// This file (UnitRequiresAtLeastNUnitsRequirement.cs) is a part of the IBBoard.WarFoundry.API project and is copyright 2011 IBBoard
// 
// The file and the library/program it is in are licensed and distributed, without warranty, under the GNU Affero GPL license, either version 3 of the License or (at your option) any later version. Please see COPYING for more information and the full license.
using System;
using System.Collections.Generic;
using IBBoard.WarFoundry.API.Objects;

namespace IBBoard.WarFoundry.API.Objects.Requirement
{
	/// <summary>
	/// A requirement where a UnitType requires at least N units of one or more unit types before any number of that object can be taken in an army.
	/// </summary>
	public class UnitRequiresAtLeastNUnitsRequirement : RequiresAtLeastNUnitsRequirement
	{
		private UnitType requirementOnType;

		public UnitRequiresAtLeastNUnitsRequirement(UnitType requirementOn) : base()
		{
			requirementOnType = requirementOn;
		}

		/// <summary>
		/// Checks whether the supplied WarFoundryObject can be added to the supplied army.
		/// </summary>
		/// <returns>
		/// A <code>Validation</code> enum to show the result of the validation
		/// </returns>
		/// <param name='wfObject'>
		/// The object that we want to add. This may be involved in the check, or it may not affect the evaluation of the requirement
		/// </param>
		/// <param name='toArmy'>
		/// The army to add the object to.
		/// </param>
		public override Validation AllowsAdding(WarFoundryObject wfObject, Army toArmy)
		{
			return IsApplicable(wfObject, toArmy) ? base.AllowsAdding(wfObject, toArmy) : Validation.NotApplicable;
		}


		private bool IsApplicable(WarFoundryObject toObject, Army toArmy)
		{
			return IsApplicable(toArmy) || IsApplicable(toObject);
		}


		private bool IsApplicable(Army toArmy)
		{
			return toArmy.GetUnitTypeCount(requirementOnType) > 0;
		}


		private bool IsApplicable(WarFoundryObject toObject)
		{
			return requirementOnType.Equals(toObject) || (toObject is Unit && requirementOnType.Equals(((Unit)toObject).UnitType));
		}


		public override Validation ValidatesArmy(Army toArmy)
		{
			return IsApplicable(toArmy) ? base.ValidatesArmy(toArmy) : Validation.NotApplicable;
		}
	}
}