<?php

namespace Controller;

use Framework\Controller;
use Infrastructure\AI\ModelConfig;
use Infrastructure\Formatting\ChatMessageFormatter;
use UseCases\Chat\ExportChatSessionUseCase;
use UseCases\Chat\ManageChatSessionsUseCase;
use UseCases\Chat\SendChatMessageUseCase;

class ChatController extends Controller
{
    private ManageChatSessionsUseCase $sessionsUseCase;
    private SendChatMessageUseCase $messageUseCase;
    private ChatMessageFormatter $formatter;

    public function __construct(
        ?ManageChatSessionsUseCase $sessionsUseCase = null,
        ?SendChatMessageUseCase $messageUseCase = null,
        ?ChatMessageFormatter $formatter = null
    ) {
        $this->sessionsUseCase = $sessionsUseCase ?? new ManageChatSessionsUseCase();
        $this->messageUseCase = $messageUseCase ?? new SendChatMessageUseCase();
        $this->formatter = $formatter ?? new ChatMessageFormatter();
    }

    public function index(): void
    {
        $uuid = $this->sessionsUseCase->createSession();
        header('Location: /chat/' . $uuid);
        exit;
    }

    public function show(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session === null) {
            header('Location: /chat');
            exit;
        }

        $this->view('chat.index', [
            'title' => $session['title'] ?? 'KI-Chat',
            'session' => $session,
            'messages' => $this->sessionsUseCase->getMessages($session['id']),
            'sessions' => $this->sessionsUseCase->getAllSessions(),
            'authorProfiles' => $this->sessionsUseCase->getAuthorProfiles(),
            'systemPrompts' => $this->sessionsUseCase->getSystemPrompts(),
            'outputStructures' => $this->sessionsUseCase->getOutputStructures(),
            'collections' => $this->sessionsUseCase->getAvailableCollections(),
            'models' => ModelConfig::getAll(),
            'defaultModel' => ModelConfig::DEFAULT_MODEL,
        ]);
    }

    public function sessionList(): void
    {
        $this->view('chat.partials.session-list', [
            'sessions' => $this->sessionsUseCase->getAllSessions(),
            'currentUuid' => $this->getString('current') ?: null,
        ]);
    }

    public function message(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session === null) {
            $this->view('chat.partials.error', ['error' => 'Session nicht gefunden.']);

            return;
        }

        $question = trim($_POST['message'] ?? '');
        $model = ModelConfig::validate($_POST['model'] ?? $session['model']);
        $sessionCollections = $this->decodeJson($session['collections'] ?? null) ?: ['documents'];
        $collections = $_POST['collections'] ?? $sessionCollections;
        $contextLimit = (int) ($_POST['context_limit'] ?? $session['context_limit'] ?? 5);
        $authorProfileId = (int) ($_POST['author_profile_id'] ?? $session['author_profile_id'] ?? 0);
        $systemPromptId = (int) ($_POST['system_prompt_id'] ?? $session['system_prompt_id'] ?? 1);
        $structureId = (int) ($_POST['structure_id'] ?? 0);
        $temperature = (float) ($_POST['temperature'] ?? $session['temperature'] ?? 0.7);
        $maxTokens = (int) ($_POST['max_tokens'] ?? $session['max_tokens'] ?? 4096);

        if ($this->sessionsUseCase->settingsHaveChanged($session, $model, $collections, $contextLimit, $authorProfileId, $temperature, $maxTokens)) {
            $this->sessionsUseCase->updateSettings($session['id'], $model, $collections, $contextLimit, $authorProfileId, $temperature, $maxTokens);
        }

        if ($question === '') {
            $this->view('chat.partials.error', ['error' => 'Bitte gib eine Frage ein.']);

            return;
        }

        if (!empty($collections)) {
            $compatibility = $this->sessionsUseCase->validateCollectionCompatibility($collections);
            if (!$compatibility['valid']) {
                $this->view('chat.partials.error', [
                    'error' => 'Collection-Fehler: ' . $compatibility['error'],
                    'details' => 'Bitte wähle nur Collections mit gleichem Embedding-Modell.',
                ]);

                return;
            }
        }

        $response = $this->messageUseCase->execute(
            sessionUuid: $uuid,
            message: $question,
            model: $model,
            collections: $collections,
            contextLimit: $contextLimit,
            authorProfileId: $authorProfileId,
            systemPromptId: $systemPromptId,
            temperature: $temperature,
            maxTokens: $maxTokens,
            structureId: $structureId
        );

        if ($response->hasError()) {
            $this->view('chat.partials.error', ['error' => $response->getError()]);

            return;
        }

        $result = $response->toArray();
        $this->view('chat.partials.response', [
            'question' => $question,
            'result' => $result,
            'model' => $model,
            'formattedAnswer' => $this->formatter->formatAnswer($result['answer'] ?? ''),
        ]);
    }

    public function updateTitle(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session === null) {
            $this->notFound('Session nicht gefunden');
        }

        $title = $this->sessionsUseCase->updateTitle($session['id'], $_POST['title'] ?? '');
        echo htmlspecialchars($title);
    }

    public function systemPrompt(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session === null) {
            $this->notFound('Session nicht gefunden');
        }

        $result = $this->sessionsUseCase->updateSystemPrompt($session['id'], $_POST['system_prompt'] ?? '');
        $this->view('chat.partials.success', ['message' => $result->message]);
    }

    public function getSystemPrompt(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session === null) {
            $this->notFound('Session nicht gefunden');
        }

        $this->view('chat.partials.system-prompt-modal', [
            'session' => $session,
            'currentPrompt' => $session['system_prompt'] ?? '',
            'defaultPrompt' => $this->sessionsUseCase->getDefaultSystemPrompt(),
        ]);
    }

    public function delete(string $uuid): void
    {
        $session = $this->sessionsUseCase->getSession($uuid);

        if ($session !== null) {
            $this->sessionsUseCase->deleteSession($session['id']);
        }

        header('HX-Redirect: /chat');
        echo 'OK';
    }

    public function export(string $uuid): void
    {
        $format = $this->getString('format') ?: 'markdown';
        $exportUseCase = new ExportChatSessionUseCase();

        $filename = $exportUseCase->generateFilename($uuid, $format);

        if ($format === 'json') {
            $data = $exportUseCase->exportAsJson($uuid);

            if ($data === null) {
                $this->notFound('Session nicht gefunden');
            }

            header('Content-Type: application/json; charset=utf-8');
            header('Content-Disposition: attachment; filename="' . $filename . '"');
            echo json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
        } else {
            $content = $exportUseCase->exportAsMarkdown($uuid);

            if ($content === null) {
                $this->notFound('Session nicht gefunden');
            }

            header('Content-Type: text/markdown; charset=utf-8');
            header('Content-Disposition: attachment; filename="' . $filename . '"');
            echo $content;
        }
    }
}