using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.Builders;
using Tango.BL.Entities;
using Tango.Core.Commands;
using Tango.Core.DI;
using Tango.Integration.Operation;
using Tango.PMR.ThreadLoading;
using Tango.PPC.Common;
using Tango.PPC.Common.Connection;
using Tango.PPC.Common.Notifications;
using Tango.Settings;
using Tango.SharedUI;

namespace Tango.PPC.UI.Dialogs
{
    public class ThreadLoadingViewVM : DialogViewVM
    {
        public enum ThreadLoadingStage
        {
            Welcome,
            Preparing,
            ReadyForLoading,
            Finalizing,
            Completed,
            PreparationError,
            FinalizationError,
        }

        [TangoInject]
        private IMachineProvider MachineProvider { get; set; }

        [TangoInject]
        private INotificationProvider NotificationProvider { get; set; }

        private PPCSettings _settings;

        private StartThreadLoadingResponse _status;
        public StartThreadLoadingResponse Status
        {
            get { return _status; }
            set { _status = value; RaisePropertyChangedAuto(); }
        }

        private List<Rml> _rmls;
        public List<Rml> Rmls
        {
            get { return _rmls; }
            set { _rmls = value; RaisePropertyChangedAuto(); }
        }

        private Rml _selectedRml;
        public Rml SelectedRml
        {
            get { return _selectedRml; }
            set { _selectedRml = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private ThreadLoadingStage _stage;
        public ThreadLoadingStage Stage
        {
            get { return _stage; }
            set { _stage = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private String _error;
        public String Error
        {
            get { return _error; }
            set { _error = value; RaisePropertyChangedAuto(); }
        }


        public RelayCommand ContinueCommand { get; set; }
        public RelayCommand AbortCommand { get; set; }

        public ThreadLoadingViewVM(bool userInvoked = false)
        {
            CanClose = false;

            TangoIOC.Default.Inject(this);
            _settings = SettingsManager.Default.GetOrCreate<PPCSettings>();

            MachineProvider.MachineOperator.ThreadLoadingStatusChanged += MachineOperator_ThreadLoadingStatusChanged;

            ContinueCommand = new RelayCommand(Continue, CanContinue);
            AbortCommand = new RelayCommand(Abort);

            AdaptToState(userInvoked);
        }

        private void AdaptToState(bool userInvoked = false)
        {
            var status = MachineProvider.MachineOperator.ThreadLoadingStatus;

            if (status != null)
            {
                if (status.State == ThreadLoadingState.Preparing)
                {
                    Stage = ThreadLoadingStage.Preparing;
                }
                else if (status.State == ThreadLoadingState.ReadyForLoading)
                {
                    Stage = ThreadLoadingStage.ReadyForLoading;
                }
                else if (status.State == ThreadLoadingState.Finalizing)
                {
                    Stage = ThreadLoadingStage.Finalizing;
                }
                else if (status.State == ThreadLoadingState.PreparationError)
                {
                    OnPreparationError(status.ErrorReason);
                }
                else if (status.State == ThreadLoadingState.FinalizationError)
                {
                    OnFinalizationError(status.ErrorReason);
                }
                else if (status.State == ThreadLoadingState.Completed)
                {
                    if (userInvoked)
                    {
                        Stage = ThreadLoadingStage.Welcome;
                    }
                    else
                    {
                        Stage = ThreadLoadingStage.Completed;
                    }
                }
            }
        }

        private void MachineOperator_ThreadLoadingStatusChanged(object sender, StartThreadLoadingResponse e)
        {
            Status = e;
            AdaptToState();
        }

        private void Continue()
        {
            if (Stage == ThreadLoadingStage.Welcome)
            {
                Stage = ThreadLoadingStage.Preparing;
                StartPreparing();
            }
            else if (Stage == ThreadLoadingStage.ReadyForLoading)
            {
                ContinueThreadLoading();
            }
            else if (Stage == ThreadLoadingStage.Completed)
            {
                Accept();
            }
            else if (Stage == ThreadLoadingStage.PreparationError)
            {
                Stage = ThreadLoadingStage.Preparing;
                StartPreparing();
            }
            else if (Stage == ThreadLoadingStage.FinalizationError)
            {
                ContinueThreadLoading();
            }
        }

        private async void StartPreparing()
        {
            try
            {
                await MachineProvider.MachineOperator.StartThreadLoading();
            }
            catch (Exception ex)
            {
                OnPreparationError(ex.Message);
            }
        }

        private async void ContinueThreadLoading()
        {
            try
            {
                Stage = ThreadLoadingStage.Finalizing;
                await MachineProvider.MachineOperator.ContinueThreadLoading(SelectedRml.GetActiveProcessGroup().ProcessParametersTables.FirstOrDefault());
            }
            catch (Exception ex)
            {
                OnFinalizationError(ex.Message);
            }
        }

        private bool CanContinue()
        {
            bool canContinue = false;

            if (Stage != ThreadLoadingStage.Preparing && Stage != ThreadLoadingStage.Finalizing)
            {
                canContinue = true;
            }

            if (Stage == ThreadLoadingStage.ReadyForLoading && SelectedRml == null)
            {
                canContinue = false;
            }

            return canContinue;
        }

        private void OnPreparationError(String error)
        {
            Error = error;
            Stage = ThreadLoadingStage.PreparationError;
        }

        private void OnFinalizationError(String error)
        {
            Error = error;
            Stage = ThreadLoadingStage.FinalizationError;
        }

        private void Abort()
        {
            Cancel();
        }

        public async override void OnShow()
        {
            base.OnShow();

            LogManager.Log("Loading site RMLS...");

            List<Rml> rmls = new List<Rml>();

            using (ObservablesContext db = ObservablesContext.CreateDefault())
            {
                rmls = await new RmlsCollectionBuilder(db).SetAll().ForHeadType(MachineProvider.Machine.MachineHeadType).ForSite(MachineProvider.Machine.SiteGuid).WithActiveParametersGroup().BuildListAsync();
            }

            var selectedRml = rmls.SingleOrDefault(x => x.Guid == _settings.LoadedRmlGuid);

            Rmls = rmls;
            SelectedRml = selectedRml != null ? selectedRml : rmls.FirstOrDefault();
        }

        protected override void Cancel()
        {
            CleanUp();
            base.Cancel();
        }

        protected override void Accept()
        {
            CleanUp();
            base.Accept();
        }

        private void CleanUp()
        {
            MachineProvider.MachineOperator.ThreadLoadingStatusChanged -= MachineOperator_ThreadLoadingStatusChanged;

            if (SelectedRml != null)
            {
                _settings.LoadedRmlGuid = SelectedRml.Guid;
                _settings.Save();
            }
        }
    }
}