using Google.Protobuf;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive;
using System.Reactive.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.Transport.Adapters;
using Tango.PMR;
using Tango.PMR.Common;
using System.Collections.ObjectModel;
using Tango.PMR.Integration;

namespace Tango.Transport
{
    public delegate void RequestHandlerCallbackDelegate<Request>(ITransporter transporter, Request request, String token);

    /// <summary>
    /// Represents a transportation engine which can send and receive <see cref="TangoMessage{T}"/> message using a <see cref="ITransportAdapter">Transport adapter</see>.
    /// </summary>
    /// <seealso cref="Tango.Transport.ITransportComponent" />
    public interface ITransporter : ITransportComponent
    {
        /// <summary>
        /// Gets or sets the <see cref="ITransportAdapter"/> used to read and write raw data.
        /// </summary>
        ITransportAdapter Adapter { get; set; }

        /// <summary>
        /// Gets or sets the transport encoder used to encode and decode tango messages.
        /// </summary>
        ITransportEncoder Encoder { get; set; }

        /// <summary>
        /// Gets the last failed state exception/reason.
        /// </summary>
        Exception FailedStateException { get; }

        /// <summary>
        /// Gets or sets the generic protocol used to serialize/deserialize generic messages.
        /// </summary>
        GenericMessageProtocol GenericProtocol { get; set; }

        /// <summary>
        /// Registers a custom request handler.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <param name="callback">The callback.</param>
        void RegisterRequestHandler<Request>(RequestHandlerCallbackDelegate<Request> callback) where Request : class;

        /// <summary>
        /// Unregisters a custom request handler.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <param name="callback">The callback.</param>
        void UnregisterRequestHandler<Request>(RequestHandlerCallbackDelegate<Request> callback) where Request : class;

        /// <summary>
        /// Copies this instance request handlers to the specified instance.
        /// </summary>
        /// <param name="transporter">The transporter to copy the handlers to.</param>
        void CopyRequestHandlers(ITransporter transporter);

        /// <summary>
        /// Sends a request.
        /// </summary>
        /// <param name="request">The request.</param>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        Task<IMessage> SendRequest(IMessage request, TransportRequestConfig config = null);

        /// <summary>
        /// Sends the request.
        /// </summary>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        Task<MessageContainer> SendRequest(MessageContainer container, TransportRequestConfig config = null);

        /// <summary>
        /// Sends a request.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="request">The request.</param>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        Task<TangoMessage<Response>> SendRequest<Request, Response>(TangoMessage<Request> request, TransportRequestConfig config = null) where Request : IMessage<Request> where Response : IMessage<Response>;

        /// <summary>
        /// Sends a continuous request.
        /// </summary>
        /// <param name="container">The container.</param>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        IObservable<MessageContainer> SendContinuousRequest(MessageContainer container, TransportContinuousRequestConfig config = null);

        /// <summary>
        /// Sends a request and expecting multiple response messages.
        /// </summary>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        IObservable<IMessage> SendContinuousRequest(IMessage request, TransportContinuousRequestConfig config = null);

        /// <summary>
        /// Sends a request and expecting multiple response messages.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        IObservable<TangoMessage<Response>> SendContinuousRequest<Request, Response>(TangoMessage<Request> request, TransportContinuousRequestConfig config = null) where Request : IMessage<Request> where Response : IMessage<Response>;

        /// <summary>
        /// Sends a generic request of any type.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="request">The request.</param>
        /// <param name="config">The configuration.</param>
        /// <returns></returns>
        Task<Response> SendGenericRequest<Request, Response>(Request request, TransportRequestConfig config = null) where Request : class where Response : class;

        /// <summary>
        /// Sends a generic response.
        /// </summary>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="response">The response.</param>
        /// <param name="token">The request token.</param>
        /// <param name="config">The response configuration.</param>
        /// <returns></returns>
        Task SendGenericResponse<Response>(Response response, String token, TransportResponseConfig config = null) where Response : class;

        /// <summary>
        /// Sends a generic request and expecting multiple generic response messages.
        /// </summary>
        /// <typeparam name="Request">The type of the request.</typeparam>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="config">Request configuration.</param>
        /// <returns></returns>
        IObservable<Response> SendGenericContinuousRequest<Request, Response>(Request request, TransportContinuousRequestConfig config = null) where Request : class where Response : class;

        /// <summary>
        /// Sends the response.
        /// </summary>
        /// <param name="container">The container.</param>
        /// <returns></returns>
        Task SendResponse(MessageContainer container, TransportResponseConfig config = null);

        /// <summary>
        /// Sends the response.
        /// </summary>
        /// <param name="response">Request token.</param>
        /// <param name="config">Response configuration.</param>
        /// <returns></returns>
        Task SendResponse(IMessage response, String token, TransportResponseConfig config = null);

        /// <summary>
        /// Sends a response.
        /// </summary>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="response">The response.</param>
        /// <returns></returns>
        Task SendResponse<Response>(TangoMessage<Response> response) where Response : IMessage<Response>;

        /// <summary>
        /// Sends a response.
        /// </summary>
        /// <typeparam name="Response">The type of the response.</typeparam>
        /// <param name="response">The response.</param>
        /// <param name="token">Request token.</param>
        /// <param name="config">Response configuration.</param>
        /// <returns></returns>
        Task SendResponse<Response>(TangoMessage<Response> response, String token, TransportResponseConfig config = null) where Response : IMessage<Response>;

        /// <summary>
        /// Sends a general error response agnostic to the type of request.
        /// </summary>
        /// <param name="exception">The exception.</param>
        /// <param name="token">Request token.</param>
        /// <returns></returns>
        Task SendErrorResponse(Exception exception, String token);

        /// <summary>
        /// Clears all message queues.
        /// </summary>
        void ClearQueues();

        /// <summary>
        /// Occurs when a new request message has been received.
        /// </summary>
        event EventHandler<RequestReceivedEventArgs> RequestReceived;

        /// <summary>
        /// Occurs when a new response message has been received.
        /// </summary>
        event EventHandler<MessageContainer> PendingResponseReceived;

        /// <summary>
        /// Occurs when a request has been sent.
        /// </summary>
        event EventHandler<IMessage> RequestSent;

        /// <summary>
        /// Occurs when a request response has been received.
        /// </summary>
        event EventHandler<IMessage> ResponseReceived;

        /// <summary>
        /// Occurs when a request has failed.
        /// </summary>
        event EventHandler<RequestFailedEventArgs> RequestFailed;

        /// <summary>
        /// Gets or sets the default request timeout.
        /// </summary>
        TimeSpan RequestTimeout { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to use a keep alive mechanism.
        /// </summary>
        bool UseKeepAlive { get; set; }

        /// <summary>
        /// Gets or sets the keep alive timeout.
        /// </summary>
        TimeSpan KeepAliveTimeout { get; set; }

        /// <summary>
        /// Gets or sets the keep alive retries.
        /// </summary>
        int KeepAliveRetries { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to auto respond to keep alive requests.
        /// </summary>
        bool EnableKeepAliveAutoResponse { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether the transporter will get in to a failed state if the <see cref="Adapter"/> has failed.
        /// </summary>
        bool FailsWithAdapter { get; set; }
    }
}