf("\n === ADMINISTRATOR MENU === \n");
        printf("1. Manage Accounts Menu\n");
        printf("2. Manage Stocks Menu\n");
        printf("3. Prepare Delivery Receipt (PHASE 2)\n");
        printf("4. Shutdown Kiosk \n");
        printf("5. Log Out \n");
        printf("Enter choice: ");
        scanf("%d", &adChoice);

        switch (adChoice)
        {
            case 1: manageAccounts(user);
                    break;
            case 2: manageStocks(stockInfo, stockctr,stemp);
                    break;
            case 3: break;
            case 4: *close=1;
                    break;
            case 5: break;
            default: printf("Invalid input. Try again.\n");
        }
    } while (adChoice!=4 && adChoice!=5);
}

/*
FUNCTION: modUserInfo allows the shopper to change his/her account details
@param: userNode *user: structure about user information
@return: void
*/
void modUserInfo (userNode *user)
{
    int uChoice=0, accept=0, i=0, nameChoice=0;
    string15 newpass;

    printf("\nModifying User Info:\n");

    do
    {
        printf("\nDo you want to...\n");
        printf("1. Change Name\n");
        printf("2. Change Address\n");
        printf("3. Change Password\n");
        printf("4. Return to Shopper Menu\n");
        printf("Enter choice: ");
        scanf("%d", &uChoice);

        switch (uChoice)
        {
            case 1: do
                    {
                        printf("\nWhat would you like to change? \n");
                        printf("1. First Name\n");
                        printf("2. Middle Name\n");
                        printf("3. Last Name\n");
                        printf("4. All Names\n");
                        printf("Enter choice: ");
                        scanf("%d", &nameChoice);
                    } while (nameChoice<1 && nameChoice>4);

                    switch (nameChoice)
                    {
                        case 1: printf("Enter New Name: \n");
                                printf("First name: ");
                                fflush(stdin);
                                fgets(user->info.name.first, 21, stdin);

                                break;

                        case 2: printf("Enter New Name: \n");
                                printf("Middle name: ");
                                fflush(stdin);
                                fgets(user->info.name.middle, 21, stdin);
                                break;

                        case 3: printf("Enter New Name: \n");
                                printf("Last name: ");
                                fflush(stdin);
                                fgets(user->info.name.last, 21, stdin);
                                break;

                        case 4: printf("Enter New Name: \n");
                                printf("First name: ");
                                fflush(stdin);
                                fgets(user->info.name.first, 21, stdin);
                                printf("Middle name: ");
                                fflush(stdin);
                                fgets(user->info.name.middle, 21, stdin);
                                printf("Last name: ");
                                fflush(stdin);
                                fgets(user->info.name.last, 21, stdin);
                                break;
                    }
                    break;

            case 2: printf("Enter New Address: \n");
                    printf("Address: ");
                    fflush(stdin);
                    fgets (user->info.address, 51, stdin);
                    break;

            case 3: do
                    {
                        printf("Enter New Password: ");
                        scanf("%s", newpass);

                        for (i=0; i<strlen(newpass); i++)
                        {
                            if (!((newpass[i] >= 'A' && newpass[i] <= 'Z') || (newpass[i] >= 'a' && newpass[i] <= 'z')))
                            {
                                accept=1;
                                strcpy (user->password, newpass);
                            }
                        }
                    } while (strlen(newpass) < 6 || strlen(newpass) > 15 || accept!=1);
                    break;

            case 4: break;
            default: printf("Invalid input. Try again.\n");
        }
    } while (uChoice!=4);
}

void browseAllProd ()
{

}

/*
FUNCTION: shopperMenu displays when a shopper logs in successfully
          It then asks the shopper what he/she wants to do
@param: userNode *user: structure with the user information
@param: stockNode *stockInfo: structure with stock information
@param: int *stockctr: to check the number of categories, which but be max of 10
@return: void
*/
void shopperMenu (userNode *user, stockNode *stockInfo, int *stockchtr)
{
    int sChoice=0;

