<?php
/**
 * MyBB 1.8
 * Copyright 2014 MyBB Group, All Rights Reserved
 *
 * Website: http://www.mybb.com
 * License: http://www.mybb.com/about/license
 *
 */

/**
 * Checks if a user with uid $uid exists in the database.
 *
 * @param int $uid The uid to check for.
 * @return boolean True when exists, false when not.
 */
function user_exists($uid)
{
    global $db;

    $query = $db->simple_select("users", "COUNT(*) as user", "uid='".(int)$uid."'", array('limit' => 1));
    if($db->fetch_field($query, 'user') == 1)
    {
        return true;
    }
    else
    {
        return false;
    }
}

/**
 * Checks if $username already exists in the database.
 *
 * @param string $username The username for check for.
 * @return boolean True when exists, false when not.
 */
function username_exists($username)
{
    $options = array(
        'username_method' => 2
    );

    return (bool)get_user_by_username($username, $options);
}

/**
 * Checks a password with a supplied username.
 *
 * @param string $username The username of the user.
 * @param string $password The plain-text password.
 * @return boolean|array False when no match, array with user info when match.
 */
function validate_password_from_username($username, $password)
{
    global $mybb;

    $options = array(
        'fields' => '*',
        'username_method' => $mybb->settings['username_method'],
    );

    $user = get_user_by_username($username, $options);

    if(!$user['uid'])
    {
        return false;
    }

    return validate_password_from_uid($user['uid'], $password, $user);
}

/**
 * Checks a password with a supplied uid.
 *
 * @param int $uid The user id.
 * @param string $password The plain-text password.
 * @param array $user An optional user data array.
 * @return boolean|array False when not valid, user data array when valid.
 */
function validate_password_from_uid($uid, $password, $user = array())
{
    global $db, $mybb;
    if(isset($mybb->user['uid']) && $mybb->user['uid'] == $uid)
    {
        $user = $mybb->user;
    }
    if(!$user['password'])
    {
        $user = get_user($uid);
    }
    if(!$user['salt'])
    {
        // Generate a salt for this user and assume the password stored in db is a plain md5 password
        $password_fields = create_password($user['password'], false, $user);
        $db->update_query("users", $password_fields, "uid='".$user['uid']."'");
    }

    if(!$user['loginkey'])
    {
        $user['loginkey'] = generate_loginkey();
        $sql_array = array(
            "loginkey" => $user['loginkey']
        );
        $db->update_query("users", $sql_array, "uid = ".$user['uid']);
    }
    if(verify_user_password($user, $password))
    {
        return $user;
    }
    else
    {
        return false;
    }
}

/**
 * Updates a user's password.
 *
 * @param int $uid The user's id.
 * @param string $password The md5()'ed password.
 * @param string $salt (Optional) The salt of the user.
 * @return array The new password.
 * @deprecated deprecated since version 1.8.6 Please use other alternatives.
 */
function update_password($uid, $password, $salt="")
{
    global $db, $plugins;

    $newpassword = array();

    // If no salt was specified, check in database first, if still doesn't exist, create one
    if(!$salt)
    {
        $query = $db->simple_select("users", "salt", "uid='$uid'");
        $user = $db->fetch_array($query);
        if($user['salt'])
        {
            $salt = $user['salt'];
        }
        else
        {
            $salt = generate_salt();
        }
        $newpassword['salt'] = $salt;
    }

    // Create new password based on salt
    $saltedpw = salt_password($password, $salt);

    // Generate new login key
    $loginkey = generate_loginkey();

    // Update password and login key in database
    $newpassword['password'] = $saltedpw;
    $newpassword['loginkey'] = $loginkey;
    $db->update_query("users", $newpassword, "uid='$uid'");

    $plugins->run_hooks("password_changed");

    return $newpassword;
}

/**
 * Salts a password based on a supplied salt.
 *
 * @param string $password The md5()'ed password.
 * @param string $salt The salt.
 * @return string The password hash.
 * @deprecated deprecated since version 1.8.9 Please use other alternatives.
 */
function salt_password($password, $salt)
{
    return md5(md5($salt).$password);
}

/**
 * Salts a password based on a supplied salt.
 *
 * @param string $password The input password.
 * @param string $salt (Optional) The salt used by the MyBB algorithm.
 * @param string $user (Optional) An array containing password-related data.
 * @return array Password-related fields.
 */
function create_password($password, $salt = false, $user = false)
{
    global $plugins;

