{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Simple Invoice",
  "type": "object",
  "properties": {
    "invoiceId": {
      "type": "string",
      "title": "Invoice ID",
      "description": "A unique identifier for the invoice."
    },
    "dateIssued": {
      "type": "string",
      "format": "date",
      "title": "Date Issued",
      "description": "The date the invoice was issued."
    },
    "dueDate": {
      "type": "string",
      "format": "date",
      "title": "Due Date",
      "description": "The date the invoice payment is due."
    },
    "billingDetails": {
      "type": "object",
      "title": "Billing Details",
      "properties": {
        "name": {
          "type": "string",
          "title": "Name",
          "description": "Name of the individual or company being billed."
        },
        "address": {
          "type": "string",
          "title": "Address",
          "description": "Billing address."
        },
        "email": {
          "type": "string",
          "format": "email",
          "title": "Email",
          "description": "Email address of the individual or company being billed."
        },
        "phone": {
          "type": "string",
          "title": "Phone",
          "description": "Phone number of the individual or company being billed."
        }
      },
      "required": [
        "name",
        "address"
      ]
    },
    "items": {
      "type": "array",
      "title": "Items",
      "description": "List of items or services included in the invoice.",
      "items": {
        "type": "object",
        "title": "Item",
        "properties": {
          "description": {
            "type": "string",
            "title": "Description",
            "description": "Description of the item or service."
          },
          "quantity": {
            "type": "number",
            "title": "Quantity",
            "description": "Quantity of the item or service."
          },
          "unitPrice": {
            "type": "number",
            "title": "Unit Price",
            "description": "Price per unit of the item or service."
          },
          "total": {
            "type": "number",
            "title": "Total",
            "description": "Total price for this item or service (quantity * unit price)."
          }
        },
        "required": [
          "description",
          "quantity",
          "unitPrice",
          "total"
        ]
      }
    },
    "subTotal": {
      "type": "number",
      "title": "Subtotal",
      "description": "The subtotal amount for all items before taxes and discounts."
    },
    "tax": {
      "anyOf": [
        {
          "type": "number"
        },
        {
          "type": "null"
        }
      ],
      "title": "Tax",
      "description": "The tax amount applied to the invoice."
    },
    "total": {
      "type": "number",
      "title": "Total",
      "description": "The total amount due for the invoice."
    },
    "notes": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "title": "Notes",
      "description": "Additional notes or comments on the invoice."
    }
  },
  "required": [
    "invoiceId",
    "dateIssued",
    "billingDetails",
    "items",
    "subTotal",
    "total"
  ]
}