<?php

/**
 * @file
 * Advanced aggregation font module.
 */

/**
 * @addtogroup default_variables
 * @{
 */

/**
 * Default value to use font face observer for asynchronous font loading.
 */
define('ADVAGG_FONT_FONTFACEOBSERVER', 0);

/**
 * Default value to use localStorage in order to prevent the FOUT.
 */
define('ADVAGG_FONT_STORAGE', 1);

/**
 * Default value to use a cookie in order to prevent the FOUT.
 */
define('ADVAGG_FONT_COOKIE', 1);

/**
 * Default value to only replace the font if it's been downloaded.
 */
define('ADVAGG_FONT_NO_FOUT', 0);

/**
 * @} End of "addtogroup default_variables".
 */

/**
 * @addtogroup hooks
 * @{
 */

/**
 * Implements hook_module_implements_alter().
 */
function advagg_font_module_implements_alter(&$implementations, $hook) {
  // Move advagg to the bottom.
  if ($hook === 'page_alter' && array_key_exists('advagg_font', $implementations)) {
    $item = $implementations['advagg_font'];
    unset($implementations['advagg_font']);
    $implementations['advagg_font'] = $item;
  }
}

/**
 * Implements hook_page_alter().
 */
function advagg_font_page_alter() {
  // Skip if advagg is disabled.
  if (!advagg_enabled()) {
    return;
  }
  $advagg_font_ffo = variable_get('advagg_font_fontfaceobserver', ADVAGG_FONT_FONTFACEOBSERVER);
  // Fontface Observer is disabled.
  if (empty($advagg_font_ffo)) {
    return;
  }

  // Add settings.
  drupal_add_js(array(
    'advagg_font' => array(),
    'advagg_font_storage' => variable_get('advagg_font_storage', ADVAGG_FONT_STORAGE),
    'advagg_font_cookie' => variable_get('advagg_font_cookie', ADVAGG_FONT_COOKIE),
    'advagg_font_no_fout' => variable_get('advagg_font_no_fout', ADVAGG_FONT_NO_FOUT),
  ), array('type' => 'setting'));

  // Add inline script for reading the cookies and adding the fonts already
  // loaded to the html class.
  if (variable_get('advagg_font_cookie', ADVAGG_FONT_COOKIE) || variable_get('advagg_font_storage', ADVAGG_FONT_STORAGE)) {
    $inline_script_min = 'for(var fonts=document.cookie.split("advaggf"),i=0;i<fonts.length;i++){var font=fonts[i].split("="),pos=font[0].indexOf("ont_");-1!==pos&&(window.document.documentElement.className+=" "+font[0].substr(4).replace(/[^a-zA-Z0-9\-]/g,""))}if(void 0!==Storage){fonts=JSON.parse(localStorage.getItem("advagg_fonts"));var current_time=(new Date).getTime();for(var key in fonts)fonts[key]>=current_time&&(window.document.documentElement.className+=" "+key.replace(/[^a-zA-Z0-9\-]/g,""))}';
    drupal_add_js($inline_script_min, array(
      'type' => 'inline',
      'group' => JS_LIBRARY - 1,
      'weight' => -50000,
      'scope' => 'above_css',
      'scope_lock' => TRUE,
      'movable' => FALSE,
      'no_defer' => TRUE,
    ));
  }

  // Get library data for fontfaceobserver.
  $library = advagg_get_library('fontfaceobserver', 'advagg_font');
  // If libraries_load() does not exist load library externally.
  if (!is_callable('libraries_load')) {
    $advagg_font_ffo = 6;
  }
  // Add fontfaceobserver.js.
  if ($advagg_font_ffo != 6 && empty($library['installed'])) {
    // The fontfaceobserver library is not installed; use external variant.
    $advagg_font_ffo = 6;
  }
  if ($advagg_font_ffo == 6) {
    // Use the external variant.
    foreach ($library['variants']['external']['files']['js'] as $data => $options) {
      drupal_add_js($data, $options);
    }
  }
  else {
    // Load the fontfaceobserver library.
    if ($advagg_font_ffo == 2) {
      // Use the inline variant.
      libraries_load('fontfaceobserver', 'inline');
    }
    else {
      libraries_load('fontfaceobserver');
    }
  }