    $fields = null;

    $parameters = compact('password', 'salt', 'user', 'fields');

    if(!defined('IN_INSTALL') && !defined('IN_UPGRADE'))
    {
        $plugins->run_hooks('create_password', $parameters);
    }

    if(!is_null($parameters['fields']))
    {
        $fields = $parameters['fields'];
    }
    else
    {
        if(!$salt)
        {
            $salt = generate_salt();
        }

        $hash = md5(md5($salt).md5($password));

        $fields = array(
            'salt' => $salt,
            'password' => $hash,
        );
    }

    return $fields;
}

/**
 * Compares user's password data against provided input.
 *
 * @param array $user An array containing password-related data.
 * @param string $password The plain-text input password.
 * @return bool Result of the comparison.
 */
function verify_user_password($user, $password)
{
    global $plugins;

    $result = null;

    $parameters = compact('user', 'password', 'result');

    if(!defined('IN_INSTALL') && !defined('IN_UPGRADE'))
    {
        $plugins->run_hooks('verify_user_password', $parameters);
    }

    if(!is_null($parameters['result']))
    {
        return $parameters['result'];
    }
    else
    {
        $password_fields = create_password($password, $user['salt'], $user);

        return my_hash_equals($user['password'], $password_fields['password']);
    }
}

/**
 * Performs a timing attack safe string comparison.
 *
 * @param string $known_string The first string to be compared.
 * @param string $user_string The second, user-supplied string to be compared.
 * @return bool Result of the comparison.
 */
function my_hash_equals($known_string, $user_string)
{
    if(version_compare(PHP_VERSION, '5.6.0', '>='))
    {
        return hash_equals($known_string, $user_string);
    }
    else
    {
        $known_string_length = my_strlen($known_string);
        $user_string_length = my_strlen($user_string);

        if($user_string_length != $known_string_length)
        {
            return false;
        }

        $result = 0;

        for($i = 0; $i < $known_string_length; $i++)
        {
            $result |= ord($known_string[$i]) ^ ord($user_string[$i]);
        }

        return $result === 0;
    }
}

/**
 * Generates a random salt
 *
 * @return string The salt.
 */
function generate_salt()
{
    return random_str(8);
}

/**
 * Generates a 50 character random login key.
 *
 * @return string The login key.
 */
function generate_loginkey()
{
    return random_str(50);
}

/**
 * Updates a user's salt in the database (does not update a password).
 *
 * @param int $uid The uid of the user to update.
 * @return string The new salt.
 */
function update_salt($uid)
{
    global $db;

    $salt = generate_salt();
    $sql_array = array(
        "salt" => $salt
    );
    $db->update_query("users", $sql_array, "uid='{$uid}'");

    return $salt;
}

/**
 * Generates a new login key for a user.
 *
 * @param int $uid The uid of the user to update.
 * @return string The new login key.
 */
function update_loginkey($uid)
{
    global $db;

    $loginkey = generate_loginkey();
    $sql_array = array(
        "loginkey" => $loginkey
    );
    $db->update_query("users", $sql_array, "uid='{$uid}'");

    return $loginkey;

}

/**
 * Adds a thread to a user's thread subscription list.
 * If no uid is supplied, the currently logged in user's id will be used.
 *
 * @param int $tid The tid of the thread to add to the list.
 * @param int $notification (Optional) The type of notification to receive for replies (0=none, 1=email, 2=pm)
 * @param int $uid (Optional) The uid of the user who's list to update.
 * @return boolean True when success, false when otherwise.
 */
function add_subscribed_thread($tid, $notification=1, $uid=0)
{
    global $mybb, $db;

    if(!$uid)
    {
        $uid = $mybb->user['uid'];
    }

    if(!$uid)
    {
        return false;
    }

    $query = $db->simple_select("threadsubscriptions", "*", "tid='".(int)$tid."' AND uid='".(int)$uid."'");
    $subscription = $db->fetch_array($query);
    if(!$subscription['tid'])
    {
        $insert_array = array(
            'uid' => (int)$uid,
            'tid' => (int)$tid,
            'notification' => (int)$notification,
            'dateline' => TIME_NOW
        );
        $db->insert_query("threadsubscriptions", $insert_array);
    }
    else
    {
        // Subscription exists - simply update notification
        $update_array = array(
            "notification" => (int)$notification
        );
        $db->update_query("threadsubscriptions", $update_array, "uid='{$uid}' AND tid='{$tid}'");
    }
    return true;
}

