// 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 WarFoundryObject 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 RequiresAtLeastNUnitsRequirement : IRequirement
	{
		private List<UnitCountRequirementData> requiredTypes;

		public RequiresAtLeastNUnitsRequirement(params UnitType[] requiredUnitTypes)
		{
			requiredTypes = new List<UnitCountRequirementData>();

			foreach (UnitType unitType in requiredUnitTypes)
			{
				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 isValid = Validation.Passed;

			foreach (UnitCountRequirementData requirement in requiredTypes)
			{
				if (GetUnitTypeCount(toArmy, requirement.UnitType, wfObject) < requirement.Count)
				{
					isValid = Validation.Failed;
					break;
				}
			}

			return isValid;
		}

		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 at least minCount of a given UnitType
		/// </summary>
		/// <param name='unitType'>
		/// The unit type to require.
		/// </param>
		/// <param name='minCount'>
		/// The minimum number of that type that must exist.
		/// </param>
		public void AddUnitTypeRequirement(UnitType unitType, int minCount)
		{
			requiredTypes.Add(new UnitCountRequirementData(unitType, minCount));
		}

		/// <summary>
		/// Adds a requirement for there to be one or more of a given UnitType
		/// </summary>
		/// <param name='unitType'>
		/// The unit type to require.
		/// </param>
		public void AddUnitTypeRequirement (UnitType unitType)
		{
			AddUnitTypeRequirement(unitType, 1);
		}

		/// <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 virtual Validation ValidatesArmy(Army toValidate)
		{
			Validation isValid = Validation.Passed;

			foreach (UnitCountRequirementData requirement in requiredTypes)
			{
				if (toValidate.GetUnitTypeCount(requirement.UnitType) < requirement.Count)
				{
					isValid = Validation.Failed;
					break;
				}
			}

			return isValid;
		}
	}
}