<?php

/**
 * @file
 * Displays Printer-friendly versions of Drupal pages.
 *
 * @ingroup print
 */

define('PRINTPDF_PATH', 'printpdf');

define('PRINT_PDF_FORMAT', 'pdf');

define('PRINT_PDF_LIB_PATH', 'sites/all/libraries');

define('PRINT_PDF_LINK_POS_DEFAULT', serialize(array('link' => 'link', 'block' => 'block', 'help' => 'help')));
define('PRINT_PDF_LINK_TEASER_DEFAULT', 0);
define('PRINT_PDF_SHOW_LINK_DEFAULT', 1);
define('PRINT_PDF_NODE_LINK_VISIBILITY_DEFAULT', 0);
define('PRINT_PDF_NODE_LINK_PAGES_DEFAULT', '');
define('PRINT_PDF_LINK_CLASS_DEFAULT', 'print-pdf');
define('PRINT_PDF_SYS_LINK_VISIBILITY_DEFAULT', 1);
define('PRINT_PDF_SYS_LINK_PAGES_DEFAULT', '');
define('PRINT_PDF_LINK_USE_ALIAS_DEFAULT', 0);
define('PRINT_PDF_BOOK_LINK_DEFAULT', 1);
define('PRINT_PDF_PDF_TOOL_DEFAULT', 0);
define('PRINT_PDF_CONTENT_DISPOSITION_DEFAULT', 2);
define('PRINT_PDF_PAPER_SIZE_DEFAULT', 'A4');
define('PRINT_PDF_PAGE_ORIENTATION_DEFAULT', 'portrait');
define('PRINT_PDF_IMAGES_VIA_FILE_DEFAULT', 0);
define('PRINT_PDF_AUTOCONFIG_DEFAULT', 1);
define('PRINT_PDF_FONT_FAMILY_DEFAULT', 'dejavusans');
define('PRINT_PDF_FONT_SIZE_DEFAULT', 10);
define('PRINT_PDF_FONT_SUBSETTING_DEFAULT', FALSE);
define('PRINT_PDF_FILENAME_DEFAULT', '[site-name] - [title] - [mod-yyyy]-[mod-mm]-[mod-dd]');
define('PRINT_PDF_DOMPDF_UNICODE_DEFAULT', 0);
define('PRINT_PDF_WKHTMLTOPDF_OPTIONS', "--footer-font-size 7 --footer-right '[page]'");
define('PRINT_PDF_DOMPDF_CACHE_DIR_DEFAULT', 'print_pdf/dompdf');
define('PRINT_PDF_TCPDF_CACHE_DIR_DEFAULT', 'print_pdf/tcpdf');

/**
 * Implementation of hook_perm().
 */
function print_pdf_perm() {
  return array('access PDF version');
}

/**
 * Implementation of hook_theme().
 */
function print_pdf_theme() {
  return array(
    'print_pdf_format_link' => array(
      'arguments' => array(),
    ),
    'print_pdf_dompdf_footer' => array(
      'arguments' => array('html' => ''),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_header' => array(
      'arguments' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_page' => array(
      'arguments' => array('pdf' => NULL),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_content' => array(
      'arguments' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_footer' => array(
      'arguments' => array('pdf' => NULL, 'html' => '', 'font' => array()),
      'file' => 'print_pdf.pages.inc',
    ),
    'print_pdf_tcpdf_footer2' => array(
      'arguments' => array('pdf' => NULL),
      'file' => 'print_pdf.pages.inc',
    ),
  );
}

/**
 * Implementation of hook_init().
 */
function print_pdf_init() {
  if (variable_get('print_pdf_autoconfig', PRINT_PDF_AUTOCONFIG_DEFAULT)) {
    $pdf_dirs = array();
    $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);

    if (basename($print_pdf_pdf_tool) == 'dompdf_config.inc.php') {
      $pdf_dirs[] = PRINT_PDF_DOMPDF_CACHE_DIR_DEFAULT . '/fonts';
    }
    elseif (basename($print_pdf_pdf_tool) == 'tcpdf.php') {
      foreach (array('cache', 'images') as $dir) {
        $pdf_dirs[] = PRINT_PDF_TCPDF_CACHE_DIR_DEFAULT . '/' . $dir;
      }
    }

    if (!empty($pdf_dirs)) {
      foreach ($pdf_dirs as $pdf_dir) {
        $directory = file_directory_path() . '/' . $pdf_dir;
        if (!is_dir($directory)) {
          $dir_tmp = '';
          foreach (explode('/', $pdf_dir) as $dir) {
            $dir_tmp .= $dir . '/';
            $directory = file_directory_path() . '/' . $dir_tmp;
            file_check_directory($directory, FILE_CREATE_DIRECTORY);
          }
        }
      }
    }
  }
}