/**
 * Remove a thread from a user's thread subscription list.
 * If no uid is supplied, the currently logged in user's id will be used.
 *
 * @param int $tid The tid of the thread to remove from the list.
 * @param int $uid (Optional) The uid of the user who's list to update.
 * @return boolean True when success, false when otherwise.
 */
function remove_subscribed_thread($tid, $uid=0)
{
    global $mybb, $db;

    if(!$uid)
    {
        $uid = $mybb->user['uid'];
    }

    if(!$uid)
    {
        return false;
    }
    $db->delete_query("threadsubscriptions", "tid='".$tid."' AND uid='{$uid}'");

    return true;
}

/**
 * Adds a forum to a user's forum subscription list.
 * If no uid is supplied, the currently logged in user's id will be used.
 *
 * @param int $fid The fid of the forum to add to the list.
 * @param int $uid (Optional) The uid of the user who's list to update.
 * @return boolean True when success, false when otherwise.
 */
function add_subscribed_forum($fid, $uid=0)
{
    global $mybb, $db;

    if(!$uid)
    {
        $uid = $mybb->user['uid'];
    }

    if(!$uid)
    {
        return false;
    }

    $fid = (int)$fid;
    $uid = (int)$uid;

    $query = $db->simple_select("forumsubscriptions", "*", "fid='".$fid."' AND uid='{$uid}'", array('limit' => 1));
    $fsubscription = $db->fetch_array($query);
    if(!$fsubscription['fid'])
    {
        $insert_array = array(
            'fid' => $fid,
            'uid' => $uid
        );
        $db->insert_query("forumsubscriptions", $insert_array);
    }

    return true;
}

/**
 * Removes a forum from a user's forum subscription list.
 * If no uid is supplied, the currently logged in user's id will be used.
 *
 * @param int $fid The fid of the forum to remove from the list.
 * @param int $uid (Optional) The uid of the user who's list to update.
 * @return boolean True when success, false when otherwise.
 */
function remove_subscribed_forum($fid, $uid=0)
{
    global $mybb, $db;

    if(!$uid)
    {
        $uid = $mybb->user['uid'];
    }

    if(!$uid)
    {
        return false;
    }
    $db->delete_query("forumsubscriptions", "fid='".$fid."' AND uid='{$uid}'");

    return true;
}

/**
 * Constructs the usercp navigation menu.
 *
 */
function usercp_menu()
{
    global $mybb, $templates, $theme, $plugins, $lang, $usercpnav, $usercpmenu;

    $lang->load("usercpnav");

    // Add the default items as plugins with separated priorities of 10
    if($mybb->settings['enablepms'] != 0 && $mybb->usergroup['canusepms'] == 1)
    {
        $plugins->add_hook("usercp_menu", "usercp_menu_messenger", 10);
    }

    if($mybb->usergroup['canusercp'] == 1)
    {
        $plugins->add_hook("usercp_menu", "usercp_menu_profile", 20);
        $plugins->add_hook("usercp_menu", "usercp_menu_misc", 30);
    }

    // Run the plugin hooks
    $plugins->run_hooks("usercp_menu");
    global $usercpmenu;

    if($mybb->usergroup['canusercp'] == 1)
    {
        eval("\$ucp_nav_home = \"".$templates->get("usercp_nav_home")."\";");
    }

    eval("\$usercpnav = \"".$templates->get("usercp_nav")."\";");

    $plugins->run_hooks("usercp_menu_built");
}

/**
 * Constructs the usercp messenger menu.
 *
 */
function usercp_menu_messenger()
{
    global $db, $mybb, $templates, $theme, $usercpmenu, $lang, $collapsed, $collapsedimg;

    $usercp_nav_messenger = $templates->get("usercp_nav_messenger");
    // Hide tracking link if no permission
    $tracking = '';
    if($mybb->usergroup['cantrackpms'])
    {
        $tracking = $templates->get("usercp_nav_messenger_tracking");
    }
    eval("\$ucp_nav_tracking = \"". $tracking ."\";");

    // Hide compose link if no permission
    $ucp_nav_compose = '';
    if($mybb->usergroup['cansendpms'] == 1)
    {
        eval("\$ucp_nav_compose = \"".$templates->get("usercp_nav_messenger_compose")."\";");
    }