    do
    {
        printf("\n === SHOPPER MENU === \n");
        printf("1. Modify User Info\n");
        printf("2. Browse All Products\n");
        printf("3. Browse Products by Category\n");
        printf("4. Browse Products on Sale\n");
        printf("5. Add to Cart\n");
        printf("6. View Cart\n");
        printf("7. Settle Outstanding Balance\n");
        printf("8. Log Out\n");
        printf("Enter choice: ");
        scanf("%d", &sChoice);

        switch (sChoice)
        {
            case 1: modUserInfo (user);
                    break;
        //  case 2: browseAllProd ();
                    break;
            case 3: break;
            case 4: break;
            case 5: break;
            case 6: break;
            case 7: break;
            case 8: break;
        }
    } while (sChoice!=8);
}

/*
FUNCTION: login allows the user to log in to a specific account
@param: userNode *user: structure with the user information
@return: void
*/
void login (userNode *user)
{
    int pchk=1, compare=2, found=0, close=0, stockctr=0, attempt=0;
    char cDump;
    string15 uname, pword;
    userNode *temp=NULL;
    stockNode *stockInfo=NULL;
    categNode *stemp=NULL;
    temp=user;

    printf(" === LOGIN === \n");
    printf("Enter username: ");
    scanf("%s%c", uname, &cDump);

    while (found==0 && temp!=NULL)
    {
        compare=strcmp(uname, temp->username);

        if (compare==0)
            found=1;
        else
            temp=temp->next;
    }

    if (found==1 && temp->isLocked==0)
    {
        do
        {
            printf("Enter password: ");
            scanf("%s%c", pword, &cDump);

            compare=strcmp(pword, temp->password);

            if (compare==0)
            {
                switch (temp->type)
                {
                    case 1:     printf("\nWelcome back, Admin!\n");
                                close=1;
                                adminMenu (user, &close, stockInfo, &stockctr,stemp);
                                break;

                    case 2:     printf("\nWelcome back, Shopper!\n");
                                close=1;
                                shopperMenu(user, stockInfo, &stockctr);
                                break;
                }
            }
            else
            {
                attempt++;
                printf("Incorrect password. Try again.\n");
                printf("%d out of 3 tries\n", attempt);

                if (attempt==3)
                {
                    user->isLocked=1;
                    printf("\nYou have tried logging in too many times.\n");
                    printf("Please contact the administrator.\n");
                }
            }
        } while (close==0 && attempt<=3 && temp->isLocked==0);
    }
    else
        printf("\nSorry, username does not exist.\n");
}

/*
FUNCTION: getUserInfo asks the user for their name (first, middle, last) information
          as well as their address
@param: userInfoType *pInfo: structure of the data of the current user with contains user information
@return: void
*/
void getUserInfo (userInfoType  *pInfo)
{
    getchar();
    printf("Enter name: \n");
    printf("First name: ");
    fgets(pInfo->name.first, 21, stdin);
    printf("Middle name: ");
    fgets(pInfo->name.middle, 21, stdin);
    printf("Last name: ");
    fgets(pInfo->name.last, 21, stdin);
    printf("Enter address: ");
    fgets (pInfo->address, 51, stdin);

    (*pInfo).address[strlen((*pInfo).address)-1]='\0';
    (*pInfo).name.first[strlen((*pInfo).name.first)-1]='\0';
    (*pInfo).name.middle[strlen((*pInfo).name.middle)-1]='\0';
    (*pInfo).name.last[strlen((*pInfo).name.last)-1]='\0';

    printf("%s, %s %s \n", pInfo->name.last, pInfo->name.first, pInfo->name.middle);
}

