function createStorage(storage) {
    const cache = new Map();
    const stringifyCache = new Map();
    const batchWrites = [];
    let flushTimer = null;

    // 优化的 JSON 序列化
    function fastStringify(obj) {
        const type = typeof obj;
        if (obj === null) return 'null';
        if (type === 'string') return `"${obj}"`;
        if (type === 'number' || type === 'boolean') return String(obj);
        if (type !== 'object') return '{}';

        const cached = stringifyCache.get(obj);
        if (cached) return cached;

        try {
            const result = JSON.stringify(obj);
            if (result.length < 1000) {
                stringifyCache.set(obj, result);
            }
            return result;
        } catch {
            return '{}';
        }
    }

    return {
        set(key, val) {
            if (!key) return;

            try {
                // 更新缓存
                cache.set(key, val);

                // 序列化并立即写入
                const serialized = fastStringify(val);
                storage.setItem(key, serialized);

                // 批量写入作为备份
                batchWrites.push([key, serialized]);
                if (!flushTimer) {
                    flushTimer = setTimeout(() => {
                        batchWrites.forEach(([k, v]) => {
                            try { storage.setItem(k, v); } catch {}
                        });
                        batchWrites.length = 0;
                        flushTimer = null;
                    }, 100);
                }
            } catch (e) {
                console.error('Storage error:', e);
            }
        },

        get(key) {
            if (!key) return null;

            // 优先读缓存
            const cached = cache.get(key);
            if (cached !== undefined) return cached;

            try {
                const val = JSON.parse(storage.getItem(key));
                cache.set(key, val);
                return val;
            } catch {
                return null;
            }
        },

        remove(key) {
            cache.delete(key);
            storage.removeItem(key);
        },
        clear() {
            cache.clear();
            stringifyCache.clear();
            storage.clear();
            batchWrites.length = 0;
            if (flushTimer) {
                clearTimeout(flushTimer);
                flushTimer = null;
            }
        }
    };
}
// 导出单例实例
export const Local = createStorage(window.localStorage);
export const Session = createStorage(window.sessionStorage);