MVVM for Multi Platforms

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using GeographicRepresentation.Interfaces;
using GeographicRepresentation.Lib.Model;

namespace GeographicRepresentation.Lib.ViewModel
{
    /// <summary>
    /// This is a base view model for a city
    /// </summary>
    public class CityViewModel : ICityViewModel
    {
        #region Members        
        /// <summary>
        /// A Model object of the city
        /// </summary>
        City m_City;

        #endregion

        #region Properties

        /// <summary>
        /// A property for extracting the city value out of the view model for saving and changing the value once
        /// a refresh is called. It is for usuage only within the current namespace
        /// </summary>
        internal City City
        {
            get
            {
                return m_City;
            }
            set
            {
                m_City = value;
            }
        }

        #endregion

        #region Methods

        #region Ctor

        public CityViewModel(City city) 
        {
            m_City = city;
        }

        #endregion

        #region ICityViewModel Members

        public Guid Id
        {
            get 
            {
                return m_City.Id;
            }
        }

        /// <summary>
        /// The City name can only be edited via the Edit mode, so it is declared virtual and would be overriden in the edit mode.
        /// </summary>
        public virtual string CityName
        {
            get
            {
                return m_City.Name;
            }
            set
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// The Population can only be edited via the Edit mode, so it is declared virtual and would be overriden in the edit mode.
        /// </summary>
        public virtual int Population
        {
            get
            {
                return m_City.Population;
            }
            set
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// The Time zone can only be edited via the Edit mode, so it is declared virtual and would be overriden in the edit mode.
        /// </summary>
        public virtual short TimeZone
        {
            get
            {
                return m_City.TimeZone;
            }
            set
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// Calculate the current time and add the differences in the time zone to return an accurate state of the current time
        /// </summary>
        /// <returns></returns>
        public DateTime GetCurrentTime()
        {
            DateTime current = DateTime.Now;
            current = current.AddHours(m_City.TimeZone);
            return current;
        }

        #endregion

        #endregion
        
    }

    /// <summary>
    /// This is the read only view model for the city
    /// </summary>
    public class ReadOnlyCityViewModel :  CityViewModel, IReadOnlyCityViewModel
    {
        #region Methods

        #region Ctor

        public ReadOnlyCityViewModel(City city) : base(city)
        {
        }

        #endregion

        #region IReadOnlyObject Members

        /// <summary>
        /// Reload the data from the repository
        /// </summary>
        public void Refresh()
        {
            DataManager.Instance.LoadDataFromStorage();
            this.City = DataManager.Instance.GetCity(this.Id);
        }

        #endregion

        #endregion
    }

    /// <summary>
    /// This is the view model which enables editing data regarding a city
    /// </summary>
    public class EditableCityViewModel : CityViewModel, IEditableCityViewModel
    {
        #region Members

        /// <summary>
        /// The countries id, in case this is a new city
        /// </summary>
        Guid m_CountryId;
        /// <summary>
        /// Keep a replica of the original city, if cancelation was made
        /// </summary>
        City m_OrigCity;

        #endregion

        #region Methods

        #region Ctor

        public EditableCityViewModel(City city) : base(city)
        {
            m_CountryId = Guid.Empty;
            m_OrigCity = new City(city);
        }

        public EditableCityViewModel(City city, Guid countryId)
            : base(city)
        {
            m_CountryId = countryId;
        }

        #endregion

        #region IEditableObject Members

        /// <summary>
        /// Save the data in the repository
        /// </summary>
        public void Save()
        {
            // Add the City into the country
            if (m_CountryId != Guid.Empty)
            {
                Country country = DataManager.Instance.GetCountry(m_CountryId);
                country.Cities.Add(this.City);
            }
            DataManager.Instance.SaveDataIntoStorage();
            if (OnSaveCompleted != null)
            {
                OnSaveCompleted(true);
            }
        }

        /// <summary>
        /// Upon cancelation of the operation, return the original values to the city
        /// </summary>
        public void Cancel()
        {
            this.City.Name = m_OrigCity.Name;
        }

        public event OperationCompletedDelegate OnSaveCompleted;

        /// <summary>
        /// The edit view model is the only place in which the property could be changed. Therefore it is overriden
        /// </summary>
        public override string CityName
        {
            get
            {
                return base.CityName;
            }
            set
            {
                this.City.Name = value;
            }
        }

        /// <summary>
        /// The edit view model is the only place in which the property could be changed. Therefore it is overriden
        /// </summary>
        public override int Population
        {
            get
            {
                return base.Population;
            }
            set
            {
                base.City.Population = value;
            }
        }

        /// <summary>
        /// The edit view model is the only place in which the property could be changed. Therefore it is overriden
        /// </summary>
        public override short TimeZone
        {
            get
            {
                return base.TimeZone;
            }
            set
            {
                base.City.TimeZone = value;
            }
        }

        #endregion

        #endregion
    }
}