{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://baodan.example/schemas/field-value-v1.json",
  "title": "Insurance FieldValue v1",
  "type": "object",
  "additionalProperties": false,
  "required": ["status", "value", "evidence"],
  "properties": {
    "status": {
      "enum": ["missing", "extracted", "conflict", "confirmed", "derived"]
    },
    "value": {
      "type": ["string", "number", "integer", "boolean", "null"]
    },
    "currency": {
      "type": ["string", "null"],
      "enum": ["USD", "HKD", "CNY", "SGD", "EUR", "GBP", null]
    },
    "unit": {"type": ["string", "null"]},
    "confidence": {"type": ["number", "null"], "minimum": 0, "maximum": 1},
    "evidence": {
      "type": "array",
      "items": {"$ref": "#/$defs/evidenceRef"}
    },
    "derivedBy": {"type": ["string", "null"]},
    "overrideReason": {"type": ["string", "null"], "minLength": 1},
    "conflictCandidates": {
      "type": "array",
      "items": {"type": ["string", "number", "integer", "boolean", "null"]}
    }
  },
  "allOf": [
    {
      "if": {"properties": {"status": {"const": "missing"}}},
      "then": {"properties": {"value": {"type": "null"}}}
    },
    {
      "if": {"properties": {"status": {"const": "derived"}}},
      "then": {"required": ["derivedBy"]}
    },
    {
      "if": {"required": ["overrideReason"]},
      "then": {"properties": {"status": {"const": "confirmed"}}}
    }
  ],
  "$defs": {
    "evidenceRef": {
      "type": "object",
      "additionalProperties": false,
      "required": ["documentId", "pageNumber"],
      "properties": {
        "documentId": {"type": "integer", "minimum": 1},
        "pageNumber": {"type": "integer", "minimum": 1},
        "bbox": {
          "type": ["array", "null"],
          "prefixItems": [
            {"type": "number"}, {"type": "number"},
            {"type": "number"}, {"type": "number"}
          ],
          "minItems": 4,
          "maxItems": 4
        },
        "tableId": {"type": ["string", "null"]},
        "rowId": {"type": ["string", "null"]},
        "columnId": {"type": ["string", "null"]},
        "textHash": {"type": ["string", "null"], "pattern": "^[0-9a-f]{64}$"}
      }
    }
  }
}