Pilot.cs

namespace WarMachines.Machines
{
    using System.Collections.Generic;
    using System.Text;
    using System.Linq;
    using WarMachines.Interfaces;

    public class Pilot: IPilot
    {
        private HashSet<IMachine> machines =
            new HashSet<IMachine>();

        public Pilot(string name)
        {
            this.Name = name;
        }

        public string Name { get; set; }

        public void AddMachine(IMachine machine)
        {
            this.machines.Add(machine);
        }

        public string Report()
        {
            StringBuilder sb = new StringBuilder();

            if (this.machines.Count == 1)
            {
                sb.Append(" - 1 machine");
            }
            else if (this.machines.Count > 1)
            {
                sb.Append(" - " + this.machines.Count + " machines");
            }
            else
            {
                sb.Append(" - no machines");
            }

            sb.Append(System.Environment.NewLine);

            foreach (var machine in machines.OrderBy
                (machine => machine.HealthPoints)
                .ThenBy(machine => machine.Name))
            {
                sb.Append("- " + machine.Name);
                sb.Append(System.Environment.NewLine);
                sb.Append(machine.ToString());

            }

            return base.ToString() + sb.ToString().TrimEnd();
        }
    }
}