<?php

  class mw_env_data_upgrade extends mw_env{

    var $data_upgrades;

    function init_data_upgrades(){
      $data_upgrade = new mw_data_upgrade($this);
      $impl_dir = ($this->bdd("sgbd") == "xml" ? "xml" : "sql")."/";
      $versions_dir = $this->path("mw_dir")."app/data/upgrades/".$impl_dir;
      if(!is_dir($versions_dir)){
        return false;
      }
      if(!$data_upgrade->load_versions("mtweb", $versions_dir)){
        return false;
      }
      if(!isset($this->data_upgrades)) $this->data_upgrades = array();
      $this->data_upgrades[] = $data_upgrade;
      return true;
    }

    function data_upgrade_required(){
      if(!isset($this->data_upgrades)) return false;
      foreach($this->data_upgrades as $data_upgrade){
        if($data_upgrade->upgrade_required()){
          return true;
        }
      }
      return false;
    }

    function do_data_upgrade(){
      if(!isset($this->data_upgrades)) return false;
      foreach($this->data_upgrades as $data_upgrade){
        if($data_upgrade->upgrade_required() && ($res = $data_upgrade->do_upgrade()) !== true){
          return $res;
        }
      }
      return true;
    }

  }

  class mw_data_upgrade{

    var $versions;
    var $env;

    function mw_data_upgrade($env){
      $this->env = $env;
    }

    function env(){
      return isset($this->env) ? $this->env : false;
    }

    function load_versions($application_name, $versions_dir){
      if($dh = opendir($versions_dir)){
        $versions_dir .= $versions_dir && substr($versions_dir, -1) != "/" ? "/" : "";
        while(($file = readdir($dh)) !== false){
          if(
               substr($file, 0, 1) != "."
            && !is_dir($versions_dir.$file)
            && strcmp(substr($file, -4), ".php") == 0
          ) $this->load_version($application_name, $versions_dir, $file);
        }
        closedir($dh);
      }
      else return false;
      return true;
    }

    function load_version($application_name, $versions_dir, $version_file){
      if(
           !$version_file
        || !file_exists($versions_dir.$version_file)
        || (substr($version_file, 0, 1) == ".")
        || is_dir($versions_dir.$version_file)
        || (substr($version_file, -4) != ".php")
      ) return false;
      $class_name = substr($version_file, 0, -4);
      if(!class_exists($class_name)) require_once $versions_dir.$version_file;
      if(!class_exists($class_name)) return false;
      $version = new $class_name($this->env(), $application_name);
      return $this->add_version($version);
    }

    function add_version($version){
      if(!$version->version()) return false;
      if(!isset($this->versions)) $this->versions = array();
      $tmp = array();
      $INSERTED = false;
      foreach($this->versions as $_version){
        if(version_compare($version->version(), $_version->version()) == 0){
          $INSERTED = true;
        }
        elseif(version_compare($version->version(), $_version->version()) < 0){
          $tmp[] = $version;
          $tmp[] = $_version;
          $INSERTED = true;
        }
        else{
          $tmp[] = $_version;
        }
      }
      if(!$INSERTED) $tmp[] = $version;
      $this->versions = $tmp;
      return true;
    }

    function upgrade_required(){
      if(!isset($this->versions)) return false;
      foreach($this->versions as $version_number => $version){
        if($version->upgrade_required()) return true;
      }
      return false;
    }

    function do_upgrade(){
      if(!isset($this->versions)) return true;
      foreach($this->versions as $version_number => $version){
        if($version->upgrade_required() && ($res = $version->do_upgrade()) !== true){
          return $res." (dans ".get_class($version).")";
        }
        if(!$version->set_data_version()){
          return "impossible de mettre a jour la version des donnees pour ".$version->application_name();
        }
      }
      return true;
    }

  }

  class mw_data_version{

    var $env;
    var $application_name;

    function version(){
      return false;
    }

    function application_name(){
      return $this->application_name;
    }

    function mw_data_version($env, $application_name){
      $this->env = $env;
      $this->application_name = $application_name;
    }

    function env(){
      return isset($this->env) ? $this->env : false;
    }

    function upgrade_required(){
      if(!isset($this->application_name)) return false;
      $env = $this->env();
      $data = $env->data();
      if(!($env_version = $env->version($this->application_name))) return false;
      if(!($data_version = $data->version($this->application_name))) return true;
      return version_compare($data_version, $env_version) < 0;
    }

    function do_upgrade(){
      return true;
    }

    function set_data_version(){
      if(!isset($this->application_name)) return false;
      $env = $this->env();
      $data = $env->data();
      return $data->set_version($this->application_name, $this->version());
    }

  }