<?php
function comment_node_hide_menu_alter(&$items) {
  $items['comment/reply/%node'] = array(
    'title' => 'Reply to comment',
    'page callback' => 'comment_node_hide_reply',
    'page arguments' => array(2),
    'access callback' => 'node_access',
    'access arguments' => array('view', 2),
    'type' => MENU_CALLBACK
  );
  dsm($items);
}

function comment_node_hide_reply($node, $pid = NULL) {
  // Set the breadcrumb trail.
  drupal_set_breadcrumb(array(l(t('Home'), NULL), l($node->title, 'node/' . $node->nid)));
  $op = isset($_POST['op']) ? $_POST['op'] : '';

  $output = '';

  if (user_access('access comments')) {
    // The user is previewing a comment prior to submitting it.
    if ($op == t('Preview')) {
      if (user_access('post comments')) {
        $output .= comment_form_box(array('pid' => $pid, 'nid' => $node->nid), NULL);
      }
      else {
        drupal_set_message(t('You are not authorized to post comments.'), 'error');
        drupal_goto("node/$node->nid");
      }
    }
    else {
      // $pid indicates that this is a reply to a comment.
      if ($pid) {
        // load the comment whose cid = $pid
        if ($comment = db_fetch_object(db_query('SELECT c.*, u.uid, u.name AS registered_name, u.signature, u.signature_format, u.picture, u.data FROM {comments} c INNER JOIN {users} u ON c.uid = u.uid WHERE c.cid = %d AND c.status = %d', $pid, COMMENT_PUBLISHED))) {
          // If that comment exists, make sure that the current comment and the parent comment both
          // belong to the same parent node.
          if ($comment->nid != $node->nid) {
            // Attempting to reply to a comment not belonging to the current nid.
            drupal_set_message(t('The comment you are replying to does not exist.'), 'error');
            drupal_goto("node/$node->nid");
          }
          // Display the parent comment
          $comment = drupal_unpack($comment);
          $comment->name = $comment->uid ? $comment->registered_name : $comment->name;
          $output .= theme('comment_view', $comment, $node);
        }
        else {
          drupal_set_message(t('The comment you are replying to does not exist.'), 'error');
          drupal_goto("node/$node->nid");
        }
      }
      // This is the case where the comment is in response to a node. Display the node.
      else if (user_access('access content')) {

      }

      // Should we show the reply box?
      if (node_comment_mode($node->nid) != COMMENT_NODE_READ_WRITE) {
        drupal_set_message(t("This discussion is closed: you can't post new comments."), 'error');
        drupal_goto("node/$node->nid");
      }
      else if (user_access('post comments')) {
        $output .= comment_form_box(array('pid' => $pid, 'nid' => $node->nid), t('Reply'));
      }
      else {
        drupal_set_message(t('You are not authorized to post comments.'), 'error');
        drupal_goto("node/$node->nid");
      }
    }
  }
  else {
    drupal_set_message(t('You are not authorized to view comments.'), 'error');
    drupal_goto("node/$node->nid");
  }

  return $output;
}