/**
 * Implementation of hook_menu().
 */
function print_pdf_menu() {
  $items = array();

  $items[PRINTPDF_PATH] = array(
    'title' => 'Printer-friendly PDF',
    'page callback' => 'print_pdf_controller',
    'access arguments' => array('access PDF version'),
    'type' => MENU_CALLBACK,
    'file' => 'print_pdf.pages.inc',
  );
  $items[PRINTPDF_PATH .'/'. PRINTPDF_PATH] = array(
    'access callback' => FALSE,
  );
  $items['admin/settings/print/pdf'] = array(
    'title' => 'PDF',
    'description' => 'Configure the settings of the PDF generation functionality.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('print_pdf_settings'),
    'access arguments'  => array('administer print'),
    'weight' => 3,
    'type' => MENU_LOCAL_TASK,
    'file' => 'print_pdf.admin.inc',
  );
  $items['admin/settings/print/pdf/options'] = array(
    'title' => 'Options',
    'weight' => 1,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/settings/print/pdf/strings'] = array(
    'title' => 'Text strings',
    'description' => 'Override the user-facing strings used in the PDF version.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('print_pdf_strings_settings'),
    'access arguments'  => array('administer print'),
    'weight' => 2,
    'type' => MENU_LOCAL_TASK,
    'file' => 'print_pdf.admin.inc',
  );

  return $items;
}

/**
 * Implementation of hook_block().
 */
function print_pdf_block($op = 'list', $delta = 0, $edit = array()) {
  switch ($op) {
    case 'list':
      $block[0]['info'] = t('Most PDFd');
      $block[0]['cache'] = BLOCK_CACHE_GLOBAL;
      return $block;
      break;
    case 'configure':
      return '';
    case 'save':
      return;
    case 'view':
      switch ($delta) {
      case 0:
        $block['subject'] = t('Most PDFd');
        $result = db_query_range("SELECT path FROM {print_pdf_page_counter} LEFT JOIN {node} n ON path = CONCAT('node/', n.nid) WHERE status <> 0 OR status IS NULL ORDER BY totalcount DESC", 0, 3);
        if (db_affected_rows()) {
          $block['content'] = '<div class="item-list"><ul>';
          while ($obj = db_fetch_object($result)) {
            $block['content'] .= '<li>'. l(_print_get_title($obj->path), $obj->path) .'</li>';
          }
          $block['content'] .= '</ul></div>';
        }
        break;
      }
      return $block;
      break;
    }
}

/**
 * Implementation of hook_requirements().
 */
function print_pdf_requirements($phase) {
  $requirements = array();
  $t = get_t();
  switch ($phase) {
    // At runtime, make sure that a PDF generation tool is selected
    case 'runtime':
      $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
      if (empty($print_pdf_pdf_tool)) {
        $requirements['print_pdf_tool'] = array(
          'title' => $t('Printer, email and PDF versions - PDF generation library'),
          'value' => $t('No PDF tool selected'),
          'description' => $t('Please configure it in the !url.', array('!url' => l($t('PDF settings page'), 'admin/settings/print/pdf'))),
          'severity' => REQUIREMENT_ERROR,
        );
      }
      else {
        if (!is_file($print_pdf_pdf_tool) || !is_readable($print_pdf_pdf_tool)) {
          $requirements['print_pdf_tool'] = array(
            'title' => $t('Printer, email and PDF versions - PDF generation library'),
            'value' => $t('File not found'),
            'description' => $t('The currently selected PDF generation library (%file) is no longer accessible.', array('%file' => $print_pdf_pdf_tool)),
            'severity' => REQUIREMENT_ERROR,
          );
        }
        elseif (basename($print_pdf_pdf_tool) == 'dompdf_config.inc.php') {
          if (variable_get('print_pdf_autoconfig', PRINT_PDF_AUTOCONFIG_DEFAULT)) {
            $directory = file_directory_path() . '/' . PRINT_PDF_DOMPDF_CACHE_DIR_DEFAULT . '/fonts';
            if (!is_dir($directory) || !is_writable($directory)) {
              $requirements['print_pdf_tool'] = array(
                'title' => $t('DOMPDF font cache directory'),
                'value' => $t('Non-writable permissions'),
                'description' => $t('You must change the %fontdir permissions to be writable, as dompdf requires write-access to that directory.', array('%fontdir' => $directory)),
                'severity' => REQUIREMENT_ERROR,
              );
            }
          }
        }
        elseif (basename($print_pdf_pdf_tool) == 'tcpdf.php') {
          $version = _print_pdf_tcpdf_version();

