{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/sage/main/json-schema/sage-invoice-schema.json",
  "title": "Sage Sales Invoice",
  "description": "A sales invoice in Sage Accounting representing a customer billing record.",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Unique invoice identifier"
    },
    "displayed_as": {
      "type": "string",
      "description": "Invoice reference number display"
    },
    "date": {
      "type": "string",
      "format": "date",
      "description": "Invoice date"
    },
    "due_date": {
      "type": "string",
      "format": "date",
      "description": "Payment due date"
    },
    "reference": {
      "type": "string",
      "description": "Invoice reference number"
    },
    "status": {
      "type": "object",
      "description": "Current invoice status",
      "properties": {
        "id": {
          "type": "string",
          "enum": ["DRAFT", "SENT", "PAID", "VOID"]
        },
        "displayed_as": {
          "type": "string"
        }
      }
    },
    "contact": {
      "type": "object",
      "description": "Customer contact reference",
      "properties": {
        "id": {"type": "string"},
        "displayed_as": {"type": "string"}
      }
    },
    "line_items": {
      "type": "array",
      "description": "Invoice line items",
      "items": {
        "type": "object",
        "properties": {
          "id": {"type": "string"},
          "description": {"type": "string"},
          "quantity": {"type": "number"},
          "unit_price": {"type": "number"},
          "net_amount": {"type": "number"},
          "tax_amount": {"type": "number"},
          "total_amount": {"type": "number"},
          "ledger_account": {
            "type": "object",
            "properties": {
              "id": {"type": "string"},
              "displayed_as": {"type": "string"}
            }
          },
          "tax_rate": {
            "type": "object",
            "properties": {
              "id": {"type": "string"},
              "displayed_as": {"type": "string"}
            }
          }
        }
      }
    },
    "net_amount": {
      "type": "number",
      "description": "Total pre-tax amount"
    },
    "tax_amount": {
      "type": "number",
      "description": "Total tax amount"
    },
    "total_amount": {
      "type": "number",
      "description": "Total invoice amount including tax"
    },
    "outstanding_amount": {
      "type": "number",
      "description": "Remaining unpaid amount"
    },
    "currency": {
      "type": "object",
      "properties": {
        "id": {"type": "string"},
        "displayed_as": {"type": "string"}
      }
    }
  },
  "required": ["id", "date", "contact", "line_items", "total_amount"]
}