<?php

  class mw_env_sgbds extends mw_env{

    private $sgbds;

    public function sgbds(){
      if(isset($this->sgbds)) return $this->sgbds;
      $this->sgbds = array();
      $impls_dir = $this->path("mw_dir")."env/sgbd";
      if(!file_exists($impls_dir) || !is_dir($impls_dir)){
        return false;
      }
      if($dh = opendir($impls_dir)){
        $OK = true;
        while($OK && ($impl_file = readdir($dh)) !== false){
          if(substr($impl_file, 0 ,1) !== "." && substr($impl_file, -4) == ".php"){
            require_once $impls_dir."/".$impl_file;
            if(class_exists($class_name = substr($impl_file, 0, -4))){
              if(
                    method_exists($class_name, "name")
                &&  method_exists($class_name, "extention_ok")
              ){
                $impl = new $class_name($this);
                if($impl->extention_ok($this)) $this->sgbds[$class_name] = $impl;
              }
            }
          }
        }
      }
      else{
        return false;
      }
      return $this->sgbds;
    }

    public function load_sgbd(){
      if(($data = $this->data()) && $this->bdd("sgbd")){
        $sgbd_impl_file = $this->path("mw_dir")."env/sgbd/mw_".$this->bdd("sgbd").".php";
        if(!file_exists($sgbd_impl_file)){
          $this->erreur("Impossible de trouver le fichier d'implementation du sgbd ".$this->bdd("sgbd"), true);
        }
        $sgbd_impl = "mw_".$this->bdd("sgbd");
        if(!class_exists($sgbd_impl)) require_once $sgbd_impl_file;
        if(!class_exists($sgbd_impl)){
          $this->erreur("Impossible de trouver la classe d'implementation du sgbd ".$this->bdd("sgbd"), true);
        }
        $sgbd = new $sgbd_impl(
          $this,
          array(
            "host" => $this->bdd("host"),
            "base" => $this->bdd("base"),
            "user" => $this->bdd("user"),
            "password" => $this->bdd("password")
          )
        );
        if(!$sgbd->extention_ok()){
          $this->erreur("L'extention php ".$this->bdd("sgbd")." n'est pas install&eacute;e", true);
        }
        $data->set_sgbd($sgbd);
      }
    }

  }

  // -------------------------------------------------------------------------------------------
  //                                                                               class mw_sgbd
  //

  abstract class mw_sgbd{

    public $env;
    public $link;
    public $host;
    public $base;
    public $user;
    public $password;
    public $EXTENTION_OK;

    public function __construct($env, $params = array()){
      $this->env = $env;
      $default_params = $this->default_params();
      $params = $this->prepare_params($params);
      $this->host = isset($params["host"]) ? $params["host"] : $default_params["host"];
      $this->base = isset($params["base"]) ? $params["base"] : $default_params["base"];
      $this->user = isset($params["user"]) ? $params["user"] : $default_params["user"];
      $this->password = isset($params["password"]) ? $params["password"] : $default_params["password"];
      $this->EXTENTION_OK = $this->validate_extention();
    }

    public function name(){
      return "";
    }

    public function default_params(){
      return array(
        "host" => "",
        "base" => "",
        "user" => "",
        "password" => ""
      );
    }

    public function prepare_params($params){
      return $params;
    }

    public function validate_extention(){
      return false;
    }

    public function authentication_required(){
      return false;
    }

    public function get_link(){
      return $this->link;
    }

    public function extention_ok(){
      return $this->EXTENTION_OK;
    }

    public function replace_prefixes($content){
      return (
        ($prefix_codes = array_keys($this->env->bdd("table_prefix"))) ?
          str_replace($prefix_codes, array_values($this->env->bdd("table_prefix")), $content)
        : $content
      );
    }

  }