<?php
// $Id: comment_subject.module,v 1.16 2010-02-07 12:08:21 sinasalek Exp $

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

/**
 * Implements 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(
    'variables' => array('token_list' => array(), 'prefix' => '[', 'suffix' => ']', 'headers' => array(t('Token'), t('Name'), t('Description'))),
  );
  $theme['comment_subject_token_chained_list'] = array(
    'variables' => array('token_list' => array(), 'prefix' => '*:', 'suffix' => '', 'headers' => array(t('Token chains'), t('Name'), t('Description'))),
  );
  return $theme;
}

/**
 * Implements hook_help().
 */
function comment_subject_help($path, $arg) {
  switch ($path) {
    case 'admin/help#comment_subject':
      $output = '<h3>' . t('About') . '</h3>';
      $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 .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      // don't translate isolated token names
      $output .= '<dt>' . '[comment:parent-title]' . '</dt>';
      $output .= '<dd>' . t('When using [comment:parent-title] 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.') . '</dd>';
      $output .= '<dd>' . t('Note that stripping prefix/suffix fully suppports [comment:*] replacements, while global replacements (e.g. [site:*]) 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.') . '</dd>';
      // don't translate isolated token names
      $output .= '<dt>' . '[comment:numbering]' . '</dt>';
      $output .= '<dd>' . t('When using [comment:numbering] option comment\'s subject are auto-incremental (e.g. "#1", "#2", an so on).')
        . '<br/>' . t('CAUTION: to achieve [comment: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).') . '</dd>';
      $output .= '</dl>';
      $output .= '<h3>' . t('Special treatment') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('WHEN the comment has NOT a parent') . '</dt>';
      $output .= '<dd>' . t('[comment:pid] evaluates to zero.') . ' '. t('ONLY when generating the subject.')
        . '<br/>' . t('(other uses of this token still evaluate to empty string according to core\'s behavior)') . '</dd>';
      $output .= '<dd>' . t('[comment:parent:numbering] evaluates to zero.')
        . '<br/>' . t('(even if used in other context, since it is owned by this module)') . '</dd>';
      $output .= '<dd>' . t('[comment:parent:numbering] doesn\'t requires subject to be disabled.')
        . '<br/>' . t('(even when [comment:parent:*] appears marked with "**")') . '</dd>';
      $output .= '</dl>';
      return $output;
  }
}

/**
 * Implements hook_node_type_delete().
 */
function comment_subject_node_type_delete($info) {
  $node_type = $info->type;
  variable_del('comment_subject_field:default_subject_pattern_' . $node_type);
  variable_del('comment_subject_field:strip_parent_title_' . $node_type);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function comment_subject_form_node_type_form_alter(&$form, $form_state) {
  // keep this condition consistent with comment.module
  if (isset($form['type'])) {
    // sink all subject related settings to the bottom    
    $form['comment']['comment_subject_field']['#weight'] = 15;
    $node_type = $form['#node_type']->type;

    $form['comment']['comment_subject_field:default_subject_pattern'] = array(
      '#title' => 'Default title pattern',
      '#description' => t('Default value for comment\'s title.') . '<br/>' . t('e.g. "Re: [comment:parent-title]", "#[comment: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 above 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' => 20,
    );

    $mark = '<b>**</b>';
    $chained_list = array();
    $token_list = comment_subject_get_token_list(array('comment', 'site'), $chained_list);
    foreach($token_list['comment'] as $key => $value) {
      if (comment_subject_requires_comment_subject_field_disabled('comment:' . $key)) {
        $token_list['comment'][$key]['description'] .= $mark;
      }
    }
    $form['#validate'][] = 'comment_subject_validate_replacement';
    $form['comment']['token_replacements']['#description'] = 
      //t('Note that not every available pattern makes sense for comment\'s default subject.') . 
      //'<br/>' . 
      t('Replacements marked with "!mark" will only be available after submission, therefore require <em>comment title</em> to be disallowed.', array('!mark' => $mark));
    
    $form['comment']['token_replacements']['table'] = array(
      // if issue #576592 gets into token module this would be theme('token_list', ...) instead
      '#markup' => theme('comment_subject_token_list', array('token_list' => $token_list)) . theme('comment_subject_token_chained_list', array('token_list' => $chained_list)),
    );
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function comment_subject_form_comment_form_alter(&$form, &$form_state) {
  if (empty($form['subject']['#default_value'])) {
    // if !$form['subject']['#access'] it means it is disabled and will be handled on hook_comment_[insert/update]
    if (!$form['subject']['#access']) {
      // nevertheless support comment preview
      $form['subject']['#access'] = TRUE; // not required, but won't harm either
      $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)) {
        // computing its candidate value not only is a waste of time/performance
        // but can't be achieved without errors, since many missing properties
        // will be used by every [comment:*] requiring subject to be disabled
        $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)
    }
    // keep this consistent with internal properties added in comment_form
    foreach (array('cid', 'pid', 'nid', 'language', 'uid') as $key) {
      $comment[$key] = $form[$key]['#value'];
    }
    $comment = (object)$comment;
    
