{
  "files": {
    "main.py": "from core import run\nfrom policy import POLICY\n\n\ndef evaluate(payload):\n    return run(payload, POLICY)\n",
    "core.py": "from helpers import merge_fields, normalize_id\n\n\ndef run(payload, policy):\n    events = payload.get('events', []) if isinstance(payload, dict) else payload\n    selected = {}\n\n    for index, event in enumerate(events):\n        identifier = normalize_id(event['id'], policy)\n        if not identifier:\n            if policy['empty_id'] == 'skip':\n                continue\n            raise ValueError('Empty normalized id')\n        version = event['version']\n        if version < policy['version_floor']:\n            continue\n        key = (identifier, version)\n        if key not in selected or policy['duplicate_policy'] == 'last':\n            selected[key] = (index, event)\n\n    ordered = sorted(selected.items(), key=lambda item: (item[0][1], item[1][0]))\n    records = {}\n    tombstones = set()\n    first_processed = {}\n    audit = []\n\n    for processed_index, ((identifier, version), (_, event)) in enumerate(ordered):\n        first_processed.setdefault(identifier, processed_index)\n        applied = False\n        if event['deleted']:\n            existed = identifier in records\n            new_tombstone = policy['tombstone_wins'] and identifier not in tombstones\n            records.pop(identifier, None)\n            if policy['tombstone_wins']:\n                tombstones.add(identifier)\n            applied = existed or new_tombstone\n        elif identifier not in tombstones:\n            fields = event['fields']\n            if policy['unknown_fields'] == 'drop':\n                fields = {key: value for key, value in fields.items() if key in ('name', 'tags', 'meta')}\n            records[identifier] = merge_fields(records.get(identifier, {}), fields, policy)\n            applied = True\n\n        if policy['audit_all'] or applied:\n            status = 'applied' if applied else 'blocked'\n            audit.append(f'{identifier}:{version}:{status}')\n\n    if policy['order'] == 'id':\n        identifiers = sorted(records)\n    else:\n        identifiers = sorted(records, key=lambda identifier: (first_processed[identifier], identifier))\n    return {\n        'records': [{'id': identifier, 'fields': records[identifier]} for identifier in identifiers],\n        'audit': audit,\n    }\n",
    "policy.py": "POLICY = {\n    'duplicate_policy': 'first',\n    'fold_case': True,\n    'tombstone_wins': True,\n    'trim_ids': True,\n    'list_merge': 'replace',\n    'nested_merge': True,\n    'null_mode': 'ignore',\n    'version_floor': 2,\n    'audit_all': True,\n    'empty_id': 'skip',\n    'order': 'id',\n    'unknown_fields': 'keep',\n}\n",
    "helpers.py": "from copy import deepcopy\n\n\nASCII_FOLD = str.maketrans('ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz')\n\n\ndef normalize_id(identifier, policy):\n    if policy['trim_ids']:\n        identifier = identifier.strip()\n    if policy['fold_case']:\n        identifier = identifier.translate(ASCII_FOLD)\n    return identifier\n\n\ndef json_equal(left, right):\n    if left is None or right is None:\n        return left is None and right is None\n    if isinstance(left, bool) or isinstance(right, bool):\n        return isinstance(left, bool) and isinstance(right, bool) and left == right\n    if isinstance(left, dict) or isinstance(right, dict):\n        return (\n            isinstance(left, dict)\n            and isinstance(right, dict)\n            and left.keys() == right.keys()\n            and all(json_equal(left[key], right[key]) for key in left)\n        )\n    if isinstance(left, list) or isinstance(right, list):\n        return (\n            isinstance(left, list)\n            and isinstance(right, list)\n            and len(left) == len(right)\n            and all(json_equal(a, b) for a, b in zip(left, right))\n        )\n    if isinstance(left, str) or isinstance(right, str):\n        return isinstance(left, str) and isinstance(right, str) and left == right\n    return left == right\n\n\ndef merge_fields(old, new, policy):\n    result = deepcopy(old)\n    for key, value in new.items():\n        if value is None:\n            if policy['null_mode'] == 'delete':\n                result.pop(key, None)\n            continue\n        previous = result.get(key)\n        if policy['nested_merge'] and isinstance(previous, dict) and isinstance(value, dict):\n            result[key] = merge_fields(previous, value, policy)\n        elif policy['list_merge'] == 'unique' and isinstance(previous, list) and isinstance(value, list):\n            additions = [item for item in value if not any(json_equal(item, existing) for existing in previous)]\n            result[key] = deepcopy(previous) + deepcopy(additions)\n        else:\n            result[key] = deepcopy(value)\n    return result\n"
  }
}