          if (version_compare($version, '5.9.001', '<')) {
            $requirements['print_pdf_tool'] = array(
              'title' => $t('Printer, email and PDF versions - PDF generation library'),
              'value' => $t('Unsupported TCPDF version'),
              'description' => $t('The currently selected version of TCPDF (@version) is not supported. Please update to a !url.', array('@version' => $version, '!url' => l($t('newer version'), 'http://sourceforge.net/projects/tcpdf/files/latest'))),
              'severity' => REQUIREMENT_ERROR,
            );
          }
          else {
            $requirements['print_pdf_tool'] = array(
              'title' => $t('Printer, email and PDF versions - PDF generation library'),
              'value' => $t('TCPDF') . ' ' . $version,
            );
          }

          if (variable_get('print_pdf_autoconfig', PRINT_PDF_AUTOCONFIG_DEFAULT)) {
            foreach (array('cache', 'images') as $dir) {
              $directory = file_directory_path() . '/' . PRINT_PDF_TCPDF_CACHE_DIR_DEFAULT . '/' . $dir;
              if (!is_dir($directory) || !is_writable($directory)) {
                $requirements['print_pdf_tool_'. $dir] = array(
                  'title' => $t('TCPDF directory'),
                  'value' => $t('Non-writable permissions'),
                  'description' => $t('You must change the %fontdir permissions to be writable, as TCPDF requires write-access to that directory.', array('%fontdir' => $directory)),
                  'severity' => REQUIREMENT_ERROR,
                );
              }
            }
          }
        }
        elseif (drupal_substr(basename($print_pdf_pdf_tool, '.exe'), 0, 11) == 'wkhtmltopdf') {
          if (function_exists('is_executable') && !is_executable($print_pdf_pdf_tool)) {
            $requirements['print_pdf_tool'] = array(
              'title' => $t('wkhtmltopdf library'),
              'value' => $t('Non-executable permissions'),
              'description' => $t('You must modify the permissions of the wkhtmltopdf file (%file) to make it executable.', array('%file' => $print_pdf_pdf_tool)),
              'severity' => REQUIREMENT_ERROR,
            );
          }
          else {
            $version = _print_pdf_wkhtmltopdf_version();
            if (version_compare($version, '0.9.6', '<')) {
              $requirements['print_pdf_tool'] = array(
                'title' => $t('Printer, email and PDF versions - PDF generation library'),
                'value' => $t('Unsupported wkhtmltopdf version'),
                'description' => $t('The currently selected version of wkhtmltopdf (@version) is not supported. Please update to a !url.', array('@version' => $version, '!url' => l($t('newer version'), 'http://code.google.com/p/wkhtmltopdf/'))),
                'severity' => REQUIREMENT_ERROR,
              );
            }
            else {
              $requirements['print_pdf_tool'] = array(
                'title' => $t('Printer, email and PDF versions - PDF generation library'),
                'value' => $t('wkhtmltopdf') . ' ' . $version,
              );
            }
          }
        }
      }
      break;
  }
  return $requirements;
}

