// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Shared.DiagnosticIds;
using Microsoft.Shared.Diagnostics;
 
namespace Microsoft.Extensions.AI;
 
/// <summary>Provides a collection of static methods for extending <see cref="IRealtimeClientSession"/> instances.</summary>
[Experimental(DiagnosticIds.Experiments.AIRealTime, UrlFormat = DiagnosticIds.UrlFormat)]
public static class RealtimeClientSessionExtensions
{
    /// <summary>Asks the <see cref="IRealtimeClientSession"/> for an object of type <typeparamref name="TService"/>.</summary>
    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
    /// <param name="session">The session.</param>
    /// <param name="serviceKey">An optional key that can be used to help identify the target service.</param>
    /// <returns>The found object, otherwise <see langword="null"/>.</returns>
    /// <exception cref="ArgumentNullException"><paramref name="session"/> is <see langword="null"/>.</exception>
    /// <remarks>
    /// The purpose of this method is to allow for the retrieval of strongly typed services that may be provided by the <see cref="IRealtimeClientSession"/>,
    /// including itself or any services it might be wrapping.
    /// </remarks>
    public static TService? GetService<TService>(this IRealtimeClientSession session, object? serviceKey = null)
    {
        _ = Throw.IfNull(session);
 
        return session.GetService(typeof(TService), serviceKey) is TService service ? service : default;
    }
 
    /// <summary>
    /// Asks the <see cref="IRealtimeClientSession"/> for an object of the specified type <paramref name="serviceType"/>
    /// and throws an exception if one isn't available.
    /// </summary>
    /// <param name="session">The session.</param>
    /// <param name="serviceType">The type of object being requested.</param>
    /// <param name="serviceKey">An optional key that can be used to help identify the target service.</param>
    /// <returns>The found object.</returns>
    /// <exception cref="ArgumentNullException"><paramref name="session"/> is <see langword="null"/>.</exception>
    /// <exception cref="ArgumentNullException"><paramref name="serviceType"/> is <see langword="null"/>.</exception>
    /// <exception cref="InvalidOperationException">No service of the requested type for the specified key is available.</exception>
    /// <remarks>
    /// The purpose of this method is to allow for the retrieval of services that are required to be provided by the <see cref="IRealtimeClientSession"/>,
    /// including itself or any services it might be wrapping.
    /// </remarks>
    public static object GetRequiredService(this IRealtimeClientSession session, Type serviceType, object? serviceKey = null)
    {
        _ = Throw.IfNull(session);
        _ = Throw.IfNull(serviceType);
 
        return
            session.GetService(serviceType, serviceKey) ??
            throw Throw.CreateMissingServiceException(serviceType, serviceKey);
    }
 
    /// <summary>
    /// Asks the <see cref="IRealtimeClientSession"/> for an object of type <typeparamref name="TService"/>
    /// and throws an exception if one isn't available.
    /// </summary>
    /// <typeparam name="TService">The type of the object to be retrieved.</typeparam>
    /// <param name="session">The session.</param>
    /// <param name="serviceKey">An optional key that can be used to help identify the target service.</param>
    /// <returns>The found object.</returns>
    /// <exception cref="ArgumentNullException"><paramref name="session"/> is <see langword="null"/>.</exception>
    /// <exception cref="InvalidOperationException">No service of the requested type for the specified key is available.</exception>
    /// <remarks>
    /// The purpose of this method is to allow for the retrieval of strongly typed services that are required to be provided by the <see cref="IRealtimeClientSession"/>,
    /// including itself or any services it might be wrapping.
    /// </remarks>
    public static TService GetRequiredService<TService>(this IRealtimeClientSession session, object? serviceKey = null)
    {
        _ = Throw.IfNull(session);
 
        if (session.GetService(typeof(TService), serviceKey) is not TService service)
        {
            throw Throw.CreateMissingServiceException(typeof(TService), serviceKey);
        }
 
        return service;
    }
}