<?php

namespace UseCases\Chat;

use Infrastructure\AI\ModelConfig;
use Infrastructure\Persistence\ChatMessageRepository;
use Infrastructure\Persistence\ChatSessionRepository;
use Infrastructure\Persistence\CollectionRepository;
use Infrastructure\Persistence\ContentConfigRepository;
use Infrastructure\Validation\CollectionValidator;

final class ManageChatSessionsUseCase
{
    private ChatSessionRepository $sessionRepo;
    private ChatMessageRepository $messageRepo;
    private ContentConfigRepository $configRepo;
    private CollectionRepository $collectionRepo;
    private CollectionValidator $collectionValidator;
    private ?array $collectionsCache = null;

    public function __construct(
        ?ChatSessionRepository $sessionRepo = null,
        ?ChatMessageRepository $messageRepo = null,
        ?ContentConfigRepository $configRepo = null,
        ?CollectionRepository $collectionRepo = null,
        ?CollectionValidator $collectionValidator = null
    ) {
        $this->sessionRepo = $sessionRepo ?? new ChatSessionRepository();
        $this->messageRepo = $messageRepo ?? new ChatMessageRepository();
        $this->configRepo = $configRepo ?? new ContentConfigRepository();
        $this->collectionRepo = $collectionRepo ?? new CollectionRepository();
        $this->collectionValidator = $collectionValidator ?? new CollectionValidator($this->collectionRepo);
    }

    public function createSession(): string
    {
        $uuid = $this->sessionRepo->generateUuid();
        $this->sessionRepo->create($uuid, 'claude-opus-4-5-20251101', '["documents"]', 5);

        return $uuid;
    }

    public function getSession(string $uuid): ?array
    {
        return $this->sessionRepo->findByUuid($uuid);
    }

    public function getAllSessions(int $limit = 50): array
    {
        return $this->sessionRepo->findAll($limit);
    }

    public function getMessages(int $sessionId): array
    {
        return $this->messageRepo->findBySessionId($sessionId);
    }

    public function updateTitle(int $sessionId, string $title): string
    {
        $title = trim($title);

        if ($title === '') {
            $title = 'Neuer Chat';
        }

        $title = mb_substr($title, 0, 100);
        $this->sessionRepo->updateTitle($sessionId, $title);

        return $title;
    }

    public function updateSettings(
        int $sessionId,
        string $model,
        array $collections,
        int $contextLimit,
        int $authorProfileId,
        float $temperature,
        int $maxTokens
    ): void {
        $model = ModelConfig::validate($model);
        $collections = $this->validateCollections($collections);
        $contextLimit = $this->validateContextLimit($contextLimit);
        $authorProfileId = $this->validateAuthorProfileId($authorProfileId);
        $temperature = $this->validateTemperature($temperature);
        $maxTokens = $this->validateMaxTokens($maxTokens);

        $this->sessionRepo->updateSettings(
            $sessionId,
            $model,
            $collections,
            $contextLimit,
            $authorProfileId > 0 ? $authorProfileId : null,
            $temperature,
            $maxTokens
        );
    }

    public function updateSystemPrompt(int $sessionId, string $systemPrompt): ChatSessionResult
    {
        $maxLength = 2000;
        $wasTruncated = mb_strlen($systemPrompt) > $maxLength;
        $systemPrompt = trim(mb_substr($systemPrompt, 0, $maxLength));

        $this->logSystemPromptChange($systemPrompt, $wasTruncated);
        $this->sessionRepo->updateSystemPrompt($sessionId, $systemPrompt);

        return ChatSessionResult::success('System-Prompt gespeichert.');
    }

    public function deleteSession(int $sessionId): void
    {
        $this->sessionRepo->delete($sessionId);
    }

    public function getAuthorProfiles(): array
    {
        return $this->configRepo->getAuthorProfiles();
    }

    public function getSystemPrompts(): array
    {
        return $this->configRepo->getSystemPrompts();
    }

    public function getOutputStructures(): array
    {
        return $this->configRepo->getStructures();
    }

    public function getStructure(int $id): ?array
    {
        return $this->configRepo->getStructure($id);
    }

