using System;
using System.Collections.ObjectModel;
using System.Threading.Tasks;
using System.Linq;
using Xamarin.Forms;
using Aurora.Services;
using Aurora.Proto.General;
using Aurora.Proto.Party;
using Aurora.Proto.Events;
using Aurora.Services.ClientService;
using Aurora.Services.PlayerService;
using Aurora.Services.EventManager;
using Aurora.Models.Media;

namespace Aurora.Design.Views.Party
{
    //TODO refactor
    enum PartyState
    {
        SelectingHost,
        InParty,
        Hosting,
        Connecting,
    }

    public class PartyViewModel : BaseViewModel
    {
        private PartyState _state;
        private string _hostname;
        private ObservableCollection<PartyMember> _members;
        private ObservableCollection<BaseMedia> _queue;
        private BaseMedia _selectedMedia;
        private PlayerService _player;
        private ClientService _client;

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

            _members = new ObservableCollection<PartyMember>();
            _queue = new ObservableCollection<BaseMedia>();

            SetState(PartyState.SelectingHost);
            this._player = PlayerService.Instance;

            PlayCommand = new Command(OnDoubleClickExecute, CanDoubleClickExecute);

            _client = ClientService.Instance;

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

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

        #region Properties

        /// <summary>
        /// Publc property for the members list
        /// </summary>
        /// <value></value>
        public ObservableCollection<PartyMember> Members
        {
            get
            {
                return _members;
            }
            set
            {
                SetProperty(ref _members, value);
            }
        }

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

        /// <summary>
        /// Public property indicating the state.
        /// </summary>
        /// <value></value>
        public bool IsNotSelectingHost
        {
            get { return _state != PartyState.SelectingHost; }
        }

        /// <summary>
        /// Public property for queue item source
        /// </summary>
        /// <value></value>
        public ObservableCollection<BaseMedia> Queue
        {
            get
            {
                return _queue;
            }
            set
            {
                if (value != _queue)
                {
                    SetProperty(ref _queue, value);
                }
            }
        }



        /// <summary>
        /// Public property for the hostname bindable field
        /// </summary>
        /// <value></value>
        public string Hostname
        {
            get { return _hostname; }
            set { SetProperty(ref _hostname, value); }
        }

        /// <summary>
        /// Public property for the currently selected song.
        /// </summary>
        /// <value></value>
        public BaseMedia SelectedSong
        {
            get { return _selectedMedia; }
            set { SetProperty(ref _selectedMedia, value); }
        }

        /// <summary>
        /// Public property for playing media
        /// </summary>
        /// <value></value>
        public Command PlayCommand { get; private set; }

        /// <summary>
        /// Public property for join command
        /// </summary>
        /// <value></value>
        public Command JoinCommand { get; set; }

        /// <summary>
        /// Pubic property for host command
        /// </summary>
        /// <value></value>
        public Command HostCommand { get; set; }

        #endregion Properties

        #region Events
        public override void OnActive()
        {
            //TODO
            //If in party subscribe to events
            //If in party get events
        }

        public override void OnInactive()
        {
            //TODO
            //unsubscribe
            //stop getting 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
                        };

                        Members.Add(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;
                    }
                case BaseEvent.DerivedEventOneofCase.MediaPlayingEvent:
                    {
                        MediaPlayingEvent derivedEvent = eventArgs.BaseEvent.MediaPlayingEvent;
                        Play(derivedEvent);
                        break;
                    }
                case BaseEvent.DerivedEventOneofCase.MediaPausedEvent:
                    {
                        MediaPausedEvent derivedEvent = eventArgs.BaseEvent.MediaPausedEvent;
                        StopPlaying();
                        break;
                    }
            }
        }

        #endregion Events

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

            //TODO add cancellation token
            try
            {
                SetState(PartyState.InParty);
                await _client.GetEvents().ConfigureAwait(true);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception occurred while receiviing events: ", ex.Message);
            }
        }

        private bool CanJoinExecute()
        {
            return true;
        }

        private async void OnHostExecute()
        {
            //Change state
            SetState(PartyState.Connecting);
            ServerService.Instance.Start();
            string localHost = ServerService.GetLocalIPAddress();
            _client.IsHost = true;
            _client.Start(localHost, SettingsService.Instance.DefaultPort.ToString());
            await JoinParty();