    $folderlinks = $folder_id = $folder_name = '';
    $foldersexploded = explode("$%%$", $mybb->user['pmfolders']);
    foreach($foldersexploded as $key => $folders)
    {
        $folderinfo = explode("**", $folders, 2);
        $folderinfo[1] = get_pm_folder_name($folderinfo[0], $folderinfo[1]);
        if($folderinfo[0] == 4)
        {
            $class = "usercp_nav_trash_pmfolder";
        }
        else if($folderlinks)
        {
            $class = "usercp_nav_sub_pmfolder";
        }
        else
        {
            $class = "usercp_nav_pmfolder";
        }

        $folder_id = $folderinfo[0];
        $folder_name = $folderinfo[1];

        eval("\$folderlinks .= \"".$templates->get("usercp_nav_messenger_folder")."\";");
    }

    if(!isset($collapsedimg['usercppms']))
    {
        $collapsedimg['usercppms'] = '';
    }

    if(!isset($collapsed['usercppms_e']))
    {
        $collapsed['usercppms_e'] = '';
    }

    eval("\$usercpmenu .= \"".$usercp_nav_messenger."\";");
}

/**
 * Constructs the usercp profile menu.
 *
 */
function usercp_menu_profile()
{
    global $db, $mybb, $templates, $theme, $usercpmenu, $lang, $collapsed, $collapsedimg;

    $changenameop = '';
    if($mybb->usergroup['canchangename'] != 0)
    {
        eval("\$changenameop = \"".$templates->get("usercp_nav_changename")."\";");
    }

    $changesigop = '';
    if($mybb->usergroup['canusesig'] == 1 && ($mybb->usergroup['canusesigxposts'] == 0 || $mybb->usergroup['canusesigxposts'] > 0 && $mybb->user['postnum'] > $mybb->usergroup['canusesigxposts']))
    {
        if($mybb->user['suspendsignature'] == 0 || $mybb->user['suspendsignature'] == 1 && $mybb->user['suspendsigtime'] > 0 && $mybb->user['suspendsigtime'] < TIME_NOW)
        {
            eval("\$changesigop = \"".$templates->get("usercp_nav_editsignature")."\";");
        }
    }

    if(!isset($collapsedimg['usercpprofile']))
    {
        $collapsedimg['usercpprofile'] = '';
    }

    if(!isset($collapsed['usercpprofile_e']))
    {
        $collapsed['usercpprofile_e'] = '';
    }

    eval("\$usercpmenu .= \"".$templates->get("usercp_nav_profile")."\";");
}

/**
 * Constructs the usercp misc menu.
 *
 */
function usercp_menu_misc()
{
    global $db, $mybb, $templates, $theme, $usercpmenu, $lang, $collapsed, $collapsedimg;

    $draftstart = $draftend = '';
    $draftcount = $lang->ucp_nav_drafts;

    $query = $db->simple_select("posts", "COUNT(pid) AS draftcount", "visible = '-2' AND uid = '{$mybb->user['uid']}'");
    $count = $db->fetch_field($query, 'draftcount');

    if($count > 0)
    {
        $draftcount = $lang->sprintf($lang->ucp_nav_drafts_active, my_number_format($count));
    }

    if($mybb->settings['enableattachments'] != 0)
    {
        eval("\$attachmentop = \"".$templates->get("usercp_nav_attachments")."\";");
    }

    if(!isset($collapsedimg['usercpmisc']))
    {
        $collapsedimg['usercpmisc'] = '';
    }

    if(!isset($collapsed['usercpmisc_e']))
    {
        $collapsed['usercpmisc_e'] = '';
    }

    $profile_link = get_profile_link($mybb->user['uid']);
    eval("\$usercpmenu .= \"".$templates->get("usercp_nav_misc")."\";");
}

/**
 * Gets the usertitle for a specific uid.
 *
 * @param int $uid The uid of the user to get the usertitle of.
 * @return string The usertitle of the user.
 */
function get_usertitle($uid=0)
{
    global $db, $mybb;

    if($mybb->user['uid'] == $uid)
    {
        $user = $mybb->user;
    }
    else
    {
        $query = $db->simple_select("users", "usertitle,postnum", "uid='$uid'", array('limit' => 1));
        $user = $db->fetch_array($query);
    }

    if($user['usertitle'])
    {
        return $user['usertitle'];
    }
    else
    {
        $usertitles = $mybb->cache->read('usertitles');
        foreach($usertitles as $title)
        {
            if($title['posts'] <= $user['postnum'])
            {
                $usertitle = $title;
                break;
            }
        }

        return $usertitle['title'];
    }
}

/**
 * Updates a users private message count in the users table with the number of pms they have.
 *
 * @param int $uid The user id to update the count for. If none, assumes currently logged in user.
 * @param int $count_to_update Bitwise value for what to update. 1 = total, 2 = new, 4 = unread. Combinations accepted.
 * @return array The updated counters
 */
function update_pm_count($uid=0, $count_to_update=7)
{
    global $db, $mybb;

