using Grpc.Core;
using MxGateway.Contracts.Proto;

namespace MxGateway.Client;

internal sealed class GrpcMxGatewayClientTransport(
    MxGatewayClientOptions options,
    MxAccessGateway.MxAccessGatewayClient rawClient) : IMxGatewayClientTransport
{
    public MxGatewayClientOptions Options { get; } = options;

    public MxAccessGateway.MxAccessGatewayClient RawClient { get; } = rawClient;

    MxAccessGateway.MxAccessGatewayClient? IMxGatewayClientTransport.RawClient => RawClient;

    public async Task<OpenSessionReply> OpenSessionAsync(
        OpenSessionRequest request,
        CallOptions callOptions)
    {
        try
        {
            return await RawClient.OpenSessionAsync(request, callOptions)
                .ResponseAsync
                .ConfigureAwait(false);
        }
        catch (RpcException exception)
        {
            throw MapRpcException(exception);
        }
    }

    public async Task<CloseSessionReply> CloseSessionAsync(
        CloseSessionRequest request,
        CallOptions callOptions)
    {
        try
        {
            return await RawClient.CloseSessionAsync(request, callOptions)
                .ResponseAsync
                .ConfigureAwait(false);
        }
        catch (RpcException exception)
        {
            throw MapRpcException(exception);
        }
    }

    public async Task<MxCommandReply> InvokeAsync(
        MxCommandRequest request,
        CallOptions callOptions)
    {
        try
        {
            return await RawClient.InvokeAsync(request, callOptions)
                .ResponseAsync
                .ConfigureAwait(false);
        }
        catch (RpcException exception)
        {
            throw MapRpcException(exception);
        }
    }

    public async IAsyncEnumerable<MxEvent> StreamEventsAsync(
        StreamEventsRequest request,
        CallOptions callOptions,
        [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default)
    {
        CancellationToken effectiveCancellationToken = cancellationToken.CanBeCanceled
            ? cancellationToken
            : callOptions.CancellationToken;

        using AsyncServerStreamingCall<MxEvent> call = RawClient.StreamEvents(request, callOptions);

        IAsyncStreamReader<MxEvent> responseStream = call.ResponseStream;
        while (true)
        {
            MxEvent? gatewayEvent;
            try
            {
                if (!await responseStream.MoveNext(effectiveCancellationToken).ConfigureAwait(false))
                {
                    break;
                }

                gatewayEvent = responseStream.Current;
            }
            catch (RpcException exception)
            {
                throw MapRpcException(exception);
            }

            yield return gatewayEvent;
        }
    }

    IAsyncEnumerable<MxEvent> IMxGatewayClientTransport.StreamEventsAsync(
        StreamEventsRequest request,
        CallOptions callOptions)
    {
        return StreamEventsAsync(request, callOptions);
    }

    private static MxGatewayException MapRpcException(RpcException exception)
    {
        return exception.StatusCode switch
        {
            StatusCode.Unauthenticated => new MxGatewayAuthenticationException(
                exception.Status.Detail,
                innerException: exception),
            StatusCode.PermissionDenied => new MxGatewayAuthorizationException(
                exception.Status.Detail,
                innerException: exception),
            _ => new MxGatewayException(exception.Status.Detail, exception),
        };
    }
}