#region Copyright & License Information
/*
 * Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
 * This file is part of OpenRA, which is free software. It is made
 * available to you under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version. For more
 * information, see COPYING.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using OpenRA.Primitives;
using OpenRA.Traits;

namespace OpenRA.Mods.Common.Traits
{
	[Desc("Creates duplicates of the actor that collects the crate.")]
	class DuplicateUnitCrateActionInfo : CrateActionInfo
	{
		[Desc("The maximum number of duplicates to make.")]
		public readonly int MaxAmount = 2;

		[Desc("The minimum number of duplicates to make. Overrules MaxDuplicatesWorth.")]
		public readonly int MinAmount = 1;

		[Desc("The maximum total value allowed for the duplicates.", "Duplication stops if the total worth will exceed this number.", "-1 = no limit")]
		public readonly int MaxDuplicateValue = -1;

		[Desc("The maximum radius (in cells) that duplicates can be spawned.")]
		public readonly int MaxRadius = 4;

		[Desc("The list of unit target types we are allowed to duplicate.")]
		public readonly BitSet<TargetableType> ValidTargets = new BitSet<TargetableType>("Ground", "Water");

		[Desc("Which factions this crate action can occur for.")]
		public readonly HashSet<string> ValidFactions = new HashSet<string>();

		[Desc("Is the new duplicates given to a specific owner, regardless of whom collected it?")]
		public readonly string Owner = null;

		public override object Create(ActorInitializer init) { return new DuplicateUnitCrateAction(init.Self, this); }
	}

	class DuplicateUnitCrateAction : CrateAction
	{
		readonly DuplicateUnitCrateActionInfo info;

		public DuplicateUnitCrateAction(Actor self, DuplicateUnitCrateActionInfo info)
			: base(self, info)
		{
			this.info = info;
		}

		public bool CanGiveTo(Actor collector)
		{
			if (collector.Owner.NonCombatant)
				return false;

			if (info.ValidFactions.Any() && !info.ValidFactions.Contains(collector.Owner.Faction.InternalName))
				return false;

			if (!info.ValidTargets.Overlaps(collector.GetEnabledTargetTypes()))
				return false;

			var positionable = collector.TraitOrDefault<IPositionable>();
			if (positionable == null)
				return false;

			return collector.World.Map.FindTilesInCircle(collector.Location, info.MaxRadius)
				.Any(c => positionable.CanEnterCell(c));
		}

		public override int GetSelectionShares(Actor collector)
		{
			if (!CanGiveTo(collector))
				return 0;

			return base.GetSelectionShares(collector);
		}

		public override void Activate(Actor collector)
		{
			var positionable = collector.Trait<IPositionable>();
			var candidateCells = collector.World.Map.FindTilesInCircle(collector.Location, info.MaxRadius)
				.Where(c => positionable.CanEnterCell(c)).Shuffle(collector.World.SharedRandom)
				.ToArray();

			var duplicates = Math.Min(candidateCells.Length, info.MaxAmount);

			// Restrict duplicate count to a maximum value
			if (info.MaxDuplicateValue > 0)
			{
				var vi = collector.Info.TraitInfoOrDefault<ValuedInfo>();
				if (vi != null && vi.Cost > 0)
					duplicates = Math.Min(duplicates, info.MaxDuplicateValue / vi.Cost);
			}

			for (var i = 0; i < duplicates; i++)
			{
				var cell = candidateCells[i]; // Avoid modified closure bug
				collector.World.AddFrameEndTask(w => w.CreateActor(collector.Info.Name, new TypeDictionary
				{
					new LocationInit(cell),
					new OwnerInit(info.Owner ?? collector.Owner.InternalName)
				}));
			}

			base.Activate(collector);
		}
	}
}
