<?php
declare(strict_types=1);

namespace Esun\SeventeenTrack\Model;

use Magento\Framework\Exception\AuthenticationException;
use Magento\Framework\Exception\InputException;
use Magento\Framework\Serialize\Serializer\Json;
use Psr\Log\LoggerInterface;

class WebhookProcessor
{
    private const MAX_BODY_BYTES = 2097152;

    public function __construct(
        private readonly Config $config,
        private readonly TrackingRepository $tracking,
        private readonly DeliveryStatusUpdater $deliveryStatusUpdater,
        private readonly Json $json,
        private readonly LoggerInterface $logger
    ) {
    }

    /** @return array{event:string,tracking_number:string,status:string,message:string} */
    public function execute(string $rawBody, string $signature): array
    {
        $apiKey = $this->config->getApiKey();
        if (!$this->config->isEnabled() || $apiKey === '') {
            throw new \RuntimeException('17TRACK is disabled or the API key is missing.');
        }
        if ($rawBody === '' || strlen($rawBody) > self::MAX_BODY_BYTES) {
            throw new InputException(__('The 17TRACK webhook body is empty or too large.'));
        }
        $this->verifySignature($rawBody, $signature, $apiKey);

        try {
            $payload = $this->json->unserialize($rawBody);
        } catch (\InvalidArgumentException $exception) {
            throw new InputException(__('The 17TRACK webhook body is not valid JSON.'), $exception);
        }
        if (!is_array($payload) || !is_array($payload['data'] ?? null)) {
            throw new InputException(__('The 17TRACK webhook payload is missing data.'));
        }

        $event = (string)($payload['event'] ?? '');
        $data = $payload['data'];
        $number = trim((string)($data['number'] ?? ''));
        if ($number === '') {
            throw new InputException(__('The 17TRACK webhook payload is missing a tracking number.'));
        }

        if ($event === 'TRACKING_UPDATED') {
            $orderIds = $this->tracking->saveTrackingInfo(
                $number,
                $data,
                $this->json->serialize($data)
            );
            if ($orderIds === []) {
                $this->logger->warning('Ignored a 17TRACK webhook for an unknown tracking number.', [
                    'tracking_number' => $number,
                ]);
                return [
                    'event' => $event,
                    'tracking_number' => $number,
                    'status' => 'ignored',
                    'message' => 'Unknown tracking number.',
                ];
            }
            $this->deliveryStatusUpdater->execute($orderIds);
            return [
                'event' => $event,
                'tracking_number' => $number,
                'status' => 'success',
                'message' => 'Tracking update processed.',
            ];
        }

        if ($event === 'TRACKING_STOPPED') {
            $this->tracking->saveStoppedInfo($number, $this->json->serialize($data));
            return [
                'event' => $event,
                'tracking_number' => $number,
                'status' => 'success',
                'message' => 'Tracking stopped event processed.',
            ];
        }

        $this->logger->info('Ignored an unsupported 17TRACK webhook event.', [
            'event' => $event,
            'tracking_number' => $number,
        ]);
        return [
            'event' => $event,
            'tracking_number' => $number,
            'status' => 'ignored',
            'message' => 'Unsupported webhook event.',
        ];
    }

    private function verifySignature(string $rawBody, string $signature, string $apiKey): void
    {
        $signature = strtolower(trim($signature));
        if (!preg_match('/^[a-f0-9]{64}$/', $signature)) {
            throw new AuthenticationException(__('The 17TRACK webhook signature is missing or invalid.'));
        }
        $expected = hash('sha256', $rawBody . '/' . $apiKey);
        if (!hash_equals($expected, $signature)) {
            throw new AuthenticationException(__('The 17TRACK webhook signature is missing or invalid.'));
        }
    }
}