<?php
/**
 * @file
 * User variable - Creating and working with user variables.
 *
 * @author
 * Oleg Sidorenko <orb@vseok.org.ua>
 */


/**
 * Set a variable if it does not exist, then create.
 * @param $name
 *   Variable name.
 * @param $value
 *   Variable value.
 * @param $common
 *   If TRUE then the variable does not depend on user ID.
 * @param $uid
 *   User ID.
 * @param $expired
 *   The lifetime of a variable (in seconds)
 *   if equal 0 then the variable is not deleted automatically.
 * @param $session
 *   If TRUE then the variable is tied to the session
 *   when set, the variable is tied to the value (eg, session ID).
 */
function user_variable_set($name, $value, $common = FALSE, $uid = 0, $expired = 0, $session = FALSE) {
  global $user_variables_array, $user;
  
  $serialized_value = serialize($value);
  $expired = ($expired > 0) ? (time() + $expired) : 0;
  
  if ($session === TRUE) {
    $session = session_id();
  }
  elseif ($session === FALSE) {
    $session = '';
  }
  
  if ($common) {
    $uid = $user->uid;
  }
  else {
    if (!$uid) {
      $uid = $user->uid;
    }
  }
  
  $query = db_merge('user_variable')->fields(array(
    'sid' => $session,
    'value' => $serialized_value,
    'expired' => $expired,
    'common' => $common ? 1 : 0,
    'name' => $name,
    'uid' => $uid,
  ));
  
  if ($common) {
    $query->key(array(
      'name' => $name,
      'common' => 1,
      'sid' => $session,
    ))->execute();
    if ($session == '') {
      $user_variables_array['common_session'][$name] = $value;
    }
    else {
      $user_variables_array['common'][$session][$name] = $value;
    }
  }
  else {
    $query->key(array(
      'name' => $name,
      'common' => 0,
      'sid' => $session,
      'uid' => $uid
    ))->execute();
    if ($session == '') {
      $user_variables_array['uid_session'][$uid][$name] = $value;
    }
    else {
      $user_variables_array['uid'][$uid][$session][$name] = $value;
    }
  }
}


/**
 * Get variable.
 * @param $name
 *   Variable name.
 * @param $common
 *   If TRUE then the variable does not depend on user ID.
 * @param $uid
 *   User ID.
 * @param $session
 *   Session ID.
 * 
 * @return
 *   Variable value.
 */
function user_variable_get($name, $common = FALSE, $uid = 0, $session = '') {
  global $user_variables_array, $user;
  if ($session === TRUE) {
    $session = session_id();
  }
  elseif ($session === FALSE) {
    $session = '';
  }
  
  if ($common) {
    if ($session == '') {
      if (isset($user_variables_array['common_session'][$name])) {
        return $user_variables_array['common_session'][$name];
      }
    }
    else {
      if (isset($user_variables_array['common'][$session][$name])) {
        return $user_variables_array['common'][$session][$name];
      }
    }
    
    //Get from DB
    $result = db_query_range(
      "SELECT value FROM {user_variable}
      WHERE common = 1 AND name = :name AND sid = :sid",
      0, 1, array(':name' => $name, ':sid' => $session)
    )->fetchObject();
    
    if ($session == '') {
      return ($user_variables_array['common_session'][$name] = (
        (isset($result->value) && $result->value) ? unserialize($result->value) : FALSE
      ));
    }
    else {
      return ($user_variables_array['common'][$session][$name] = (
        (isset($result->value) && $result->value) ? unserialize($result->value) : FALSE
      ));
    }
  }
  else {  //$common = FALSE
    if (!$uid) {
      $uid = $user->uid;
    }
    
    if ($session == '') {
      if (isset($user_variables_array['uid_session'][$uid][$name])) {
        return $user_variables_array['uid_session'][$uid][$name];
      }
    }
    else {
      if (isset($user_variables_array['uid'][$uid][$session][$name])) {
        return $user_variables_array['uid'][$uid][$session][$name];
      }
    }

    //Get from DB
    $result = db_query_range(
      "SELECT value FROM {user_variable}
      WHERE name = :name AND common = 0 AND uid = :uid AND sid = :sid",
      0, 1, array(':name' => $name, ':uid' => $uid, ':sid' => $session)
      )->fetchObject();
    
    if ($session == '') {
      return ($user_variables_array['uid_session'][$uid][$name] = (
        (isset($result->value) && $result->value) ? unserialize($result->value) : FALSE
      ));
    }
    else {
      return ($user_variables_array['uid'][$uid][$session][$name] = (
        (isset($result->value) && $result->value) ? unserialize($result->value) : FALSE
      ));
    }
  }
}


/**
 * Remove the variable with the given name.
 * @param $name
 *   Variable name.
 * @param $common
 *   If TRUE then the variable does not depend on user ID.
 * @param $uid
 *   User ID.
 * @param $session
 *   Session ID.
 */
function user_variable_del($name, $common = FALSE, $uid = 0, $session = '') {
  global $user_variables_array, $user;
  if ($session === TRUE) {
    $session = session_id();
  }
  elseif ($session === FALSE) {
    $session = '';
  }
  
  if ($common) {
    db_query("DELETE FROM {user_variable}
      WHERE common = 1 AND name = :name AND sid = :sid",
      array(':name' => $name, ':sid' => $session)
    );
    if ($session == '') {
      unset($user_variables_array['common_session'][$name]);
    }
    else {
      unset($user_variables_array['common'][$session][$name]);
    }
  }
  else {
    if (!$uid) {
      $uid = $user->uid;
    }
    
    db_query("DELETE FROM {user_variable}
      WHERE common = 0 AND name = :name AND uid = :uid AND sid = :sid",
      array(':name' => $name, ':uid' => $uid, ':sid' => $session)
    );
    
    if ($session == '') {
      unset($user_variables_array['uid_session'][$uid][$name]);
    }
    else {
      unset($user_variables_array['uid'][$uid][$session][$name]);
    }
  }
}


/**
 * Implementation of hook_cron().
 */
function user_variable_cron() {
  db_query("DELETE FROM {user_variable} WHERE expired < :time AND expired <> 0",
    array(':time' => time())
  );
}