"""Shared utilities for webui data modules."""
from __future__ import annotations

import sys
import time
from pathlib import Path

# Ensure project src is on path
_project_root = Path(__file__).resolve().parent.parent.parent.parent
if str(_project_root) not in sys.path:
    sys.path.insert(0, str(_project_root / "src"))

from ietf_analyzer.config import Config
from ietf_analyzer.db import Database
from ietf_analyzer.readiness import compute_readiness, compute_readiness_batch

# Simple TTL cache for expensive computations (t-SNE, clustering, similarity)
_cache: dict[str, tuple[float, object]] = {}
_CACHE_TTL = 300  # 5 minutes


def _extract_month(time_str: str | None) -> str:
    """Normalize a date string to YYYY-MM format."""
    if not time_str:
        return "unknown"
    if len(time_str) >= 7 and time_str[4] == '-':
        return time_str[:7]  # Already YYYY-MM-DD
    if len(time_str) >= 6 and time_str[:4].isdigit():
        return time_str[:4] + '-' + time_str[4:6]  # YYYYMMDD → YYYY-MM
    return time_str[:7]

def _cached(key: str, fn, ttl: float = _CACHE_TTL):
    """Return cached result or compute and cache it."""
    now = time.monotonic()
    if key in _cache:
        ts, val = _cache[key]
        if now - ts < ttl:
            return val
    val = fn()
    _cache[key] = (now, val)
    return val

def get_db() -> Database:
    """Get a Database instance using default config."""
    config = Config.load()
    return Database(config)