using System;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Linq;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;
using Microsoft.Extensions.Logging;
using xCommons.Extensions;
using xExceptions.Constants;
using xIdentityModels.Models;
using xPushService.Base;
using xPushService.Extensions;
using xWebinarService.Constants;
using xWebinarService.Models.Dtos;
using xWebinarService.Providers;

namespace xWebinarService.Hub
{
    public class XWebinarHub : XBaseWebRTCHub
    {
        //
        #region Props ...
        public readonly XWebinarProvider webinarProvider;
        #endregion

        //
        #region Constructor ...
        public XWebinarHub(
            ILogger<XWebinarHub> logger,
            XWebinarProvider webinarProvider
        ) : base(logger)
        {
            this.webinarProvider = webinarProvider;
        }
        #endregion

        //
        #region Actions ...
        /// <summary>
        /// a Webinar Owner Open Webinar for Broadcasting ...
        /// </summary>
        /// <param name="webinarId"></param>
        /// <returns></returns>
        [Authorize]
        public async Task WebinarOpened(Guid webinarId)
        {
            //
            // Validate Arg ...
            var isValid = !webinarId.IsNull() &&
                !webinarId.IsDefaultGuid();
            if (!isValid)
            {
                //
                logger.LogError($"Invalid Webinar Provider ...");
                return;
            }

            //
            // Reading and Validate Requirements ...
            var userInfo = Context.GetUserInfo();
            var connectionId = Context.ConnectionId;
            isValid = !userInfo.IsNullOrDefault() &&
                !connectionId.IsNullOrEmpty();
            if (!isValid)
            {
                //
                logger.LogError($"Invaid User Info ...");
                return;
            }

            //
            // Retrieve Webinar Model and Validate it Exists ...
            try
            {
                //
                // Retrieve Webinar ...
                var webinar = await webinarProvider.GetWebinar(webinarId);

                //
                // Validate Webinar ...
                isValid = !webinar.IsNullOrDefault();
                if (!isValid)
                {
                    //
                    XException.NotFound.Throw();
                    logger.LogError($"Webinar Not Found ...");
                }

                //
                // Validate User is Webinar Owner ...
                isValid =
                    !userInfo.UserId.IsNullOrEmpty() &&
                    userInfo.UserId == webinar.OwnerId;
                if (!isValid)
                {
                    //
                    XException.NotAllowed.Throw();
                    logger.LogError($"Not Allowed to Present Webinar ...");
                }

                //
                // Now try to Enable Webinar and Notify Webinars Client Which it's Open ...
                webinar.Enabled = true;
                webinar = await webinarProvider.UpdateWebinar(webinar);
                await Clients.AllExcept(connectionId).SendAsync(XWebinarHubAction.WebinarOpened.GetStringValue(), webinarId);

                //
                // Create a Group and Put User on it ...
                await Groups.AddToGroupAsync(connectionId, webinarId.ToString());
            }
            catch { }
        }

        /// <summary>
        /// Close a Webinar by it's Owner ...
        /// </summary>
        /// <param name="webinarId"></param>
        /// <returns></returns>
        [Authorize]
        public async Task WebinarClosed(Guid webinarId)
        {
            //
            // Validate Arg ...
            var isValid = !webinarId.IsNull() &&
                !webinarId.IsDefaultGuid();
            if (!isValid)
            {
                //
                logger.LogError($"Invalid Webinar Provider ...");
                return;
            }

            //
            // Reading and Validate Requirements ...
            var userInfo = Context.GetUserInfo();
            var connectionId = Context.ConnectionId;
            isValid = !userInfo.IsNullOrDefault() &&
                !connectionId.IsNullOrEmpty();
            if (!isValid)
            {
                //
                logger.LogError($"Invaid User Info ...");
                return;
            }

            //
            // Retrieve Webinar Model and Validate it Exists ...
            try
            {
                //
                // Retrieve Webinar ...
                var webinar = await webinarProvider.GetWebinar(webinarId);

                //
                // Validate Webinar ...
                isValid = !webinar.IsNullOrDefault();
                if (!isValid)
                {
                    //
                    XException.NotFound.Throw();
                    logger.LogError($"Webinar Not Found ...");
                }

                //
                // Validate User is Webinar Owner ...
                isValid =
                    !userInfo.UserId.IsNullOrEmpty() &&
                    userInfo.UserId == webinar.OwnerId;
                if (!isValid)
                {
                    //
                    XException.NotAllowed.Throw();
                    logger.LogError($"Not Allowed to Present Webinar ...");
                }

                //
                // Now try to Enable Webinar and Notify Webinars Client Which it's Open ...
                webinar.Enabled = false;
                webinar = await webinarProvider.UpdateWebinar(webinar);
                await Clients.AllExcept(connectionId).SendAsync(XWebinarHubAction.WebinarClosed.GetStringValue(), webinarId);

                //
                var webinarName = webinarId.ToString();
                await Clients.OthersInGroup(webinarName).SendAsync(XWebinarHubAction.WebinarClosed.ToString());
                await Groups.RemoveFromGroupAsync(connectionId, webinarName);
            }
            catch { }
        }

        /// <summary>
        /// a Webinar Subscriber Joined to Opened Webinar ...
        /// </summary>
        /// <param name="webinarId"></param>
        /// <returns></returns>
        [Authorize]
        public async Task ViewerJoined(Guid webinarId)
        {
            //
            // Validate ...
            var isValid = !webinarId.IsNull() &&
                !webinarId.IsDefaultGuid();
            if (!isValid)
            {
                //
                logger.LogError($"Invalid Webinar Provider ...");
                return;
            }

