api/cache.py

import time
from typing import Any, Optional


class TTLCache:
    """Simple dict-based TTL cache."""

    def __init__(self, maxsize: int = 100, ttl: int = 3600):
        self.maxsize = maxsize
        self.ttl = ttl
        self._cache: dict[str, tuple[float, Any]] = {}

    @staticmethod
    def _normalize_key(key: str) -> str:
        return key.strip().lower()

    def get(self, key: str) -> Optional[Any]:
        normalized = self._normalize_key(key)
        entry = self._cache.get(normalized)
        if entry is None:
            return None
        timestamp, value = entry
        if time.time() - timestamp < self.ttl:
            return value
        del self._cache[normalized]
        return None

    def set(self, key: str, value: Any) -> None:
        normalized = self._normalize_key(key)
        # Evict oldest if at capacity and inserting a new key
        if normalized not in self._cache and len(self._cache) >= self.maxsize:
            oldest_key = min(self._cache, key=lambda k: self._cache[k][0])
            del self._cache[oldest_key]
        self._cache[normalized] = (time.time(), value)

    def clear(self) -> None:
        self._cache.clear()


# Cache instances
retrieval_cache = TTLCache(maxsize=100, ttl=3600)
generation_cache = TTLCache(maxsize=100, ttl=3600)