<?php
/**
 * @file
 * Force anonymous users to login before being able to checkout.
 */

/**
 * Implements hook_menu().
 */
function commerce_checkout_redirect_menu() {
  $items = array();
  $items['admin/commerce/config/checkout_redirect'] = array(
    'title' => t('Checkout Redirect'),
    'description' => t('Checkout redirect module settings'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('commerce_checkout_redirect_settings'),
    'access arguments' => array('configure store'),
    'type' => MENU_NORMAL_ITEM,
  );
  return $items;
}

/**
 * Implements hook_entity_property_info_alter().
 */
function commerce_checkout_redirect_entity_property_info_alter(&$info) {
  $properties = &$info['user']['properties'];

  // Add the commerce_checkout_redirect property to the user,
  // useful for resolving redirect conflicts.
  $properties['commerce_checkout_redirect'] = array(
    'label' => t('User is in the checkout redirect process'),
    'description' => t('The user is in the checkout redirect process.'),
    'type' => 'boolean',
    'computed' => TRUE,
  );
}

/**
 * Creates settings form for module.
 */
function commerce_checkout_redirect_settings($form, &$form_state) {
  $form = array();
  $form['commerce_checkout_redirect_path'] = array(
    '#type' => 'textfield',
    '#title' => t('Checkout redirect path'),
    '#description' => t('Set the checkout redirect path for an anonymous user.
      Leave blank to use the default \'user/login\' page. If you redirect to
      other page then make sure you add user login block on that page.'),
    '#default_value' => variable_get('commerce_checkout_redirect_path')
  );
  $form['commerce_checkout_redirect_message'] = array(
    '#type' => 'textarea',
    '#title' => t('Checkout redirect login message'),
    '#description' => t('The message that should be displayed for the login page in the checkout process.'),
    '#default_value' => variable_get('commerce_checkout_redirect_message', t('You need to be logged in to be able to checkout.')),
    '#rows' => 2,
  );
  $form['commerce_checkout_redirect_anonymous'] = array(
    '#type' => 'checkbox',
    '#title' => t('Continue without register'),
    '#description' => t('Allow anonymous checkout.'),
    '#default_value' => variable_get('commerce_checkout_redirect_anonymous', FALSE),
  );
  $form['commerce_checkout_redirect_username_as_order_email'] = array(
    '#type' => 'checkbox',
    '#title' => t('Use username as order email.'),
    '#description' => t('This will use the login username to be used as order email.'),
    '#default_value' => variable_get('commerce_checkout_redirect_username_as_order_email', FALSE),
    '#states' => array (
      'visible' => array(
       ':input[name="commerce_checkout_redirect_anonymous"]' => array('checked' => true),
      ),
    ),
  );
  $form['commerce_checkout_redirect_anonymous_as_login_option'] = array(
    '#type' => 'checkbox',
    '#title' => t('Use anonymous checkout as option to login form.'),
    '#description' => t('This will provide the Anonymous checkout as alternative to login in the login form (radio options).'),
    '#default_value' => variable_get('commerce_checkout_redirect_anonymous_as_login_option', FALSE),
    '#states' => array (
      'visible' => array(
       ':input[name="commerce_checkout_redirect_anonymous"]' => array('checked' => true),
      ),
    ),
  );

  // Chekout button help text for e-mail verification when a visitor creates an account.
  if (variable_get('user_email_verification', TRUE)) {
    $form['commerce_checkout_redirect_reset_password_message'] = array(
      '#type' => 'textarea',
      '#title' => t('Reset password checkout redirect message'),
      '#description' => t('The message that should be displayed for the reset password page for new account in the checkout process.'),
      '#default_value' => variable_get('commerce_checkout_redirect_reset_password_message', t('You can also continue with the checkout process.')),
      '#rows' => 2,
    );
  }

