<?php
// $Id: comment_subject.module,v 1.15 2010-02-07 11:38:18 sinasalek Exp $

define('COMMENT_SUBJECT__DEFAULT_SUBJECT_PATTERN', 'Re: [comment-parent-title-raw]');

// cleaner code over lazzy loading (see history of bug fix #680444)
module_load_include('inc', 'comment_subject', 'comment_subject.token');

/**
 * Implementation of hook_theme().
 */
function comment_subject_theme(&$cache, $type, $module_name, $module_path) {
  $theme = array();
  // if issue #576592 gets into token module this will be no longer needed
  $theme['comment_subject_token_list'] = array(
    'arguments' => array('token_list' => array(), 'prefix' => '[', 'suffix' => ']')
  );
  return $theme;
}

/**
 * Implementation of hook_help().
 */
function comment_subject_help($path, $arg) {
  switch ($path) {
    case 'admin/help#comment_subject':
      $output = '<p>' . t('Provides a default comment subject like: "Re: [parent comment/node title]", auto-incremental numbering, and optional integration with token for author, date, etc. This option can be set on a per content type basis.') . '</p>';
      $output .= '<p>' . t('Users can still edit the comment subject to their liking if comment titles are enabled in the comment settings.') . '</p>';
      $output .= '<p>' . t('When using [comment-parent-title-raw] comment\'s subject is derived from the node title, or the comment that the new comment is a reply to. In addition enabling "strip prefix/suffix from parent\'s title" allows (for instance) avoiding repeated "Re:" prefix and/or "by username" suffix.') . '</p>';
      $output .= '<p>' . t('Note that stripping prefix/suffix fully suppports [comment-*] replacements, while global replacements won\'t let the stripping algorithm behave as expected. Nevertheless, some immutable tokens might be used (for instance [site-name], [site-mail]), but if their values change in time the prefix/suffix stripping shall fail.') . '</p>';
      $output .= '<p>' . t('When using [comment-auto-numbering] option comment\'s subject are auto-incremental (e.g. "#1", "#2", an so on).')
        . '<br/>' . t('CAUTION: to achieve [comment-auto-numbering] replacement works as expected previous existing comments shouldn\'t be deleted. Otherwise numbering sequence won\'t be guaranted (i.e. existing comments won\'t get updated and new comments will count just existing ones).') . '</p>';
      return $output;
  }
}

/**
 * Implementation of hook_node_type().
 */
function comment_subject_node_type($op, $info) {
  switch ($op) {
    case 'delete':
      $node_type = $info->type;
      variable_del('comment_subject_field:default_subject_pattern_' . $node_type);
      variable_del('comment_subject_field:strip_parent_title_' . $node_type);
      break;
  }
}

/**
 * Implementation of hook_form_alter().
 */
function comment_subject_form_alter(&$form, &$form_state, $form_id) {
  // keep this condition consistent with comment.module
  if ($form_id == 'node_type_form' && isset($form['identity']['type'])) {
    $form['comment']['comment_subject_field']['#weight'] = 10;
    $node_type = $form['#node_type']->type;
    
    $form['comment']['comment_subject_field:default_subject_pattern'] = array(
      '#title' => 'Default subject pattern',
      '#description' => t('Default value for subject field (e.g. "Re: [comment-parent-title-raw]", "#[comment-auto-numbering]").'),
      '#type' => 'textfield',
      '#default_value' => variable_get('comment_subject_field:default_subject_pattern_' . $node_type, COMMENT_SUBJECT__DEFAULT_SUBJECT_PATTERN),
      '#weight' => 12,
      '#maxlength' => NULL, // avoid maxlength=128
    );
    
    $form['comment']['comment_subject_field:strip_parent_title'] = array(
      '#title' => 'Strip prefix/suffix from parent\'s title',
      '#description' => t('Avoids repetitive prefix/suffix when using the parent\'s title in the default subject pattern (recommended).'),
      '#type' => 'checkbox',
      '#default_value' => variable_get('comment_subject_field:strip_parent_title_' . $node_type, TRUE), 
      '#weight' => 13,
    );
    
