<?php

/**
 * @file
 * Sends system emails in HTML.
 */

/**
 * Implements hook_permission().
 *
 * Defines a permission for setting the per-user plaintext option.
 */
function htmlmail_permission() {
  $args = array(
    '!htmlmail' => url('http://drupal.org/project/htmlmail'),
    '%htmlmail' => 'HTML Mail',
  );

  return array(
    'choose htmlmail_plaintext' => array(
      'title' => t('Choose to receive plaintext emails via %htmlmail', $args),
      'description' => t(
        'Granting this permission allows users to choose whether to receive all their emails in plaintext, rather than the default format provided by the <a href="!htmlmail">%htmlmail</a> module.', $args
      ),
    ),
  );
}

/**
 * Implements hook_help().
 */
function htmlmail_help($path, $arg) {
  switch ($path) {
    case 'admin/config/system/htmlmail':
      return '<h2>' . t('Theming') . '</h2><p>' . t('The email message goes through three transformations before sending:') . '</p>';
    case 'admin/help#htmlmail':
      return '<p>'
        . t('<a href="!htmlmail">HTML Mail</a> lets you theme your messages the same way you theme the rest of your website.',
          array('!htmlmail' => 'http://drupal.org/project/htmlmail')
        ) . '</p>';
    default:
      return '';
  }
}

/**
 * Implements hook_menu().
 */
function htmlmail_menu() {
  $items['admin/config/system/htmlmail'] = array(
    'title' => 'HTML Mail',
    'description' => 'Configure HTML Mail system-wide settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('htmlmail_admin_settings'),
    'access arguments' => array('administer site configuration'),
    'file' => 'htmlmail.admin.inc',
  );
  $items['admin/config/system/htmlmail/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => '-2'
  );
  $items['admin/config/system/htmlmail/test'] = array(
    'title' => 'Send Test',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('htmlmail_test_form'),
    'access arguments' => array('access administration pages'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'htmlmail.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_theme().
 *
 * Auto-detects htmlmail template files in the selected theme and in the
 * htmlmail module directory.
 */
function htmlmail_theme() {
  $items = array();
  $module_path = drupal_get_path('module', 'htmlmail');
  $pattern = '/^htmlmail.*\.tpl\.php$/';
  $files = file_scan_directory($module_path, $pattern, array('key' => 'name'));
  if ($theme = htmlmail_get_selected_theme()) {
    $theme_path = drupal_get_path('theme', $theme);
    $files = array_merge($files,
      file_scan_directory($theme_path, $pattern, array('key' => 'name'))
    );
  }
  else {
    $theme_path = $module_path;
  }
  ksort($files);
  foreach ($files as $file) {
    $path = dirname($file->uri);
    $template = substr($file->name, 0, -4);
    $suggestion = str_replace('--', '__', $template);
    $items[$suggestion] = array(
      'variables' => array('message' => array()),
      'template' => $template,
      'path' => $path,
      'theme path' => $theme_path,
    );
  }
  return $items;
}

/**
 * Process variables to format email messages.
 *
 * @see htmlmail.tpl.php
 */
function template_preprocess_htmlmail(array &$variables) {
  $variables['debug'] = variable_get('htmlmail_debug', '0');
  $variables['theme'] = htmlmail_get_selected_theme($variables);
  $variables['module_path'] = drupal_get_path('module', 'htmlmail');
  if (empty($variables['theme'])) {
    $variables['theme'] = 'no theme';
    $variables['theme_path'] = $variables['module_path'];
  }
  else {
    $variables['theme_path'] = drupal_get_path('theme', $variables['theme']);
  }
  $variables['theme_url'] = url(
    $variables['theme_path'], array('absolute' => TRUE)
  );
  $variables['message_id'] = $variables['module'] . '_' . $variables['key'];
  $suggestion = 'htmlmail__' . $variables['module'];
  $variables['theme_hook_suggestions'][] = $suggestion;
  $suggestion .= '__' . $variables['key'];
  $variables['theme_hook_suggestions'][] = $suggestion;
}

/**
 * Implements hook_mail().
 */
function htmlmail_mail($key, &$message, $params) {
  $message['module'] = 'htmlmail';
  $message['key'] = $key;
  $message['subject'] = $params['subject'];
  $message['body'] = explode(
    MAIL_LINE_ENDINGS . MAIL_LINE_ENDINGS,
    $params['body']
  );
  return $message;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function htmlmail_form_user_profile_form_alter(&$form, &$form_state) {
  if ($form['#user_category'] != 'account') {
    return;
  }
  if (!(user_access('choose htmlmail_plaintext') || user_access('administer users'))) {
    return;
  }
  $account = $form['#user'];
  $mail = $form['account']['mail'];
  $form['account']['mail'] = array(
    'mail' => $mail,
    'htmlmail_plaintext' => array(
      '#type' => 'checkbox',
      '#title' => t('Plaintext-only emails'),
      '#default_value' => empty($account->data['htmlmail_plaintext']) ? 0 : 1,
      '#description' => t('The %htmlmail module can send emails with fonts, styles, and other HTML formatting.  If you prefer to receive all your emails in unformatted plain text, select this option.',
        array('%htmlmail' => 'HTML Mail')
      ),
    ),
  );
}

/**
 * Implements hook_user_presave().
 */
function htmlmail_user_presave(&$edit, $account, $category) {
  if (user_access('choose htmlmail_plaintext') || user_access('administer users')) {
    $edit['data']['htmlmail_plaintext'] = empty($edit['htmlmail_plaintext']) ? 0 : 1;
    unset($edit['htmlmail_plaintext']);
  }
}

/**
 * Returns an associative array of allowed themes.  The keys are the
 * machine-readable names and the values are the .info file names.
 * Based on code from the og_theme module.
 */
function &htmlmail_get_allowed_themes() {
  $allowed = &drupal_static(__FUNCTION__);
  if (!isset($allowed)) {
    $allowed = array('' => t('No theme'));
    $themes = list_themes();
    module_load_include('inc', 'system', 'system.admin');
    uasort($themes, 'system_sort_modules_by_info_name');
    foreach ($themes as $key => $value) {
      if ($value->status) {
        $allowed[$key] = check_plain($value->info['name']);
      }
    }
  }
  return $allowed;
}

/**
 * Returns the selected theme to use for outgoing emails.
 */
function htmlmail_get_selected_theme(&$message = array()) {
  $selected = isset($message['theme'])
    ? $message['theme'] : variable_get('htmlmail_theme', '');
  if ($selected) {
    // Make sure the selected theme is allowed.
    $themes = &htmlmail_get_allowed_themes();
    if (empty($themes[$selected])) {
      $selected = '';
    }
  }
  return $selected;
}

/**
 * Checks whether a given recipient email prefers plaintext-only messages.
 *
 * @param $email
 *   The recipient email address.
 *
 * @return
 *   FALSE if the recipient prefers plaintext-only messages; otherwise TRUE.
 */
function htmlmail_is_allowed($email) {
  return !($recipient = user_load_by_mail($email))
    || empty($recipient->data['htmlmail_plaintext']);
}