// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
namespace SocialWeather;
 
public class FormatterResolver
{
    private readonly IServiceProvider _serviceProvider;
 
    private readonly Dictionary<string, Dictionary<Type, Type>> _formatters
        = new Dictionary<string, Dictionary<Type, Type>>();
 
    public FormatterResolver(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }
 
    public void AddFormatter<T, TFormatterType>(string formatType)
        where TFormatterType : IStreamFormatter<T>
    {
        Dictionary<Type, Type> typeFormatters;
        if (!_formatters.TryGetValue(formatType, out typeFormatters))
        {
            typeFormatters = _formatters[formatType] = new Dictionary<Type, Type>();
        }
        typeFormatters[typeof(T)] = typeof(TFormatterType);
    }
 
    public IStreamFormatter<T> GetFormatter<T>(string formatType)
    {
        Dictionary<Type, Type> typeFormatters;
        Type typeFormatterType;
        if (_formatters.TryGetValue(formatType, out typeFormatters) &&
            typeFormatters.TryGetValue(typeof(T), out typeFormatterType))
        {
            return (IStreamFormatter<T>)_serviceProvider.GetRequiredService(typeFormatterType);
        }
 
        return null;
    }
}