    $form['comment']['token_replacements'] = array(
      '#type' => 'fieldset',
      '#title' => t('Replacements for default subject pattern'),
      '#collapsible' => TRUE,
      '#collapsed' => TRUE,
      '#weight' => 13,
    );
    
    if (module_exists('token')) {
      $token_list = token_get_list('comment');
      $form['comment']['token_replacements']['#description'] = t('Note that not every available pattern makes sense for comment\'s default subject.'); 
    }
    else {
      $token_list = comment_subject_token_list('comment');
      $form['comment']['token_replacements']['#description'] = t('If !token_module was enabled more replacements would be available.', array('!token_module' => '<a href="http://drupal.org/project/token">token module</a>')); 
    }
    foreach($token_list['comment'] as $key => $value) {
      if (comment_subject_requires_comment_subject_field_disabled($key)) {
        $token_list['comment'][$key] .= '**';
      }
    }
    $form['#validate'][] = 'comment_subject_validate_replacement';
    $form['comment']['token_replacements']['#description'] .= '<br/>' . t('Use -raw replacements for text to avoid problems with HTML entities.');
    $form['comment']['token_replacements']['#description'] .= '<br/>' . t('Replacements marked with "**" will only be available after submission, therefore require <em>comment subject field</em> to be disabled.');
    
    $form['comment']['token_replacements']['table'] = array(
      // if issue #576592 gets into token module this would be theme('token_list', ...) instead
      '#value' => theme('comment_subject_token_list', $token_list),
    );
  }
  elseif($form_id == 'comment_form' && empty($form['subject']['#default_value'])) {
    // if $form['subject'] doesn't exists it means it is disabled and will be handled on hook_comment insert/update
    if (!isset($form['subject'])) {
      // nevertheless support comment preview
      $form['subject']['#type'] = 'value'; // use 'hidden' when testing for quick inspect DOM
      
      $node_type = node_load($form['nid']['#value'])->type;
      $pattern = variable_get('comment_subject_field:default_subject_pattern_' . $node_type, COMMENT_SUBJECT__DEFAULT_SUBJECT_PATTERN);
      $unsupported = comment_subject_unsupported_on_preview($pattern);
      if (!empty($unsupported)) {
        $form['subject']['#default_value'] = t('(generated subject)');
        return; // don't fall through
      }
      // fall through (the subject is disable, but there are no unsupported tokens for preview)
    }
    $comment = (object)array('nid' => $form['nid']['#value'], 'pid' => $form['pid']['#value'], 'cid' => $form['cid']['#value']);
    $form['subject']['#default_value'] = _comment_subject_get_subject($comment);
  }
}

function comment_subject_requires_comment_subject_field_disabled($key) {
  return (!in_array($key, array('comment-nid', 'comment-pid', 'comment-parent-title', 'comment-parent-title-raw')));
}

function _comment_subject_token_replace($str, $comment) {
  if (module_exists('token')) {
    $result = token_replace($str, 'comment', $comment);
  }
  else {
    // Note: duplicating code should be avoided,
    // but this is the (little) cost to be independent from token module
    // and not having it as a required dependency
    $tokens = comment_subject_token_values('comment', $comment);
    foreach ($tokens as $key => $value) {
      $tokens[$key] = '[' . $key . ']';
      $values[] = $value;
    }
    $result = str_replace($tokens, $values, $str);
  }
  return $result;
}

function _comment_subject_get_subject($comment) {
  $node_type = node_load($comment->nid)->type;

  $pattern = variable_get('comment_subject_field:default_subject_pattern_' . $node_type, COMMENT_SUBJECT__DEFAULT_SUBJECT_PATTERN);
  $strip_parent_title = variable_get('comment_subject_field:strip_parent_title_' . $node_type, TRUE);
  
  if ($strip_parent_title && $comment->pid) {
    // stripping algorithm
    // supporting both sanitized and unsanitized version, 
    // even though HTML entities will come up double encoded for the sanitized version
    $using_parent_title_raw = (strpos($pattern, '[comment-parent-title-raw]') !== FALSE);
    $using_parent_title_encoded = (strpos($pattern, '[comment-parent-title]') !== FALSE); 
    if ($using_parent_title_raw || $using_parent_title_encoded) {
      // comment_subject_validate_replacement ensures both tokens can't be used at the same time
      list($prefix, $suffix) = explode($using_parent_title_raw ? '[comment-parent-title-raw]' : '[comment-parent-title]', $pattern);
      
      $parent_comment = _comment_load($comment->pid);
      $parent_prefix = _comment_subject_token_replace($prefix, $parent_comment);
      $parent_suffix = _comment_subject_token_replace($suffix, $parent_comment);
      
