using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
using Tango.BL.Entities;
using Tango.Core.Commands;
using Tango.FSE.Common;
using Tango.FSE.Common.Navigation;
using Tango.FSE.UsersAndRoles.Navigation;
using Tango.FSE.UsersAndRoles.Views;
using static Tango.FSE.UsersAndRoles.ViewModels.OrganizationUsersViewVM;

namespace Tango.FSE.UsersAndRoles.ViewModels
{
    public class OrganizationUsersViewVM : UsersAndRolesViewModel, INavigationObjectReceiver<NavigationObject>
    {
        public class NavigationObject
        {
            public Organization Organization { get; set; }
            public User SelectedUser { get; set; }
        }

        private bool _requiresReloading;
        private User _initialUser;

        private Organization _organization;
        /// <summary>
        /// Gets or sets the organization.
        /// </summary>
        public Organization Organization
        {
            get { return _organization; }
            set { _organization = value; RaisePropertyChangedAuto(); }
        }

        private ObservableCollection<User> _users;
        /// <summary>
        /// Gets or sets the users.
        /// </summary>
        public ObservableCollection<User> Users
        {
            get { return _users; }
            set { _users = value; RaisePropertyChangedAuto(); }
        }

        private User _selectedUser;
        public User SelectedUser
        {
            get { return _selectedUser; }
            set { _selectedUser = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets or sets the users view source.
        /// </summary>
        public ICollectionView UsersView { get; set; }

        private String _filter;
        /// <summary>
        /// Gets or sets the users search filter.
        /// </summary>
        public String Filter
        {
            get { return _filter; }
            set { _filter = value; RaisePropertyChangedAuto(); OnFilterChanged(); }
        }

        private bool _showDeleted;
        public bool ShowDeleted
        {
            get { return _showDeleted; }
            set { _showDeleted = value; RaisePropertyChangedAuto(); UsersView?.Refresh(); }
        }

        /// <summary>
        /// Navigates to the user details view with the specified user.
        /// </summary>
        public RelayCommand<User> EditUserCommand { get; set; }

        /// <summary>
        /// Removes the specified user.
        /// </summary>
        public RelayCommand<User> RemoveUserCommand { get; set; }

        /// <summary>
        /// Adds a new user.
        /// </summary>
        public RelayCommand AddUserCommand { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="OrganizationUsersViewVM"/> class.
        /// </summary>
        public OrganizationUsersViewVM()
        {
            Users = new ObservableCollection<User>();
            EditUserCommand = new RelayCommand<User>(EditUser);
            RemoveUserCommand = new RelayCommand<User>(SuspendUser);
            AddUserCommand = new RelayCommand(AddUser, () => IsFree);
        }

        private void AddUser()
        {
            ModularNavigationManager.NavigateTo(UsersAndRolesView.UserDetailsView, new UserDetailsViewVM.NavigationObject()
            {
                IsNewUser = true,
                Organization = Organization
            });
        }

        private async void SuspendUser(User user)
        {
            if (await NotificationProvider.ShowWarningQuestion($"Are you sure you want to suspend '{user.Contact.FullName}' ?"))
            {
                try
                {
                    IsFree = false;

                    using (NotificationProvider.PushTaskItem("Suspending account..."))
                    {
                        var updatedUser = await Services.OrganizationsService.SuspendUser(user);
                        Users.Replace(user, updatedUser);
                    }

                    await NotificationProvider.ShowSuccess("The selected user is now suspended and can be reactivated.");
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, $"Error suspending user '{user.Email}'.");
                    await NotificationProvider.ShowError($"Error suspending the selected user\n{ex.FlattenMessage()}");
                }
                finally
                {
                    IsFree = true;
                }
            }
        }

        private void EditUser(User user)
        {
            ModularNavigationManager.NavigateTo(UsersAndRolesView.UserDetailsView, new UserDetailsViewVM.NavigationObject()
            {
                User = user
            });
        }

        private async Task LoadUsers()
        {
            if (Organization != null)
            {
                try
                {
                    IsFree = false;
                    var users = await Services.OrganizationsService.GetOrganizationUsers(Organization.Guid, true);
                    var usersCollection = new ObservableCollection<User>(users);
                    UsersView = CollectionViewSource.GetDefaultView(usersCollection);
                    UsersView.Filter = FilterUsers;
                    Users = usersCollection;
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, $"Error loading organization users for organization '{Organization.Name}'.");
                    await NotificationProvider.ShowError($"Error loading the selected organization users.\n{ex.FlattenMessage()}");
                    await NavigationManager.NavigateBack();
                }
                finally
                {
                    IsFree = true;
                }
            }
            else
            {
                await NotificationProvider.ShowError("No organization selected.");
            }
        }

        private void OnFilterChanged()
        {
            UsersView?.Refresh();
        }

        private bool FilterUsers(object obj)
        {
            var user = obj as User;
            String filter = Filter ?? String.Empty;

            if (user != null)
            {
                return (!filter.IsNotNullOrEmpty() || user.Contact.FullName.ToLower().Contains(filter.ToLower()) || user.Email.ToLower().Contains(filter.ToLower())) && (!user.Deleted || ShowDeleted);
            }

            return true;
        }

        /// <summary>
        /// Called when the navigation system has navigated to this VM view.
        /// </summary>
        public async override void OnNavigatedTo()
        {
            base.OnNavigatedTo();

            if (_requiresReloading)
            {
                await LoadUsers();

                if (_initialUser != null)
                {
                    SelectedUser = Users.SingleOrDefault(x => x.Guid == _initialUser.Guid);
                }
            }

            _requiresReloading = false;
            _initialUser = null;
        }

        /// <summary>
        /// Called when navigation system is going to navigate to this instance with the specified object.
        /// </summary>
        /// <param name="obj">The object.</param>
        public void OnNavigatedToWithObject(NavigationObject obj)
        {
            Organization = obj.Organization;
            _initialUser = obj.SelectedUser;
            _requiresReloading = true;
        }
    }
}