{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "german-ocr-3/schemas/letter.json",
  "title": "GermanOCR3 Letter (Brief)",
  "description": "Schema fuer deutsche Geschaefts- oder Behoerdenbriefe (DIN-5008-naher Aufbau).",
  "type": "object",
  "additionalProperties": false,
  "required": ["document_type", "language", "subject", "body"],
  "properties": {
    "document_type": {"const": "letter"},
    "language": {"type": "string", "default": "de"},

    "sender": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "properties": {
        "name": {"type": ["string", "null"]},
        "address": {"type": ["string", "null"]},
        "email": {"type": ["string", "null"]},
        "phone": {"type": ["string", "null"]}
      }
    },
    "recipient": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "properties": {
        "name": {"type": ["string", "null"]},
        "address": {"type": ["string", "null"]}
      }
    },

    "place": {"type": ["string", "null"]},
    "date": {"description": "Briefdatum YYYY-MM-DD", "type": ["string", "null"]},
    "reference": {
      "description": "Aktenzeichen / Ihr Zeichen / Unser Zeichen.",
      "type": ["object", "null"],
      "additionalProperties": false,
      "properties": {
        "ihr_zeichen": {"type": ["string", "null"]},
        "ihre_nachricht_vom": {"type": ["string", "null"]},
        "unser_zeichen": {"type": ["string", "null"]},
        "unsere_nachricht_vom": {"type": ["string", "null"]}
      }
    },

    "subject": {"type": ["string", "null"]},
    "salutation": {"type": ["string", "null"]},
    "body": {
      "description": "Kompletter Brieftext, Absaetze mit \\n\\n getrennt.",
      "type": ["string", "null"]
    },
    "closing": {"type": ["string", "null"]},
    "signatory": {"type": ["string", "null"]},
    "enclosures": {"type": "array", "items": {"type": "string"}, "default": []},

    "deadlines_mentioned": {
      "type": "array",
      "default": [],
      "items": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "date": {"type": ["string", "null"]},
          "context": {"type": ["string", "null"]}
        }
      }
    },

    "raw_text": {"type": ["string", "null"]},
    "confidence": {"type": ["number", "null"], "minimum": 0, "maximum": 1},
    "notes": {"type": "array", "items": {"type": "string"}, "default": []}
  }
}