/**
 * Implementation of hook_link().
 */
function print_pdf_link($type, $node = NULL, $teaser = FALSE) {
  $print_pdf_link_pos = variable_get('print_pdf_link_pos', unserialize(PRINT_PDF_LINK_POS_DEFAULT));
  $print_pdf_link_use_alias = variable_get('print_pdf_link_use_alias', PRINT_PDF_LINK_USE_ALIAS_DEFAULT);
  $allowed_type = print_pdf_link_allowed(array('type' => $type, 'node' => $node, 'teaser' => $teaser));
  if (($allowed_type) && !empty($print_pdf_link_pos['link'])) {
    drupal_add_css(drupal_get_path('module', 'print') .'/css/printlinks.css');
    $links = array();
    $format = theme('print_pdf_format_link');

    // Show book link
    if ($allowed_type === PRINT_ALLOW_BOOK_LINK) {
      $links['book_pdf'] = array('href' => PRINTPDF_PATH .'/book/export/html/'. $node->nid,
                                 'title' => $format['text'],
                                 'attributes' => $format['attributes'],
                                 'html' => $format['html'],
      );

      return $links;
    }
    elseif ($allowed_type === PRINT_ALLOW_NORMAL_LINK) {
      $query_arr = $_GET;
      if ($type == 'comment') {
        $query_arr['comment'] = $node->cid;
      }
      $query = print_query_string_encode($query_arr, array('q'));
      if (empty($query)) $query = NULL;

      if (($print_pdf_link_use_alias) && ($alias = drupal_lookup_path('alias', 'node/'. $node->nid))) {
        $path = $alias;
      }
      else {
        $path = $node->nid;
      }

      $links['print_pdf'] = array('href' => PRINTPDF_PATH .'/'. $path,
                                  'title' => $format['text'],
                                  'attributes' => $format['attributes'],
                                  'html' => $format['html'],
                                  'query' => $query,
      );

      return $links;
    }
  }
  else {
    return;
  }
}

/**
 * Implementation of hook_help().
 */
function print_pdf_help($path, $arg) {
  $print_pdf_link_pos = variable_get('print_pdf_link_pos', unserialize(PRINT_PDF_LINK_POS_DEFAULT));
  if (($path !== 'node/%') && !(empty($print_pdf_link_pos['help']))) {
    static $output = FALSE;

    if ($output === FALSE) {
      $output = TRUE;

      $link = print_pdf_insert_link();
      if ($link) {
        return "<span class='print-syslink'>$link</span>";
      }
    }
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function print_pdf_nodeapi(&$node, $op = 'view', $teaser, $page) {
  switch ($op) {
    case 'view':
      // Insert content corner links
      $print_pdf_link_pos = variable_get('print_pdf_link_pos', unserialize(PRINT_PDF_LINK_POS_DEFAULT));
      if (($teaser === FALSE) && !empty($print_pdf_link_pos['corner']) &&
          isset($node->build_mode) && ($node->build_mode === NODE_BUILD_NORMAL)) {
        $node->content['print_links']['#value'] .= print_pdf_insert_link(NULL, $node);
      }
      break;
    case 'load':
      $res = db_fetch_object(db_query("SELECT link, comments, url_list FROM {print_pdf_node_conf} WHERE nid = %d", $node->nid));

      $node->print_pdf_display = $res ? intval($res->link) : variable_get('print_pdf_display_'. $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
      $node->print_pdf_display_comment = $res ? intval($res->comments) : variable_get('print_pdf_display_comment_'. $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      $node->print_pdf_display_urllist = $res ? intval($res->url_list) : variable_get('print_pdf_display_urllist_'. $node->type, PRINT_TYPE_URLLIST_DEFAULT);
      break;
    case 'insert':
    case 'update':
      if (user_access('administer print') || user_access('node-specific print configuration')) {
        if (!isset($node->print_pdf_display)) $node->print_pdf_display = variable_get('print_pdf_display_'. $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
        if (!isset($node->print_pdf_display_comment)) $node->print_pdf_display_comment = variable_get('print_pdf_display_comment_'. $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
        if (!isset($node->print_pdf_display_urllist)) $node->print_pdf_display_urllist = variable_get('print_pdf_display_urllist_'. $node->type, PRINT_TYPE_URLLIST_DEFAULT);

