<?php

/**
 * @file
 * Handles compiling of .less files.
 *
 * The theme system allows for nearly all output of the Drupal system to be
 * customized by user themes.
 */

define('LESS_PERMISSION', 'administer less');

/**
 * Implements hook_menu().
 */
function less_menu() {
  $items = array();

  $items['admin/config/development/less'] = array(
    'title' => 'LESS settings',
    'description' => 'Administer LESS settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('less_settings'),
    'access arguments' => array(LESS_PERMISSION),
    'file' => 'less.admin.inc',
    'type' => MENU_NORMAL_ITEM,
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function less_permission() {
  return array(
    LESS_PERMISSION => array(
      'title' => t('Administer LESS'),
      'description' => t('Access the LESS settings page and view debug messages.'),
    ),
  );
}

/**
 * Builds the less cache
 */
function _less_pre_render($styles) {
  
  $less_devel = variable_get('less_devel', FALSE);
  $less_dir = variable_get('less_dir', '');
  
  // Force regeneration LESS files if developer mode is enabled
  if ($less_devel || !$less_dir) {
    $less_dir = _less_new_dir();
    if ($less_devel && user_access(LESS_PERMISSION) && flood_is_allowed('less_devel_warning', 1)) {
      flood_register_event('less_devel_warning');
      drupal_set_message(t('LESS files are being regenerated on every request. Remember to <a href="!url">turn off</a> this feature on production websites.', array("!url" => url('admin/config/development/less'))), 'status');
    }
  }
  
  $less_path = 'public://less/' . $less_dir;
  
  foreach ($styles['#items'] as $key => $info) {
    $input_file = $info['data'];
    if (drupal_substr($input_file, -5) == '.less') {
      
      $file_uri = file_uri_target($input_file);
      $css_path = $less_path . '/' . dirname($file_uri ? $file_uri : $input_file);

      if (!is_dir($css_path) && !file_prepare_directory($css_path, FILE_CREATE_DIRECTORY)) {
        // There is a problem with the directory.
        $param = array('%dir' => $css_path);
        if (user_access(LESS_PERMISSION)) {
          drupal_set_message(t('LESS could not create a directory in %dir', $param), 'error');
        }
        watchdog('LESS', t('LESS could not create a directory in %dir', $param), array(), WATCHDOG_ERROR);
        return;
      }

      $output_file = $css_path . '/' . basename($input_file, '.less');
      // correct file names of files not following the .css.less naming convention
      if (drupal_substr($output_file, -4) != '.css') {
        $output_file .= '.css';
      }

      if (!is_file($output_file)) {
        
        if (_less_inc()) {
            
          $less = new lessc();
  
          $contents = drupal_load_stylesheet($input_file, FALSE);
  
          // Build the base URL of this CSS file: start with the full URL.
          $css_base_url = file_create_url($input_file);
          // Move to the parent.
          $css_base_url = substr($css_base_url, 0, strrpos($css_base_url, '/'));
          // Simplify to a relative URL if the stylesheet URL starts with the
          // base URL of the website.
          if (substr($css_base_url, 0, strlen($GLOBALS['base_root'])) == $GLOBALS['base_root']) {
            $css_base_url = substr($css_base_url, strlen($GLOBALS['base_root']));
          }
  
          _drupal_build_css_path(NULL, $css_base_url . '/');
          // Prefix all paths within this CSS file, ignoring external and absolute paths.
          $data = preg_replace_callback('/url\(\s*[\'"]?(?![a-z]+:|\/+)([^\'")]+)[\'"]?\s*\)/i', '_drupal_build_css_path', $contents);
  
          try {
            $output_data = $less->parse($data);
            file_unmanaged_save_data($output_data, $output_file, FILE_EXISTS_REPLACE);
          }
          catch (Exception $e) {
            $message = 'LESS error: @message, %input_file';
            $message_vars = array('@message' => $e->getMessage(), '%input_file' => $input_file);
            watchdog('LESS', $message, $message_vars, WATCHDOG_ERROR);
            if (user_access(LESS_PERMISSION)) {
              drupal_set_message(t($message, $message_vars), 'error');
            }
          }
          
        }

      }

      if (is_file($output_file)) {
        $styles['#items'][$key]['data'] = $output_file;
      }

    }

  }

  return $styles;
}

/**
 * Implements hook_flush_caches().
 *
 * Flushes compiled LESS files during cache flush, except during cron.
 *
 * @return An array of cache table names.
 */
function less_flush_caches() {
  if (!drupal_static('less_cron')) {
    _less_new_dir();
  }
  return array();
}

/**
 * Implements hook_cron_queue_info().
 */
function less_cron_queue_info() {
  drupal_static('less_cron', TRUE);
}

/**
 * Helper function to create a new less dir.
 */
function _less_new_dir() {
  $less_dir = uniqid('', TRUE);
  $less_path = 'public://less/' . $less_dir;
  file_prepare_directory($less_path, FILE_CREATE_DIRECTORY);
  variable_set('less_dir', $less_dir);
  return $less_dir;
}

/**
 * Implements hook_cron().
 */
function less_cron() {
  $less_dir = variable_get('less_dir', '');
  
  $file_scan_options = array(
    'nomask' => '/(\.\.?|CVS|' . preg_quote($less_dir) . ')$/', //adding current dir to excludes
    'recurse' => FALSE,
  );
  $found_files = file_scan_directory('public://less', '/^.+$/', $file_scan_options);

  foreach ($found_files as $found_file) {
    file_unmanaged_delete_recursive($found_file->uri);
  }
}

function less_element_info_alter(&$type) {
  array_unshift($type['styles']['#pre_render'], '_less_pre_render');
}

/**
 * Finds and loads the lessphp library
 */
function _less_inc() {
  static $loaded = NULL;
  
  if (!isset($loaded)) {
    
    // locations to check for lessphp, by order of preference
    $include_locations = array();
    
    // Composer created path
    $include_locations[] = dirname(__FILE__) . '/vendor/autoload.php';
    
    // load libraries module for during install
    module_load_include('module', 'libraries');
    
    if (function_exists('libraries_get_path')) {
      // add libraries supported path
      $include_locations[] = libraries_get_path('lessphp') . '/lessc.inc.php';
    }
    
    // add legacy path as final possible location
    $include_locations[] = dirname(__FILE__) . '/lessphp/lessc.inc.php';
    
    foreach ($include_locations as $include_location) {
      if (is_file($include_location)) {
        require_once $include_location;
        break;
      }
    }
    
    $loaded = class_exists('lessc', TRUE);
  }

  return $loaded;
}