<?php
/**
 * Phase 2 Backfill: Generate hashes for existing invoices
 * Run: php scripts/backfill_hashes.php
 */

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

use App\Core\Database;
use App\Core\Encryption;

$db = Database::getInstance();

echo "═══════════════════════════════════════════\n";
echo "  مُصادَق — Backfill Invoice Hashes\n";
echo "═══════════════════════════════════════════\n\n";

// 1. Fetch all invoices without a hash
$stmt = $db->query("SELECT id, company_id, supplier_tin, invoice_number, invoice_date FROM invoices WHERE invoice_hash IS NULL");
$invoices = $stmt->fetchAll();

if (empty($invoices)) {
    echo "✅ No invoices found needing a hash update.\n";
    exit;
}

echo "📦 Found " . count($invoices) . " invoices to process...\n";

$updated = 0;
$skipped = 0;

foreach ($invoices as $inv) {
    // Decrypt supplier_tin if it's encrypted (assuming it is based on upload logic)
    $rawTin = Encryption::decrypt($inv['supplier_tin'] ?? '') ?: ($inv['supplier_tin'] ?? '');
    
    $invoiceNum  = $inv['invoice_number'] ?? '';
    $invoiceDate = $inv['invoice_date'] ?? '';

    if (empty($rawTin) || empty($invoiceNum) || empty($invoiceDate)) {
        echo "  ⚠️  Skipping invoice [{$inv['id']}]: Missing critical data for hash calculation.\n";
        $skipped++;
        continue;
    }

    // Generate Hash
    $rawHashString = $inv['company_id'] . '_' . $rawTin . '_' . $invoiceNum . '_' . $invoiceDate;
    $invoiceHash = hash('sha256', strtolower($rawHashString));

    try {
        $updateStmt = $db->prepare("UPDATE invoices SET invoice_hash = ? WHERE id = ?");
        $updateStmt->execute([$invoiceHash, $inv['id']]);
        $updated++;
        echo "  ✅ Updated invoice [{$inv['id']}] | Hash: " . substr($invoiceHash, 0, 8) . "...\n";
    } catch (\PDOException $e) {
        if (str_contains($e->getMessage(), 'Duplicate entry')) {
            echo "  🚫 Duplicate hash found for invoice [{$inv['id']}]. Skipping update.\n";
            $skipped++;
        } else {
            echo "  ❌ Failed to update [{$inv['id']}]: " . $e->getMessage() . "\n";
            $skipped++;
        }
    }
}

echo "\n═══════════════════════════════════════════\n";
echo "  Backfill Complete!\n";
echo "  ✅ Updated: {$updated} | ⏭️ Skipped/Failed: {$skipped}\n";
echo "═══════════════════════════════════════════\n";