{"files":{"main.py":"from core import run\nfrom policy import POLICY\ndef evaluate(payload):\n    return run(payload, POLICY)\n","policy.py":"POLICY = {\n    'duplicate_policy': 'last',\n    'fold_case': False,\n    'tombstone_wins': False,\n    'trim_ids': False,\n    'list_merge': 'unique',\n    'nested_merge': False,\n    'null_mode': 'delete',\n    'version_floor': 3,\n    'audit_all': False,\n    'empty_id': 'error',\n    'order': 'input',\n    'unknown_fields': 'drop',\n}\n","helpers.py":"import copy\n\ndef fold(s):\n    return ''.join(chr(ord(c) + 32) if 'A' <= c <= 'Z' else c for c in s)\n\ndef merge_into(old, new, policy):\n    for k, v in new.items():\n        if v is None:\n            if policy['null_mode'] == 'delete':\n                old.pop(k, None)\n            continue\n        if k in old:\n            o = old[k]\n            if isinstance(o, dict) and isinstance(v, dict) and policy['nested_merge']:\n                merge_into(o, v, policy)\n                continue\n            if isinstance(o, list) and isinstance(v, list) and policy['list_merge'] == 'unique':\n                add = [copy.deepcopy(x) for x in v if not any(x == y for y in o)]\n                old[k] = o + add\n                continue\n        old[k] = copy.deepcopy(v)\n    return old\n","core.py":"import copy\nfrom helpers import fold, merge_into\n\ndef run(payload, policy):\n    events = payload.get('events', []) if isinstance(payload, dict) else payload\n    groups = {}\n    for i, e in enumerate(events):\n        nid = e.get('id')\n        if policy['trim_ids']:\n            nid = nid.strip()\n        if policy['fold_case']:\n            nid = fold(nid)\n        if nid == '':\n            if policy['empty_id'] == 'error':\n                raise ValueError('empty id')\n            continue\n        v = e.get('version')\n        if v < policy['version_floor']:\n            continue\n        key = (nid, v)\n        if key not in groups:\n            groups[key] = [i, i]\n        else:\n            if policy['duplicate_policy'] == 'last':\n                groups[key][1] = i\n            \n    items = [(key[1], sel, key[0]) for key, (first, sel) in groups.items()]\n    items.sort(key=lambda t: (t[0], t[1]))\n    records = {}\n    tomb = set()\n    first_idx = {}\n    audit = []\n    for pos, (v, sel, nid) in enumerate(items):\n        e = events[sel]\n        if nid not in first_idx:\n            first_idx[nid] = pos\n        applied = False\n        if e.get('deleted'):\n            if nid in records:\n                del records[nid]\n                applied = True\n                if policy['tombstone_wins']:\n                    tomb.add(nid)\n            elif policy['tombstone_wins'] and nid not in tomb:\n                tomb.add(nid)\n                applied = True\n        else:\n            if nid not in tomb:\n                cur = records.setdefault(nid, {})\n                merge_into(cur, e.get('fields') or {}, policy)\n                applied = True\n        if applied or policy['audit_all']:\n            audit.append('%s:%d:%s' % (nid, v, 'applied' if applied else 'blocked'))\n    out = []\n    for nid, f in records.items():\n        f = copy.deepcopy(f)\n        if policy['unknown_fields'] == 'drop':\n            f = {k: x for k, x in f.items() if k in ('name', 'tags', 'meta')}\n        out.append((nid, f))\n    if policy['order'] == 'id':\n        out.sort(key=lambda t: t[0])\n    else:\n        out.sort(key=lambda t: (first_idx[t[0]], t[0]))\n    return {'records': [{'id': n, 'fields': f} for n, f in out], 'audit': audit}\n"}}