<?php
/**
 * Background Worker for AI Invoice Extraction
 * Processes images in the invoice_processing_queue.
 */

declare(strict_types=1);

require_once __DIR__ . '/../bootstrap/init.php';

use App\Services\InvoiceProcessor;

// Prevent multiple instances (Lock file)
$lockFile = STORAGE_PATH . '/logs/process_batches.lock';
$fp = fopen($lockFile, 'c+');
if (!flock($fp, LOCK_EX | LOCK_NB)) {
    exit("Worker already running.\n");
}

echo "Starting Musadaq AI Worker [" . date('Y-m-d H:i:s') . "]\n";

try {
    $db = Database::getInstance();

    while (true) {
        $stmt = $db->prepare("
            SELECT id FROM invoice_processing_queue
            WHERE status = 'pending'
            ORDER BY created_at ASC
            LIMIT 1
        ");
        $stmt->execute();
        $queueId = $stmt->fetchColumn();

        if (!$queueId) {
            echo "Queue empty. Waiting...\n";
            sleep(5);
            continue;
        }

        echo "Processing Queue ID: $queueId\n";
        $success = InvoiceProcessor::processQueueItem((int)$queueId);
        
        if ($success) {
            echo "Success for Queue ID $queueId\n";
        } else {
            echo "Failed for Queue ID $queueId\n";
        }
    }

} catch (Exception $e) {
    echo "Fatal Worker Error: " . $e->getMessage() . "\n";
} finally {
    flock($fp, LOCK_UN);
    fclose($fp);
}