const storage = {
    set: function(key, value, ttl = null) {
        const item = {
            value: value,
            expiry: ttl ? Date.now() + ttl : null
        };
        localStorage.setItem(key, JSON.stringify(item));
    },
    
    get: function(key) {
        const itemStr = localStorage.getItem(key);
        if (!itemStr) return null;
        
        try {
            const item = JSON.parse(itemStr);
            
            // Check if expired
            if (item.expiry && Date.now() > item.expiry) {
                localStorage.removeItem(key);
                return null;
            }
            
            return item.value;
        } catch(e) {
            return null;
        }
    },
    
    remove: function(key) {
        localStorage.removeItem(key);
    },
    
    clear: function() {
        localStorage.clear();
    },
    
    // Get all keys with optional prefix filter
    keys: function(prefix = "") {
        const keys = [];
        for(let i = 0; i < localStorage.length; i++) {
            const key = localStorage.key(i);
            if(key.startsWith(prefix)) {
                keys.push(key);
            }
        }
        return keys;
    },
    
    // Get storage usage in bytes
    size: function() {
        let total = 0;
        for(let i = 0; i < localStorage.length; i++) {
            const key = localStorage.key(i);
            const value = localStorage.getItem(key);
            total += key.length + value.length;
        }
        return total;
    }
};

// Usage
storage.set("user", {name: "John", age: 30}, 3600000); // Expires in 1 hour
storage.set("theme", "dark");

const user = storage.get("user"); // Returns object or null if expired
console.log(user);

// Session storage wrapper (same API but with sessionStorage)
const session = {...storage};
session.set = function(key, value, ttl = null) {
    const item = {
        value: value,
        expiry: ttl ? Date.now() + ttl : null
    };
    sessionStorage.setItem(key, JSON.stringify(item));
};
session.get = function(key) {
    const itemStr = sessionStorage.getItem(key);
    if (!itemStr) return null;
    try {
        const item = JSON.parse(itemStr);
        if (item.expiry && Date.now() > item.expiry) {
            sessionStorage.removeItem(key);
            return null;
        }
        return item.value;
    } catch(e) {
        return null;
    }
};