{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://concert.foundation/signet/v0.1/invoice.schema.json",
  "title": "Invoice",
  "description": "An invoice, fully aligned to EN 16931 so it is convertible to Peppol BIS Billing / UBL Invoice / Factur-X. This alignment is what makes a SIGNET network natively compliant with the EU ViDA cross-border e-invoicing mandate.",
  "$comment": "Field $comment values cite EN 16931 Business Terms (BT) and Business Groups (BG).",
  "type": "object",
  "required": [
    "id",
    "issueDate",
    "currency",
    "seller",
    "buyer",
    "lines",
    "taxTotal",
    "payableAmount"
  ],
  "additionalProperties": false,
  "properties": {
    "@context": {
      "type": [
        "string",
        "object",
        "array"
      ]
    },
    "type": {
      "const": "Invoice"
    },
    "id": {
      "$comment": "EN 16931 BT-1 Invoice number",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Identifier"
        }
      ]
    },
    "invoiceTypeCode": {
      "type": "string",
      "$comment": "EN 16931 BT-3 Invoice type code (e.g. 380 commercial invoice)"
    },
    "issueDate": {
      "type": "string",
      "format": "date-time",
      "$comment": "EN 16931 BT-2 Invoice issue date"
    },
    "currency": {
      "type": "string",
      "pattern": "^[A-Z]{3}$",
      "$comment": "EN 16931 BT-5 Invoice currency code (ISO 4217)"
    },
    "contract": {
      "$comment": "EN 16931 BT-12 Contract reference",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Identifier"
        }
      ]
    },
    "order": {
      "$comment": "EN 16931 BT-13 Purchase order reference",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Identifier"
        }
      ]
    },
    "settles": {
      "$comment": "SIGNET-original (not an EN 16931 BT). The Obligation(s) this invoice settles. Omitted on Peppol BIS projection.",
      "type": "array",
      "items": {
        "$ref": "definitions.schema.json#/definitions/Identifier"
      }
    },
    "seller": {
      "$comment": "EN 16931 BG-4 SELLER (BT-27 seller name resolved via Party)",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Identifier"
        }
      ]
    },
    "buyer": {
      "$comment": "EN 16931 BG-7 BUYER (BT-44 buyer name resolved via Party)",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Identifier"
        }
      ]
    },
    "lines": {
      "type": "array",
      "minItems": 1,
      "items": {
        "$ref": "definitions.schema.json#/definitions/InvoiceLine"
      },
      "$comment": "EN 16931 BG-25 INVOICE LINE"
    },
    "vatBreakdown": {
      "type": "array",
      "items": {
        "$ref": "definitions.schema.json#/definitions/VatBreakdown"
      },
      "$comment": "EN 16931 BG-23 VAT BREAKDOWN"
    },
    "lineExtensionTotal": {
      "$comment": "EN 16931 BT-106 Sum of invoice line net amount",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Value"
        }
      ]
    },
    "taxExclusiveTotal": {
      "$comment": "EN 16931 BT-109 Invoice total amount without VAT",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Value"
        }
      ]
    },
    "taxTotal": {
      "$comment": "EN 16931 BT-110 Invoice total VAT amount",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Value"
        }
      ]
    },
    "taxInclusiveTotal": {
      "$comment": "EN 16931 BT-112 Invoice total amount with VAT",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Value"
        }
      ]
    },
    "payableAmount": {
      "$comment": "EN 16931 BT-115 Amount due for payment",
      "allOf": [
        {
          "$ref": "definitions.schema.json#/definitions/Value"
        }
      ]
    },
    "paymentDueDate": {
      "type": "string",
      "format": "date-time",
      "$comment": "EN 16931 BT-9 Payment due date"
    },
    "paymentTerms": {
      "type": "string",
      "$comment": "EN 16931 BT-20 Payment terms"
    }
  }
}