        _print_pdf_node_conf_modify($node->nid, $node->print_pdf_display, $node->print_pdf_display_comment, $node->print_pdf_display_urllist);
      }
      break;
    case 'delete':
      db_query("DELETE FROM {print_pdf_node_conf} WHERE nid = %d", $node->nid);
      db_query("DELETE FROM {print_pdf_page_counter} WHERE path = 'node/%d'", $node->nid);
      break;
  }
}

/**
 * Implementation of hook_form_alter().
 */
function print_pdf_form_alter(&$form, $form_state, $form_id) {
  // Add the node-type settings option to activate the PDF version link
  if ((user_access('administer print') || user_access('node-specific print configuration')) && (($form_id == 'node_type_form') ||
      (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] .'_node_form' == $form_id))) {
    $form['print']['pdf_label'] = array(
      '#type' => 'markup',
      '#value' => '<p><strong>'. t('PDF version') .'</strong></p>',
    );

    $form['print']['print_pdf_display'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show link'),
    );
    $form['print']['print_pdf_display_comment'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show link in individual comments'),
    );
    $form['print']['print_pdf_display_urllist'] = array(
      '#type' => 'checkbox',
      '#title' => t('Show Printer-friendly URLs list'),
    );

    if ($form_id == 'node_type_form') {
      $form['print']['print_pdf_display']['#default_value'] = variable_get('print_pdf_display_'. $form['#node_type']->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
      $form['print']['print_pdf_display_comment']['#default_value'] = variable_get('print_pdf_display_comment_'. $form['#node_type']->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      $form['print']['print_pdf_display_urllist']['#default_value'] = variable_get('print_pdf_display_urllist_'. $form['#node_type']->type, PRINT_TYPE_URLLIST_DEFAULT);
    }
    else {
      $node = $form['#node'];
      $form['print']['print_pdf_display']['#default_value'] = isset($node->print_pdf_display) ? $node->print_pdf_display : variable_get('print_pdf_display_'. $node->type, PRINT_TYPE_SHOW_LINK_DEFAULT);
      $form['print']['print_pdf_display_comment']['#default_value'] = isset($node->print_pdf_display_comment) ? $node->print_pdf_display_comment : variable_get('print_pdf_display_comment_'. $node->type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      $form['print']['print_pdf_display_urllist']['#default_value'] = isset($node->print_pdf_display_urllist) ? $node->print_pdf_display_urllist : variable_get('print_pdf_display_urllist_'. $node->type, PRINT_TYPE_URLLIST_DEFAULT);
    }
  }
}

/**
 * Update the print_pdf_node_conf table to reflect the given attributes
 *
 * If updating to the default values, delete the record.
 *
 * @param $nid
 *   value of the nid field (primary key)
 * @param $link
 *   value of the link field (0 or 1)
 * @param $comments
 *   value of the comments field (0 or 1)
 * @param $url_list
 *   value of the url_list field (0 or 1)
 */
function _print_pdf_node_conf_modify($nid, $link, $comments, $url_list) {
    db_query("UPDATE {print_pdf_node_conf} SET link = %d, comments = %d, url_list = %d WHERE nid = %d", $link, $comments, $url_list, $nid);
    if (!db_affected_rows()) {
      @db_query("INSERT INTO {print_pdf_node_conf} (nid, link, comments, url_list) VALUES (%d, %d, %d, %d)", $nid, $link, $comments, $url_list);
    }
}

/**
 * Format the PDF version link
 *
 * @return
 *   array of formatted attributes
 * @ingroup themeable
 */
function theme_print_pdf_format_link() {
  $print_pdf_link_class  = variable_get('print_pdf_link_class', PRINT_PDF_LINK_CLASS_DEFAULT);
  $print_pdf_content_disposition = variable_get('print_pdf_content_disposition', PRINT_PDF_CONTENT_DISPOSITION_DEFAULT);
  $print_pdf_show_link = variable_get('print_pdf_show_link', PRINT_PDF_SHOW_LINK_DEFAULT);
  $print_pdf_link_text = filter_xss(variable_get('print_pdf_link_text', t('PDF version')));

