<?php
// $Id: relationship.inc,v 1.6 2006/11/30 21:19:26 eaton Exp $

function relationship_set($source_nid, $relationship_type, $target_nid, $uid = NULL, $weight = NULL, $table = 'relationship') {
  $existing = relationship_get($source_nid, $relationship_type, $target_nid, $uid);
  if (count($existing)) {
    foreach ($existing as $relationship) {
      relationship_update($relationship->rid, $weight, $table);
    }
  }
  else {
    relationship_insert($source_nid, $relationship_type, $target_nid, $uid, $weight, $table);
  }
}

function relationship_insert($source_nid, $relationship_type, $target_nid, $uid = NULL, $weight = 0, $table = 'relationship') {
  if ($uid === NULL) {
    $sql = "INSERT INTO {%s} (source_nid, relationship_type, target_nid, weight, created) VALUES (%d, '%s', %d, %d, %d);";
    db_query($sql, $table, $source_nid, $relationship_type, $target_nid, $weight, time());
  }
  else {
    $sql = "INSERT INTO {%s} (source_nid, relationship_type, target_nid, uid, weight, created) VALUES (%d, '%s', %d, %d, %d, %d);";
    db_query($sql, $table, $source_nid, $relationship_type, $target_nid, $uid, $weight, time());
  }
}

function relationship_update($rid, $weight, $table = 'relationship') {
  $sql = "UPDATE {%s} r SET weight = %d WHERE rid = %d";
  db_query($sql, $table, $weight, $rid);
}

function relationship_get($source_nid = NULL, $relationship_type = NULL, $target_nid = NULL, $uid = -1, $table = 'relationship') {
  return _relationship_operation('SELECT', $source_nid, $relationship_type, $target_nid, $uid, $table);
}

function relationship_unset($source_nid = NULL, $relationship_type = NULL, $target_nid = NULL, $uid = -1, $table = 'relationship') {
  _relationship_operation('DELETE', $source_nid, $relationship_type, $target_nid, $uid, $table);
}

function _relationship_operation($op = 'SELECT', $source_nid = NULL, $relationship_type = NULL, $target_nid = NULL, $uid = -1, $table = 'relationship') {
  $params = array($table);

  if (isset($source_nid)) {
    $filters[] = "r.source_nid = %d";
    $params[] = $source_nid;
  }

  if (isset($relationship_type)) {
    $filters[] = "r.relationship_type = '%s'";
    $params[] = $relationship_type;
  }

  if (isset($target_nid)) {
    $filters[] = "r.target_nid = %d";
    $params[] = $target_nid;
  }

  if ($uid === NULL) {
    $filters[] = "r.uid IS NULL";
  }
  else if ($uid > -1) {
    $filters[] = "r.uid = %d";
    $params[] = $uid;
  }

  switch ($op) {
    case 'SELECT':
      $relationships = array();
      if (count($params)) {
        $sql = 'SELECT r.* FROM {%s} r WHERE ' . implode(' AND ', $filters) . ' ORDER BY r.weight ASC;';
        $result = db_query($sql, $params);
        while ($relationship = db_fetch_object($result)) {
          $relationships[] = $relationship;
        }
      }
      return $relationships;
    case 'DELETE':
      if (count($params)) {
        $sql = 'DELETE FROM {%s} r WHERE ' . implode(' AND ', $filters) . ';';
        db_query($sql, $params);
      }
      break;
  }
}