using System;
using System.Collections.Generic;
using System.Data;

//
// assume que a tabela tinha coluna ID
// se quiserem podem usar a coluna NIF como campo chave da tabela; teriam que alterar algum código no Identity Map
//

public abstract class ActiveRecord
{
    int _id;

    public int ID
    {
        get { return _id; }
    }

    // ... métodos auxiliares de acesso a dados
    public abstract int Save();

    protected IDictionary<int, Entity> loaded = new Dictionary<int, Entity>();
}

public class Address
{
    string addr1;
    string addr2;
    string local;
    string postal;

    public Address(string addr1, string addr2, string local, string postal)
    {
        this.addr1 = addr1;
        this.addr2 = addr2;
        this.local = local;
        this.postal = postal;
    }
}

public class Entity : ActiveRecord
{
    protected abstract object CreateObject(DataRow r);
    protected Entity(DataRow r)
    {
        name = (string)r["Nome"];
        nif = (string)r["NIF"];
        email = (string)r["Email"];
        addr = new Address(r["Rua"], r["rua2linha"], r["localidadelocal"], r["codpostal"]);
        telefone = (string)r["telefone"];
    }

    string name;
    string nif;
    Address addr;
    string email;
    string telefone;

    public static IList<Entity> GetByName(string namePattern)
    {
        IList<Entity> ret = new List<Entity>();

        DataSet ds = ExecuteQuery("SELECT * FROM Contactos WHERE Nome LIKE ?", new object[] { namePattern+"%" } );
        foreach (DataRow r in ds.Tables[0].Rows)
        {
            Entity e;

            if (loaded.ContainsKey((int)r["ID"]))
                e = loaded[(int)r["ID"]];
            else
            {
                if ((byte)r["tipo"] == 0)
                    e = new Person(r);
                else
                    e = new Organization(r);
                loaded.Add((int)r["ID"], e);
            }

            ret.Add(e);
        }
        return ret;
    }
}

public class Person : Entity
{
    protected Person(DataRow r)
        : base(r)
    {
        dateOfBirth = (DateTime)r["DataNascimento"];
    }

    DateTime dateOfBirth;

    public int Age
    {
        get 
        {
            TimeSpan ts = DateTime.Now - dateOfBirth;
            return ts.Days/365;
        }
    }
}

public class Organization : Entity
{
    protected Organization(DataRow r) : base(r)
    {
    }
}