  $img = drupal_get_path('module', 'print') .'/icons/pdf_icon.gif';
  $title = t('Display a PDF version of this page.');
  $class = strip_tags($print_pdf_link_class);
  $new_window = ($print_pdf_content_disposition == 1);
  $format = _print_format_link_aux($print_pdf_show_link, $print_pdf_link_text, $img);

  return array('text' => $format['text'],
               'html' => $format['html'],
               'attributes' => print_fill_attributes($title, $class, $new_window),
              );
}

/**
 * Auxiliary function to display a formatted PDF version link
 *
 * Function made available so that developers may call this function from
 * their defined pages/blocks.
 *
 * @param $path
 *   path of the original page (optional). If not specified, the current URL
 *   is used
 * @param $node
 *   an optional node object, to be used in defining the path, if used, the
 *   path argument is irrelevant
 * @return
 *   string with the HTML link to the printer-friendly page
 */
function print_pdf_insert_link($path = NULL, $node = NULL) {
  if ($node !== NULL) {
    $nid = $node->nid;
    $path = 'node/'. $nid;
    $allowed_type = print_pdf_link_allowed(array('node' => $node));
  }
  else {
    if ($path === NULL) {
      $nid = preg_replace('!^node/([\d]+)!', '$1', $_GET['q']);
      $path = $_GET['q'];
    }
    else {
      $nid = NULL;
    }
    $allowed_type = print_pdf_link_allowed(array('path' => $path));
  }

  if ($allowed_type) {
    if ($nid !== NULL) {
      if ($allowed_type === PRINT_ALLOW_BOOK_LINK) {
        $path = 'book/export/html/'. $nid;
      }
      else {
        if (variable_get('print_pdf_link_use_alias', PRINT_PDF_LINK_USE_ALIAS_DEFAULT) && ($alias = drupal_lookup_path('alias', $path))) {
          $path = $alias;
        }
        else {
          $path = $nid;
        }
      }
      $path = PRINTPDF_PATH .'/'. $path;
      $query = print_query_string_encode($_GET, array('q'));
      if (empty($query)) {
        $query = NULL;
      }
    }
    else {
      $query = NULL;
    }
    drupal_add_css(drupal_get_path('module', 'print') .'/css/printlinks.css');
    $format = theme('print_pdf_format_link');
    return '<span class="print_pdf">'. l($format['text'], $path, array('attributes' => $format['attributes'], 'query' => $query, 'absolute' => TRUE, 'html' => $format['html'])) .'</span>';
  }
  else {
    return FALSE;
  }
}

/**
 * Check if the link to the PDF version is allowed depending on the settings
 *
 * @param $args
 *   array containing the possible parameters:
 *    teaser, node, type, path
 * @return
 *   FALSE if not allowed
 *   PRINT_ALLOW_NORMAL_LINK if a normal link is allowed
 *   PRINT_ALLOW_BOOK_LINK if a link is allowed in a book node
 */
function print_pdf_link_allowed($args) {
  $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
  if ((!empty($args['teaser']) && !variable_get('print_pdf_link_teaser', PRINT_PDF_LINK_TEASER_DEFAULT))
      || !user_access('access PDF version') || (empty($print_pdf_pdf_tool))) {
    // If the teaser link is disabled or the user is not allowed
    return FALSE;
  }
  if (!empty($args['path'])) {
    $nid = preg_replace('!^node/!', '', drupal_get_normal_path($args['path']));
    if (ctype_digit($nid)) {
      $args['node'] = node_load($nid);
    }
  }
  if (!empty($args['node'])) {
    static $node_type = FALSE;