            //TODO add cancellation token
            try
            {
                SetState(PartyState.Hosting);
                await _client.GetEvents().ConfigureAwait(true);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception occurred while receiviing events: ", ex.Message);
            }
        }

        private bool CanHostExecute()
        {
            return true;
        }

        public override void OnPlayButtonExecute()
        {
            _player.Play();
            switch (_player.PlaybackState)
            {
                case PlaybackState.Buffering:
                    {
                        _player.Play();
                        break;
                    }
                case PlaybackState.Playing:
                    {
                        _player.Pause();
                        break;
                    }
            }
        }

        public override bool CanPlayButtonExecute()
        {
            return this._state == PartyState.Hosting && this._player.IsLoaded;
        }

        public override bool CanNextButtonExecute()
        {
            return this._state == PartyState.Hosting;
        }

        public override bool CanPreviousButtonExecute()
        {
            return this._state == PartyState.Hosting;
        }

        /// <summary>
        /// On double click execute, fire media playing event
        /// </summary>
        public void OnDoubleClickExecute()
        {
            AudioMetadata meta = _selectedMedia.Metadata as AudioMetadata;
            MediaPlayingEvent mediaPlaying = new MediaPlayingEvent()
            {
                Media = new RemoteMediaData()
                {
                    Id = _selectedMedia.Id,
                    Title = meta.Title,
                    Artist = meta.Artist,
                    Album = meta.Album,
                }
            };

            EventManager.Instance.FireEvent(new BaseEvent()
            {
                MediaPlayingEvent = mediaPlaying
            });
        }

        public bool CanDoubleClickExecute()
        {
            return this._state == PartyState.Hosting;
        }


        #endregion Commands

        #region Private Methods
        /// <summary>
        /// Join the remote party.
        /// </summary>
        /// <returns></returns>
        private async Task JoinParty()
        {
            try
            {
                JoinPartyResponse resp = await _client.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);
                req.EventTypes.Add(EventType.MediaPlaying);
                req.EventTypes.Add(EventType.MediaStopped);
                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));
                _client.RemoteEventClient.SubscribeToEvents(req);

                QueueResponse queueResponse = _client.RemotePartyClient.GetQueue(new Empty());

                Queue.Clear();
                //Convert received data to remote audio models
                foreach (RemoteMediaData data in queueResponse.MediaList)
                {
                    //Assign received metadata (since this can't be aquired from a file)
                    AudioMetadata meta = new AudioMetadata();
                    meta.Title = data.Title;
                    meta.Album = data.Album;
                    meta.Artist = data.Artist;
                    meta.Duration = data.Duration;

                    RemoteAudio remote = new RemoteAudio(data.Id,
                        meta,
                        _client.RemotePartyClient);

                    Queue.Add(remote);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error subscribing to events: " + ex.Message);
            }
        }

        private async Task LeaveParty()
        {
            //Stop receiving events
            _client.StopEvents();

            //Unsubscribe
            UnsubscribeAllRequest unsubscribeReq = new UnsubscribeAllRequest();
            await _client.RemoteEventClient.UnsubscribeFromAllAsync(unsubscribeReq);

            //Leave party
            LeavePartyRequest leaveReq = new LeavePartyRequest();
            await _client.RemotePartyClient.LeavePartyAsync(leaveReq);
        }

        /// <summary>
        /// Refresh members list.
        /// </summary>
        private void RefreshMembers()
        {
            MembersResponse response = _client.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 async void Play(MediaPlayingEvent args)
        {
            //TODO this design assumes all played music is in a queue
            //TODO this is a slow design depending on size of queue
            if (_queue.Any((BaseMedia media) => media.Id == args.Media.Id))
            {
                BaseMedia media = _queue.First((BaseMedia med) => med.Id == args.Media.Id);
                base.Media = media;
                await _player.LoadMedia(base.Media).ConfigureAwait(true);
                _player.Play();
            }
        }

        private void StopPlaying()
        {
            _player.Pause();
        }

        #endregion Private Methods
    }
}