<?php

/**
 * Implementation of hook_menu_alter().
 */
function content_profile_replace_menu_alter(&$items) {
  $items['user/%user_uid_optional']['page callback'] = 'content_profile_replace_user_view';
}

/**
 * Implementation of hook_init().
 *
 * Redirects content profile node to the user profile (which is replaced by
 * this module)
 */
function content_profile_replace_init() {
  // If we are viewing a node
  if (arg(0) == 'node' && is_numeric(arg(1)) && is_null(arg(2))) {
    // we need to load the node to find out it's author but we can't
    // use node_load() on hook_init(). http://drupal.org/node/740100
    // We will use a custom query then
    $nid = arg(1);
    $uid = db_result(db_query("SELECT n.uid FROM {node} n WHERE n.nid = %d", $nid));
    if ($nid == content_profile_replace_is_replaceable($uid)) {
      drupal_goto('user/' . $uid);
    }
  }
}

/**
 * Modified version of drupal node_load().
 * Load ONLY a node object from the database, it won't execute nodeapi's hooks.
 * Specially doing this so I can use it on hook_init() for redirection but not
 * use the core's node_load because of http://drupal.org/node/740100.
 *
 * @param $param
 *   Either the nid of the node or an array of conditions to match against in the database query
 * @param $revision
 *   Which numbered revision to load. Defaults to the current version.
 * @param $reset
 *   Whether to reset the internal node_load cache.
 *
 * @return
 *   A onlycore-populated node object.
 */
function content_profile_replace_node_load($param = array(), $revision = NULL, $reset = NULL) {
  static $nodes = array();

  if ($reset) {
    $nodes = array();
  }

  $cachable = ($revision == NULL);
  $arguments = array();
  if (is_numeric($param)) {
    if ($cachable) {
      // Is the node statically cached?
      if (isset($nodes[$param])) {
        return is_object($nodes[$param]) ? drupal_clone($nodes[$param]) : $nodes[$param];
      }
    }
    $cond = 'n.nid = %d';
    $arguments[] = $param;
  }
  elseif (is_array($param)) {
    // Turn the conditions into a query.
    foreach ($param as $key => $value) {
      $cond[] = 'n.'. db_escape_table($key) ." = '%s'";
      $arguments[] = $value;
    }
    $cond = implode(' AND ', $cond);
  }
  else {
    return FALSE;
  }

  // Retrieve a field list based on the site's schema.
  $fields = drupal_schema_fields_sql('node', 'n');
  $fields = array_merge($fields, drupal_schema_fields_sql('node_revisions', 'r'));
  $fields = array_merge($fields, array('u.name', 'u.picture', 'u.data'));
  // Remove fields not needed in the query: n.vid and r.nid are redundant,
  // n.title is unnecessary because the node title comes from the
  // node_revisions table.  We'll keep r.vid, r.title, and n.nid.
  $fields = array_diff($fields, array('n.vid', 'n.title', 'r.nid'));
  $fields = implode(', ', $fields);
  // Rename timestamp field for clarity.
  $fields = str_replace('r.timestamp', 'r.timestamp AS revision_timestamp', $fields);
  // Change name of revision uid so it doesn't conflict with n.uid.
  $fields = str_replace('r.uid', 'r.uid AS revision_uid', $fields);

  // Retrieve the node.
  // No db_rewrite_sql is applied so as to get complete indexing for search.
  if ($revision) {
    array_unshift($arguments, $revision);
    $node = db_fetch_object(db_query('SELECT '. $fields .' FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revisions} r ON r.nid = n.nid AND r.vid = %d WHERE '. $cond, $arguments));
  }
  else {
    $node = db_fetch_object(db_query('SELECT '. $fields .' FROM {node} n INNER JOIN {users} u ON u.uid = n.uid INNER JOIN {node_revisions} r ON r.vid = n.vid WHERE '. $cond, $arguments));
  }

  if ($node && $node->nid) {
    if ($cachable) {
      $nodes[$node->nid] = is_object($node) ? drupal_clone($node) : $node;
    }
  }

  return $node;
}

/**
 * Function to decide whether a profile page can be replaced by content profile
 * For now just checking if there's only one node.
 * TODO: Provide UI for advance use cases, i.e. selection of a specific 
 * node/content type for replacement.
 *
 * @param int $uid
 *   user id
 * @return mixed
 *   FALSE if no replacement is found or node ID of the content profile
 */
function content_profile_replace_is_replaceable($uid) {
  $nid = FALSE;
  foreach (content_profile_get_types('names') as $type => $type_name) {
    // Using custom module instead of content_profile_load($type, $uid);
    // I am not caching anything as content_profile_load() but I don't think is
    // necessary, otherwise I have also do a custom content_profile_load().
    $params = array('type' => $type, 'uid' => $uid);
    $nodes[] = content_profile_replace_node_load($lang ? $params + array('language' => $lang) : $params, NULL, $reset);
  }

  if (count($nodes) == 1 && $nodes[0]->nid) {
    $nid = $nodes[0]->nid;
  }
  return $nid;
}

/**
 * Replacement menu callback for user/%user_uid_optional that shows
 * the content profile node instead of the drupal user profile page.
 *
 * It defaults to the drupal user page if no profile exists for the user
 */
function content_profile_replace_user_view($account) {
  // Only display the node if only one node was found as a content profile
  $nid = content_profile_replace_is_replaceable($account->uid);
  $node = node_load($nid);
  // Display the node if exists and if the user have access to it
  // This access validation goes on top of the user/%user_uid_optional access.

  if (node_access('view', $node)) {
    $node = node_load($nid);
    $content = node_page_view($node);
  }
  else {
    $content = user_view($account);
  }

  return $content;
}