{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "http://product-information-graph.org/schema/2026-05-08/jsonld/Entity.json",
  "title": "CASCaRA Entity Schema for JSON-LD",
  "description": "Validates <strong>Entity</strong> class definitions for individual information objects. Configures which properties (cas:enumeratedProperty) and which outgoing links are allowed (cas:enumeratedTargetLink). Entities classify primary information objects such as Requirements, Components and Diagrams in a systems engineering context. Supports specialization hierarchies via cas:specializes and optional visual representation via cas:icon.",
  "type": "object",
  "properties": {
    "@id": {
      "$ref": "#/$defs/idString"
    },
    "@type": {
      "type": "string",
      "enum": [ "owl:Class" ]
    },
    "cas:specializes": {
      "$ref": "#/$defs/idObject"
    },
    "cas:itemType": {
      "type": "object",
      "required": [ "@id" ],
      "properties": {
        "@id": {
          "type": "string",
          "enum": [ "cas:Entity" ],
          "description": "The CASCaRA metamodel item type for cas:Entity"
        }
      },
      "additionalProperties": false
    },
    "cas:revision": {
      "type": "string",
      "description": "Revision identifier for version control"
    },
    "cas:priorRevision": {
      "type": "array",
      "description": "Array of prior revision identifiers",
      "maxItems": 2,
      "items": {
        "type": "string"
      }
    },
    "dcterms:modified": {
      "type": "string",
      "format": "date-time",
      "description": "ISO 8601 timestamp of last modification"
    },
    "dcterms:creator": {
      "type": "string",
      "description": "Creator/author of this relationship instance"
    },
    "dcterms:title": {
      "type": "array",
      "minItems": 1,
      "items": {
        "$ref": "#/$defs/languageValue"
      }
    },
    "dcterms:description": {
      "type": "array",
      "minItems": 1,
      "items": {
        "$ref": "#/$defs/languageValue"
      }
    },
    "skos:definition": {
      "type": "array",
      "minItems": 1,
      "items": {
        "$ref": "#/$defs/languageValue"
      }
    },
    "cas:enumeratedProperty": {
      "type": "array",
      "description": "Array of Property class references that can be used with this Entity",
      "items": {
        "$ref": "#/$defs/idObject"
      }
    },
    "cas:enumeratedTargetLink": {
      "type": "array",
      "description": "Array of Link class references that can be used as outgoing links from this Entity",
      "items": {
        "$ref": "#/$defs/idObject"
      }
    },
    "cas:Icon": {
      "type": "object",
      "description": "Optional icon representation for this Entity type",
      "properties": {
        "@value": {
          "type": "string",
          "description": "Icon identifier or path"
        }
      },
      "additionalProperties": false
    }
  },
  "required": [
    "@id",
    "@type",
    "cas:itemType",
    "dcterms:title"
  ],
  "additionalProperties": false,
  "$defs": {
    "idString": {
      "type": "string",
      "pattern": "^(?:[A-Za-z_][A-Za-z0-9_-]*:[^:\\s]+|https?://[^\\s]+)$",
      "description": "A valid ID string: either a namespaced identifier (prefix:name) or a URL"
    },
        "idObject": {
            "type": "object",
            "required": [ "@id" ],
            "properties": {
                "@id": {
                    "$ref": "#/$defs/idString"
                }
            },
            "additionalProperties": false,
            "description": "JSON-LD ID object wrapper"
        },
        "languageValue": {
            "type": "object",
            "required": [ "@value" ],
            "properties": {
                "@value": {
                    "type": "string",
                    "minLength": 1,
                   "description": "The actual text content"
                },
                "@language": {
                    "type": "string",
                    "pattern": "^[a-z]{2}(-[A-Z]{2})?$",
                    "description": "IETF language tag (e.g., 'en', 'de', 'en-US')"
                }
            },
            "additionalProperties": false,
            "description": "Multi-language text value with optional language tag"
        }
  }
}