/*
FUNCTION: checkUnique is to verify if the username is unique or not
@param: string15 uname: chosen username of new user
@param: userNode *user: structure with the user information
@return: int: 0 if not unique, 1 if unique
*/
int checkUnique (string15 uname, userNode *user)
{
    int unique=1;
    userNode *temp=NULL;

    temp=user;

    while(temp!=NULL)
    {
        if (strcmp(temp->username, uname)==0)
        {
            unique=0;
            temp=NULL;
        }
        else
            temp=temp->next;
    }

    return unique;
}

/*
FUNCTION: signUp allows the user to create more accounts and adding it to the current
         list of users
@param: userNode *user: structure which contains infomation of all users
@param: userNode *pNew: structure which contains information of the current user
@return: void
*/
void signUp (userNode *user, userNode *pNew)
{
    int go=0, chk=0, i=0, compare=2, accept=0, choice=0, close=1, change=0;
    char cDump;
    /* for authorization code */
    string8 ac;
    string15 uname, pword;

    if (user==NULL)
    {
        /* first account to sign up */
        do
        {
            printf("=== SIGN UP ===\n");
            printf("Enter username: ");
            scanf("%s%c", uname, &cDump);
        } while ((strlen(uname) < 3 || strlen(uname) > 15));

        strcpy (pNew->username, uname);
    }

    else
    {
        /* second account and onwards to sign up */
        do
        {
            printf("=== SIGN UP ===\n");
            printf("Enter username: ");
            scanf("%s%c", uname, &cDump);

            if (strlen(uname) >=3 && strlen(uname)<=15)
            {
                compare=checkUnique(uname, user);

                if (compare==1)
                {
                    accept=1;
                    strcpy (pNew->username, uname);
                }

                else if (compare!=1)
                {
                    accept=0;
                    printf("Username unavailable. Try again.\n");
                }
            }
        } while (strlen(uname) < 3 || strlen(uname) > 15 || accept==0 || compare!=1);
    }

    printf("Username is: %s\n", pNew->username);

    accept=0;

    do
    {
        printf("Enter password: ");
        scanf("%s", pword);

        if (strlen(pword) >= 6 || strlen(pword) <= 15)
        {
            for (i=0; i<strlen(pword); i++)
            {
                if (!((pword[i] >= 'A' && pword[i] <= 'Z') || (pword[i] >= 'a' && pword[i] <= 'z')))
                {
                    accept=1;
                    chk=1;
                    strcpy (pNew->password, pword);
                }
            }

            if (accept!=1)
                printf("Invalid password. Input at least 1 non-letter.\n");
        }
        else
            accept=0;

    } while (chk==0 || accept!=1 || strlen(pword) < 6 || strlen(pword) > 15);

    printf("Password is: %s\n", pNew->password);

    getUserInfo(&pNew->info);   /* (&pUser->info) */

    /* to ask the user to ask which type of account (s)he prefers to make */
    do
    {
        printf("\nChoose your type of account: \n");
        printf("1. Administrator\n");
        printf("2. Shopper\n");
        printf("Enter choice: ");
        scanf("%d", &choice);

        while (choice!=1 && choice!=2)
        {
            printf("Invalid choice. Try again.\n");
            printf("Choose your type of account: \n");
            printf("1. Administrator\n");
            printf("2. Shopper\n");
            printf("Enter choice: ");
            scanf("%d", &choice);
        }
        pNew->type=choice;

        switch (pNew->type)
        {
            /* if user chooses to be an administrator */
            case 1: do
                    {
                        printf("Input authorization code: ");
                        scanf("%s", ac);

                        /* to check if authorization code is valid */
                        if (strcmp(ac, "DLSU2017")==0)
                            printf("\nHello New Admin!\n");

                        else
                        {
                            printf("\nSorry, invalid authorization code.\n");
                            printf("1. Try again\n");
                            printf("2. Change account type\n");
                            printf("Enter choice: ");
                            scanf("%d", &change);

                            while (change!=1 && change!=2)
                                printf("\nInvalid input!\n");

                            switch (change)
                            {
                                case 1: close=1;
                                        break;
                                case 2: close=0;
                                        break;
                            }
                        }
                    } while (strcmp(ac, "DLSU2017")!=0 && close!=0);
                    break;

            /* if user chooses to be a shopper */
            case 2: printf("\nHello Shopper!\n\n");
                    pNew->creditLimit=5000.00;
                    pNew->outstanding=0.00;
                    pNew->nItems=0;
                    pNew->isLocked=0;

