using System.Collections;
using System.ServiceModel.DomainServices.Client;
using System.Windows;
using HowToSamples.Web;
using Intersoft.Client.Data.ComponentModel;
using Intersoft.Client.Data.Provider.Ria;
using Intersoft.Client.Framework.Input;

namespace HowToSamples.ViewModels
{
    public class ExportingViewModel: ViewModelBase
    {
        public ExportingViewModel()
        {
            this.Manager = new NorthwindDomainContext();
            this.CanUserExport = true;
            this.QueryDescriptor = new QueryDescriptor();
            this.ExportCommand = new DelegateCommand(ExecuteExportCommand);
        }

        private bool _canUserExport;
        private IEnumerable _exportItems;
        private IEnumerable _products;
        private QueryDescriptor _queryDescriptor;
       
        private NorthwindDomainContext Manager { get; set; }

        public bool CanUserExport
        {
            get { return this._canUserExport; }
            set
            {
                if (this._canUserExport != value)
                {
                    this._canUserExport = value;
                    this.OnPropertyChanged("CanUserExport");
                }
            }
        }

        public DelegateCommand ExportCommand { get; set; }

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

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

        public QueryDescriptor QueryDescriptor
        {
            get
            {
                return this._queryDescriptor;
            }
            set
            {
                if (this._queryDescriptor != value)
                {
                    if (this._queryDescriptor != null)
                        this._queryDescriptor.QueryChanged -= new System.EventHandler(OnQueryChanged);

                    this._queryDescriptor = value;
                    this._queryDescriptor.QueryChanged += new System.EventHandler(OnQueryChanged);

                    this.OnPropertyChanged("QueryDescriptor");
                }
            }
        }

        public void ExecuteExportCommand(object parameter)
        {
            Intersoft.Client.Data.ComponentModel.QueryDescriptor queryDescriptor = this.QueryDescriptor.CreateCopy(true, true, false); // copy the query descriptor, but exclude the page descriptor
            var query = this.Manager.GetProductsQuery().OrderBy(p => p.ProductID).Parse(queryDescriptor);

            this.Manager.Load(
               query,
               op =>
               {
                   if (op.IsComplete)
                   {
                       Intersoft.Client.Data.ComponentModel.PagedCollectionView current = this.Products as Intersoft.Client.Data.ComponentModel.PagedCollectionView;
                       Intersoft.Client.Data.ComponentModel.PagedCollectionView exportedItems = new Intersoft.Client.Data.ComponentModel.PagedCollectionView(op.Entities);

                       exportedItems.CopyDefinitionsFrom(current, true, false, false, false);
                       this.ExportItems = exportedItems; // supply the export process with correct collection.
                   }
                   else
                   {
                       MessageBox.Show(op.Error.ToString());
                   }
               },

               true);            
        }

        public virtual void LoadProducts()
        {
            if (Intersoft.Client.Framework.ISControl.IsInDesignModeStatic)
                return;

            var query = this.Manager.GetProductsQuery().OrderBy(p => p.ProductID).Parse(this.QueryDescriptor);
            query.IncludeTotalCount = true;

            this.Manager.Load(
               query,
               op =>
               {
                   if (op.IsComplete)
                   {
                       this.Products = new Intersoft.Client.Data.ComponentModel.PagedCollectionView(op.Entities);
                       this.QueryDescriptor.PageDescriptor.TotalItemCount = op.TotalEntityCount;
                   }
                   else
                   {
                       MessageBox.Show(op.Error.ToString());
                   }
               },

               true);
        }

        private void OnQueryChanged(object sender, System.EventArgs e)
        {            
            this.LoadProducts();
        }
    }
}