  return system_settings_form($form);
}

/**
 * Implements hook_commerce_checkout_router().
 */
function commerce_checkout_redirect_commerce_checkout_router($order, $checkout_page) {
  // Get the id of the first and last checkout page
  $checkout_pages = commerce_checkout_pages();
  $first_checkout_page = key($checkout_pages);
  end($checkout_pages);
  $last_checkout_page = key($checkout_pages);
  // Check if the user's shopping cart order exists with something in the cart
  if (($checkout_page['page_id'] == $first_checkout_page)) {
    if (commerce_cart_order_load() && commerce_checkout_redirect_items_in_cart()) {
      if (user_is_anonymous() && empty($_SESSION['commerce_checkout_redirect_bypass'])) {
        $_SESSION['commerce_checkout_redirect_anonymous'] = TRUE;
        $commerce_checkout_redirect_message = variable_get('commerce_checkout_redirect_message', t('You need to be logged in to be able to checkout.'));
        if (!empty($commerce_checkout_redirect_message)) {
          drupal_set_message($commerce_checkout_redirect_message);
        }
        $redirect_path = variable_get('commerce_checkout_redirect_path', 'user/login');
        if($redirect_path == '') {
          $redirect_path = 'user/login';
        }
        return drupal_goto($redirect_path);
      }
    }
  }
  elseif ($checkout_page['page_id'] == $last_checkout_page) {
    unset($_SESSION['commerce_checkout_redirect_bypass']);
  }
}

/**
 * Implements hook_commerce_checkout_pane_info_alter().
 *
 */
function commerce_checkout_redirect_commerce_checkout_pane_info_alter(&$checkout_panes) {
  // Disable the Account Information pane if the
  // login username it will be used for order email.
  if (variable_get('commerce_checkout_redirect_username_as_order_email', FALSE)) {
    $checkout_panes['account']['page'] = 'disabled';
    $checkout_panes['account']['enabled'] = FALSE;
  }
}

/**
 * Implements hook_module_implements_alter().
 */
function commerce_checkout_redirect_module_implements_alter(&$implementations, $hook) {
  if ($hook != 'user_login') {
    return;
  }
  // Move our hook implementation to the top,
  // so the commerce_checkout_redirect user property could be used
  // by other hook implementations.
  $module = 'commerce_checkout_redirect';
  $group = array($module => $implementations[$module]);
  unset($implementations[$module]);
  $implementations = $group + $implementations;
}

/**
 * Implements hook_user_login().
 */
function commerce_checkout_redirect_user_login(&$edit, &$account) {
  // Add commerce_checkout_redirect property to the account object,
  // on checkout user login.
  if (!empty($_SESSION['commerce_checkout_redirect_anonymous'])) {
    $account->commerce_checkout_redirect = TRUE;
  }
}

