using System;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Threading;
using System.Linq;
using Xamarin.Forms;
using Grpc.Core;
using Aurora.Services;
using Aurora.Proto.General;
using Aurora.Proto.Party;
using Aurora.Proto.Playback;
using Aurora.Proto.Events;
using Aurora.Services.ClientService;

namespace Aurora.Design.Views.Party
{
    enum PartyState
    {
        SelectingHost,
        InParty,
        Connecting,
    }

    public class PartyViewModel : BaseViewModel
    {
        private PartyState _state;
        private string _hostname;
        private ObservableCollection<PartyMember> _members;

        public PartyViewModel()
        {
            this.JoinCommand = new Command(OnJoinExecute, CanJoinExecute);
            this.HostCommand = new Command(OnHostExecute, CanHostExecute);

            _members = new ObservableCollection<PartyMember>();

            SetState(PartyState.SelectingHost);

            //Hook up event handler
            ClientService.Instance.EventReceived += this.OnEventReceived;
        }

        ~PartyViewModel()
        {
            //Task.Run(ServerService.Instance.Stop);
        }

        #region Properties

        public ObservableCollection<PartyMember> Members
        {
            get
            {
                return _members;
            }
            set
            {
                SetProperty(ref _members, value);
            }
        }

        public bool IsSelectingHost
        {
            get { return _state == PartyState.SelectingHost; }
        }

        public bool IsNotSelectingHost
        {
            get { return _state != PartyState.SelectingHost; }
        }

        public Command JoinCommand { get; set; }
        public Command HostCommand { get; set; }

        public string Hostname
        {
            get { return _hostname; }
            set { SetProperty(ref _hostname, value); }
        }

        #endregion Properties

        #region Events
        /// <summary>
        /// An event handler for the client receiving update events
        /// </summary>
        /// <param name="sender">The object that sent the event</param>
        /// <param name="eventArgs">The event arguments</param>
        public void OnEventReceived(object sender, EventReceivedEventArgs eventArgs)
        {
            switch (eventArgs.BaseEvent.DerivedEventCase)
            {
                case BaseEvent.DerivedEventOneofCase.None:
                    {
                        throw new InvalidOperationException();
                    }
                case BaseEvent.DerivedEventOneofCase.PartyMemberJoinedEvent:
                    {
                        PartyMemberJoinedEvent derivedEvent = eventArgs.BaseEvent.PartyMemberJoinedEvent;
                        PartyMember member = new PartyMember
                        {
                            UserName = derivedEvent.Member.UserName,
                            Id = derivedEvent.Member.Id,
                            IpAddress = derivedEvent.Member.IpAddress,
                            Port = derivedEvent.Member.Port
                        };

                        AddMember(member);

                        break;
                    }
                case BaseEvent.DerivedEventOneofCase.PartyMemberLeftEvent:
                    {
                        PartyMemberJoinedEvent derivedEvent = eventArgs.BaseEvent.PartyMemberJoinedEvent;
                        var found = Members.Where(x => x.Id == derivedEvent.Member.Id);
                        foreach (PartyMember member in found)
                        {
                            _members.Remove(member);
                        }
                        break;
                    }
            }
        }

        #endregion Events

        #region Commands
        private async void OnJoinExecute()
        {
            ClientService.Instance.Start(Hostname, SettingsService.Instance.DefaultPort.ToString());
            await JoinParty();

            SetState(PartyState.Connecting);
        }

        private bool CanJoinExecute()
        {
            return true;
        }

        private async void OnHostExecute()
        {
            ServerService.Instance.Start();
            string localHost = ServerService.GetLocalIPAddress();
            ClientService.Instance.Start(localHost, SettingsService.Instance.DefaultPort.ToString());
            await JoinParty();

            ClientService.Instance.GetEvents();

            //Change state
            SetState(PartyState.Connecting);
        }

        private bool CanHostExecute()
        {
            return true;
        }


        #endregion Commands

        #region Private Methods
        /// <summary>
        /// Join the remote party.
        /// </summary>
        /// <returns></returns>
        private async Task JoinParty()
        {
            try
            {
                JoinPartyResponse resp = await ClientService.Instance.RemotePartyClient.JoinPartyAsync(new JoinPartyRequest
                {
                    UserName = SettingsService.Instance.Username,
                });

                SettingsService.Instance.ClientId = resp.ClientId;

                RefreshMembers();

                //Subscribe to events
                SubscribeRequest req = new SubscribeRequest();
                req.EventTypes.Add(EventType.PartyMemberJoined);
                req.EventTypes.Add(EventType.PartyMemberLeft);
                if (!string.IsNullOrWhiteSpace(SettingsService.Instance.ClientId))
                {
                    req.ClientId = SettingsService.Instance.ClientId;
                }


                Console.WriteLine(string.Format("CLIENT {0} - SubscribeToEvents called from client with id", SettingsService.Instance.ClientId));
                ClientService.Instance.RemoteEventClient.SubscribeToEvents(req);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error subscribing to events: " + ex.Message);
            }
        }

        /// <summary>
        /// Refresh members list.
        /// </summary>
        private void RefreshMembers()
        {
            MembersResponse response = ClientService.Instance.RemotePartyClient.GetPartyMembers(new Empty());
            //Add members
            foreach (PartyMember member in response.Members)
            {
                Members.Add(member);
            }
        }

        private void SetState(PartyState state)
        {
            _state = state;
            OnPropertyChanged("IsSelectingHost");
            OnPropertyChanged("IsNotSelectingHost");
        }

        private void AddMember(PartyMember member)
        {
            Members.Add(member);
        }

        #endregion Private Methods
    }
}