      $parent_title = _comment_subject_token_replace('[comment-parent-title-raw]', $comment);
      if (!empty($parent_prefix) && strpos($parent_title, $parent_prefix) === 0) {
        $parent_title = substr($parent_title, strlen($parent_prefix));
      }
      // strrpos only works for a single character in PHP4
      if (!empty($parent_suffix) && strpos(strrev($parent_title), strrev($parent_suffix)) === 0) {
        $parent_title = strrev(substr(strrev($parent_title), strlen($parent_suffix)));
      }
      
      // $parent_title was already stripped of $parent_prefix and $parent_suffix
      if ($using_parent_title_raw) {
        $pattern = str_replace('[comment-parent-title-raw]', $parent_title, $pattern);
      }
      else {
        // also support the sanitized version, even though HTML entities will come up double encoded
        $pattern = str_replace('[comment-parent-title]', check_plain($parent_title), $pattern);
      }
    }
  }
  
  $subject = _comment_subject_token_replace($pattern, $comment);
  
  // comment subjects can not be longer than 64 characters
  $subject = truncate_utf8($subject, 64, TRUE, TRUE);
  
  return $subject;
}

/**
 * Implementation of hook_comment().
 */
function comment_subject_comment($edit, $op) {
  switch($op) {
    case 'insert': // no break;
    case 'update':
      $node_type = node_load($edit['nid'])->type;
      // if user subject is enabled can't figure out whether should be updated or leave user input as is
      if (!variable_get('comment_subject_field_' . $node_type, 1)) {
        // update required for every [comment-*] replacement requiring subject to be disabled
        $comment = _comment_load($edit['cid']);
        $subject = _comment_subject_get_subject($comment);
        $query = "UPDATE {comments} SET subject = '%s' WHERE cid = %d";
        db_query($query, $subject, $edit['cid']);
      }
      break;
  }
}

function comment_subject_validate_replacement($form, &$form_state) {
  // when stripping algorithm is enabled check for unsupported use of both
  // [comment-parent-title-raw] and [comment-parent-title] at the same time
  if ($form_state['values']['comment_subject_field:strip_parent_title']) {
    $element_key = 'comment_subject_field:default_subject_pattern';
    $pattern = $form_state['values'][$element_key];
    if (strpos($pattern, '[comment-parent-title-raw]') != FALSE && strpos($pattern, '[comment-parent-title]') != FALSE) {
      form_set_error($element_key, t('It makes no sense to use these tokens [comment-parent-title-raw] and [comment-parent-title] at the same time.'));
    }
  }
  
  // if "comment subject field" is enabled
  // check for tokens which only will be available after submission
  $matches = array();
  if ($form_state['values']['comment_subject_field']) {
    $element_key = 'comment_subject_field:default_subject_pattern';
    $unsupported = comment_subject_unsupported_on_preview($form_state['values'][$element_key]);
    if (!empty($unsupported)) {
      form_set_error($element_key, t('There are some token replacements in use which requires <em>comment subject field</em> to be disabled: @unsupported', array('@unsupported' => '[' . implode('], [', $unsupported) . ']')));
    }
  }
}

function comment_subject_unsupported_on_preview($default_subject_pattern) {
  $unsupported = array();
  if (preg_match_all('/\\[(comment-.*)\\]/U', $default_subject_pattern, $matches)) {
    foreach($matches[1] as $replacement) {
      if (comment_subject_requires_comment_subject_field_disabled($replacement)) {
        $unsupported[] = $replacement;
      } 
    }
  }
  return $unsupported;
}

// if issue #576592 gets into token module this will require a rollback
// to conditional declare theme_token_list (if !module_exists('token'))
function theme_comment_subject_token_list($token_list, $prefix = '[', $suffix = ']') {
  $headers = array(t('Token'), t('Replacement value'));
  $rows = array();
  foreach ($token_list as $key => $category) {
    $rows[] = array(array('data' => drupal_ucfirst($key) .' '. t('tokens'), 'class' => 'region', 'colspan' => 2));
    foreach ($category as $token => $description) {
      $row = array();
      $row[] = $prefix . $token . $suffix;
      $row[] = $description;
      $rows[] = $row;
    }
  }

  $output = theme('table', $headers, $rows, array('class' => 'description'));
  return $output;
}