<?php

declare(strict_types=1);

namespace UseCases\Chat;

// @responsibility: Lädt Chat-Session mit allen Nachrichten

use Infrastructure\Persistence\ChatMessageRepository;
use Infrastructure\Persistence\ChatSessionRepository;

class LoadChatSessionUseCase
{
    private ChatSessionRepository $sessionRepo;
    private ChatMessageRepository $messageRepo;

    public function __construct(
        ?ChatSessionRepository $sessionRepo = null,
        ?ChatMessageRepository $messageRepo = null
    ) {
        $this->sessionRepo = $sessionRepo ?? new ChatSessionRepository();
        $this->messageRepo = $messageRepo ?? new ChatMessageRepository();
    }

    /**
     * Load session by UUID with all messages
     */
    public function execute(string $uuid): ?ChatSessionDTO
    {
        $session = $this->sessionRepo->findByUuid($uuid);

        if ($session === null) {
            return null;
        }

        $messages = $this->messageRepo->findBySessionId($session['id']);

        return new ChatSessionDTO($session, $messages);
    }

    /**
     * Create a new session and return it
     */
    public function createNew(
        string $model = 'claude-opus-4-5-20251101',
        array $collections = ['documents'],
        int $contextLimit = 5
    ): ChatSessionDTO {
        $uuid = $this->sessionRepo->generateUuid();
        $collectionsJson = json_encode($collections);

        $this->sessionRepo->create($uuid, $model, $collectionsJson, $contextLimit);

        // Load the freshly created session
        $session = $this->sessionRepo->findByUuid($uuid);

        return new ChatSessionDTO($session ?? [], []);
    }
}