/**
 * Implements hook_form_alter().
 */
function commerce_checkout_redirect_form_alter(&$form, &$form_state, $form_id) {
  $commerce_checkout_redirect_anonymous = variable_get('commerce_checkout_redirect_anonymous', FALSE);
  $user_forms = array(
    'user_login',
    'user_register_form',
    'user_login_block',
    'user_profile_form',
  );
  $all_user_forms = $user_forms + array('user_pass_reset');
  if (in_array($form_id, $all_user_forms)) {
    // Check if user has an active cart order.
    if ($order = commerce_cart_order_load()) {
      // Check if there's anything in the cart and if user has not yet selected checkout method.
      if (commerce_checkout_redirect_items_in_cart() && empty($_SESSION['commerce_checkout_redirect_bypass']) && !empty($_SESSION['commerce_checkout_redirect_anonymous'])) {
        if (in_array($form_id, $all_user_forms)) {
          // Append the checkout redirect function on user's forms.
          $form['#submit'][] = 'commerce_checkout_redirect_redirect_anonymous_submit';
          unset($form['#action']);
          // Anonymous checkout button.
          if (variable_get('commerce_checkout_redirect_anonymous', FALSE)) {
            $form_state['#order'] = $order;
            $form['actions']['continue_button'] = array(
              '#name' => 'continue_button',
              '#type'   => 'submit',
              '#value'  => t('Checkout without an account'),
              '#limit_validation_errors' => array(),
              '#submit' => array('commerce_checkout_redirect_anonymous_continue_checkout'),
              '#states' => array (
                'visible' => array(
                 ':input[name="have_pass"]' => array('value' => '0'),
                ),
              ),
            );
            // Anonymous checkout as alternative to login form.
            if (variable_get('commerce_checkout_redirect_anonymous_as_login_option', FALSE)) {
              $form['have_pass'] = array(
                '#type' => 'radios',
                '#title' => t('Do you have a password?'),
                '#options' => array(0 => t('No (You can create an account later)'), 1 => t('Yes')),
                '#weight' => 10,
                '#default_value' => 0,
              );
              $form['pass']['#states'] = array(
                'visible' => array(
                 ':input[name="have_pass"]' => array('value' => '1'),
                ),
              );
              $form['actions']['submit']['#states'] = array(
                'visible' => array(
                 ':input[name="have_pass"]' => array('value' => '1'),
                ),
              );
              $form['pass']['#weight'] = 10;
              $form['actions']['continue_button']['#value'] = t('Continue');
              $form['actions']['continue_button']['#states'] = array (
                'visible' => array(
                 ':input[name="have_pass"]' => array('value' => '0'),
                ),
              );
            }
            // Use the username as order email.
            // Email validation for the username form element
            if (variable_get('commerce_checkout_redirect_username_as_order_email', FALSE)) {
              $form['name']['#title'] = t('Email');
              $form['actions']['continue_button']['#limit_validation_errors'] = array(array('name'));
              $form['actions']['continue_button']['#validate'][] = 'commerce_checkout_redirect_username_as_order_email_form_validate';
            }
          }
        }
        // Reset password form.
        // E-mail verification when a visitor creates an account.
        elseif ($form_id == 'user_pass_reset' && !empty($form['actions'])) {
          // Provide the checkout as an alternative to the new account
          // reset password process.
          // Message (help text) for the "Continue with checkout" button.
          $checkout_redirect_reset_password_message = variable_get('commerce_checkout_redirect_reset_password_message', t('You can also continue with the checkout process.'));
          if (!empty($checkout_redirect_reset_password_message)) {
            $form['actions']['checkout_message']['#markup'] = '<p>' . $checkout_redirect_reset_password_message . '</p>';
          }
          // "Continue with checkout" submit button.
          $form['actions']['checkout'] = array(
            '#type' => 'submit',
            '#value' => t('Continue with checkout'),
          );
          // Append the checkout redirect function on user's forms.
          $form['#submit'][] = 'commerce_checkout_redirect_redirect_anonymous_submit';
          // Unset the action, use submit form function(s) instead.
          unset($form['#action']);
        }
      }
    }
  }
  // For resetting the session variables for back to cart checkout button.
  if (strpos($form_id, 'commerce_checkout_form_') === 0 && !empty($form['buttons']['cancel'])) {
    $form['buttons']['cancel']['#submit'][] = 'commerce_checkout_redirect_checkout_form_cancel_submit';
  }
}

