using System;
using System.Collections;
using Intersoft.Client.Data.ComponentModel;
using Intersoft.ClientUI.Samples.DataControls.ModelServices;

namespace Intersoft.ClientUI.Samples.DataControls.ViewModels
{
        public class CustomerViewModel : ViewModelBase
        {
                #region Constructors

                public CustomerViewModel()
                {
                        this.CustomersSource = CustomersRepository.Instance;
                        this.Presenter = new MessagePresenter();
                        this.LookUpDescriptor = new QueryDescriptor();
                        
                        // Initialize Sort Descriptor
                        this.LookUpDescriptor.SuspendQueryChanged = true;
                        this.LookUpDescriptor.SortDescriptors.Add(new SortDescriptor() { PropertyName = "ContactName", Direction = ListSortDirection.Ascending });
                        this.LookUpDescriptor.SuspendQueryChanged = false;
                }
                
                #endregion
                
                #region Fields

                private IEnumerable _customers;
                private QueryDescriptor _lookUpDescriptor;
                
                #endregion
                
                #region Properties

                protected IDataRepository CustomersSource { get; set; }

                public IEnumerable Customers
                {
                        get { return this._customers; }
                        set
                        {
                                if (_customers != value)
                                {
                                        _customers = value;
                                        OnPropertyChanged("Customers");
                                }
                        }
                }

                public QueryDescriptor LookUpDescriptor
                {
                        get { return _lookUpDescriptor; }
                        set
                        {
                                if (_lookUpDescriptor != value)
                                {
                                        if (_lookUpDescriptor != null)
                                                _lookUpDescriptor.QueryChanged -= new EventHandler(OnLookUpQueryChanged);

                                        _lookUpDescriptor = value;
                                        _lookUpDescriptor.QueryChanged += new EventHandler(OnLookUpQueryChanged);

                                        OnPropertyChanged("LookUpDescriptor");
                                }
                        }
                }

                protected virtual MessagePresenter Presenter { get; private set; }

                #endregion
                
                #region Methods
                
                private void OnLookUpQueryChanged(object sender, EventArgs e)
                {
                        this.CustomersSource.GetData
                        (
                                this.LookUpDescriptor,
                                (customers) =>
                                {
                                        if (this.LookUpDescriptor.PageDescriptor.PageIndex > 0)
                                        {
                                                ObservableCollection<object> items = this.Customers as ObservableCollection<object>;
                                                foreach (var customer in customers)
                                                {
                                                        items.Add(customer);
                                                }
                                        }
                                        else
                                        {
                                                ObservableCollection<object> items = new ObservableCollection<object>(customers.Cast<object>());
                                                this.Customers = items;
                                        }
                                },
                                (totalItemCount) =>
                                {
                                        if (totalItemCount != -1)
                                                this.LookUpDescriptor.PageDescriptor.TotalItemCount = totalItemCount;
                                },
                                (error) =>
                                {
                                        this.Presenter.ShowErrorMessage(
                                                "An exception has occurred during data loading\n." +
                                                "Message: " + error.Message +
                                                "Stack Trace: " + error.StackTrace);
                                }
                        );
                }
                
                #endregion
        }
}