<?php
	session_start();
	$uri = $_SERVER['REQUEST_URI'];
	function displaylogon($alert, $uri)
	{

			echo "<form method='post' action='$uri'>";
			echo "<table>";
			echo "<tr><td>Login Name<br /></td></tr>" ;
			echo "<tr><td><input type='text' name='loginname' size='15'/></td></tr>";
			echo "<tr><td>Login Password</td></tr>";
			echo "<tr><td><input type='password' name='loginpassword'  maxlength='15' size='15'/></td></tr>";
			echo "<tr><td><span class='alert'>$alert</span></td></tr>";
			echo "<tr><td><input type='submit' name='loginbutton' value='Login' /></td></tr>";
			echo "</table>";
			echo "</form>";
			echo "<br />";
			echo "<br />";
			echo "<a href='../main/registeruser.php'>New User</a>";
			echo "<br />";
	}
	function displaywelcome($uri)
	{
			echo "<p>";

			if($_SESSION['admin']==true)
			{
				echo "Welcome Administrator";
				echo "<br/>";
				echo "<br/>";
				echo "<a href='../admin/admin.php'>Admin Page</a>";
			}
			else
			{
				echo "Welcome " . $_SESSION['firstname'];
				echo "<br/>";
				echo "<br/>";
				echo "<a href='../main/cart.php'>View Cart</a>";
			}
			echo "</p>";

			echo "<form action='../main/homepage.php' method='post'>";
				echo "<table>";
					echo "<tr>";
						echo "<td><input type='hidden' value='true' name='logout' />";
						echo "<input type='submit' value='Log out' /></td>";
					echo "</tr>";
				echo "</table>";
			echo "</form>";
	}

	if($_POST['logout']==true)
	{
		//log the user out
		session_destroy();

		$alert =  "You are now logged out.";
		displaylogon($alert, $uri);
	}
	else
	{

		if (isset($_SESSION['username']))
		{
			if($_POST['logout']==true)
			{
				//log the user out
				session_destroy();
				header('location:..\main\homepage.php?');
				//$alert =  "You are now logged out.";
				//displaylogon($alert, $uri);
			}
			else
			{
				displaywelcome($uri);
			}
		}
		else if(isset($_POST['loginname']))
		{
			//check for admin login
			if((strcmp("super",$_POST['loginname'])==0)&& (strcmp("super",$_POST['loginpassword'])==0))
			{
				//set up session variables
				session_register('firstname');
				session_register('username');
				session_register('admin');
				$_SESSION['admin']=true;
				$_SESSION['firstname']= 'super';
				$_SESSION['username']= 'super';

				displaywelcome($uri);

			}
			else
			{
				//check user name is valid
				@ $fp = fopen("../datafiles/users.txt","r");
				if ($fp == null)
				{
					$alert =  "An error has occurred, please try again.";
					displaylogon($alert, $uri);
				}
				else
				{
					$match = false;
					while (!feof($fp))
					{
						$line = fgetss($fp);
						//only check if line from file is not blank.
						if (!(($line =="") ||  ($line==null)))
						{
							$linearray = explode("\t",$line);
							//check if username and password match
							if((strnatcasecmp($linearray[2],$_POST['loginname'])==0)&& (strcmp($linearray[0],$_POST['loginpassword'])==0))
							{
								$match = true;
							}
						}
					}

					if ($match == true)
					{
						//set up session variables
						session_register('firstname');
						session_register('username');
						$_SESSION['firstname']= $_POST['loginpassword'];
						$_SESSION['username']= $_POST['loginname'];

						displaywelcome($uri);


					}
					else
					{
						$alert =  "Username or password is incorrect.";
						displaylogon($alert, $uri);
					}
					fclose($fp);
				}
			}
		}
		else
		{
			//send the user back to where they came from
			$alert="";
			displaylogon($alert, $uri);


		}
	}
?>