  // Add advagg_font.js; sets cookie and changes the class of the top level
  // element once a font has been downloaded.
  $file_path = drupal_get_path('module', 'advagg_font') . '/advagg_font.js';
  drupal_add_js($file_path, array(
    'async' => TRUE,
    'defer' => TRUE,
  ));
}

/**
 * Implements hook_menu().
 */
function advagg_font_menu() {
  $file_path = drupal_get_path('module', 'advagg_font');
  $config_path = advagg_admin_config_root_path();

  $items[$config_path . '/advagg/font'] = array(
    'title' => 'Async Font Loader',
    'description' => 'Load external fonts in a non blocking manner.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('advagg_font_admin_settings_form'),
    'type' => MENU_LOCAL_TASK,
    'access arguments' => array('administer site configuration'),
    'file path' => $file_path,
    'file' => 'advagg_font.admin.inc',
    'weight' => 10,
  );

  return $items;
}

/**
 * @} End of "addtogroup hooks".
 */

/**
 * @addtogroup 3rd_party_hooks
 * @{
 */

/**
 * Implements hook_libraries_info().
 */
function advagg_font_libraries_info() {
  $libraries['fontfaceobserver'] = array(
    // Only used in administrative UI of Libraries API.
    'name' => 'fontfaceobserver',
    'vendor url' => 'https://github.com/bramstein/fontfaceobserver',
    'download url' => 'https://github.com/bramstein/fontfaceobserver/archive/master.zip',
    'version arguments' => array(
      'file' => 'package.json',
      // 1.50. : "version": "1.5.0".
      'pattern' => '/"version":\\s+"([0-9\.]+)"/',
      'lines' => 10,
    ),
    'remote' => array(
      'callback' => 'advagg_get_github_version_json',
      'url' => 'https://rawgit.com/bramstein/fontfaceobserver/master/package.json',
    ),
    'files' => array(
      'js' => array(
        'fontfaceobserver.js' => array(
          'type' => 'file',
          'group' => JS_LIBRARY,
          'async' => TRUE,
          'defer' => TRUE,
        ),
      ),
    ),
    'variants' => array(),
  );
  // Get the latest tagged version for external file loading.
  $version = advagg_get_remote_libraries_version('fontfaceobserver', $libraries['fontfaceobserver']);
  $libraries['fontfaceobserver']['variants'] += array(
    'external' => array(
      'files' => array(
        'js' => array(
          "https://cdn.rawgit.com/bramstein/fontfaceobserver/v{$version}/fontfaceobserver.js" => array(
            'type' => 'external',
            'data' => "https://cdn.rawgit.com/bramstein/fontfaceobserver/v{$version}/fontfaceobserver.js",
            'async' => TRUE,
            'defer' => TRUE,
          ),
        ),
      ),
    ),
  );
  // Inline if local js is there.
  $libraries_paths = array();
  if (is_callable('libraries_get_libraries')) {
    $libraries_paths = libraries_get_libraries();
  }
  if (!empty($libraries_paths['fontfaceobserver']) && is_readable($libraries_paths['fontfaceobserver'] . '/fontfaceobserver.js')) {
    $libraries['fontfaceobserver']['variants'] += array(
      'inline' => array(
        'files' => array(
          'js' => array(
            'loadCSS_inline' => array(
              'type' => 'inline',
              'data' => (string) @advagg_file_get_contents($libraries_paths['fontfaceobserver'] . '/fontfaceobserver.js'),
              'no_defer' => TRUE,
            ),
          ),
        ),
      ),
    );
  }

  return $libraries;
}

/**
 * @} End of "addtogroup 3rd_party_hooks".
 */

/**
 * @addtogroup advagg_hooks
 * @{
 */

/**
 * Implements hook_advagg_current_hooks_hash_array_alter().
 */
function advagg_font_advagg_current_hooks_hash_array_alter(&$aggregate_settings) {
  $aggregate_settings['variables']['advagg_font_fontfaceobserver'] = variable_get('advagg_font_fontfaceobserver', ADVAGG_FONT_FONTFACEOBSERVER);
}