    // If no user id, assume that we mean the current logged in user.
    if((int)$uid == 0)
    {
        $uid = $mybb->user['uid'];
    }

    $uid = (int)$uid;
    $pmcount = array();
    if($uid == 0)
    {
        return $pmcount;
    }

    // Update total number of messages.
    if($count_to_update & 1)
    {
        $query = $db->simple_select("privatemessages", "COUNT(pmid) AS pms_total", "uid='".$uid."'");
        $total = $db->fetch_array($query);
        $pmcount['totalpms'] = $total['pms_total'];
    }

    // Update number of unread messages.
    if($count_to_update & 2 && $db->field_exists("unreadpms", "users") == true)
    {
        $query = $db->simple_select("privatemessages", "COUNT(pmid) AS pms_unread", "uid='".$uid."' AND status='0' AND folder='1'");
        $unread = $db->fetch_array($query);
        $pmcount['unreadpms'] = $unread['pms_unread'];
    }

    if(!empty($pmcount))
    {
        $db->update_query("users", $pmcount, "uid='".$uid."'");
    }
    return $pmcount;
}

/**
 * Return the language specific name for a PM folder.
 *
 * @param int $fid The ID of the folder.
 * @param string $name The folder name - can be blank, will use language default.
 * @return string The name of the folder.
 */
function get_pm_folder_name($fid, $name="")
{
    global $lang;

    if($name != '')
    {
        return $name;
    }

    switch($fid)
    {
        case 1:
            return $lang->folder_inbox;
            break;
        case 2:
            return $lang->folder_sent_items;
            break;
        case 3:
            return $lang->folder_drafts;
            break;
        case 4:
            return $lang->folder_trash;
            break;
        default:
            return $lang->folder_untitled;
    }
}

/**
 * Generates a security question for registration.
 *
 * @param int $old_qid Optional ID of the old question.
 * @return string The question session id.
 */
function generate_question($old_qid=0)
{
    global $db;

    if($db->type == 'pgsql' || $db->type == 'sqlite')
    {
        $order_by = 'RANDOM()';
    }
    else
    {
        $order_by = 'RAND()';
    }

    if($old_qid)
    {
        $excl_old = ' AND qid != '.(int)$old_qid;
    }

    $query = $db->simple_select('questions', 'qid, shown', "active=1{$excl_old}", array('limit' => 1, 'order_by' => $order_by));
    $question = $db->fetch_array($query);

    if(!$db->num_rows($query))
    {
        // No active questions exist
        return false;
    }
    else
    {
        $sessionid = random_str(32);

        $sql_array = array(
            "sid" => $sessionid,
            "qid" => $question['qid'],
            "dateline" => TIME_NOW
        );
        $db->insert_query("questionsessions", $sql_array);

        $update_question = array(
            "shown" => $question['shown'] + 1
        );
        $db->update_query("questions", $update_question, "qid = '{$question['qid']}'");

        return $sessionid;
    }
}

/**
 * Check whether we can show the Purge Spammer Feature
 *
 * @param int $post_count The users post count
 * @param int $usergroup The usergroup of our user
 * @param int $uid The uid of our user
 * @return boolean Whether or not to show the feature
 */
function purgespammer_show($post_count, $usergroup, $uid)
{
        global $mybb, $cache;

        // only show this if the current user has permission to use it and the user has less than the post limit for using this tool
        $bangroup = $mybb->settings['purgespammerbangroup'];
        $usergroups = $cache->read('usergroups');

        return ($mybb->user['uid'] != $uid && is_member($mybb->settings['purgespammergroups']) && !is_super_admin($uid)
            && !$usergroups[$usergroup]['cancp'] && !$usergroups[$usergroup]['canmodcp'] && !$usergroups[$usergroup]['issupermod']
            && (str_replace($mybb->settings['thousandssep'], '', $post_count) <= $mybb->settings['purgespammerpostlimit'] || $mybb->settings['purgespammerpostlimit'] == 0)
            && !is_member($bangroup, $uid) && !$usergroups[$usergroup]['isbannedgroup']);
}