دليل التكامل الشامل مع منظومة الفاتورة الإلكترونية المصرية 2026:
الربط البرمجي، خوارزمية التسلسل التام، وتجنب غرامات 100,000 ج.م

const crypto = require('crypto');

/**
 * ETA Canonical Serialization Algorithm (Egyptian Tax Authority)
 * Recursively serializes JSON payload for SHA-256 signing.
 */
function serializeForEta(obj) {
  let serialized = '';
  if (Array.isArray(obj)) {
    for (const item of obj) {
      serialized += serializeForEta(item);
    }
  } else if (obj !== null && typeof obj === 'object') {
    // Sort keys alphabetically
    const sortedKeys = Object.keys(obj).sort();
    for (const key of sortedKeys) {
      if (key === 'signatures') continue; // exclude signature block
      serialized += `"${key.toUpperCase()}"`;
      serialized += serializeForEta(obj[key]);
    }
  } else {
    // Primitive values
    serialized += `"${String(obj)}"`;
  }
  return serialized;
}

function calculateEtaHash(invoicePayload) {
  const canonicalString = serializeForEta(invoicePayload);
  const hash = crypto.createHash('sha256').update(canonicalString, 'utf8').digest('hex');
  return { canonicalString, hash };
}

module.exports = { serializeForEta, calculateEtaHash };

{
  "issuer": {
    "address": {
      "branchID": "0",
      "country": "EG",
      "governate": "Cairo",
      "regionCity": "Maadi",
      "streetName": "Road 9",
      "buildingNumber": "42"
    },
    "type": "B",
    "id": "100234567",
    "name": "شركة أومني تاكس لتقنية المعلومات ش.م.م"
  },
  "receiver": {
    "address": {
      "country": "EG",
      "governate": "Giza",
      "regionCity": "Dokki",
      "streetName": "Tahrir St",
      "buildingNumber": "101"
    },
    "type": "B",
    "id": "300456789",
    "name": "شركة التجارة السريعة ذ.م.م"
  },
  "documentType": "I",
  "documentTypeVersion": "1.0",
  "dateTimeIssued": "2026-09-12T10:00:00Z",
  "taxpayerActivityCode": "6201",
  "internalID": "INV-2026-0045",
  "invoiceLines": [
    {
      "description": "استشارات وتطوير أنظمة الامتثال الضريبي",
      "itemType": "EGS",
      "itemCode": "EG-100234567-SRV01",
      "unitType": "EA",
      "quantity": 1,
      "unitValue": {
        "currencySold": "EGP",
        "amountEGP": 25000.00
      },
      "salesTotal": 25000.00,
      "total": 27750.00,
      "valueDifference": 0.00,
      "totalTaxableFees": 0.00,
      "netTotal": 25000.00,
      "itemsDiscount": 0.00,
      "taxableItems": [
        {
          "taxType": "T1",
          "amount": 3500.00,
          "subType": "V009",
          "rate": 14.00
        },
        {
          "taxType": "T4",
          "amount": 750.00,
          "subType": "W002",
          "rate": 3.00
        }
      ]
    }
  ],
  "totalSalesAmount": 25000.00,
  "totalDiscountAmount": 0.00,
  "netAmount": 25000.00,
  "taxTotals": [
    {
      "taxType": "T1",
      "amount": 3500.00
    },
    {
      "taxType": "T4",
      "amount": 750.00
    }
  ],
  "totalAmount": 27750.00,
  "extraDiscountAmount": 0.00,
  "totalItemsDiscountAmount": 0.00,
  "signatures": [
    {
      "signatureType": "I",
      "value": "MIIK/gYJKoZIhvcNAQcCoIIK7zCCCusCAQExDTALBglghkgBZQMEAgEwgg..."
    }
  ]
}