// This file (AbstractRequirement.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;

namespace IBBoard.WarFoundry.API.Objects.Requirement
{
	public abstract class AbstractUnitRequirement<OBJECT_TYPE> : IRequirement where OBJECT_TYPE : IWarFoundryObject
	{
		private List<UnitCountRequirementData> requiredTypes;
		private OBJECT_TYPE allowedObject;

		public AbstractUnitRequirement(OBJECT_TYPE allowedObject, params UnitType[] requiredUnitTypes)
		{
			this.allowedObject = allowedObject;
			requiredTypes = new List<UnitCountRequirementData>();

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

		public abstract string RequirementID { get; }

		protected List<UnitCountRequirementData> ConstraintTypes { get { return requiredTypes; } }

		public abstract void AddUnitTypeRequirement(UnitType unitType);

		public override bool Equals(object obj)
		{
			if (obj == null)
			{
				return false;
			}
			else if (obj.GetType().Equals(this.GetType()))
			{
				return TypeEquals((AbstractUnitRequirement<OBJECT_TYPE>)obj);
			}
			else
			{
				return false;
			}
		}

		protected virtual bool TypeEquals(AbstractUnitRequirement<OBJECT_TYPE> obj)
		{
			AbstractUnitRequirement<OBJECT_TYPE> otherReq = obj as AbstractUnitRequirement<OBJECT_TYPE>;
			if (!this.AllowedObject.Equals(otherReq.AllowedObject))
			{
				return false;
			}
			else if (!Collections.Collections.AreEqual(ConstraintTypes, otherReq.ConstraintTypes))
			{
				return false;
			}
			else
			{
				return true;
			}
		}

		public override int GetHashCode()
		{
			int hash = GetType().FullName.GetHashCode() + AllowedObject.GetHashCode();

			foreach (UnitCountRequirementData limit in ConstraintTypes)
			{
				hash += limit.GetHashCode();
			}

			return hash;
		}

		protected virtual bool IsApplicable(IWarFoundryObject toObjectAdded, Army toArmy, AddingContext context)
		{
			return IsApplicable(toArmy, context) || IsApplicable(toObjectAdded, context);
		}

		protected virtual bool IsApplicable(Army toArmy, AddingContext context)
		{
			return false;
		}

		protected virtual bool IsApplicable(IWarFoundryObject toObject, AddingContext context)
		{
			return false;
		}

		public string GetValidationMessage(Army army)
		{
			string message = "";

			Validation result = ValidatesArmy(army);
			if (!Validates.AsOkay(result))
			{
				message = GetValidationFailedMessage(army);
			}

			return message;
		}

		protected virtual string ValidationFailedMessage { get { return "Army must contain: {0}."; } }

		private string GetValidationFailedMessage(Army army)
		{
			return String.Format(ValidationFailedMessage, GetFailedRequirementsString(army));
		}

		protected abstract string GetFailedRequirementsString(Army army);

		public string GetAllowsAddingMessage(IWarFoundryObject toAdd, Army toArmy)
		{
			string message = "";

			Validation result = AllowsAdding(toAdd, toArmy);
			if (!Validates.AsOkay(result))
			{
				message = GetAllowsAddingFailedMessage(toAdd, toArmy);
			}

			return message;
		}

		protected virtual string AllowsAddingFailedMessage { get { return ValidationFailedMessage; } }

		protected string GetAllowsAddingFailedMessage(IWarFoundryObject toAdd, Army toArmy)
		{
			return String.Format(AllowsAddingFailedMessage, GetFailedAddingRequirementsString(toAdd, toArmy));
		}

		protected abstract string GetFailedAddingRequirementsString(IWarFoundryObject toAdd, Army toArmy);

		/// <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 Validation AllowsAdding(IWarFoundryObject wfObject, Army toArmy)
		{
			return AllowsAdding(wfObject, toArmy, null);
		}

		/// <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>
		/// <param name='context'>The context for the action (may be null)</param>
		public Validation AllowsAdding(IWarFoundryObject wfObject, Army toArmy, AddingContext context)
		{
			return IsApplicable(wfObject, toArmy, context) ? CheckAllowsAdding(wfObject, toArmy, context) : Validation.NotApplicable;
		}

		protected abstract Validation CheckAllowsAdding(IWarFoundryObject wfObject, Army toArmy, AddingContext context);

		public abstract  Validation ValidatesArmy(Army army);

		protected UnitType GetUnitTypeFromObject(IWarFoundryObject toObject)
		{
			UnitType unitType = null;

			if (toObject is UnitType)
			{
				unitType = (UnitType)toObject;
			}
			else if (toObject is Unit)
			{
				unitType = ((Unit)toObject).UnitType;
			}

			return unitType;
		}

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

		protected int GetUnitTypesCount(Army army, UnitType[] unitTypes)
		{
			return GetUnitTypesCount(army, unitTypes, null);
		}

		protected int GetUnitTypesCount(Army toArmy, UnitType[] unitTypes, IWarFoundryObject wfObject)
		{
			int count = 0;

			foreach (UnitType unitType in unitTypes)
			{
				count += GetUnitTypeCount(toArmy, unitType, wfObject);
			}

			return count;
		}

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

		protected int GetObjectCount(Army toArmy, IWarFoundryObject wfObject)
		{
			return GetObjectCountFromArmy(toArmy) + GetObjectCountFromObject(wfObject);
		}

		protected abstract int GetObjectCountFromArmy(Army toArmy);

		protected abstract int GetObjectCountFromArmy(Army toArmy, OBJECT_TYPE obj);

		protected virtual int GetObjectCountFromObject(IWarFoundryObject wfObject)
		{
			return allowedObject.Equals(wfObject) ? 1 : 0;
		}

		public OBJECT_TYPE AllowedObject { get { return allowedObject; } }

		protected string GetUnitTypeList(UnitCountRequirementData limit)
		{
			List<String> namesList = new List<String>();

			foreach (UnitType unitType in limit.UnitTypes)
			{
				namesList.Add(unitType.Name);
			}

			string[] names = namesList.ToArray();
			return String.Join(" or ", names);
		}
	}
}