/**
 * @} End of "addtogroup advagg_hooks".
 */

/**
 * Get the replacements array for the css.
 *
 * @param string $css_string
 *   String of CSS.
 *
 * @return array
 *   An array containing the replacemnts and the font class name.
 */
function advagg_font_get_replacements_array($css_string) {
  // Get the CSS that contains a font-family rule.
  $length = strlen($css_string);
  $property_position = 0;
  $property = 'font';
  $property_alt = 'font-family';
  $replacements = array();
  $fonts_with_no_replacements = array();
  $lower = strtolower($css_string);
  $safe_fonts_list = array(
    'georgia' => TRUE,
    'palatino' => TRUE,
    'times new roman' => TRUE,
    'times' => TRUE,

    'arial' => TRUE,
    'helvetica' => TRUE,
    'gadget' => TRUE,
    'verdana' => TRUE,
    'geneva' => TRUE,
    'tahoma' => TRUE,
    'garamond' => TRUE,
    'bookman' => TRUE,
    'comic sans ms' => TRUE,
    'cursive' => TRUE,
    'trebuchet ms' => TRUE,
    'arial black' => TRUE,
    'impact' => TRUE,
    'charcoal' => TRUE,

    'courier new' => TRUE,
    'courier' => TRUE,
    'monaco' => TRUE,

    'system' => TRUE,
  );

  while (($property_position = strpos($lower, $property, $property_position)) !== FALSE) {
    // Find the start of the values for the property.
    $start_of_values = strpos($css_string, ':', $property_position);
    // Get the property at this location of the css.
    $property_in_loop = trim(substr($css_string, $property_position, ($start_of_values - $property_position)));

    // Make sure this property is one of the ones we're looking for.
    if ($property_in_loop !== $property && $property_in_loop !== $property_alt) {
      $property_position += strlen($property);
      continue;
    }

    // Get position of the last closing bracket plus 1 (start of this section).
    $start = strrpos($css_string, '}', -($length - $property_position));
    if ($start === FALSE) {
      // Property is in the first selector and a declaration block (full rule
      // set).
      $start = 0;
    }
    else {
      // Add one to start after the }.
      $start++;
    }

    // Get closing bracket (end of this section).
    $end = strpos($css_string, '}', $property_position);
    if ($end === FALSE) {
      // The end is the end of this file.
      $end = $length;
    }

    // Get closing ; in order to get the end of the declaration of the property.
    $declaration_end_a = strpos($css_string, ';', $property_position);
    $declaration_end_b = strpos($css_string, '}', $property_position);
    if ($declaration_end_a === FALSE) {
      $declaration_end = $declaration_end_b;
    }
    else {
      $declaration_end = min($declaration_end_a, $declaration_end_b);
    }
    if ($declaration_end > $end) {
      $declaration_end = $end;
    }
    // Add one in order to capture the } when we ge the full rule set.
    $end++;
    // Advance position for the next run of the while loop.
    $property_position = $end;

    // Get values assigned to this property.
    $values_string = substr($css_string, $start_of_values + 1, $declaration_end - ($start_of_values + 1));
    // Parse values string into an array of values.
    $values_array = explode(',', $values_string);
    if (empty($values_array)) {
      continue;
    }

    // Values array, first element is a quoted string.
    $dq = strpos($values_array[0], '"');
    $sq = strpos($values_array[0], "'");
    $quote_pos = ($sq !== FALSE) ? $sq : $dq;
    // Skip if the first font is not quoted.
    if ($quote_pos === FALSE) {
      continue;
    }

    $values_array[0] = trim($values_array[0]);
    // Skip if only one font is listed.
    if (count($values_array) === 1) {
      $fonts_with_no_replacements[$values_array[0]] = '';
      continue;
    }

