using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.ActionLogs;
using Tango.BL.Builders;
using Tango.BL.Entities;
using Tango.Core.Commands;
using Tango.Core.Threading;
using Tango.MachineStudio.Common;
using Tango.MachineStudio.Common.Authentication;
using Tango.MachineStudio.Common.Notifications;
using Tango.MachineStudio.Sites.Contracts;
using Tango.MachineStudio.Sites.Models;

namespace Tango.MachineStudio.Sites.ViewModels
{
    public class MainViewVM : StudioViewModel<IMainView>
    {
        private ObservablesContext _db;
        private INotificationProvider _notification;
        private IAuthenticationProvider _authentication;
        private IActionLogManager _actionLogManager;
        private ActionTimer _filter_timer;

        private List<SiteModel> _sites;
        public List<SiteModel> Sites
        {
            get { return _sites; }
            set { _sites = value; RaisePropertyChangedAuto(); }
        }

        private SiteModel _selectedSite;
        public SiteModel SelectedSite
        {
            get { return _selectedSite; }
            set { _selectedSite = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private String _filter;
        public String Filter
        {
            get { return _filter; }
            set { _filter = value; RaisePropertyChangedAuto(); OnFilterChanged(); }
        }

        private SiteDetailsViewVM _siteDetailsViewVM;
        public SiteDetailsViewVM SiteDetailsViewVM
        {
            get { return _siteDetailsViewVM; }
            set { _siteDetailsViewVM = value; RaisePropertyChangedAuto(); }
        }

        public RelayCommand AddSiteCommand { get; set; }

        public RelayCommand RemoveSiteCommand { get; set; }

        public RelayCommand ManageSiteCommand { get; set; }

        public RelayCommand BackToSitesCommand { get; set; }

        public MainViewVM(INotificationProvider notificationProvider, IAuthenticationProvider authentication, IActionLogManager actionLogManager)
        {
            _notification = notificationProvider;
            _authentication = authentication;
            _actionLogManager = actionLogManager;
            _filter_timer = new ActionTimer(TimeSpan.FromMilliseconds(500));

            ManageSiteCommand = new RelayCommand(() => LoadSelectedSite(), () => SelectedSite != null);
            BackToSitesCommand = new RelayCommand(() => { View.NavigateTo(SitesNavigationView.SitesView); });
            AddSiteCommand = new RelayCommand(AddNewSite);
            RemoveSiteCommand = new RelayCommand(RemoveSelectedSite, () => SelectedSite != null);
        }

        private async void RemoveSelectedSite()
        {
            if (!_notification.ShowQuestion("Are you sure you wish to remove the selected site?")) return;

            try
            {
                using (_notification.PushTaskItem("Removing site..."))
                {
                    IsFree = false;
                    await Task.Factory.StartNew(() =>
                    {
                        var site = _db.Sites.SingleOrDefault(x => x.Guid == SelectedSite.Guid);
                        site.Delete(_db);
                        _db.SaveChanges();
                        _actionLogManager.InsertLog(BL.Enumerations.ActionLogType.SiteDeleted, _authentication.CurrentUser, site.Name, site, "Site deleted using Machine Studio.");
                        Sites.Remove(SelectedSite);
                        LoadSites();
                    });
                }
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error removing site.");
                _notification.ShowError($"Error removing site.\n{ex.FlattenMessage()}");
            }
            finally
            {
                IsFree = true;
            }
        }

        private async void AddNewSite()
        {
            try
            {
                String name = _notification.ShowTextInput("Enter site name", "name");
                if (String.IsNullOrWhiteSpace(name)) return;

                using (_notification.PushTaskItem("Creating site..."))
                {
                    IsFree = false;
                    SiteDetailsViewVM = new SiteDetailsViewVM();
                    SiteDetailsViewVM.Saved += SiteDetailsViewVM_Saved;
                    await SiteDetailsViewVM.Init(SelectedSite?.Guid, _notification, _authentication, _actionLogManager, true, name);
                    View.NavigateTo(SitesNavigationView.SiteDetailsView);
                }
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error creating site.");
                _notification.ShowError($"Error creating site.\n{ex.FlattenMessage()}");
            }
            finally
            {
                IsFree = true;
            }
        }

        private async void LoadSelectedSite()
        {
            try
            {
                using (_notification.PushTaskItem("Loading site details..."))
                {
                    IsFree = false;
                    SiteDetailsViewVM = new SiteDetailsViewVM();
                    SiteDetailsViewVM.Saved += SiteDetailsViewVM_Saved;
                    await SiteDetailsViewVM.Init(SelectedSite.Guid, _notification, _authentication, _actionLogManager, false);
                    View.NavigateTo(SitesNavigationView.SiteDetailsView);
                }
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error loading site details.");
                _notification.ShowError($"Error loading site details.\n{ex.FlattenMessage()}");
            }
            finally
            {
                IsFree = true;
            }
        }

        private void SiteDetailsViewVM_Saved(object sender, EventArgs e)
        {
            OnFilterChanged();
            View.NavigateTo(SitesNavigationView.SitesView);
        }

        private void OnFilterChanged()
        {
            if (Filter != null)
            {
                _filter_timer.ResetReplace(() =>
                {
                    try
                    {
                        LoadSites();
                    }
                    catch (Exception ex)
                    {
                        LogManager.Log(ex, "Error loading sites list.");
                    }
                });
            }
        }

        private void LoadSites()
        {
            using (_notification.PushTaskItem("Loading sites..."))
            {
                Sites = (from site in _db.Sites
                         join organization in _db.Organizations on site.OrganizationGuid equals organization.Guid
                         join sites_rmls in _db.SitesRmls on site.Guid equals sites_rmls.SiteGuid into rmls
                         join sites_catalogs in _db.SitesCatalogs on site.Guid equals sites_catalogs.SiteGuid into catalogs
                         join sites_machines in _db.Machines on site.Guid equals sites_machines.SiteGuid into machines
                         where Filter == null || Filter == "" || site.Name.ToLower().StartsWith(Filter.ToLower()) || organization.Name.ToLower().StartsWith(Filter.ToLower())
                         select new
                         {
                             Site = site,
                             OrganizationName = organization.Name,
                             ThreadCount = rmls.Count(x => x.SiteGuid == site.Guid),
                             CatalogCount = catalogs.Count(x => x.SiteGuid == site.Guid),
                             MachineCount = machines.Count(x => x.SiteGuid == site.Guid)
                         }).Distinct().ToList().DistinctBy(x => x.Site.Guid).Select(x => new SiteModel()
                         {
                             Guid = x.Site.Guid,
                             ID = x.Site.ID,
                             Name = x.Site.Name,
                             Description = x.Site.Description,
                             ThreadCount = x.ThreadCount,
                             CatalogCount = x.CatalogCount,
                             MachineCount = x.MachineCount,
                             Organization = x.OrganizationName,
                         }).ToList();
            }
        }

        public override void OnApplicationReady()
        {
            _db = ObservablesContext.CreateDefault();
        }
    }
}