    public function getAvailableCollections(): array
    {
        if ($this->collectionsCache === null) {
            $this->collectionsCache = $this->collectionRepo->getSearchable();

            if ($this->collectionsCache === []) {
                $this->collectionsCache = [
                    ['collection_id' => 'documents', 'display_name' => 'Dokumente', 'points_count' => 0, 'vector_size' => 1024],
                ];
            }
        }

        return $this->collectionsCache;
    }

    public function validateCollectionCompatibility(array $collectionIds): array
    {
        if (empty($collectionIds)) {
            return ['valid' => true, 'error' => null];
        }

        $result = $this->collectionValidator->validateSelection($collectionIds);

        return [
            'valid' => $result->isValid(),
            'error' => $result->getError(),
        ];
    }

    public function getDefaultSystemPrompt(): string
    {
        return <<<'PROMPT'
            Du bist ein hilfreicher Assistent für Fragen zu systemischem Teamcoaching und Teamentwicklung.

            Beantworte die Frage des Nutzers basierend auf dem bereitgestellten Kontext.
            - Antworte auf Deutsch
            - Sei präzise und hilfreich
            - Wenn der Kontext die Frage nicht beantwortet, sage das ehrlich
            - Verweise auf die Quellen wenn passend
            PROMPT;
    }

    public function settingsHaveChanged(array $session, string $model, array $collections, int $contextLimit, int $authorProfileId, float $temperature, int $maxTokens): bool
    {
        $currentModel = $session['model'] ?? '';
        $currentCollections = $session['collections'] ?? '["documents"]';
        $currentLimit = (int) ($session['context_limit'] ?? 5);
        $currentProfileId = (int) ($session['author_profile_id'] ?? 0);
        $currentTemperature = (float) ($session['temperature'] ?? 0.7);
        $currentMaxTokens = (int) ($session['max_tokens'] ?? 4096);

        $collectionsJson = json_encode($collections);

        return $model !== $currentModel
            || $collectionsJson !== $currentCollections
            || $contextLimit !== $currentLimit
            || $authorProfileId !== $currentProfileId
            || $temperature !== $currentTemperature
            || $maxTokens !== $currentMaxTokens;
    }

    private function validateCollections(array|string $collections): array
    {
        $availableIds = array_column($this->getAvailableCollections(), 'collection_id');

        if (is_string($collections)) {
            $collections = [$collections];
        }

        $valid = array_filter($collections, fn ($c) => in_array($c, $availableIds, true));

        return array_values($valid);
    }

    private function validateContextLimit(int $limit): int
    {
        $allowedLimits = [3, 5, 10, 15];

        return in_array($limit, $allowedLimits, true) ? $limit : 5;
    }

    private function validateAuthorProfileId(int $profileId): int
    {
        if ($profileId === 0) {
            return 0;
        }

        $profile = $this->configRepo->getAuthorProfile($profileId);

        return $profile !== null ? $profileId : 0;
    }

    private function validateTemperature(float $temperature): float
    {
        return max(0.0, min(1.0, $temperature));
    }

    private function validateMaxTokens(int $maxTokens): int
    {
        $allowedValues = [1024, 2048, 4096, 8192];

        return in_array($maxTokens, $allowedValues, true) ? $maxTokens : 4096;
    }

    private function logSystemPromptChange(string $prompt, bool $wasTruncated): void
    {
        $logData = [
            'prompt_length' => mb_strlen($prompt),
            'truncated' => $wasTruncated,
            'ip' => $_SERVER['REMOTE_ADDR'] ?? 'unknown',
            'timestamp' => date('c'),
        ];

        try {
            $devDb = \Infrastructure\Config\DatabaseFactory::dev();
            $stmt = $devDb->prepare(
                "INSERT INTO mcp_log (tool, operation, parameters, result, logged_at)
                 VALUES ('chat', 'system_prompt_change', :params, 'logged', NOW())"
            );
            $stmt->execute(['params' => json_encode($logData)]);
        } catch (\Exception $e) {
            // Silently fail
        }
    }
}