    // Save the first value to a variable; starting at the quote.
    $removed_value_original = substr($values_array[0], max($quote_pos - 1, 0));

    // Resave first value.
    if ($quote_pos > 1) {
      $values_array[0] = trim(substr($values_array[0], 0, $quote_pos - 1));
    }

    // Get value as a classname. Remove quotes, trim, lowercase, and replace
    // spaces with dashes.
    $removed_value_classname = strtolower(trim(str_replace(array('"', "'"), '', $removed_value_original)));
    $removed_value_classname = str_replace(' ', '-', $removed_value_classname);

    // Remove value if it contains a quote.
    $values_array_copy = $values_array;
    foreach ($values_array as $key => $value) {
      if (strpos($value, '"') !== FALSE || strpos($value, "'") !== FALSE) {
        unset($values_array[$key]);
      }
      elseif ($key !== 0) {
        break;
      }
    }

    if (empty($values_array)) {
      // See if there's a "safe" fallback that is quoted.
      $values_array = $values_array_copy;
      foreach ($values_array as $key => $value) {
        if (strpos($value, '"') !== FALSE || strpos($value, "'") !== FALSE) {
          if ($key !== 0) {
            $lower_key = trim(trim(strtolower(trim($value)), '"'), "'");
            if (!empty($safe_fonts_list[$lower_key])) {
              break;
            }
          }
          unset($values_array[$key]);
        }
        elseif ($key !== 0) {
          break;
        }
      }
      if (empty($values_array)) {
        // No unquoted values left; do not modify the css.
        $key = array_shift($values_array_copy);
        $fonts_with_no_replacements[$key] = implode(',', $values_array_copy);
        continue;
      }
    }

    $extra = '';
    if (isset($values_array[0])) {
      $extra = $values_array[0] . ' ';
      unset($values_array[0]);
    }
    // Rezero the keys.
    $values_array = array_values($values_array);
    // Save next value.
    $next_value_original = trim($values_array[0]);
    // Create the values string.
    $new_values_string = $extra . implode(',', $values_array);

    // Get all selectors.
    $end_of_selectors = strpos($css_string, '{', $start);
    $selectors = substr($css_string, $start, $end_of_selectors - $start);
    // Ensure selectors is not a media query.
    if (stripos($selectors, "@media") !== FALSE) {
      // Move the start to the end of the media query.
      $start = $end_of_selectors + 1;
      // Get the selectors again.
      $end_of_selectors = strpos($css_string, '{', $start);
      $selectors = substr($css_string, $start, $end_of_selectors - $start);
    }

    // From advagg_load_stylesheet_content().
    // Perform some safe CSS optimizations.
    // Regexp to match comment blocks.
    // Regexp to match double quoted strings.
    // Regexp to match single quoted strings.
    $comment     = '/\*[^*]*\*+(?:[^/*][^*]*\*+)*/';
    $double_quot = '"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"';
    $single_quot = "'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'";
    // Strip all comment blocks, but keep double/single quoted strings.
    $selectors_stripped = preg_replace(
      "<($double_quot|$single_quot)|$comment>Ss",
      "$1",
      $selectors
    );

    // Add css class to all the selectors.
    $selectors_array = explode(',', $selectors_stripped);
    foreach ($selectors_array as &$selector) {
      $selector = ' .' . $removed_value_classname . ' ' . $selector;
    }
    $new_selectors = implode(',', $selectors_array);

    // Get full rule set.
    $full_rule_set = substr($css_string, $start, $end - $start);
    // Replace values.
    $new_values_full_rule_set = str_replace($values_string, $new_values_string, $full_rule_set);
    // Add in old rule set with new selectors.
    $new_selectors_full_rule_set = $new_selectors . '{' . $property_in_loop . ': ' . $values_string . ';}';

    // Record info.
    $replacements[] = array(
      $full_rule_set,
      $new_values_full_rule_set,
      $new_selectors_full_rule_set,
      $removed_value_original,
      $removed_value_classname,
      $next_value_original,
    );
  }
  return array($replacements, $fonts_with_no_replacements);
}