{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Tax Knowledge Graph Schema",
  "definitions": {
    "temporal_properties": {
      "type": "object",
      "properties": {
        "valid_from": { "type": "string", "format": "date-time" },
        "valid_to": { "type": "string", "format": "date-time" },
        "asserted_at": { "type": "string", "format": "date-time" },
        "retracted_at": { "type": ["string", "null"], "format": "date-time" },
        "source": { "type": "string" },
        "extractor_version": { "type": "string" }
      },
      "required": ["valid_from", "asserted_at", "source", "extractor_version"]
    },
    "provenance": {
      "type": "object",
      "properties": {
        "doc_id": { "type": "string" },
        "page": { "type": "integer", "minimum": 1 },
        "bbox": {
          "type": "object",
          "properties": {
            "x": { "type": "number" },
            "y": { "type": "number" },
            "width": { "type": "number" },
            "height": { "type": "number" }
          },
          "required": ["x", "y", "width", "height"]
        },
        "text_hash": { "type": "string" },
        "ocr_confidence": { "type": "number", "minimum": 0, "maximum": 1 }
      },
      "required": ["doc_id", "page", "text_hash"]
    }
  },
  "oneOf": [
    {
      "title": "TaxpayerProfile",
      "type": "object",
      "properties": {
        "node_type": { "const": "TaxpayerProfile" },
        "taxpayer_id": { "type": "string" },
        "type": { "enum": ["Individual", "Partnership", "Company"] },
        "residence": { "type": "string" },
        "contact": {
          "type": "object",
          "properties": {
            "email": { "type": "string", "format": "email" },
            "phone": { "type": "string" },
            "address": { "type": "string" }
          }
        },
        "tax_years": { "type": "array", "items": { "type": "string" } },
        "utr": { "type": "string", "pattern": "^[0-9]{10}$" },
        "ni_number": {
          "type": "string",
          "pattern": "^[A-CEGHJ-PR-TW-Z]{2}\\d{6}[A-D]$"
        }
      },
      "allOf": [{ "$ref": "#/definitions/temporal_properties" }],
      "required": ["node_type", "taxpayer_id", "type"]
    },
    {
      "title": "TaxYear",
      "type": "object",
      "properties": {
        "node_type": { "const": "TaxYear" },
        "label": { "type": "string" },
        "start_date": { "type": "string", "format": "date" },
        "end_date": { "type": "string", "format": "date" },
        "jurisdiction_ref": { "type": "string" }
      },
      "allOf": [{ "$ref": "#/definitions/temporal_properties" }],
      "required": [
        "node_type",
        "label",
        "start_date",
        "end_date",
        "jurisdiction_ref"
      ]
    },
    {
      "title": "Document",
      "type": "object",
      "properties": {
        "node_type": { "const": "Document" },
        "doc_id": { "type": "string" },
        "kind": {
          "enum": [
            "bank_statement",
            "invoice",
            "receipt",
            "p_and_l",
            "balance_sheet",
            "payslip",
            "dividend_voucher",
            "property_statement",
            "prior_return",
            "letter",
            "certificate"
          ]
        },
        "source": { "type": "string" },
        "mime": { "type": "string" },
        "date_range": {
          "type": "object",
          "properties": {
            "start": { "type": "string", "format": "date" },
            "end": { "type": "string", "format": "date" }
          }
        },
        "checksum": { "type": "string" },
        "file_size": { "type": "integer" },
        "pages": { "type": "integer", "minimum": 1 }
      },
      "allOf": [{ "$ref": "#/definitions/temporal_properties" }],
      "required": ["node_type", "doc_id", "kind", "source", "checksum"]
    },
    {
      "title": "Evidence",
      "type": "object",
      "properties": {
        "node_type": { "const": "Evidence" },
        "snippet_id": { "type": "string" },
        "doc_ref": { "type": "string" },
        "page": { "type": "integer", "minimum": 1 },
        "bbox": {
          "type": "object",
          "properties": {
            "x": { "type": "number" },
            "y": { "type": "number" },
            "width": { "type": "number" },
            "height": { "type": "number" }
          },
          "required": ["x", "y", "width", "height"]
        },
        "text_hash": { "type": "string" },
        "ocr_confidence": { "type": "number", "minimum": 0, "maximum": 1 },
        "extracted_text": { "type": "string" }
      },
      "allOf": [{ "$ref": "#/definitions/temporal_properties" }],
      "required": [
        "node_type",
        "snippet_id",
        "doc_ref",
        "page",
        "bbox",
        "text_hash"
      ]
    },
    {
      "title": "IncomeItem",
      "type": "object",
      "properties": {
        "node_type": { "const": "IncomeItem" },
        "type": {
          "enum": [
            "employment",
            "self_employment",
            "property",
            "dividend",
            "interest",
            "other"
          ]
        },
        "gross": { "type": "number" },
        "net": { "type": "number" },
        "tax_withheld": { "type": "number" },
        "period_start": { "type": "string", "format": "date" },
        "period_end": { "type": "string", "format": "date" },
        "currency": { "type": "string", "pattern": "^[A-Z]{3}$" },
        "description": { "type": "string" }
      },
      "allOf": [
        { "$ref": "#/definitions/temporal_properties" },
        { "$ref": "#/definitions/provenance" }
      ],
      "required": ["node_type", "type", "gross", "currency"]
    },
    {
      "title": "ExpenseItem",
      "type": "object",
      "properties": {
        "node_type": { "const": "ExpenseItem" },
        "type": { "enum": ["business", "property", "capital", "personal"] },
        "amount": { "type": "number" },
        "category": { "type": "string" },
        "capitalizable_flag": { "type": "boolean" },
        "currency": { "type": "string", "pattern": "^[A-Z]{3}$" },
        "description": { "type": "string" },
        "allowable": { "type": "boolean" }
      },
      "allOf": [
        { "$ref": "#/definitions/temporal_properties" },
        { "$ref": "#/definitions/provenance" }
      ],
      "required": ["node_type", "type", "amount", "currency"]
    }
  ]
}