using Google.Protobuf;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Subjects;
using System.Text;
using System.Threading.Tasks;
using Tango.PMR;
using Tango.PMR.Common;

namespace Tango.Transport
{
    /// <summary>
    /// Represents a generic transport message.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <seealso cref="Tango.Transport.TransportMessageBase" />
    internal class TransportMessage<T> : TransportMessageBase
    {
        private TaskCompletionSource<T> _completionSource;

        public Subject<T> ContinuesResponseSubject { get; set; }

        public bool AtLeastOneResponseReceived { get; set; }

        public DateTime LastResponseTime { get; set; }

        public bool Completed { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="TransportMessage{T}"/> class.
        /// </summary>
        /// <param name="token">The token.</param>
        /// <param name="message">The message.</param>
        /// <param name="direction">The direction.</param>
        /// <param name="toBytes">To bytes.</param>
        /// <param name="completionSource">The completion source.</param>
        public TransportMessage(string token, object message, TransportMessageDirection direction, Func<byte[]> toBytes, TaskCompletionSource<T> completionSource) : base(token, message, direction, toBytes)
        {
            _completionSource = completionSource;
        }

        /// <summary>
        /// Notifies the message observer of the new result.
        /// </summary>
        /// <param name="result">The result.</param>
        public override void SetResult(object result, bool completed)
        {
            Completed = completed;

            if (!IsContinuous)
            {
                if (!_completionSource.Task.IsCompleted)
                {
                    if (_completionSource.GetType() == typeof(TaskCompletionSource<IMessage>))
                    {
                        _completionSource.SetResult((T)result.GetType().GetProperty("Message").GetValue(result));
                    }
                    else if (_completionSource.GetType() == typeof(TaskCompletionSource<MessageContainer>))
                    {
                        _completionSource.SetResult((T)result.GetType().GetProperty("Container").GetValue(result));
                    }
                    else
                    {
                        _completionSource.SetResult((T)result);
                    }
                }
            }
            else
            {
                LastResponseTime = DateTime.Now;
                AtLeastOneResponseReceived = true;

                if (ContinuesResponseSubject.GetType() == typeof(Subject<IMessage>))
                {
                    ContinuesResponseSubject.OnNext((T)result.GetType().GetProperty("Message").GetValue(result));
                }
                else if (ContinuesResponseSubject.GetType() == typeof(Subject<MessageContainer>))
                {
                    ContinuesResponseSubject.OnNext((T)result.GetType().GetProperty("Container").GetValue(result));
                }
                else
                {
                    ContinuesResponseSubject.OnNext((T)result);
                }

                if (completed)
                {
                    ContinuesResponseSubject.OnCompleted();
                }
            }
        }

        /// <summary>
        /// Notifies the message observer of an exception.
        /// </summary>
        /// <param name="ex">The ex.</param>
        public override void SetException(Exception ex)
        {
            Completed = true;

            if (!IsContinuous)
            {
                if (!_completionSource.Task.IsCompleted)
                {
                    _completionSource.SetException(ex);
                }
            }
            else
            {
                AtLeastOneResponseReceived = true;
                ContinuesResponseSubject.OnError(ex);
            }
        }
    }
}