"""Reference checker: does a piece of text cite CWE / ATT&CK ids whose names match the official MITRE data?
Used to FILTER third-party AI-written Q&A (Trendyol, Fenrir, Heimdall, ...): a row is dropped if it cites a CWE id that does not exist, or names an
enterprise ATT&CK technique / CWE with a name that does not match. (We cannot check every fact, but we can remove rows that are provably wrong.)"""
import difflib, json, os, re, zipfile
import xml.etree.ElementTree as ET

HERE = os.path.dirname(os.path.abspath(__file__))
_z = zipfile.ZipFile(os.path.join(HERE, "raw", "cwec.xml.zip")); _root = ET.fromstring(_z.read(_z.namelist()[0])); _ns = {"c": _root.tag.split("}")[0][1:]}
CWE = {"CWE-" + w.get("ID"): w.get("Name") for w in _root.findall(".//c:Weakness", _ns)}
CWE.update({"CWE-" + w.get("ID"): w.get("Name") for w in _root.findall(".//c:Category", _ns)})
ATT = {}
for _o in json.load(open(os.path.join(HERE, "raw", "enterprise-attack.json")))["objects"]:
    if _o["type"] == "attack-pattern":
        for _r in _o.get("external_references", []):
            if _r.get("source_name") == "mitre-attack": ATT[_r["external_id"]] = _o["name"]
P_CWE = re.compile(r"\b(CWE-\d+)\b\s*[\(:–—-]\s*([A-Z][A-Za-z0-9 ,'/\-]{4,70})")
P_CWE_ID = re.compile(r"\bCWE-(\d+)\b")
P_ATT = re.compile(r"\b(T\d{4}(?:\.\d{3})?)\b\s*[\(:–—-]\s*([A-Z][A-Za-z0-9 ,'/\-&:]{3,70})")
NONENT = re.compile(r"T0\d{3}|T14\d{2}|T15\d{2}")        # ICS / Mobile technique ids: not in the enterprise file, so we do not judge them


def _sim(a, b): return difflib.SequenceMatcher(None, a.lower(), b.lower()).ratio()


def ref_ok(text):
    """True if no citation in `text` is provably wrong."""
    text = text or ""
    for m in P_CWE_ID.finditer(text):
        if "CWE-" + m.group(1) not in CWE: return False
    for m in P_CWE.finditer(text):
        i, name = m.group(1), m.group(2).strip()
        off = CWE[i]
        if _sim(name[: len(off) + 6], off) < 0.55 and off.lower() not in name.lower() and name.lower().split(" (")[0] not in off.lower(): return False
    for m in P_ATT.finditer(text):
        i, name = m.group(1), m.group(2).strip()
        if i not in ATT:
            if NONENT.match(i) or i.split(".")[0] in ATT: continue
            return False
        off = ATT[i]
        if _sim(name[: len(off) + 6], off) < 0.55 and off.lower() not in name.lower() and name.lower() not in off.lower(): return False
    return True