#!/usr/bin/perl -W
use strict;
use 5.010;
use Data::Dumper;

my $heading = <<HEAD;
A script that allows a user to perform system administration tasks 
Programmer name:          Michael A. Gregor
Course:                   COSC 146
Lab#:                     7
Due Date:                 3/10/16
lab7.pl

HEAD
print $heading;

my %passwords = (tom => "BigApple");
my %types     = (tom => "admin");

my $menu = <<MENU;

         System Administration Tasks

1- Create a new account
2- Delete an account
3- Change an account password
4- List users in alphabetical order 
5- Exit the system

MENU


while (print $menu) 
{
    my $choice = prompt4input ("Make your choice: ");
    
    if ($choice == 1) {createAccount();  next;}
    if ($choice == 2) {deleteAccount();  next;}
    if ($choice == 3) {changePassword(); next;}
    if ($choice == 4) {listUsers();      next;}
    if ($choice == 5) {print "Good-bye!";exit(0);}
    if ($choice == 6) {print Dumper (\%passwords);
                       print Dumper (\%types); next;}
    
    print ("Bad Choice...Try Again!\n");
}

sub prompt4input  #returns response to a prompt string
{
   my $prompt = shift;
   
   print $prompt;
   my $input = <STDIN>;
   $input =~ s/^\s*//;  #remove leading  whitespace
   $input =~ s/\s*$//;  #remove trailing whitespace
   
   return $input;
}   

sub createAccount
{
    print "Creating Account...\n";
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if (exists $passwords{$userID}) 
    {
       print "Error: Duplicate user id: $userID ";
       return;  #### update added
    }
    
    my $account_type;
    while ($account_type = prompt4input(
           "Enter the account type, admin (or regular): "),
           $account_type !~ /admin|regular/)
    {
        
       $passwords{$userID} = $password;
       $types{$userID}     = $account_type;    
    }
    print "Account for \'$userID\' was successfully created \n";
}

sub deleteAccount
{
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if ($passwords{$userID} != "$password")
    {
        print "invalid user id/password combination!\n";
        return;
    }
    
    if ($types{$userID} != "admin")
    {
        print "$userID is not an admin...can not delete!\n";
        return;
    }
    delete $passwords{$userID};
    delete $types{$userID};
}

sub changePassword
{
    my $userID   = prompt4input ("Enter your userID: ");
    my $password = prompt4input ("Enter your password: ");
    
    if ($passwords{$userID} != "$password")
    {
        print "invalid user id/password combination!\n";
        return;
    }
    my $newPassword = prompt4input ("Enter new password: ");
    $passwords{$userID} = $newPassword;
}

sub listUsers
{
     # sort the users in descending order
     my $counter = 1;
     for my $userID (reverse sort keys %passwords) 
     {
         print "$userID\t";
         print "\n" if $counter++ % 3 == 0;  #divisible by 3 evenly
     }
     print "\n";
}