cache_manager.py

import time
from collections import OrderedDict

class CacheManager:
    """
    A simple LRU (Least Recently Used) Cache with Time-to-Live (TTL) support.
    """
    def __init__(self, capacity: int = 100, ttl_seconds: int = 3600):
        """
        Initialize the cache.
        :param capacity: Maximum number of items to store.
        :param ttl_seconds: Time in seconds before an item expires.
        """
        self.cache = OrderedDict()
        self.capacity = capacity
        self.ttl_seconds = ttl_seconds
        print(f"🚀 CacheManager initialized with capacity={capacity} and TTL={ttl_seconds}s")

    def get(self, key: str):
        """
        Retrieve an item from the cache.
        :param key: The key to lookup.
        :return: The cached value if found and valid, else None.
        """
        if key in self.cache:
            result, timestamp = self.cache[key]
            # Check if expired
            if time.time() - timestamp < self.ttl_seconds:
                # Move to end to mark as recently used
                self.cache.move_to_end(key)
                print(f"⚡ Cache HIT for query: '{key}'")
                return result
            else:
                # Remove expired item
                print(f"⌛ Cache EXPIRED for query: '{key}'")
                del self.cache[key]
        return None

    def set(self, key: str, value):
        """
        Add an item to the cache.
        :param key: The key to store.
        :param value: The value to store.
        """
        if key in self.cache:
            self.cache.move_to_end(key)
        
        self.cache[key] = (value, time.time())
        print(f"💾 Cache SET for query: '{key}'")
        
        # Enforce capacity
        if len(self.cache) > self.capacity:
            removed = self.cache.popitem(last=False) # Remove first (least recently used)
            print(f"🗑️ Cache full. Removed old entry: '{removed[0]}'")

    def clear(self):
        """Clear the entire cache."""
        self.cache.clear()
        print("🧹 Cache cleared.")