<?php
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Simple login module
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Register the module
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function register_simple_login($handler, $navigation)
{
    $handler->register_handler(
        "Simple login",
        "simple_login");

    $handler->register_handler(
        "Check login",
        "check_login");

    $handler->register_handler(
        "Logged in",
        "logged_in");

    $handler->register_handler(
        "Log out",
        "log_out");

// Add simple login to the navigation
    $navigation -> add_item(
        "Simple login",
        make_url("Simple_login"));
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Main handler for simple login
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function simple_login()
{
// Make sure a user is not already logged in and display
// login form
    $content = "";
    if(!isset($_SESSION["simple_user"]))
    {
        $content = instance_view("login");
        $content = $content->parse_to_variable(array(
            'target' => make_url("Check_login")));
    }

// If theare is already a user logged in, redirect to
// logged in page
    else
    {
        redirect(make_url("Logged_in"));
    }

    return make_return("Simple login", $content);
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Check that the user exists
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function check_login()
{
// get sumitted username and password from the login form
    $username = $_POST['username'];
    $password = $_POST['password'];

// Create an instance of the users model
    $users = instance_model("users");

// Check that the user entered actually exists.
    $user = $users->check_user($username, $password);

// If the above returned an empty string, raise an error
    if($user == "")
        raise_error("Username or password is incorrect");

// Set sesion variable to indicate that a user is logged in
    $_SESSION['simple_user'] = $user;

// Redirect to logged in page
    redirect(make_url("Logged_in"));
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Page that indicates that a user is logged in
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function logged_in()
{
// surround pages requireing authentication with this if
// statement
    if(simple_auth())
    {
    // display logged in message
        $content = instance_view("logged_in");
        $content = $content->parse_to_variable(array(
            'user'   => $_SESSION['simple_user'],
            'target' => make_url("Log out")));

        return make_return("Logged in", $content);;
    }
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Log out
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function log_out()
{
// wipe session varaible and redirect
    unset($_SESSION['simple_user']);
    redirect(make_url("Simple_login"));
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * Check that a user is logged in
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
function simple_auth()
{
// Redirect to login form if no user is logged in, return
// false to indicate error
    if(!isset($_SESSION["simple_user"]))
    {
        redirect(make_url("Simple_login"));
        return false;
    }

// else return true to indicate successful auth
    else
    {
        return true;
    }
}