                    /* to tell the user more information about his/her account */
                    printf("Your Credit Limit is: PhP %.2f.\n", pNew->creditLimit);
                    printf("Your Outstanding Balance is: PhP %.2f.\n", pNew->outstanding);
                    printf("Your Cart currently contains: %d items.\n", pNew->nItems);
                    break;

            default: printf("Invalid input!\n");
        }
    } while (close==0 && change==2);

    /* recap for the user */
    printf("\n === REMEMBER ===\n");
    printf("Username is: %s\n", pNew->username);
    printf("Password is: %s\n\n", pNew->password);
}

/*
FUNCTION: displayAllRecur displays all the usernames available
@param: userNode *user: structure which contains infomation of all users
@return: void
*/
void displayAllRecur (userNode *user)
{
    if (user!=NULL)
    {
        printf("%s \n", user->username);
        user=user->next;
    }
}

/*
FUNCTION: freeAll frees all the data from the user structures
@param: userNode **user: structure containing the data of the all users
@return: void
*/
void freeAll (userNode **user)
{
    userNode *pDel;

    pDel=NULL;

    while (user!=NULL)
    {
        pDel=*user;
        *user=(*user)->next;
        free(pDel);
    }
}

/*
FUNCTION: freeAllStocks frees all the data from the stock structures
@param: stockNode **pStocks: structure containing the data of the stocks
@return: void
*/
void freeAllStocks (stockNode **pStocks)
{
    stockNode *pDel;

    pDel=NULL;

    while(pStocks!=NULL)
    {
        pDel=*pStocks;
        *pStocks=(*pStocks)->next;
        free(pDel);
    }
}

int main()
{
    int choice=0, close=0, nChoice=0;
    userNode *user, *pNew, *pLast, *pRun, *pTrail;
    stockNode *pStocks;

    user=NULL;
    pNew=NULL;
    pLast=NULL;
    pRun=NULL;
    pTrail=NULL;
    pStocks=NULL;

    printf("\t\t\t\t\t\t========== WELCOME! ==========\n");

    do
    {
        printf("\n=== MAIN MENU ===\n");
        printf("1. Login\n");
        printf("2. Sign-up\n");
        printf("3. Exit\n");
        printf("Enter choice: ");
        scanf("%d", &choice);
        printf("\n");

        while(choice!=1 && choice!=2 && choice!=3)
        {
            fflush(stdin);
            printf("Try Again!\n");
            printf("\n=== MAIN MENU ===\n");
            printf("1. Login\n");
            printf("2. Sign-up\n");
            printf("3. Exit\n");
            printf("Enter choice: ");
            scanf("%d", &choice);
            printf("\n");
        }

        switch (choice)
        {
            case 1:     if (user==NULL)
                            printf("There are not any users yet! Sign up first.\n");
                        else
                        {
                            printf("You chose to login!\n\n");
                            login(user);
                        }
                        break;

            case 2:     printf("You chose to sign-up!\n\n");
                        do
                        {
                            pNew=malloc(sizeof(userNode));
                            signUp(user, pNew);
                            pNew->next=NULL;

                            if (user==NULL)
                                user=pNew;

                            else if (strcmp(user->username, pNew->username)>0)
                            {
                                pNew->next=user;
                                user=pNew;
                            }

                            else
                            {
                                pRun=user;
                                while (pRun!=NULL && strcmp(pRun->username, pNew->username)<0)
                                {
                                    pTrail=pRun;
                                    pRun=pRun->next;
                                }
                                pTrail->next=pNew;
                                pNew->next=pRun;
                            }

                            do
                            {
                                printf("Would you like to add another user?\n");
                                printf("1. Yes\n");
                                printf("2. No\n");
                                printf("Enter choice: ");
                                scanf("%d", &nChoice);
                            } while (nChoice!=1 && nChoice!=2);

                        } while (nChoice==1);
                        break;

            case 3:     printf("Closing program...\n");
                        close=1;
                        break;

            default: printf("Invalid input.\n");
        }
    } while (close==0 || nChoice==2 || nChoice==0 && choice!=3);

    if (user!=NULL)
        freeAll(&user);

    if (pStocks!=NULL)
        freeAllStocks (&pStocks);

    return 0;
}