using System;

using System.Linq;

using System.Collections.Generic;

using System.Threading.Tasks;

using System.Diagnostics;

​

// definicje

public record MoodDto(DateTime Day, int Value);

​

public interface IMoodService {

    Task<List<MoodDto>> GetMoods(int id);   

}

​

// bazowa klasa

public class MoodService : IMoodService

{

    //ctor(DbContext context)...

​

    public async Task<List<MoodDto>> GetMoods(int id)

    {

        // _context.Moods...;

        await Task.Delay(3000); // odczyt z bazy trwa np. 3s

        return new() 

        {

            new MoodDto(DateTime.Now, Random.Shared.Next(0,5)),

            new MoodDto(DateTime.Now, Random.Shared.Next(0,5)),

            new MoodDto(DateTime.Now, Random.Shared.Next(0,5))

        };

    }

}

​

// dekorator 1 - cachujący

public class CachingMoodService : IMoodService

{

    private readonly IMoodService _service;

    private readonly Dictionary<int, List<MoodDto>> _cache = new();

    public CachingMoodService(IMoodService service)

    {

        _service = service;

    }

    public async Task<List<MoodDto>> GetMoods(int id)

    {

        if(!_cache.ContainsKey(id))

        {

            var mood = await _service.GetMoods(id);

            _cache.Add(id, mood);

        }

        return _cache[id];

    }

}

​

// dekorator 2 - logujący

public class LoggingMoodService : IMoodService

{

    private readonly IMoodService _service;

    public string Name {get;set;} = "MoodService";

    public LoggingMoodService(IMoodService service)

    {

        _service = service;

    }

    public async Task<List<MoodDto>> GetMoods(int id)

    {

        Console.WriteLine($"|{Name}| /‾‾ Reading moods for userId {id}...");

        var timer = new Stopwatch();

        timer.Start();

        var moods = await _service.GetMoods(id);

        timer.Stop();

        var str = string.Join(", ", moods.Select(x=>x.Value));

        Console.WriteLine($"|{Name}| \\__ Moods for userId {id}: [{str}]. Time taken: {timer.Elapsed.TotalSeconds:F3}s");

        return moods;

    }

}

​

​

​

public class Program

{

    public static async Task Main()

    {

        // kolejnosc ma znaczenie ;*

        IMoodService moodService = new LoggingMoodService(new CachingMoodService(new MoodService()));

        var user1Id = 1;

        var moods1 = await moodService.GetMoods(user1Id);

        Console.WriteLine();

        var moods1_2 = await moodService.GetMoods(user1Id);

        Console.WriteLine();

        var moods1_3 = await moodService.GetMoods(user1Id);

        Console.WriteLine();

        var user2Id = 2;

        var moods2 = await moodService.GetMoods(user2Id);

        Console.WriteLine();

        var moods2_2 = await moodService.GetMoods(user2Id);

    }

}