<?php
/** Manage the configurations of the module done by administrator in a config 
    file
    It is based on the module configuration defaults
    POC : 
$config = new config();
$config->default = array ("param"=>"default",
                          "param2"=>array (1,2,3),
                          "param3"=>null);
$var = $config->get ("param");
  */
class config
{
  public $default = array (); // All the parameters allowed with their default
                              // value
  public $confFile = "./datas/configuration.php"; // Use the .php to protect
                              // the informations by adding a killing feature in
                              // the file

  /** Get the value of the provided parameter recorded in .ini file
      If it is not set in .ini file, use the default value */
  public function get ($param)
  {
    if (!array_key_exists ($param, $this->default))
      throw new Exception ("Unknown parameter '$param'");
    if (!file_exists ($this->confFile))
    {
      if (@file_put_contents ($this->confFile, 
                              "<?php\r\n\$conf = array ();\r\n")
          === FALSE)
        throw new Exception (sprintf (
                 "No configuration file '%s' available and it can't be created",
                 $this->confFile));
    }
    $conf = array ();
    $rc = include ($this->confFile);
    if ($rc !== 1)
      throw new Exception ("Error in configuration file");
    if (array_key_exists ($param, $conf))
      return $conf[$param];
    return $this->default[$param];
  }

  /** Define a value for the parameter in the config file. Add all the default
      values if they are not defined */
  public function set ($param, $value)
  {
    if (!array_key_exists ($param, $this->default))
      throw new Exception ("Unknown parameter '$param'");
    if (!file_exists ($this->confFile))
    {
      if (@file_put_contents ($this->confFile,
                              "<?php\r\n\$conf =array ();\r\n")
          === FALSE)
        throw new Exception (sprintf (
                 "No configuration file '%s' available and it can't be created",
                 $this->confFile));
    }
    if (!is_writeable ($this->confFile))
      throw new Exception (sprintf (
                                   "Configuration file '%s' is write protected",
                                   $this->confFile));
    $conf = array ();
    $rc = include ($this->confFile);
    if ($rc !== 1)
      throw new Exception ("Error in configuration file");
    $newconf = array_merge ($this->default, $conf, array ($param=>$value));
    $txt = "<?php\r\n";
    $txt .= "\$conf = array(\r\n";
    $txt = $this->writePHP ($newconf, $txt, 4);
    $txt .= ");\r\n";

    if (@file_put_contents ($this->confFile, $txt, LOCK_EX) === FALSE)
      throw new Exception (sprintf ("Can't save configuration file '%s'",
                                    $this->confFile));
  }

  private function writePHP ($values, $phpcode, $indent)
  {
    foreach ($values as $key=>$val)
    {
      $phpcode .= str_pad (" ", $indent);
      $phpcode .= (is_numeric ($key)) ? $key : "\"$key\"";
      $phpcode .= " => ";
      if (is_bool ($val))
      {
        if ($val === FALSE) $phpcode .= "FALSE,\r\n";
        else $phpcode .= "TRUE,\r\n";
      }
      elseif (is_null ($val))
        $phpcode .= "NULL,\r\n";
      elseif (is_int ($val) || is_float ($val))
        $phpcode .= "$val,\r\n";
      elseif (is_string ($val))
        $phpcode .= "\"$val\",\r\n";
      elseif (is_array ($val))
      {
        $phpcode .= "array (\r\n";
        $phpcode = $this->writePHP ($val, $phpcode, $indent+4);
        $phpcode .= str_pad (" ", $indent);
        $phpcode .= "),\r\n";
      }
      else
        throw new Exception ("Config : missing type ".gettype ($val));
    }

    return $phpcode;
  }
}