{"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': '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": "import copy\n\n\ndef norm_id(raw, policy):\n    s = raw if isinstance(raw, str) else ('' if raw is None else str(raw))\n    if policy['trim_ids']:\n        s = s.strip()\n    if policy['fold_case']:\n        s = ''.join(chr(ord(c) + 32) if 'A' <= c <= 'Z' else c for c in s)\n    return s\n\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 norm_id, merge_into\n\n\ndef run(payload, policy):\n    if isinstance(payload, dict):\n        events = payload.get('events', [])\n    else:\n        events = payload\n    groups = {}\n    order = []\n    for i, ev in enumerate(events):\n        nid = norm_id(ev.get('id'), policy)\n        if nid == '':\n            if policy['empty_id'] == 'error':\n                raise ValueError('empty id')\n            continue\n        ver = ev.get('version')\n        if ver < policy['version_floor']:\n            continue\n        key = (nid, ver)\n        if key not in groups:\n            groups[key] = [i, i]\n            order.append(key)\n        else:\n            groups[key][1] = i\n    sel = []\n    for key in order:\n        first, last = groups[key]\n        idx = first if policy['duplicate_policy'] == 'first' else last\n        sel.append((key[1], idx, key[0]))\n    sel.sort(key=lambda t: (t[0], t[1]))\n    records = {}\n    tombs = set()\n    first_idx = {}\n    audit = []\n    for pos, (ver, idx, nid) in enumerate(sel):\n        ev = events[idx]\n        if nid not in first_idx:\n            first_idx[nid] = pos\n        applied = False\n        if ev.get('deleted'):\n            if nid in records:\n                del records[nid]\n                applied = True\n                if policy['tombstone_wins']:\n                    tombs.add(nid)\n            elif policy['tombstone_wins'] and nid not in tombs:\n                tombs.add(nid)\n                applied = True\n        else:\n            if not (policy['tombstone_wins'] and nid in tombs):\n                fields = ev.get('fields') or {}\n                if policy['unknown_fields'] == 'drop':\n                    fields = {k: v for k, v in fields.items() if k in ('name', 'tags', 'meta')}\n                rec = records.get(nid)\n                if rec is None:\n                    rec = {}\n                    records[nid] = rec\n                merge_into(rec, fields, policy)\n                applied = True\n        if applied or policy['audit_all']:\n            audit.append('%s:%s:%s' % (nid, ver, 'applied' if applied else 'blocked'))\n    ids = list(records.keys())\n    if policy['order'] == 'id':\n        ids.sort()\n    else:\n        ids.sort(key=lambda n: (first_idx[n], n))\n    return {'records': [{'id': n, 'fields': copy.deepcopy(records[n])} for n in ids], 'audit': audit}\n"}}