Implement manual prefix setting for configuration ldap

apps/user_ldap/lib/Command/CreateEmptyConfig.php

@@ -31,11 +31,34 @@ protected function configure(): void {
 				InputOption::VALUE_NONE,
 				'outputs only the prefix'
 			)
+			->addOption(
+				'set-prefix',
+				's',
+				InputOption::VALUE_OPTIONAL,
+				'manually set the prefix (must be unique)',
+			)
 		;
 	}
 
 	protected function execute(InputInterface $input, OutputInterface $output): int {
-		$configPrefix = $this->helper->getNextServerConfigurationPrefix();
+		$configPrefix = $input->getOption('set-prefix');
+		if (is_string($configPrefix)) {
+			if ($configPrefix === '') {
+				$output->writeln('The prefix cannot be empty');
+				return self::FAILURE;
+			}
+			if (preg_match('/^[a-zA-Z0-9-_]+$/', $configPrefix) !== 1) {
+				$output->writeln('The prefix may only contain alphanumeric characters, dashes and underscores');
+				return self::FAILURE;
+			}
+			$configPrefix = $this->helper->registerNewServerConfigurationPrefix($configPrefix);
+			if ($configPrefix === false) {
+				$output->writeln('The prefix is already in use');
+				return self::FAILURE;
+			}
+		} else {
+			$configPrefix = $this->helper->getNextServerConfigurationPrefix();
+		}
 		$configHolder = new Configuration($configPrefix);
 		$configHolder->ldapConfigurationActive = false;
 		$configHolder->saveConfiguration();

apps/user_ldap/lib/Helper.php

@@ -105,11 +105,13 @@ public function getServerConfigurationHosts(): array {
 	public function getNextServerConfigurationPrefix(): string {
 		$prefixes = $this->getServerConfigurationPrefixes();
 
-		if (count($prefixes) === 0) {
+		$filteredPrefixes = array_filter($prefixes, fn($p) => preg_match('/^s\d{2}$/', $p));
+
+		if (count($filteredPrefixes) === 0) {
 			$prefix = 's01';
 		} else {
-			sort($prefixes);
-			$lastKey = array_pop($prefixes);
+			sort($filteredPrefixes);
+			$lastKey = array_pop($filteredPrefixes);
 			$lastNumber = (int)str_replace('s', '', $lastKey);
 			$prefix = 's' . str_pad((string)($lastNumber + 1), 2, '0', STR_PAD_LEFT);
 		}
@@ -119,6 +121,22 @@ public function getNextServerConfigurationPrefix(): string {
 		return $prefix;
 	}
 
+	/**
+	 * registers the given prefix as used, if it is not already in use
+	 *
+	 * @param string $prefix the prefix to register
+	 * @return string|false the given prefix on success, false if it is already in use
+	 */
+	public function registerNewServerConfigurationPrefix(string $prefix): string|false {
+		$prefixes = $this->getServerConfigurationPrefixes();
+		if (in_array($prefix, $prefixes)) {
+			return false;
+		}
+		$prefixes[] = $prefix;
+		$this->appConfig->setValueArray('user_ldap', 'configuration_prefixes', $prefixes);
+		return $prefix;
+	}
+
 	private function getServersConfig(string $value): array {
 		$regex = '/' . $value . '$/S';