<?php

namespace App\Jobs;

use App\Events\NewEmailReceived;
use App\Models\Email;
use App\Models\EmailBody;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\Middleware\WithoutOverlapping;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Log;
use MongoDB\Laravel\Collection;

class ProcessIncomingEmail implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    /**
     * The number of times the job may be attempted.
     */
    public int $tries = 3;

    /**
     * The backoff strategy (seconds) between retries.
     *
     * @var array<int, int>
     */
    public array $backoff = [5, 15, 30];

    /**
     * Create a new job instance.
     *
     * @param  array<string, mixed>  $payload  The validated webhook payload.
     */
    public function __construct(
        public array $payload,
    ) {
        $this->onQueue('emails');
        $this->onConnection('redis');
    }

    /**
     * Get the middleware the job should pass through.
     *
     * @return array<int, object>
     */
    public function middleware(): array
    {
        return [
            (new WithoutOverlapping($this->payload['hash']))->dontRelease(),
        ];
    }

    /**
     * Execute the job.
     */
    public function handle(): void
    {
        $metadata = $this->payload['metadata'];
        $bodyText = $this->payload['bodyText'] ?? null;
        $bodyHtml = $this->payload['bodyHtml'] ?? null;

        $preview = $this->generatePreview($bodyText, $bodyHtml);

        $email = Email::updateOrCreate(
            ['unique_id_hash' => $this->payload['hash']],
            [
                'recipient_email' => $metadata['recipientEmail'],
                'recipient_name' => $metadata['recipientName'] ?? '',
                'sender_email' => $metadata['senderEmail'],
                'sender_name' => $metadata['senderName'] ?? '',
                'domain' => $metadata['domain'],
                'subject' => $metadata['subject'] ?? '',
                'preview' => $preview,
                'attachments_json' => $metadata['attachments'] ?? [],
                'attachment_size' => $metadata['attachmentSize'] ?? 0,
                'received_at' => $metadata['received_at'],
            ]
        );

        EmailBody::updateOrCreate(
            ['unique_id_hash' => $this->payload['hash']],
            [
                'body_text' => $bodyText,
                'body_html' => $bodyHtml,
            ]
        );

        // Track analytics for receiving email
        $mailbox = \App\Models\Mailbox::where('address', $email->recipient_email)->first();

        TrackAnalytics::dispatch(
            eventType: 'email_received',
            mailboxHash: $mailbox?->mailbox_hash ?? 'unknown',
            domainHash: $mailbox?->domain_hash ?? 'unknown',
            metadata: [
                'email_id' => $email->id,
                'sender' => $email->sender_email,
                'recipient' => $email->recipient_email,
                'attachment_count' => count($metadata['attachments'] ?? []),
                'found_mailbox' => $mailbox !== null,
            ],
            ipAddress: '0.0.0.0', // Server-side event
            userAgent: 'MailOps/IncomingWorker'
        );

        $this->ensureTtlIndex();

        NewEmailReceived::dispatch($email);
    }

    /**
     * Generate an excerpt from the email body for the preview column.
     *
     * Prefers body_text. Falls back to body_html with tags stripped.
     */
    private function generatePreview(?string $bodyText, ?string $bodyHtml): string
    {
        if (! empty($bodyText)) {
            return mb_substr(trim($bodyText), 0, 500);
        }

        if (! empty($bodyHtml)) {
            // Replace all HTML tags with spaces to prevent words from running together
            $html = preg_replace('/<[^>]*>/', ' ', $bodyHtml);

            // Decode HTML entities (e.g. &nbsp;, &amp;)
            $decoded = html_entity_decode($html ?? '', ENT_QUOTES | ENT_HTML5, 'UTF-8');

            // Collapse multiple spaces into a single space
            $stripped = preg_replace('/\s+/', ' ', $decoded);

            return mb_substr(trim($stripped ?? ''), 0, 500);
        }

        return '';
    }

    /**
     * Ensure the MongoDB TTL index exists on the `recent_email_bodies` collection.
     *
     * Uses a cache flag to avoid checking on every job execution.
     */
    private function ensureTtlIndex(): void
    {
        Cache::rememberForever('mongodb_ttl_index_ensured', function () {
            $ttlSeconds = config('services.mailops.email_body_ttl_seconds', 259200);

            EmailBody::raw(function ($collection) use ($ttlSeconds) {
                /* @var \MongoDB\Collection $collection */
                $collection->createIndex(
                    ['created_at' => 1],
                    ['expireAfterSeconds' => $ttlSeconds, 'name' => 'ttl_created_at']
                );
            });

            return true;
        });
    }

    /**
     * Handle a job failure.
     */
    public function failed(?\Throwable $exception): void
    {
        Log::error('ProcessIncomingEmail failed', [
            'hash' => $this->payload['hash'] ?? 'unknown',
            'error' => $exception?->getMessage(),
        ]);
    }
}