    $node = $args['node'];
    if (isset($node->type)) {
      $node_type = $node->type;
    }
    // Node
    $print_pdf_node_link_visibility = variable_get('print_pdf_node_link_visibility', PRINT_PDF_NODE_LINK_VISIBILITY_DEFAULT);
    $print_pdf_node_link_pages = variable_get('print_pdf_node_link_pages', PRINT_PDF_NODE_LINK_PAGES_DEFAULT);

    if (!_print_page_match($print_pdf_node_link_visibility, "node/". $node->nid, $print_pdf_node_link_pages)) {
      // Page not in visibility list
      return FALSE;
    }
    elseif (isset($args['type']) && ($args['type'] == 'comment') && isset($node_type)) {
      // Link is for a comment, return the configured setting
      // Cache this statically to avoid duplicate queries for every comment.
      static $res = array();
      if (!isset($res[$node->nid])) {
        $res[$node->nid] = db_fetch_object(db_query("SELECT comments FROM {print_pdf_node_conf} WHERE nid = %d", $node->nid));
      }
      $print_display_comment = ($res && ($res[$node->nid] !== FALSE)) ? intval($res[$node->nid]->comments) : variable_get('print_pdf_display_comment_'. $node_type, PRINT_TYPE_COMMENT_LINK_DEFAULT);
      if ($print_display_comment) {
        return PRINT_ALLOW_NORMAL_LINK;
      }
    }
    else {
      // Node link
      if (isset($node->print_pdf_display) && !$node->print_pdf_display) {
        // Link for this node is disabled
        return FALSE;
      }
      elseif (isset($node->book)) {
        // Node is a book;
        $print_pdf_book_link = variable_get('print_pdf_book_link', PRINT_PDF_BOOK_LINK_DEFAULT);
        switch ($print_pdf_book_link) {
          case 1:
            if (user_access('access printer-friendly version')) {
              return PRINT_ALLOW_BOOK_LINK;
            }
            break;
          case 2:
            return PRINT_ALLOW_NORMAL_LINK;
        }
      }
      else {
        return PRINT_ALLOW_NORMAL_LINK;
      }
    }
  }
  else {
    // 'System' page
    $print_pdf_sys_link_visibility = variable_get('print_pdf_sys_link_visibility', PRINT_PDF_SYS_LINK_VISIBILITY_DEFAULT);
    $print_pdf_sys_link_pages = variable_get('print_pdf_sys_link_pages', PRINT_PDF_SYS_LINK_PAGES_DEFAULT);

    return _print_page_match($print_pdf_sys_link_visibility, $_GET['q'], $print_pdf_sys_link_pages);
  }
  return FALSE;
}

/**
 * Find out the version of the TCPDF library
 */
function _print_pdf_tcpdf_version() {
  $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
  if (variable_get('print_pdf_autoconfig', PRINT_PDF_AUTOCONFIG_DEFAULT)) {
    // prevent TCPDF default configs
    define('K_TCPDF_EXTERNAL_CONFIG', TRUE);
  }
  require_once($print_pdf_pdf_tool);

  // Hide warnings, as some TCPDF constants may still be undefined
  if (class_exists('TCPDF')) {
    @$pdf = new TCPDF();

    if (class_exists('TCPDF_STATIC')) {
      return TCPDF_STATIC::getTCPDFVersion();
    }
    elseif (method_exists($pdf, 'getTCPDFVersion')) {
      return $pdf->getTCPDFVersion();
    }
    elseif (defined('PDF_PRODUCER')) {
      sscanf(PDF_PRODUCER, "TCPDF %s", $version);

      return $version;
    }
  }
  return 'unknown';
}

/**
 * Find out the version of the wkhtmltopdf library
 */
function _print_pdf_wkhtmltopdf_version() {
  $print_pdf_pdf_tool = variable_get('print_pdf_pdf_tool', PRINT_PDF_PDF_TOOL_DEFAULT);
  $descriptor = array(0 => array('pipe', 'r'), 1 => array('pipe', 'w'), 2 => array('pipe', 'w'));

  $cmd = '"'. realpath($print_pdf_pdf_tool) .'" --version';
  $process = proc_open($cmd, $descriptor, $pipes, NULL, NULL);
  if (is_resource($process)) {
    $content = stream_get_contents($pipes[1]);
    $out = preg_match('!.*?(\d+\.\d+\.\d+).*$!m', $content, $matches);
    fclose($pipes[0]);
    fclose($pipes[1]);
    fclose($pipes[2]);
    $retval = proc_close($process);
  }

  return ($matches[1]);
}

/**
 * Implements hook_views_api().
 */
function print_pdf_views_api() {
  return array(
    'api' => 2.0,
    'path' => drupal_get_path('module', 'print_pdf'),
  );
}
