<?php

declare(strict_types=1);

namespace OCA\EducAI\Talk;

use Exception;
use OCP\Http\Client\IClientService;
use OCP\IURLGenerator;
use OCA\EducAI\Service\SettingsService;
use Psr\Log\LoggerInterface;

/**
 * Response sink that posts through the signed Talk bot HTTP API.
 *
 * This is the legacy webhook transport and also the only way to deliver
 * out-of-context replies (rate-limit queue, test rooms) where no native
 * BotInvokeEvent is in flight. Every send is an HMAC-signed request back into
 * the same Nextcloud instance, so it should not be used for the normal
 * native-event path.
 */
class HttpReplySink implements ResponseSink {
	private IClientService $clientService;
	private SettingsService $settingsService;
	private IURLGenerator $urlGenerator;
	private LoggerInterface $logger;
	private string $roomToken = '';

	public function __construct(
		IClientService $clientService,
		SettingsService $settingsService,
		IURLGenerator $urlGenerator,
		LoggerInterface $logger
	) {
		$this->clientService = $clientService;
		$this->settingsService = $settingsService;
		$this->urlGenerator = $urlGenerator;
		$this->logger = $logger;
	}

	public function bindRoom(string $roomToken): void {
		$this->roomToken = $roomToken;
	}

	public function send(string $message, int|bool $replyTo = false, bool $silent = false): bool {
		try {
			if (trim($message) === '') {
				$this->logger->debug('Skipping empty message - not sending to Talk');
				return true; // Return true to not trigger error handling.
			}

			$secret = $this->settingsService->getWebhookSecret();
			if (empty($secret)) {
				$this->logger->error('Cannot send reply: webhook secret not configured');
				return false;
			}

			$replyToId = is_int($replyTo) ? $replyTo : 0;

			// Get Nextcloud base URL
			$baseUrl = $this->urlGenerator->getAbsoluteURL('');
			$endpoint = $baseUrl . 'ocs/v2.php/apps/spreed/api/v1/bot/' . $this->roomToken . '/message';

			// Prepare request body
			$requestBody = [
				'message' => $message,
			];

			if ($replyToId > 0) {
				$requestBody['replyTo'] = $replyToId;
			}

			// Add unique reference ID
			$random = bin2hex(random_bytes(32));
			$requestBody['referenceId'] = sha1($random);

			// Convert to JSON
			$jsonBody = json_encode($requestBody);

			// Create signature (HMAC of random + message)
			$hash = hash_hmac('sha256', $random . $message, $secret);

			$this->logger->debug('Sending reply to Talk', [
				'endpoint' => $endpoint,
				'room_token' => $this->roomToken,
				'message_length' => strlen($message),
				'reply_to' => $replyToId,
			]);

			$client = $this->clientService->newClient();

			$response = $client->post($endpoint, [
				'headers' => [
					'Content-Type' => 'application/json',
					'OCS-APIRequest' => 'true',
					'X-Nextcloud-Talk-Bot-Random' => $random,
					'X-Nextcloud-Talk-Bot-Signature' => $hash,
				],
				'body' => $jsonBody,
				'timeout' => 10,
			]);

			$statusCode = $response->getStatusCode();
			if ($statusCode >= 200 && $statusCode < 300) {
				$this->logger->info('Successfully sent reply to Talk', [
					'room_token' => $this->roomToken,
				]);
				return true;
			}

			$this->logger->warning('Unexpected status code from Talk API', [
				'status_code' => $statusCode,
				'response_body_length' => strlen((string)$response->getBody()),
			]);
			return false;

		} catch (Exception $e) {
			$this->logger->error('Failed to send reply to Talk: ' . $e->getMessage(), [
				'exception' => $e,
				'room_token' => $this->roomToken,
			]);
			return false;
		}
	}

	public function react(string $emoji): void {
		// The signed bot API supports reactions, but the current pipeline does
		// not emit reactions. Kept as a no-op to satisfy the abstraction.
	}

	public function supportsStreaming(): bool {
		return true;
	}
}