// 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 N of a UnitType can only be taken if there are M of a unit type in the army.
	/// </summary>
	public class UnitRequiresNUnitsForMUnitsRequirement : RequiresNUnitsForMObjectsRequirement<UnitType>
	{
		//Note: We're sticking with the old requirement name to prevent breakage
		public static readonly string REQUIREMENT_ID = "RequiresNUnitsForMUnits";

		public UnitRequiresNUnitsForMUnitsRequirement(UnitType requirementOn, params UnitType[] requiredUnitTypes) : base(requirementOn, requiredUnitTypes)
		{
			//Do nothing
		}

		/// <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(IWarFoundryObject wfObject, Army toArmy)
		{
			return IsApplicable(wfObject, toArmy) ? base.AllowsAdding(wfObject, toArmy) : Validation.NotApplicable;
		}

		protected override bool IsApplicable(IWarFoundryObject toObject, Army toArmy)
		{
			return IsApplicable(toObject) || IsApplicableForRequiredType(toObject, toArmy);
		}

		protected override bool IsApplicable(IWarFoundryObject toObject)
		{
			return AllowedObject.Equals(toObject) || (toObject is Unit && AllowedObject.Equals(((Unit)toObject).UnitType));
		}

		private bool IsApplicableForRequiredType(IWarFoundryObject toObject, Army toArmy)
		{
			bool isApplicable = false;
			UnitType addedType = toObject as UnitType;

			if (addedType == null)
			{
				addedType = (toObject is Unit) ? ((Unit)toObject).UnitType : null;
			}

			if (addedType != null && toArmy.GetUnitTypeCount(AllowedObject) > 0)
			{
				foreach (UnitCountRequirementData limit in ConstraintTypes)
				{
					if (Arrays.Contains(limit.UnitTypes, addedType))
					{
						isApplicable = true;
						break;
					}
				}
			}

			return isApplicable;
		}

		public override string RequirementID
		{
			get
			{
				return REQUIREMENT_ID;
			}
		}

		protected override int GetObjectCountFromArmy(Army toArmy)
		{
			return GetObjectCountFromArmy(toArmy, AllowedObject);
		}

		protected override int GetObjectCountFromArmy(Army toArmy, UnitType unitType)
		{
			return toArmy.GetUnitTypeCount(unitType);
		}

		protected override int GetAllowedObjectCount(Army army)
		{
			return army.GetUnitTypeCount(AllowedObject);
		}
	}
}