#region Copyright & License Information
/*
 * Copyright 2007-2015 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. For more information,
 * see COPYING.
 */
#endregion

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

namespace OpenRA.Mods.Common.Traits
{
	[Desc("Attach this to the player actor (not a building!) to define a new shared build queue.",
		"Will only work together with the Production: trait on the actor that actually does the production.",
		"You will also want to add PrimaryBuildings: to let the user choose where new units should exit.")]
	public class ClassicProductionQueueInfo : ProductionQueueInfo, Requires<TechTreeInfo>, Requires<PowerManagerInfo>, Requires<PlayerResourcesInfo>
	{
		[Desc("If you build more actors of the same type,", "the same queue will get its build time lowered for every actor produced there.")]
		public readonly bool SpeedUp = false;

		[Desc("Every time another production building of the same queue is",
			"constructed, the build times of all actors in the queue",
			"decreased by a percentage of the original time.")]
		public readonly int[] BuildTimeSpeedReduction = { 100, 85, 75, 65, 60, 55, 50 };

		public override object Create(ActorInitializer init) { return new ClassicProductionQueue(init, this); }
	}

	public class ClassicProductionQueue : ProductionQueue
	{
		static readonly ActorInfo[] NoItems = { };

		readonly Actor self;
		readonly ClassicProductionQueueInfo info;

		public ClassicProductionQueue(ActorInitializer init, ClassicProductionQueueInfo info)
			: base(init, init.Self, info)
		{
			self = init.Self;
			this.info = info;
		}

		[Sync] bool isActive = false;

		public override void Tick(Actor self)
		{
			// PERF: Avoid LINQ.
			isActive = false;
			foreach (var x in self.World.ActorsWithTrait<Production>())
			{
				if (x.Actor.Owner == self.Owner && x.Trait.Info.Produces.Contains(Info.Type))
				{
					var b = x.Actor.TraitOrDefault<Building>();
					if (b != null && b.Locked)
						continue;
					isActive = true;
					break;
				}
			}

			base.Tick(self);
		}

		public override IEnumerable<ActorInfo> AllItems()
		{
			return isActive ? base.AllItems() : NoItems;
		}

		public override IEnumerable<ActorInfo> BuildableItems()
		{
			return isActive ? base.BuildableItems() : NoItems;
		}

		public override TraitPair<Production> MostLikelyProducer()
		{
			return self.World.ActorsWithTrait<Production>()
				.Where(x => x.Actor.Owner == self.Owner
					&& x.Trait.Info.Produces.Contains(Info.Type))
				.OrderByDescending(x => x.Actor.IsPrimaryBuilding())
				.ThenByDescending(x => x.Actor.ActorID)
				.FirstOrDefault();
		}

		protected override bool BuildUnit(ActorInfo unit)
		{
			// Find a production structure to build this actor
			var bi = unit.TraitInfo<BuildableInfo>();

			// Some units may request a specific production type, which is ignored if the AllTech cheat is enabled
			var type = developerMode.AllTech ? Info.Type : bi.BuildAtProductionType ?? Info.Type;

			var producers = self.World.ActorsWithTrait<Production>()
				.Where(x => x.Actor.Owner == self.Owner
					&& x.Trait.Info.Produces.Contains(type))
					.OrderByDescending(x => x.Actor.IsPrimaryBuilding())
					.ThenByDescending(x => x.Actor.ActorID);

			if (!producers.Any())
			{
				CancelProduction(unit.Name, 1);
				return true;
			}

			foreach (var p in producers.Where(p => !p.Actor.IsDisabled()))
			{
				if (p.Trait.Produce(p.Actor, unit, p.Trait.Faction))
				{
					FinishProduction();
					return true;
				}
			}

			return false;
		}

		public override int GetBuildTime(string unitString)
		{
			return GetBuildTime(self.World.Map.Rules.Actors[unitString]);
		}

		public override int GetBuildTime(ActorInfo unit, BuildableInfo bi = null)
		{
			if (self.World.AllowDevCommands && self.Owner.PlayerActor.Trait<DeveloperMode>().FastBuild)
				return 0;

			var time = (int)(unit.GetBuildTime() * Info.BuildSpeed);

			if (info.SpeedUp)
			{
				var type = (bi ?? unit.TraitInfo<BuildableInfo>()).BuildAtProductionType ?? info.Type;

				var selfsameProductionsCount = self.World.ActorsWithTrait<Production>()
					.Count(p => p.Actor.Owner == self.Owner && p.Trait.Info.Produces.Contains(type));

				var speedModifier = selfsameProductionsCount.Clamp(1, info.BuildTimeSpeedReduction.Length) - 1;
				time = (time * info.BuildTimeSpeedReduction[speedModifier]) / 100;
			}

			return time;
		}
	}
}