<?php
declare(strict_types=1);

namespace App\Repository;

use PDO;

/**
 * Repository für das KEA DHCP Host-Management.
 * Interagiert direkt mit der 'hosts' Tabelle in der KEA-Datenbank.
 */
final class KeaHostRepository
{
    public function __construct(
        private PDO $pdo,
        private ?KeaHostMetadataRepository $metadata = null
    ) {}

    /**
     * Ruft eine Liste aller Host-Reservierungen ab (Geräte-Inventar).
     */
    public function findAll(int $limit = 50): array
    {
        try {
            // 'dhcp_identifier' ist in KEA i.d.R. die MAC-Adresse (bei type=1)
            $stmt = $this->pdo->prepare(
                'SELECT host_id, dhcp_identifier, ipv4_address, hostname, user_context
                 FROM hosts
                 ORDER BY host_id DESC
                 LIMIT :limit'
            );
            $stmt->bindValue(':limit', $limit, PDO::PARAM_INT);
            $stmt->execute();

            return $this->withMetadata($stmt->fetchAll(PDO::FETCH_ASSOC));
        } catch (\PDOException $e) {
            if ($this->isMissingTable($e)) {
                throw new \RuntimeException(
                    'KEA schema not initialized. Enable APP_DB_AUTO_INIT or run kea-admin db-init pgsql.',
                    0,
                    $e
                );
            }
            throw $e;
        }
    }

    /**
     * Sucht einen Host anhand der MAC-Adresse (dhcp_identifier).
     */
    public function findByMac(string $mac): ?array
    {
        // Hinweis: KEA speichert MACs in PostgreSQL oft als BYTEA.
        // Je nach Treiber-Konfiguration muss $mac hier ggf. als Hex-String (z.B. '\x...')
        // formatiert übergeben werden.
        try {
            $stmt = $this->pdo->prepare(
                'SELECT host_id, dhcp_identifier, ipv4_address, hostname, user_context
                 FROM hosts
                 WHERE dhcp_identifier = :mac
                 LIMIT 1'
            );
            $stmt->execute(['mac' => $mac]);

            $row = $stmt->fetch(PDO::FETCH_ASSOC);
            return $row ?: null;
        } catch (\PDOException $e) {
            if ($this->isMissingTable($e)) {
                throw new \RuntimeException(
                    'KEA schema not initialized. Enable APP_DB_AUTO_INIT or run kea-admin db-init pgsql.',
                    0,
                    $e
                );
            }
            throw $e;
        }
    }

    private function isMissingTable(\PDOException $e): bool
    {
        return $e->getCode() === '42P01';
    }

    /**
     * Erstellt eine neue Host-Reservierung inkl. Metadaten.
     *
     * @param string $mac MAC-Adresse
     * @param string $ip IPv4-Adresse
     * @param int $subnetId Die ID des Subnets (dhcp4_subnet_id), in dem die IP liegt
     * @param string|null $hostname Optionaler Hostname
     * @param array $metadata Zusätzliche Infos fuer die separate Nexus-DHCP-Metadatenbank.
     */
    public function create(string $mac, string $ip, int $subnetId, ?string $hostname = null, array $metadata = []): int
    {
        // dhcp_identifier_type 1 = HW_ADDRESS (Ethernet)
        $stmt = $this->pdo->prepare(
            'INSERT INTO hosts (dhcp_identifier, dhcp_identifier_type, dhcp4_subnet_id, ipv4_address, hostname)
             VALUES (:mac, 1, :subnetId, :ip, :hostname)'
        );

        $stmt->execute([
            'mac'      => $mac,
            'subnetId' => $subnetId,
            'ip'       => $ip,
            'hostname' => $hostname,
        ]);

        $hostId = $this->lastInsertIdSafe();
        if ($this->metadata !== null && $metadata !== []) {
            $this->metadata->saveForHost($hostId, $mac, $ip, $metadata);
        }

        return $hostId;
    }

    private function withMetadata(array $hosts): array
    {
        if ($hosts === [] || $this->metadata === null) {
            return $hosts;
        }

        $metadataByHost = $this->metadata->findByHostIds(array_column($hosts, 'host_id'));
        foreach ($hosts as &$host) {
            $hostId = (int)($host['host_id'] ?? 0);
            $host['metadata'] = $metadataByHost[$hostId] ?? [];
        }
        unset($host);

        return $hosts;
    }

    private function driver(): string
    {
        return (string)$this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
    }

    private function lastInsertIdSafe(): int
    {
        $driver = $this->driver();

        if ($driver === 'pgsql') {
            // KEA Standard-Sequenz für die hosts Tabelle
            $id = $this->pdo->lastInsertId('hosts_host_id_seq');
            if ($id !== '') {
                return (int)$id;
            }
        }

        return (int)$this->pdo->lastInsertId();
    }
}