/**
 * Submit callback for the user forms that will perform the redirection.
 */
function commerce_checkout_redirect_redirect_anonymous_submit($form, &$form_state) {
  // Because the user in the order may have been updated (from uid 0 to the real
  // uid for example), clear static cache before trying to get the order.
  drupal_static_reset('commerce_cart_order_id');
  if (!empty($_SESSION['commerce_checkout_redirect_anonymous'])) {
    // One time login link (reset password) for creating new account.
    if ($form['#form_id'] == 'user_pass_reset') {
      // Login for the new account to continue
      // with the checkout process.
      // @see user_pass_reset()
      if ($form_state['clicked_button']['#id'] == 'edit-checkout') {
        global $user;
        $users = user_load_multiple(array($form_state['build_info']['args'][0]), array('status' => '1'));
        $user = reset($users);
        $GLOBALS['user'] = $user;
        // User login with user_login_finalize().
        user_login_finalize();
        // Let the user's password be changed without the current password check.
        $token = drupal_random_key();
        $_SESSION['pass_reset_' . $GLOBALS['user']->uid] = $token;
      }
      // Continue the reset password process.
      else {
        drupal_goto('user/reset/' . implode('/', $form_state['build_info']['args']) . '/login');
      }
    }
    $order_id = commerce_cart_order_id($GLOBALS['user']->uid);
    if (user_is_logged_in() && $order_id) {
      unset($_SESSION['commerce_checkout_redirect_anonymous']);
      // Reset commerce_checkout_redirect user property.
      if (isset($GLOBALS['user']->commerce_checkout_redirect)) {
        unset($GLOBALS['user']->commerce_checkout_redirect);
      }
      $form_state['redirect'] = 'checkout/' . $order_id;
    }
  }
}

/**
 * Form validation handler for login form for using username as order email.
*/
function commerce_checkout_redirect_username_as_order_email_form_validate($form, &$form_state) {
  $mail = trim($form_state['values']['name']);
  form_set_value($form['name'], $mail, $form_state);
  // Validate the e-mail address, and check if it is taken by an existing user.
  if ($error = user_validate_mail($form_state['values']['name'])) {
    form_set_error('name', $error);
  }
  else {
    $mail_taken = (bool) db_select('users')
      ->fields('users', array('uid'))
      ->condition('uid', $GLOBALS['user']->uid, '<>')
      ->condition('mail', db_like($form_state['values']['name']), 'LIKE')
      ->range(0, 1)
      ->execute()
      ->fetchField();
    if ($mail_taken) {
      // Format error message dependent on whether the user is logged in or not.
      if ($GLOBALS['user']->uid) {
        form_set_error('name', t('The e-mail address %email is already taken.', array('%email' => $form_state['values']['name'])));
      }
      else {
        form_set_error('name', t('The e-mail address %email is already registered. <a href="@password">Have you forgotten your password?</a>', array('%email' => $form_state['values']['name'], '@password' => url('user/password'))));
      }
    }
  }
}

/**
 * Submit callback to allow an anonymous users to continue without logging in.
 */
function commerce_checkout_redirect_anonymous_continue_checkout($form, &$form_state) {
  // If the user chooses to continue without an account, set this variable so user
  // is only redirected once per order (or once per session if the session expires first).
  $_SESSION['commerce_checkout_redirect_bypass'] = TRUE;
  $order = $form_state['#order'];
  // Using the username as order email.
  if (variable_get('commerce_checkout_redirect_username_as_order_email', FALSE)) {
    $order->mail = $form_state['values']['name'];
    commerce_order_save($order);
  }
  $form_state['redirect'] = 'checkout';
}

/**
 * Submit callback for the reset the checkout to cart.
 */
function commerce_checkout_redirect_checkout_form_cancel_submit($form, &$form_state) {
  if (!empty($_SESSION['commerce_checkout_redirect_anonymous'])) {
    unset($_SESSION['commerce_checkout_redirect_anonymous']);
  }
  if (!empty($_SESSION['commerce_checkout_redirect_bypass'])) {
    unset($_SESSION['commerce_checkout_redirect_bypass']);
  }
}

/**
 * Function to check if the cart contains any items.
 */
function commerce_checkout_redirect_items_in_cart(){
  global $user;
  // Check if there a shopping cart order for the current user
  // and if it is not empty.
  if ($order = commerce_cart_order_load($user->uid)) {
    $order_wrapper = entity_metadata_wrapper('commerce_order', $order);
    if (commerce_line_items_quantity($order_wrapper->commerce_line_items, commerce_product_line_item_types()) > 0) {
      return TRUE;
    }
  }

  return FALSE;
}