{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api.wm.com/schemas/invoice.json",
  "title": "Waste Management Invoice",
  "description": "Schema for a Waste Management invoice including summary fields, line items, and applied fees.",
  "type": "object",
  "required": ["invoiceId", "invoiceDate", "dueDate", "totalAmount", "status"],
  "properties": {
    "invoiceId": {
      "type": "string",
      "description": "Unique invoice identifier."
    },
    "invoiceDate": {
      "type": "string",
      "format": "date",
      "description": "Date the invoice was issued."
    },
    "dueDate": {
      "type": "string",
      "format": "date",
      "description": "Payment due date."
    },
    "totalAmount": {
      "type": "number",
      "description": "Total invoice amount including all fees."
    },
    "status": {
      "type": "string",
      "enum": ["Paid", "Unpaid", "Overdue", "Void"],
      "description": "Payment status of the invoice."
    },
    "lineItems": {
      "type": "array",
      "description": "Individual line items on the invoice.",
      "items": {
        "type": "object",
        "required": ["description", "amount"],
        "properties": {
          "description": {
            "type": "string",
            "description": "Description of the line item."
          },
          "amount": {
            "type": "number",
            "description": "Amount for this line item."
          },
          "serviceId": {
            "type": "string",
            "description": "Service ID this line item relates to."
          }
        }
      }
    },
    "fees": {
      "type": "array",
      "description": "Surcharges and regulatory fees applied to the invoice.",
      "items": {
        "type": "object",
        "required": ["feeType", "amount"],
        "properties": {
          "feeType": {
            "type": "string",
            "enum": ["Fuel Surcharge", "Environmental Fee", "Regulatory Cost Recovery", "State Fee"],
            "description": "Type of fee applied."
          },
          "amount": {
            "type": "number",
            "description": "Amount of this fee."
          }
        }
      }
    }
  }
}