// This file (RequiresNoMoreThanNOfUnitTypeRequirement.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 IBBoard.WarFoundry.API.Objects;
using System.Collections.Generic;

namespace IBBoard.WarFoundry.API.Objects.Requirement
{
	/// <summary>
	/// A requirement where a WarFoundryObject cannot be taken in an army if more than N of a UnitType will be in the army.
	/// </summary>
	public class RequiresNoMoreThanNOfUnitTypeRequirement : IRequirement
	{
		private List<UnitCountRequirementData> limitedTypes;

		public RequiresNoMoreThanNOfUnitTypeRequirement(params UnitType[] limitedUnitTypes)
		{
			limitedTypes = new List<UnitCountRequirementData>();

			foreach (UnitType unitType in limitedUnitTypes)
			{
				AddUnitTypeRequirement(unitType);
			}
		}

		/// <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 virtual Validation AllowsAdding(WarFoundryObject wfObject, Army toArmy)
		{
			Validation canAdd = Validation.Passed;
			
			foreach (UnitCountRequirementData limit in limitedTypes)
			{
				if (GetUnitTypeCount(toArmy, limit.UnitType, wfObject) > limit.Count)
				{
					canAdd = Validation.Failed;
					break;
				}
			}
			
			return canAdd;
		}

		private int GetUnitTypeCount(Army toArmy, UnitType unitType, WarFoundryObject wfObject)
		{
			return toArmy.GetUnitTypeCount(unitType) + GetCountFromObject(wfObject, unitType);
		}

		private int GetCountFromObject(WarFoundryObject wfObject, UnitType limitedType)
		{
			return (limitedType.Equals(wfObject) || (wfObject is Unit && ((Unit)wfObject).UnitType.Equals(limitedType))) ? 1 : 0;
		}

		/// <summary>
		/// Adds a requirement for there to be no more than maxCount of a given UnitType
		/// </summary>
		/// <param name='unitType'>
		/// The unit type to limit.
		/// </param>
		/// <param name='minCount'>
		/// The maximum number of that type that must exist.
		/// </param>
		public void AddUnitTypeRequirement(UnitType unitType, int maxCount)
		{
			limitedTypes.Add(new UnitCountRequirementData(unitType, maxCount));
		}

		/// <summary>
		/// Adds a requirement for there to be none of a given UnitType
		/// </summary>
		/// <param name='unitType'>
		/// The unit type to limit.
		/// </param>
		public void AddUnitTypeRequirement(UnitType unitType)
		{
			AddUnitTypeRequirement(unitType, 0);
		}

		/// <summary>
		/// Checks whether the supplied army is currently valid according to this requirement.
		/// </summary>
		/// <returns>
		/// A <code>Validation</code> enum to show the result of the validation
		/// </returns>
		/// <param name='toValidate'>
		/// The army to validate
		/// </param>
		public Validation ValidatesArmy(Army army)
		{
			Validation canAdd = Validation.Passed;
			
			foreach (UnitCountRequirementData limit in limitedTypes)
			{
				if (army.GetUnitTypeCount(limit.UnitType) > limit.Count)
				{
					canAdd = Validation.Failed;
					break;
				}
			}
			
			return canAdd;
		}
	}
}