"""GTIN KB audit (section 10) — validity, cross-tenant matches and conflicts.

Reads the seed payload (ground truth of what was observed per tenant) plus the KB tables.
"""
import json
import sys
from collections import defaultdict
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[2]))

from central.app.ai.fingerprint import validate_gtin


def main(payload_path="docs/runs/ai_kb_seed_payload.json", output="docs/GTIN_KB_AUDIT_V1.json") -> dict:
    payload = json.loads(Path(payload_path).read_text(encoding="utf8"))
    by_gtin = defaultdict(list)
    invalid_gtin_raw = 0
    for product in payload["products"]:
        raw = product.get("gtin")
        if raw is None:
            continue
        if validate_gtin(raw) is None:
            invalid_gtin_raw += 1  # defensive: export already validates
            continue
        by_gtin[raw].append(product)
    duplicated_same_product = sum(1 for entries in by_gtin.values() if len(entries) > 1)
    conflicting = 0
    cross_tenant = 0
    conflict_examples = []
    for gtin, entries in by_gtin.items():
        ncms = {entry.get("ncm") for entry in entries if entry.get("ncm")}
        databases = {obs["database"] for entry in entries for obs in entry["observations"]}
        if len(ncms) > 1:
            conflicting += 1
            if len(conflict_examples) < 10:
                conflict_examples.append({"gtin": gtin, "ncms": sorted(ncms)})
        if len(databases) > 1:
            cross_tenant += 1
    report = {
        "artifact": "GTIN_KB_AUDIT_V1",
        "gtin_valid": len(by_gtin),
        "gtin_invalid_raw": invalid_gtin_raw,
        "gtin_duplicated_same_product": duplicated_same_product,
        "gtin_conflicting_products": conflicting,
        "gtin_cross_tenant_matches": cross_tenant,
        "conflict_examples": conflict_examples,
        "policy": "same GTIN across tenants is STRONG evidence for sharing global product knowledge; tenant fiscal context is never shared",
    }
    Path(output).write_text(json.dumps(report, indent=2, ensure_ascii=False), encoding="utf-8")
    return report


if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("--payload-path", default="/tmp/ai_kb_seed_payload.json")
    parser.add_argument("--output", default="/tmp/gtin_audit.json")
    args = parser.parse_args()
    print(json.dumps(main(args.payload_path, args.output), indent=2))