using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Authentication;
using System.Text;
using System.Threading.Tasks;
using Tango.Transport.Web;
using Tango.Web.Security;

namespace Tango.Web
{
    public abstract class TangoWebClient<TLoginRequest, TLoginResponse> : IDisposable where TLoginRequest : WebRequestMessage where TLoginResponse : WebTokenResponse
    {
        private WebTransportClient _client;
        private bool _disposed;
        private TLoginRequest _lastLoginRequest;

        private DeploymentSlot? _environment;
        public DeploymentSlot? Environment
        {
            get { return _environment; }
            set
            {
                if (_environment != value)
                {
                    _lastLoginRequest = null;
                    IsAuthenticated = false;
                }

                _environment = value;
            }
        }

        public String Address { get; set; }
        public String Controller { get; private set; }
        public String Token { get; private set; }
        public WebToken WebToken { get; private set; }
        public bool IsAuthenticated { get; private set; }

        public TimeSpan RequestTimeout
        {
            get { return _client.RequestTimeout; }
            set { _client.RequestTimeout = value; }
        }

        public TangoWebClient(DeploymentSlot environment, String controller)
        {
            _client = new WebTransportClient();
            Controller = controller;
            Environment = environment;
        }

        public TangoWebClient(DeploymentSlot environment, String controller, String token) : this(environment, controller)
        {
            Token = token;
        }

        public TangoWebClient(String address, String controller, String token)
        {
            _client = new WebTransportClient();
            Address = address;
            Controller = controller;
            Token = token;
        }

        public TangoWebClient(TangoWebClient<TLoginRequest, TLoginResponse> cloned)
        {
            _client = new WebTransportClient();
            Environment = cloned.Environment;
            Address = cloned.Address;
            Controller = cloned.Controller;
            IsAuthenticated = cloned.IsAuthenticated;
            RequestTimeout = cloned.RequestTimeout;
            WebToken = cloned.WebToken;
            _lastLoginRequest = cloned._lastLoginRequest;
            Token = cloned.Token;
        }

        public T Clone<T>() where T : TangoWebClient<TLoginRequest, TLoginResponse>
        {
            return Activator.CreateInstance(typeof(T), new object[] { this }) as T;
        }

        public async Task<TLoginResponse> Login(TLoginRequest request)
        {
            var response = await _client.PostJson<TLoginRequest, TLoginResponse>(GetActionAddress("Login"), request);
            Token = response.AccessToken;
            _client.AuthenticationToken = Token;

            WebToken = WebToken.FromToken(Token);

            _lastLoginRequest = request;
            IsAuthenticated = true;
            return response;
        }

        protected virtual async Task<TResponse> Post<TRequest, TResponse>(String action, TRequest request) where TRequest : class, IWebRequestMessage where TResponse : class, IWebResponseMessage
        {
            if (IsAuthenticated)
            {
                if (DateTime.UtcNow >= WebToken.Expiration)
                {
                    await Login(_lastLoginRequest);
                }
            }

            try
            {
                var response = await _client.PostJson<TRequest, TResponse>(GetActionAddress(action), request);
                return response;
            }
            catch (TokenExpiredException)
            {
                try
                {
                    await Login(_lastLoginRequest);
                    var response = await _client.PostJson<TRequest, TResponse>(GetActionAddress(action), request);
                    return response;
                }
                catch
                {
                    throw;
                }
            }
            catch (Exception ex)
            {
                throw;
            }
        }

        private String GetActionAddress(String action)
        {
            return GetServiceAddress() + action;
        }

        protected virtual String GetServiceAddress()
        {
            if (Environment != null)
            {
                return Environment.Value.ToAddress() + $"/api/{Controller}/";
            }
            else
            {
                return Address + $"/api/{Controller}/";
            }
        }

        public virtual void Dispose()
        {
            if (!_disposed)
            {
                _disposed = true;
                _client.Dispose();
            }
        }
    }
}