            //
            // Retrieve requirements ...
            var userInfo = Context.GetUserInfo();
            var connectionId = Context.ConnectionId;
            isValid = !userInfo.IsNullOrDefault() &&
                !connectionId.IsNullOrEmpty();
            if (!isValid)
            {
                //
                logger.LogError($"Invaid User Info ...");
                return;
            }

            //
            try
            {
                //
                // Reading Webinar ...
                var webinar = await webinarProvider.GetWebinar(webinarId);
                isValid = !webinar.IsNullOrDefault();
                if (!isValid)
                {
                    //
                    logger.LogError($"Webinar Not Found ...");
                    XException.NotFound.Throw();
                }

                //
                // Validate User is Webinar Subscriber ...
                // Or Webinar is Open ...
                if (webinar.Type != XWebinarType.Public)
                {
                    //
                    isValid = await webinarProvider.IsSubscribed(
                        webinarId: webinarId,
                        subscriberId: userInfo.UserId
                    );
                    if (!isValid)
                    {
                        //
                        logger.LogError("User Not Have Permission to Join Webinar ...");
                        XException.NotAllowed.Throw();
                    }
                }

                //
                var webinarName = webinarId.ToString();

                //
                // Add User to Webinar ...
                await Groups.AddToGroupAsync(connectionId, webinarName);

                //
                // Notify Other Users which a Viewer Joined ...
                await Clients.OthersInGroup(webinarName).SendAsync(XWebinarHubAction.ViewerJoined.GetStringValue(), connectionId, userInfo.UserId, userInfo.UserName);
            }
            catch
            { }
        }

        /// <summary>
        /// a Webina Subscriber Lefts Group ...
        /// </summary>
        /// <param name="webinarId"></param>
        /// <returns></returns>
        [Authorize]
        public async Task ViewerLeaved(Guid webinarId)
        {
            //
            // Validate ...
            var isValid = !webinarId.IsNull() &&
                !webinarId.IsDefaultGuid();
            if (!isValid)
            {
                //
                logger.LogError($"Invalid Webinar Provider ...");
                return;
            }

            //
            // Retrieve requirements ...
            var userInfo = Context.GetUserInfo();
            var connectionId = Context.ConnectionId;
            isValid = !userInfo.IsNullOrDefault() &&
                !connectionId.IsNullOrEmpty();
            if (!isValid)
            {
                //
                logger.LogError($"Invaid User Info ...");
                return;
            }

            //
            try
            {
                //
                // Reading Webinar ...
                var webinar = await webinarProvider.GetWebinar(webinarId);
                isValid = !webinar.IsNullOrDefault();
                if (!isValid)
                {
                    //
                    logger.LogError($"Webinar Not Found ...");
                    XException.NotFound.Throw();
                }

                //
                // Validate User is Webinar Subscriber ...
                // Or Webinar is Open ...
                if (webinar.Type != XWebinarType.Public)
                {
                    //
                    isValid = await webinarProvider.IsSubscribed(
                        webinarId: webinarId,
                        subscriberId: userInfo.UserId
                    );
                    if (!isValid)
                    {
                        //
                        logger.LogError("User Not Have Permission to Join Webinar ...");
                        XException.NotAllowed.Throw();
                    }
                }

                //
                var webinarName = webinarId.ToString();

                //
                // Add User to Webinar ...
                await Groups.RemoveFromGroupAsync(connectionId, webinarName);

                //
                // Notify Other Users which a Viewer Leaved ...
                await Clients.OthersInGroup(webinarName).SendAsync(XWebinarHubAction.ViewerLeaved.GetStringValue(), 
                    connectionId, 
                    userInfo.UserId, 
                    userInfo.UserName
                );
            }
            catch
            { }
        }

        /// <summary>
        /// Send a Message to Specified Webinar ...
        /// </summary>
        /// <param name="webinarId"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        [Authorize]
        public async Task Message(Guid webinarId, string message)
        {
            //
            // Validate ...
            var isValid = !webinarId.IsNull() &&
                !webinarId.IsDefaultGuid();
            if (!isValid)
            {
                //
                logger.LogError($"Invalid Webinar Provider ...");
                return;
            }

            //
            // Retrieve requirements ...
            var userInfo = Context.GetUserInfo();
            var connectionId = Context.ConnectionId;
            isValid = !userInfo.IsNullOrDefault() &&
                !connectionId.IsNullOrEmpty();
            if (!isValid)
            {
                //
                logger.LogError($"Invaid User Info ...");
                return;
            }

            //
            try
            {
                //
                // Reading Webinar ...
                var webinar = await webinarProvider.GetWebinar(webinarId);
                isValid = !webinar.IsNullOrDefault();
                if (!isValid)
                {
                    //
                    logger.LogError($"Webinar Not Found ...");
                    XException.NotFound.Throw();
                }

                //
                // Validate User is Webinar Owner or Subscriber ...
                // Or Webinar is Open ...
                if (webinar.Type != XWebinarType.Public)
                {
                    //
                    isValid = userInfo.UserId == webinar.OwnerId ||
                        (await webinarProvider.IsSubscribed(
                            webinarId: webinarId,
                            subscriberId: userInfo.UserId
                        ));
                    if (!isValid)
                    {
                        //
                        logger.LogError("User Not Have Permission to Join Webinar ...");
                        XException.NotAllowed.Throw();
                    }
                }

                //
                var webinarName = webinarId.ToString();

                //
                // Notify Other Users which a Viewer Leaved ...
                await Clients.OthersInGroup(webinarName).SendAsync(XWebinarHubAction.Message.GetStringValue(), 
                    connectionId, 
                    userInfo.UserId, 
                    userInfo.UserName, 
                    message
                );
            }
            catch
            { }
        }
        #endregion
    }
}