// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Remote;
 
namespace Microsoft.CodeAnalysis.ExternalAccess.Pythia.Api;
 
internal readonly struct PythiaRemoteHostClient
{
    private readonly ServiceHubRemoteHostClient _client;
    private readonly PythiaServiceDescriptorsWrapper _serviceDescriptors;
    private readonly PythiaRemoteServiceCallbackDispatcherRegistry _callbackDispatchers;
 
    internal PythiaRemoteHostClient(ServiceHubRemoteHostClient client, PythiaServiceDescriptorsWrapper serviceDescriptors, PythiaRemoteServiceCallbackDispatcherRegistry callbackDispatchers)
    {
        _client = client;
        _serviceDescriptors = serviceDescriptors;
        _callbackDispatchers = callbackDispatchers;
    }
 
    public static async Task<PythiaRemoteHostClient?> TryGetClientAsync(HostWorkspaceServices services, PythiaServiceDescriptorsWrapper serviceDescriptors, PythiaRemoteServiceCallbackDispatcherRegistry callbackDispatchers, CancellationToken cancellationToken = default)
    {
        var client = await RemoteHostClient.TryGetClientAsync(services.SolutionServices, cancellationToken).ConfigureAwait(false);
        if (client is null)
            return null;
 
        return new PythiaRemoteHostClient((ServiceHubRemoteHostClient)client, serviceDescriptors, callbackDispatchers);
    }
 
    private PythiaRemoteServiceConnectionWrapper<TService> CreateConnection<TService>(object? callbackTarget) where TService : class
        => new(_client.CreateConnection<TService>(_serviceDescriptors.UnderlyingObject, _callbackDispatchers, callbackTarget));
 
    // no solution, no callback:
 
    public async ValueTask<bool> TryInvokeAsync<TService>(Func<TService, CancellationToken, ValueTask> invocation, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget: null);
        return await connection.TryInvokeAsync(invocation, cancellationToken).ConfigureAwait(false);
    }
 
    public async ValueTask<Optional<TResult>> TryInvokeAsync<TService, TResult>(Func<TService, CancellationToken, ValueTask<TResult>> invocation, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget: null);
        return await connection.TryInvokeAsync(invocation, cancellationToken).ConfigureAwait(false);
    }
 
    // no solution, callback:
 
    public async ValueTask<bool> TryInvokeAsync<TService>(Func<TService, PythiaRemoteServiceCallbackIdWrapper, CancellationToken, ValueTask> invocation, object callbackTarget, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget);
        return await connection.TryInvokeAsync(invocation, cancellationToken).ConfigureAwait(false);
    }
 
    public async ValueTask<Optional<TResult>> TryInvokeAsync<TService, TResult>(Func<TService, PythiaRemoteServiceCallbackIdWrapper, CancellationToken, ValueTask<TResult>> invocation, object callbackTarget, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget);
        return await connection.TryInvokeAsync(invocation, cancellationToken).ConfigureAwait(false);
    }
 
    // solution, no callback:
 
    public async ValueTask<bool> TryInvokeAsync<TService>(Solution solution, Func<TService, PythiaPinnedSolutionInfoWrapper, CancellationToken, ValueTask> invocation, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget: null);
        return await connection.TryInvokeAsync(solution, invocation, cancellationToken).ConfigureAwait(false);
    }
 
    public async ValueTask<Optional<TResult>> TryInvokeAsync<TService, TResult>(Solution solution, Func<TService, PythiaPinnedSolutionInfoWrapper, CancellationToken, ValueTask<TResult>> invocation, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget: null);
        return await connection.TryInvokeAsync(solution, invocation, cancellationToken).ConfigureAwait(false);
    }
 
    // solution, callback:
 
    public async ValueTask<bool> TryInvokeAsync<TService>(Solution solution, Func<TService, PythiaPinnedSolutionInfoWrapper, PythiaRemoteServiceCallbackIdWrapper, CancellationToken, ValueTask> invocation, object callbackTarget, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget);
        return await connection.TryInvokeAsync(solution, invocation, cancellationToken).ConfigureAwait(false);
    }
 
    public async ValueTask<Optional<TResult>> TryInvokeAsync<TService, TResult>(Solution solution, Func<TService, PythiaPinnedSolutionInfoWrapper, PythiaRemoteServiceCallbackIdWrapper, CancellationToken, ValueTask<TResult>> invocation, object callbackTarget, CancellationToken cancellationToken) where TService : class
    {
        using var connection = CreateConnection<TService>(callbackTarget);
        return await connection.TryInvokeAsync(solution, invocation, cancellationToken).ConfigureAwait(false);
    }
}