Add Two-factor recovery code model

- [DBA] Add NULL value handling in condition array

src/Database/DBA.php

@@ -1484,6 +1484,8 @@ class DBA
 						$new_values = array_merge($new_values, array_values($value));
 						$placeholders = substr(str_repeat("?, ", count($value)), 0, -2);
 						$condition_string .= "`" . $field . "` IN (" . $placeholders . ")";
+					} elseif (is_null($value)) {
+						$condition_string .= "`" . $field . "` IS NULL";
 					} else {
 						$new_values[$field] = $value;
 						$condition_string .= "`" . $field . "` = ?";

src/Model/TwoFactorRecoveryCode.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Friendica\Model;
+
+use Friendica\BaseObject;
+use Friendica\Database\DBA;
+use Friendica\Util\DateTimeFormat;
+use PragmaRX\Random\Random;
+use PragmaRX\Recovery\Recovery;
+
+class TwoFactorRecoveryCode extends BaseObject
+{
+	public static function countValidForUser($uid)
+	{
+		return DBA::count('2fa_recovery_codes', ['uid' => $uid, 'used' => null]);
+	}
+
+	public static function existsForUser($uid, $code)
+	{
+		return DBA::exists('2fa_recovery_codes', ['uid' => $uid, 'code' => $code, 'used' => null]);
+	}
+
+	public static function getListForUser($uid)
+	{
+		$codesStmt = DBA::select('2fa_recovery_codes', ['code', 'used'], ['uid' => $uid]);
+
+		return DBA::toArray($codesStmt);
+	}
+
+	public static function markUsedForUser($uid, $code)
+	{
+		DBA::update('2fa_recovery_codes', ['used' => DateTimeFormat::utcNow()], ['uid' => $uid, 'code' => $code]);
+
+		return DBA::affectedRows() > 0;
+	}
+
+	public static function generateForUser($uid)
+	{
+		$Random = (new Random())->pattern('[a-z0-9]');
+
+		$RecoveryGenerator = new Recovery($Random);
+
+		$codes = $RecoveryGenerator
+			->setCount(12)
+			->setBlocks(2)
+			->setChars(6)
+			->lowercase(true)
+			->toArray();
+
+		$generated = DateTimeFormat::utcNow();
+		foreach ($codes as $code) {
+			DBA::insert('2fa_recovery_codes', [
+				'uid' => $uid,
+				'code' => $code,
+				'generated' => $generated
+			]);
+		}
+	}
+
+	public static function deleteForUser($uid)
+	{
+		DBA::delete('2fa_recovery_codes', ['uid' => $uid]);
+	}
+
+	public static function regenerateForUser($uid)
+	{
+		self::deleteForUser($uid);
+		self::generateForUser($uid);
+	}
+}