<?php
declare(strict_types=1);

namespace App\Services;

use App\Core\Database;
use App\Core\AI;
use App\Core\Encryption;
use App\Middleware\QuotaMiddleware;
use App\Services\NotificationService;
use Exception;

class InvoiceProcessor
{
    /**
     * Processes a single invoice queue item by its ID.
     */
    public static function processQueueItem(int $queueId): bool
    {
        $db = Database::getInstance();

        $stmt = $db->prepare("
            SELECT q.*, b.tenant_id, b.company_id, b.uploaded_by, b.total_images 
            FROM invoice_processing_queue q
            JOIN invoice_batches b ON q.batch_id = b.id COLLATE utf8mb4_unicode_ci
            WHERE q.id = ? AND q.status = 'pending'
        ");
        $stmt->execute([$queueId]);
        $item = $stmt->fetch();

        if (!$item) {
            return false;
        }

        $batchId = $item['batch_id'];
        $tenantId = $item['tenant_id'];
        $companyId = $item['company_id'];
        $userId = $item['uploaded_by'];
        $imagePath = $item['image_path'];

        // Mark as processing
        $db->prepare("UPDATE invoice_processing_queue SET status = 'processing' WHERE id = ?")->execute([$queueId]);

        if (!file_exists($imagePath)) {
            $db->prepare("UPDATE invoice_processing_queue SET status = 'failed', error_message = 'File not found' WHERE id = ?")->execute([$queueId]);
            return false;
        }

        $mimeType = mime_content_type($imagePath) ?: 'image/jpeg';
        $fileContent = file_get_contents($imagePath);
        $base64Data = base64_encode($fileContent);

        $extracted = AI::extractInvoiceData($base64Data, $mimeType);

        if (!$extracted) {
            $db->prepare("UPDATE invoice_processing_queue SET status = 'failed', error_message = 'AI failed to extract' WHERE id = ?")->execute([$queueId]);
            return false;
        }

        try {
            $db->beginTransaction();
            $invoiceId = vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex(random_bytes(16)), 4));
            
            $supplierTin = $extracted['supplier']['tin'] ?? '';
            $invoiceNum = $extracted['invoice_number'] ?? '';
            $invoiceDate = $extracted['invoice_date'] ?? '';
            $validDate = (!empty($invoiceDate) && strtotime($invoiceDate)) ? $invoiceDate : null;

            $stmt = $db->prepare("
                INSERT INTO invoices (
                    id, tenant_id, company_id, uploaded_by, original_file_path, status,
                    invoice_number, invoice_date, invoice_type, invoice_category,
                    supplier_tin, supplier_name, supplier_address,
                    buyer_tin, buyer_name, buyer_national_id,
                    subtotal, tax_amount, discount_total, grand_total, currency_code,
                    created_at
                ) VALUES (
                    ?, ?, ?, ?, ?, 'extracted',
                    ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
                    ?, ?, ?, ?, ?,
                    NOW()
                )
            ");

            $stmt->execute([
                $invoiceId, $tenantId, $companyId, $userId, $imagePath,
                $invoiceNum, $validDate, $extracted['invoice_type'] ?? 'cash', $extracted['invoice_category'] ?? 'simplified',
                Encryption::encrypt($supplierTin), Encryption::encrypt($extracted['supplier']['name'] ?? ''), Encryption::encrypt($extracted['supplier']['address'] ?? ''),
                Encryption::encrypt($extracted['buyer']['tin'] ?? ''), Encryption::encrypt($extracted['buyer']['name'] ?? ''), Encryption::encrypt($extracted['buyer']['national_id'] ?? ''),
                $extracted['subtotal'] ?? 0, $extracted['tax_amount'] ?? 0, $extracted['discount_total'] ?? 0, $extracted['grand_total'] ?? 0, $extracted['currency_code'] ?? 'JOD'
            ]);

            // Save Lines
            if (!empty($extracted['lines'])) {
                $lineStmt = $db->prepare("INSERT INTO invoice_lines (id, invoice_id, line_number, description, quantity, unit_price, tax_rate, line_total) VALUES (?,?,?,?,?,?,?,?)");
                foreach ($extracted['lines'] as $idx => $line) {
                    $lineStmt->execute([
                        vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex(random_bytes(16)), 4)),
                        $invoiceId, $line['line_number'] ?? ($idx + 1), $line['description'] ?? '', $line['quantity'] ?? 1, $line['unit_price'] ?? 0, $line['tax_rate'] ?? 0, $line['line_total'] ?? $line['total_amount'] ?? 0
                    ]);
                }
            }

            $db->prepare("UPDATE invoice_processing_queue SET status = 'done', invoice_id = ?, processed_at = NOW() WHERE id = ?")->execute([$invoiceId, $queueId]);
            $db->prepare("UPDATE invoice_batches SET processed_images = processed_images + 1 WHERE id = ?")->execute([$batchId]);

            QuotaMiddleware::incrementInvoiceUsage($tenantId);

            $db->commit();

            // Progress Push
            try {
                $stmt = $db->prepare("SELECT total_images, processed_images, uploaded_by FROM invoice_batches WHERE id = ?");
                $stmt->execute([$batchId]);
                $currentBatch = $stmt->fetch();
                if ($currentBatch) {
                    $notifier = new NotificationService();
                    $notifier->sendDataNotification($currentBatch['uploaded_by'], [
                        'type' => 'batch_progress',
                        'batch_id' => $batchId,
                        'processed' => $currentBatch['processed_images'],
                        'total' => $currentBatch['total_images']
                    ]);
                }
            } catch (\Exception $pushErr) {}

        } catch (\Exception $e) {
            if ($db->inTransaction()) {
                $db->rollBack();
            }
            try {
                $db->prepare("UPDATE invoice_processing_queue SET status = 'failed', error_message = ? WHERE id = ?")->execute([$e->getMessage(), $queueId]);
            } catch (\Exception $e2) {}
            return false;
        }

        // Check if batch complete
        self::checkBatchCompletion($batchId);

        return true;
    }

    public static function checkBatchCompletion(string $batchId): void
    {
        $db = Database::getInstance();
        $stmt = $db->prepare("SELECT total_images, processed_images, uploaded_by FROM invoice_batches WHERE id = ?");
        $stmt->execute([$batchId]);
        $batch = $stmt->fetch();
        if ($batch && $batch['processed_images'] >= $batch['total_images']) {
            $db->prepare("UPDATE invoice_batches SET status = 'done', completed_at = NOW() WHERE id = ?")->execute([$batchId]);
            
            try {
                $notifier = new NotificationService();
                $title = "اكتملت معالجة الدفعة";
                $body = "تمت معالجة جميع الفواتير بنجاح. يمكنك الآن مراجعتها وتدقيقها في لوحة التحكم قبل اعتمادها.";
                $notifier->sendNotification($batch['uploaded_by'], $title, $body, ['batch_id' => $batchId]);
            } catch (\Exception $e) {}
        }
    }
}