<?php
class logger
{
  /* The logger class can be used with :
     $d=new logger;
     $d->timezone = "Europe/Paris";
     $d->logtype="display|file";
     $d->logfile="/tmp/toto.log";
     $d->logwrite ("Super log default");
     $d->logwrite ("Super log DEBUG", $d::DEBUG);
     $d->logwrite ("Super log NOTICE", $d::NOTICE); */
  // TODO : Add SQL support
  public $logtype = "display"; // display, file, syslog
                               // can be merged with a pipe : "display|syslog"
  public $logfile = FALSE;
  public $timezone = "UTC";
  public $loglevelmin = LOG_NOTICE;
 // See http://fr2.php.net/manual/en/function.openlog.php for $syslogFacility
  public $syslogFacility = LOG_USER;
  public $syslogPrefix = FALSE;

  /* Priorities :
  LOG_EMERG   system is unusable
  LOG_ALERT   action must be taken immediately
  LOG_CRIT    critical conditions
  LOG_ERR     error conditions
  LOG_WARNING warning conditions
  LOG_NOTICE  normal, but significant, condition
  LOG_INFO    informational message
  LOG_DEBUG   debug-level message */
  private $priorities = array (LOG_EMERG   => "EMERG",
                               LOG_ALERT   => "ALERT",
                               LOG_CRIT    => "CRITICAL",
                               LOG_ERR     => "ERROR",
                               LOG_WARNING => "WARNING",
                               LOG_NOTICE  => "NOTICE",
                               LOG_INFO    => "INFO",
                               LOG_DEBUG   => "DEBUG"); 

  /** Store a new message log in the log manager defined by $logtype */
  public function log ($message, $priority=LOG_NOTICE)
  {
    if ($this->loglevelmin < $priority)
      return;
    $back = reset (debug_backtrace());
    $message .= " [".basename ($back["file"]).":".$back["line"]."]";
    $logsType = explode ("|", $this->logtype);
    if (in_array ("display", $logsType))
      $this->logdisplay ($message, $priority);
    if (in_array ("file", $logsType))
      $this->logfile ($message, $priority);
    if (in_array ("syslog", $logsType))
      $this->logsyslog ($message, $priority);
  }

  /** Log $message on file */
  private function logfile ($message, $priority)
  {
    if ($this->logfile === FALSE)
      throw new Exception ("Undefined file where logging");
    if (!file_exists ($this->logfile))
    {
      if (! is_dir (dirname ($this->logfile)))
        throw new Exception ("You must create the ".dirname ($this->logfile).
                             "directory");
      if (! is_writable (dirname ($this->logfile)))
        throw new Exception ("The directory ".dirname ($this->logfile)." must"
                            ." be writable to create log file");
    }

    if (!is_writable ($this->logfile))
    {
      if (function_exists ("posix_geteuid"))
        $user = posix_geteuid ();
      elseif (getenv('USERNAME') !== FALSE)
        $user = getenv('USERNAME');
      else
        $user = "";
      throw new Exception ("Logfile $this->logfile is not writable for user ".
                           $user);
    }

    ini_set ("date.timezone", $this->timezone);
    $message = date ("Y/m/d H:i:s")." [".$this->priorities[$priority]."] ".
               $message."\n";
    file_put_contents ($this->logfile, $message, FILE_APPEND);
  }

  /** Log $message on screen with adding date. Add the HTML flags if not in CLI
    */
  private function logdisplay ($message, $priority)
  {
    if (php_sapi_name () !== "cli")
      echo "<tt>";
    ini_set ("date.timezone", $this->timezone);
    $message = date ("Y/m/d H:i:s")." [".$this->priorities[$priority]."] ".
               $message;
    echo "$message";
    if (php_sapi_name () !== "cli")
      echo "</tt><br/>";
    echo "\n";
  }

  /** Log $message on syslog */
  private function logsyslog ($message, $priority)
  {
    openlog ($this->syslogPrefix, NULL, $this->syslogFacility);
    syslog ($priority, $message);
  }
}