#region Copyright notice and license
// Copyright 2015, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion
using System;
using Grpc.Core.Internal;

namespace Grpc.Core.Internal
{
    /// <summary>
    /// Observer that writes all arriving messages to a call abstraction (in blocking fashion)
    /// and then halfcloses the call. Used for server-side call handling.
    /// </summary>
    internal class ServerStreamingOutputObserver<TRequest, TResponse> : IObserver<TResponse>
    {
        readonly AsyncCallServer<TRequest, TResponse> call;

        public ServerStreamingOutputObserver(AsyncCallServer<TRequest, TResponse> call)
        {
            this.call = call;
        }

        public void OnCompleted()
        {
            var taskSource = new AsyncCompletionTaskSource();
            call.StartSendStatusFromServer(new Status(StatusCode.OK, ""), taskSource.CompletionDelegate);
            // TODO: how bad is the Wait here?
            taskSource.Task.Wait();
        }

        public void OnError(Exception error)
        {
            // TODO: implement this...
            throw new InvalidOperationException("This should never be called.");
        }

        public void OnNext(TResponse value)
        {
            var taskSource = new AsyncCompletionTaskSource();
            call.StartSendMessage(value, taskSource.CompletionDelegate);
            // TODO: how bad is the Wait here?
            taskSource.Task.Wait();
        }
    }
}