{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://explicit-learning.local/schemas/normalized_item.schema.json",
  "title": "Normalized source item",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "schema_version",
    "base_id",
    "source",
    "source_revision",
    "source_config",
    "source_split",
    "source_native_id",
    "question",
    "question_sha256",
    "choices",
    "choices_sha256",
    "answer_raw",
    "answer_canonical",
    "answer_type",
    "image_paths",
    "image_sha256",
    "provenance",
    "policy"
  ],
  "properties": {
    "schema_version": {"const": 2},
    "base_id": {"$ref": "#/$defs/sha256"},
    "source": {"type": "string", "minLength": 1},
    "source_revision": {"type": "string", "pattern": "^[a-f0-9]{40}$"},
    "source_config": {"type": "string", "minLength": 1},
    "source_split": {"type": "string", "minLength": 1},
    "source_native_id": {"type": "string", "minLength": 1},
    "subject": {"type": ["string", "null"]},
    "question": {"type": "string", "minLength": 1},
    "question_sha256": {"$ref": "#/$defs/sha256"},
    "choices": {
      "type": "array",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": ["key", "text"],
        "properties": {
          "key": {"type": "string", "minLength": 1},
          "text": {"type": "string", "minLength": 1}
        }
      }
    },
    "choices_sha256": {"$ref": "#/$defs/sha256"},
    "answer_raw": {"type": ["string", "number", "boolean"]},
    "answer_canonical": {"type": ["string", "number", "boolean"]},
    "answer_type": {
      "type": "string",
      "enum": ["multiple_choice", "integer", "number", "expression", "short_text", "boolean"]
    },
    "image_paths": {
      "type": "array",
      "minItems": 1,
      "items": {"type": "string", "minLength": 1}
    },
    "image_sha256": {
      "type": "array",
      "minItems": 1,
      "items": {"$ref": "#/$defs/sha256"}
    },
    "provenance": {
      "type": "object",
      "additionalProperties": true,
      "required": ["native_row_json_sha256"],
      "properties": {
        "native_row_json_sha256": {"$ref": "#/$defs/sha256"},
        "inferred_source": {"type": ["string", "null"]}
      }
    },
    "policy": {
      "type": "string",
      "enum": [
        "c1_train_candidate",
        "c1_certified_eval_candidate",
        "c2_train_candidate",
        "untouched_evaluation_only",
        "blocked"
      ]
    },
    "license_gate": {"type": ["string", "null"]}
  },
  "$defs": {
    "sha256": {
      "type": "string",
      "pattern": "^[a-f0-9]{64}$"
    }
  }
}