<?php
    include("header.php");

     if (isset($_POST['submit'])) {

        //load contents of form into variables
        $pw = $_POST['pass'];
        $name = $_POST['username'];
        stripslashes($pw);
        stripslashes($name);

        //register session
        session_register();

        //pass in username and password into session
        $_SESSION['uName'] = $name;
        $_SESSION['uPw'] = $pw;

        //checks if username exists in database.
        $check1 = mysql_query("SELECT password FROM users WHERE username = '$name'");


        //if no user exists it prompts user to login.
         if(mysql_num_rows($check1) == 0){
            die('<div class="alert">Click <a href="register.php">here</a> to register</a></div>');
         }

        //checks if the password for the user is correct.
         $check = mysql_query("SELECT * FROM users WHERE username = '$name' and password = '$pw'")or die(mysql_error());
         $count = mysql_num_rows($check);


         //if so it redirects to mainpage
         if($count == 1 ){
              header("Location: mainpage.php");
         }

         //prompts user that their password was wrong.
         else{
            die ('<div class="alert">incorect password</div>');
         }
         }

         //redirects if register button is selected
        if (isset($_POST['register'])) {

                      header("Location: register.php");
        }

        //if submit not yet selected process login form.
     else
     {
     ?>

        <form id="form1" name="form1" method="post" action="<?php echo $_SERVER['PHP_SELF']?>">
        <table width="219" border="0"  class="login"> <td></td>
             <tr>
                <td width="68" ><strong>Username</strong></td><td width="144">
                <input type="text" name="username" maxlength="40">
             </td></tr>
             <tr>
             <td><p><strong>Password</strong>:</p></td><td>
             <input type="password" name="pass" maxlength="50">
             </td></tr>
             <tr>
             <td colspan="2" align="center">
             <input type="submit" name="submit" value="Login">
             <input type="submit" name="register" value="Register">
             </td></tr>
             </table>
             </form>
             <?php
     }
 ?>
 </body>
 </html>