<?php

  class mw_xml extends mw_sgbd{

    public $xml_data;
    public $data_handlers;
    public $last_data_handler;

    public function name(){
      return "XML";
    }

    public function default_params(){
      return array(
        "host" => "content/data/xml",
        "base" => "mw",
        "user" => "",
        "password" => ""
      );
    }

    public function authentication_required(){
      return false;
    }

    public function prepare_params($params){
      if(isset($params["host"])){
        $params["host"] .= $params["host"] && substr($params["host"], -1) != "/" ? "/" : "";
      }
      if(isset($params["base"])){
        $params["base"] .= $params["base"] && substr($params["base"], -1) != "/" ? "/" : "";
      }
      $this->data_handlers = array();
      $this->last_data_handler = 0;
      return $params;
    }

    public function validate_extention(){
      if(
            !file_exists($this->env->app_file("data/impl/xml/mw_xml_data.php"))
        ||  !file_exists($this->env->app_file("data/impl/xml/mw_xml_data_handler.php"))
      ){
        return false;
      }
      if(!class_exists("mw_xml_data")) require_once $this->env->app_file("data/impl/xml/mw_xml_data.php");
      if(!class_exists("mw_xml_data_handler")) require_once $this->env->app_file("data/impl/xml/mw_xml_data_handler.php");
      if(
            !class_exists("mw_xml_data")
        ||  !class_exists("mw_xml_data_handler")
      ){
        return false;
      }
      $this->xml_data = new mw_xml_data($this->host, $this->base);
      return true;
    }

    public function connect($host, $base, $user, $password){
      if($host.$base && is_dir($host.$base) && is_writable($host.$base)){
        $this->xml_data = new mw_xml_data($this->host, $this->base);
        return true;
      }
      return null;
    }

    public function select_db($base){
      $this->base = $base.($base && substr($base, -1) != "/" ? "/" : "");
      return $this->connect($this->host, $this->base, $this->user, $this->password);
    }

    public function data_exists($data_path){
      return is_dir($this->host.$this->base.$data_path);
    }

    public function create_data($data_path){
      if(!is_dir($this->host.$this->base.$data_path)) @mkdir($this->host.$this->base.$data_path);
      if(is_dir($this->host.$this->base.$data_path)){
        if($dh = $this->open_data($data_path, false)){
          $this->close_data($dh);
          return true;
        }
      }
      return null;
    }

    public function get_data($data_path, $data_id){
      $dh = ++$this->last_data_handler;
      $this->data_handlers[$dh] = new mw_xml_data_handler($this->xml_data, $data_path);
      if($this->data_handlers[$dh]->open_data(false)){
        $res = $this->data_handlers[$dh]->get_data($data_id);
        $this->close_data($dh);
        return $res;
      }
      return null;
    }

    public function open_data($data_path, $FETCH = true){
      $dh = ++$this->last_data_handler;
      $this->data_handlers[$dh] = new mw_xml_data_handler($this->xml_data, $data_path);
      if($this->data_handlers[$dh]->open_data($FETCH)){
        return $dh;
      }
      $this->close_data($dh);
      return null;
    }

    public function fetch_data($dh){
      if(isset($this->data_handlers[$dh])){
        return $this->data_handlers[$dh]->fetch_assoc();
      }
      return false;
    }

    public function add_data($data_path, $data, $index = null){
      $dh = ++$this->last_data_handler;
      $this->data_handlers[$dh] = new mw_xml_data_handler($this->xml_data, $data_path);
      if($this->data_handlers[$dh]->open_data(false)){
        $res = $this->data_handlers[$dh]->add_data($data, $index);
        if($res) $res = $this->last_index($dh);
        $this->close_data($dh);
        return $res;
      }
      return null;
    }

    public function last_index($dh){
      if(isset($this->data_handlers[$dh])){
        return $this->data_handlers[$dh]->last_index;
      }
      return null;
    }

    public function set_data($data_path, $data_id, $data){
      $dh = ++$this->last_data_handler;
      $this->data_handlers[$dh] = new mw_xml_data_handler($this->xml_data, $data_path);
      if($this->data_handlers[$dh]->open_data(false)){
        $res = $this->data_handlers[$dh]->set_data($data_id.".xml", $data);
        $this->close_data($dh);
        return $res;
      }
      return null;
    }

    public function del_data($data_path, $data_id){
      $dh = ++$this->last_data_handler;
      $this->data_handlers[$dh] = new mw_xml_data_handler($this->xml_data, $data_path);
      if($this->data_handlers[$dh]->open_data(false)){
        $res = $this->data_handlers[$dh]->del_data($data_id.".xml");
        $this->close_data($dh);
        return $res;
      }
      return null;
    }

    public function close_data($dh){
      if(isset($this->data_handlers[$dh])){
        $this->data_handlers[$dh]->close_data();
        unset($this->data_handlers[$dh]);
      }
    }

    public function remove_data($data_path){
      $OK = strlen($data_path) > 0;
      if($OK && is_dir($this->host.$this->base.$data_path) && is_writable($this->host.$this->base.$data_path)){
        $data_path .= substr($data_path, -1) == "/" ? "" : "/";
        if($dh = opendir($this->host.$this->base.$data_path)){
          while($OK && ($file = readdir($dh)) !== false){
            if(is_dir($this->host.$this->base.$data_path.$file)){
              if($file != "." && $file != "..") $OK = $this->remove_data($data_path.$file);
            }
            else $OK = @unlink($this->host.$this->base.$data_path.$file);
          }
          closedir($dh);
        }
        else $OK = null;
      }
      else $OK = null;
      if($OK) @rmdir($this->host.$this->base.$data_path);
      return $OK;
    }

  }