using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Threading;

​

public class Program

{

    private static LocalCache localCache = new LocalCache();

​

    public static void Main()

    {

        // Primeira chamada sem cache

        var stopwatch = Stopwatch.StartNew();

        var records1 = GenerateRecords(3000);

        stopwatch.Stop();

        Console.WriteLine($"First call without cache Time: {stopwatch.ElapsedMilliseconds} ms");

​

        // Segunda chamada com cache

        stopwatch.Restart();

        var records2 = GenerateRecords(3000);

        stopwatch.Stop();

        Console.WriteLine($"Second call with cache Time: {stopwatch.ElapsedMilliseconds} ms");

​

        // Terceira chamada sem cache pois o valor mudou

        stopwatch.Restart();

        var records3 = GenerateRecords(3001);

        stopwatch.Stop();

        Console.WriteLine($"Third call with cache Time: {stopwatch.ElapsedMilliseconds} ms");

    }

​

    public static List<KeyValuePair<string, string>> GenerateRecords(int count)

    {

        var cacheKey = $"GenerateRecords-{count}";

​

        var cachedValue = localCache.Get(cacheKey);

​

        if (cachedValue != null)

        {

            return (List<KeyValuePair<string, string>>)cachedValue;

        }

​

        var records = new List<KeyValuePair<string, string>>();

        for (int i = 0; i < count; i++)

        {

            // Simula um processo custoso

            Thread.Sleep(1); // Atraso de 1 milissegundo

            records.Add(new KeyValuePair<string, string>("key" + i, "value" + i));

        }

​

        localCache.Set(cacheKey, records, TimeSpan.FromMinutes(10));

​

        return records;

    }

}

​

public class LocalCache

{

    private Dictionary<string, (DateTime expiration, object value)> cache = new();

​

    public void Set(string key, object value, TimeSpan ttl)

    {

        var expiration = DateTime.Now.Add(ttl);

        cache[key] = (expiration, value);

    }

​

    public object Get(string key)

    {

        if (cache.TryGetValue(key, out var entry) && entry.expiration > DateTime.Now)

        {

            return entry.value;

        }

        cache.Remove(key);

        return null;

    }

}

​