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

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

        public DataComboBoxViewModel()            
        {          
            if (!this.IsInDesignMode)
            {                
                this.EmployeesSource = EmployeesRepository.Instance;                
                this.Presenter = new MessagePresenter();
                this.LookUpDescriptor = new QueryDescriptor();         
            }            
        }

        #endregion

        #region Fields

        private IEnumerable _employees;
        private QueryDescriptor _lookUpDescriptor;

        #endregion


        #region Properties

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

        protected IDataRepository EmployeesSource { get; set; }

        protected bool IsInDesignMode
        {
            get
            {
                return Intersoft.Client.Framework.ISControl.IsInDesignModeStatic;
            }
        }

        
        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.EmployeesSource.GetData
            (
                this.LookUpDescriptor,
                (employees) =>
                {
                    this.Employees = employees;
                },
                (totalItemCount) =>
                {
                },
                (error) =>
                {
                    this.Presenter.ShowErrorMessage(
                        "An exception has occurred during data loading\n." +
                        "Message: " + error.Message +
                        "Stack Trace: " + error.StackTrace);
                }
            );
        }

        #endregion
    }
}