    $form['subject']['#default_value'] = _comment_subject_get_subject($comment);
  }
}

function comment_subject_requires_comment_subject_field_disabled($key) {
  // consider both 'comment:node' and 'comment:node:*' separately (avoid matching 'comment:nodeXYZ')
  if (strpos($key, 'comment:node:') === 0) return FALSE;
  return (!in_array($key, array('comment:node', 'comment:parent-title', 'comment:nid', 'comment:pid', 'comment:uid', 'comment:parent:numbering')));
}

function _comment_subject_token_replace($str, $comment) {
  // [comment:pid] evaluates to zero when there is no parent (legacy behavior)
  // also avoid "Warning: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load() (line 108 of .../includes/entity.inc)." 
  if (empty($comment->pid)) $comment->pid = 0;
  
  $result = token_replace($str, array('comment' => $comment), array('sanitize' => FALSE));
  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 && $comment->pid) {
    // stripping algorithm
    if (strpos($pattern, '[comment:parent-title]') !== FALSE) {
      list($prefix, $suffix) = explode('[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]', $comment);
      if (!empty($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
      $pattern = str_replace('[comment:parent-title]', $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;
}

/**
 * Implements hook_comment_insert(). 
 */
function comment_subject_comment_insert($comment) {
  _comment_subject_update($comment);
}

/**
 * Implements hook_comment_update(). 
 */
function comment_subject_comment_update($comment) {
  _comment_subject_update($comment);
}

function _comment_subject_update($comment) {
  // admin can change the author or other info exposed by tokens
  // therefore requires update (only if comment subject is disabled) 
  // having subject enabled the existing text is considered user input
  // (for those cases only #default_value is provided by form_alter)
  $node_type = node_load($comment->nid)->type;
  $cid = $comment->cid;
  // 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
    $comment = comment_load($cid);
    $subject = _comment_subject_get_subject($comment);
    db_update('comment')
      ->fields(array('subject' => $subject))
      ->condition('cid', $cid)
      ->execute();
  }
}

function comment_subject_validate_replacement($form, &$form_state) {
  // 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;
}

function comment_subject_get_token_list(array $types = array('site'), array &$chained_list = array()) {
  $token_info = token_info();
  $token_list = array();
  $chains = array();
  foreach ($token_info['tokens'] as $type => $tokens) {
    if (in_array($type, $types)) {
      $token_list[$type] = $tokens;
      foreach ($tokens as $key => $data) {
        if (!empty($data['type'])) {
          $chains[$data['type']][] = $key; 
        }
      }
    }
  }
  
  // @TODO: refactor this whole function so chains can be discovered in deep
  // right now only discovers the 1st chain level
  // e.g. [comment:created:*] and its chains *:created:long, etc
  // e.g. [comment:node:*] and its chains *:node:changed, etc
  // but it doesn't go deep to find chain *:changed:long (e.g. [comment:node:changed:long]) 
  
  // now look for the chained types
  $chained_types = array_keys($chains);
  //$chained_list = array(); received by ref
  foreach ($token_info['tokens'] as $type => $tokens) {
    if (in_array($type, $chained_types)) {
      foreach ($chains[$type] as $chain) {
        $chained_list[$chain] = $tokens;
      }
      unset($chained_types[$type]);
    }
  }
  return $token_list;
}

// 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(array $variables) {
  $token_list = $variables['token_list'];
  $prefix = $variables['prefix'];
  $suffix = $variables['suffix'];
  $headers = $variables['headers'];
  
  $rows = array();
  $chains_text = '<b>' . t('chains:') . '</b> ';
  foreach ($token_list as $type => $tokens) {
    $rows[] = array(array('data' => drupal_ucfirst($type) .' '. t('tokens'), 'class' => 'region', 'colspan' => 3));
    foreach ($tokens as $key => $data) {
      $chains = '';
      if (!empty($data['type'])) {
        $key = '<b>' . $key . ':*</b>';
        $chains = $chains_text;
      }
      $row = array();
      $row[] = $prefix . $type . ':' . $key . $suffix;
      $row[] = t($data['name']);
      $row[] = $chains . t($data['description']);
      $rows[] = $row;
    }
  }

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

function theme_comment_subject_token_chained_list(array $variables) {
  return theme_comment_subject_token_list($variables);
}