<?php defined("SYSPATH") or die("No direct script access.");
/**
 * Gallery - a web based photo album viewer and editor
 * Copyright (C) 2000-2008 Bharat Mediratta
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
 */

/**
 * This is the API for handling users.
 *
 * Note: by design, this class does not do any permission checking.
 */
class user_Core {
  /**
   * Return the form for creating / modifying users.
   */
  public static function get_edit_form($user) {
    $form = new Forge(
      url::site("users/{$user->id}?_method=put"), "", "post", array("id" => "gUserForm"));
    $group = $form->group(_("User Info"));

    $group->input("name")
      ->label(_("Name"))
      ->id("gName")
      ->value($user->name);

    $group->input("display_name")
      ->label(_("Display Name"))
      ->id("gDisplayName")
      ->value($user->display_name);

    $group->password("password")
      ->label(_("Password"))
      ->id("gPassword");

    $group->input("email")
      ->label(_("Email"))
      ->id("gEmail")
      ->value($user->email);

    $group->submit(_("Modify"));
    $form->add_rules_from($user);
    return $form;
  }

  /**
   * Return the active user.  If there's no active user, return the guest user.
   *
   * @return User_Model
   */
  static function active() {
    return Session::instance()->get("user", self::guest());
  }

  /**
   * Return the guest user.
   *
   * @todo consider caching
   *
   * @return User_Model
   */
  static function guest() {
    return ORM::factory("user", 1);
  }

  /**
   * Change the active user.
   *
   * @return User_Model
   */
  static function set_active($user) {
    return Session::instance()->set("user", $user);
  }

  /**
   * Create a new user.
   *
   * @param string  $name
   * @param string  $display_name
   * @param string  $password
   * @return User_Model
   */
  static function create($name, $display_name, $password) {
    $user = ORM::factory("user")->where("name", $name);
    if ($user->loaded) {
      throw new Exception("@todo USER_ALREADY_EXISTS $name");
    }

    $user->name = $name;
    $user->display_name = $display_name;
    $user->password = $password;
    $user->save();

    // Everybody user
    $group = ORM::factory("group", 1);
    $group->add($user);

    // Registered users
    $group = ORM::factory("group", 2);
    $group->add($user);

    module::event("user_created", $user);
    return $user;
  }

  /**
   * Is the password provided correct?
   *
   * @param user User Model
   * @param string $password a plaintext password
   * @return boolean true if the password is correct
   */
  public static function is_correct_password($user, $password) {
    $valid = $user->password;

    $salt = substr($valid, 0, 4);
    /* Support both old (G1 thru 1.4.0; G2 thru alpha-4) and new password schemes: */
    $guess = (strlen($valid) == 32) ? md5($password) : ($salt . md5($salt . $password));
    if (!strcmp($guess, $valid)) {
      return true;
    }

    /* Passwords with <&"> created by G2 prior to 2.1 were hashed with entities */
    $sanitizedPassword = html::specialchars($password, false);
    $guess = (strlen($valid) == 32) ? md5($sanitizedPassword)
          : ($salt . md5($salt . $sanitizedPassword));
    if (!strcmp($guess, $valid)) {
      return true;
    }

    /* Also support hashes generated by phpass for interoperability with other applications */
    if (strlen($valid) == 34) {
      $hashGenerator = new PasswordHash(10, true);
      return $hashGenerator->CheckPassword($password, $valid);
    }

    return false;
  }

  /**
   * Create the hashed passwords.
   * @param string $password a plaintext password
   * @return string hashed password
   */
  public static function hash_password($password) {
    return user::_md5Salt($password);
  }

  /**
   * Perform the post authentication processing
   * @param object $user the user object.
   */
  public static function login($user) {
    $user->login_count += 1;
    $user->last_login = time();
    $user->save();

    user::set_active($user);
    module::event("user_login", $user);
  }

  /**
   * Create a hashed password using md5 plus salt.
   * @param string $password plaintext password
   * @param string $salt (optional) salt or hash containing salt (randomly generated if omitted)
   * @return string hashed password
   */
  private static function _md5Salt($password, $salt="") {
    if (empty($salt)) {
      for ($i = 0; $i < 4; $i++) {
        $char = mt_rand(48, 109);
        $char += ($char > 90) ? 13 : ($char > 57) ? 7 : 0;
        $salt .= chr($char);
      }
    } else {
      $salt = substr($salt, 0, 4);
    }
    return $salt . md5($salt . $password);
  }
}