"""JSON-backed log rule loading for runtime-editable log analysis."""

from __future__ import annotations

import json
from pathlib import Path

RULES_PATH = Path(__file__).resolve().parents[2] / "config" / "log_rules.json"
_rules_cache: dict[str, list[dict]] | None = None
_rules_cache_mtime: float | None = None


def load_category_patterns() -> dict[str, list[dict]]:
    global _rules_cache, _rules_cache_mtime
    try:
        stat = RULES_PATH.stat()
        if _rules_cache is not None and _rules_cache_mtime == stat.st_mtime:
            return _rules_cache

        data = json.loads(RULES_PATH.read_text())
        categories = data.get("categories", {})
        loaded: dict[str, list[dict]] = {}
        for category, rules in categories.items():
            loaded[category] = []
            for rule in rules:
                if not all(
                    key in rule
                    for key in ("pattern", "nf", "severity", "description", "remediation")
                ):
                    continue
                loaded[category].append(rule)

        _rules_cache = loaded
        _rules_cache_mtime = stat.st_mtime
        return loaded
    except Exception:
        return {}