#region Copyright & License Information
/*
 * Copyright 2007-2011 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;
using System.Collections.Generic;
using System.Linq;
using OpenRA.Mods.RA.Buildings;
using OpenRA.Traits;

namespace OpenRA.Mods.RA
{
	public class ProductionQueueInfo : ITraitInfo
	{
		public readonly string Type = null;
		public float BuildSpeed = 0.4f;
		public readonly int LowPowerSlowdown = 3;
		
		public readonly string ReadyAudio = "unitrdy1.aud";
		public readonly string BlockedAudio = "nobuild1.aud";
		public readonly string QueuedAudio = "train1.aud";
		public readonly string OnHoldAudio = "onhold1.aud";
		public readonly string CancelledAudio = "cancld1.aud";
		
		public virtual object Create(ActorInitializer init) { return new ProductionQueue(init.self, init.self.Owner.PlayerActor, this); }
	}

	public class ProductionQueue : IResolveOrder, ITick, ITechTreeElement, INotifyCapture, ISync
	{
		public readonly Actor self;
		public ProductionQueueInfo Info;
		PowerManager PlayerPower;
		PlayerResources playerResources;
		string Race;
		
		// A list of things we are currently building
		public List<ProductionItem> Queue = new List<ProductionItem>();
				
		[Sync]
		public int QueueLength { get { return Queue.Count; } }
		[Sync]
		public int CurrentRemainingCost { get { return QueueLength == 0 ? 0 : Queue[0].RemainingCost; } }
		[Sync]
		public int CurrentRemainingTime { get { return QueueLength == 0 ? 0 : Queue[0].RemainingTime; } }
		[Sync]
		public int CurrentSlowdown { get { return QueueLength == 0 ? 0 : Queue[0].slowdown; } }
		[Sync]
		public bool CurrentPaused { get { return QueueLength == 0 ? false : Queue[0].Paused; } }
		[Sync]
		public bool CurrentDone { get { return QueueLength == 0 ? false : Queue[0].Done; } }
		
		// A list of things we could possibly build, even if our race doesn't normally get it
		public Dictionary<ActorInfo, ProductionState> Produceable;

		public ProductionQueue( Actor self, Actor playerActor, ProductionQueueInfo info )
		{
			this.self = self;
			this.Info = info;
			playerResources = playerActor.Trait<PlayerResources>();
			PlayerPower = playerActor.Trait<PowerManager>();
			
			Race = self.Owner.Country.Race;
			Produceable = InitTech(playerActor);
		}
		
		public void OnCapture(Actor self, Actor captor, Player oldOwner, Player newOwner)
		{
			PlayerPower = newOwner.PlayerActor.Trait<PowerManager>();
			playerResources = newOwner.PlayerActor.Trait<PlayerResources>();
			Queue.Clear();

			// Produceable contains the tech from the original owner - this is desired so we don't clear it.
			Produceable = InitTech(self.Owner.PlayerActor);
		}

		Dictionary<ActorInfo, ProductionState> InitTech(Actor playerActor)
		{
			var tech = new Dictionary<ActorInfo, ProductionState>();
			var ttc = playerActor.Trait<TechTree>();

			foreach (var a in AllBuildables(Info.Type))
			{
				var bi = a.Traits.Get<BuildableInfo>();
				// Can our race build this by satisfying normal prereqs?
				var buildable = bi.Owner.Contains(Race);
				tech.Add(a, new ProductionState() { Visible = buildable && !bi.Hidden });
				if (buildable)
					ttc.Add(a.Name, a.Traits.Get<BuildableInfo>().Prerequisites.ToList(), this);
			}

			return tech;
		}
		
		IEnumerable<ActorInfo> AllBuildables(string category)
		{
			return Rules.Info.Values
				.Where( x => x.Name[ 0 ] != '^' )
				.Where( x => x.Traits.Contains<BuildableInfo>() )
				.Where( x => x.Traits.Get<BuildableInfo>().Queue == category );
		}
			
		public void OverrideProduction(ActorInfo type, bool buildable)
		{
			Produceable[type].Buildable = buildable;
			Produceable[type].Sticky = true;
		}
				
		public void PrerequisitesAvailable(string key)
		{
			var ps = Produceable[ Rules.Info[key] ];
			if (!ps.Sticky)
				ps.Buildable = true;
		}
		
		public void PrerequisitesUnavailable(string key)
		{
			var ps = Produceable[ Rules.Info[key] ];
			if (!ps.Sticky)
				ps.Buildable = false;
		}

		public ProductionItem CurrentItem()
		{
			return Queue.ElementAtOrDefault(0);
		}
		
		public IEnumerable<ProductionItem> AllQueued()
		{
			return Queue;
		}
		
		public virtual IEnumerable<ActorInfo> AllItems()
		{			
			if (self.World.LobbyInfo.GlobalSettings.AllowCheats && self.Owner.PlayerActor.Trait<DeveloperMode>().AllTech)
				return Produceable.Select(a => a.Key);
			
			return Produceable.Where(a => a.Value.Buildable || a.Value.Visible).Select(a => a.Key);
		}
		
		public virtual IEnumerable<ActorInfo> BuildableItems()
		{
			if (self.World.LobbyInfo.GlobalSettings.AllowCheats && self.Owner.PlayerActor.Trait<DeveloperMode>().AllTech)
				return Produceable.Select(a => a.Key);
			
			return Produceable.Where(a => a.Value.Buildable).Select(a => a.Key);
		}
		
		public bool CanBuild(ActorInfo actor)
		{
			return Produceable.ContainsKey(actor) && Produceable[actor].Buildable;
		}
		
		public virtual void Tick( Actor self )
		{		
			while( Queue.Count > 0 && !BuildableItems().Any(b => b.Name == Queue[ 0 ].Item) )
			{
				playerResources.GiveCash(Queue[0].TotalCost - Queue[0].RemainingCost); // refund what's been paid so far.
				FinishProduction();
			}
			if( Queue.Count > 0 )
				Queue[ 0 ].Tick( playerResources, PlayerPower );
		}

		public void ResolveOrder( Actor self, Order order )
		{
			switch( order.OrderString )
			{
			case "StartProduction":
				{
					var unit = Rules.Info[order.TargetString];
					var bi = unit.Traits.Get<BuildableInfo>();
					if (bi.Queue != Info.Type)
						return; /* Not built by this queue */
				
					var cost = unit.Traits.Contains<ValuedInfo>() ? unit.Traits.Get<ValuedInfo>().Cost : 0;
					var time = GetBuildTime(order.TargetString);

					if (!BuildableItems().Any(b => b.Name == order.TargetString))
						return;	/* you can't build that!! */
				
					for (var n = 0; n < order.TargetLocation.X; n++)	// repeat count
					{
						bool hasPlayedSound = false;
						BeginProduction(new ProductionItem(this, order.TargetString, (int)time, cost,
								() => self.World.AddFrameEndTask(
									_ =>
									{
										var isBuilding = unit.Traits.Contains<BuildingInfo>();
										
										if (isBuilding && !hasPlayedSound)
										{
											Sound.PlayToPlayer(order.Player, Info.ReadyAudio);
											hasPlayedSound = true;
										}
										else if (!isBuilding)
										{
											if (BuildUnit(order.TargetString))
												Sound.PlayToPlayer(order.Player, Info.ReadyAudio);
											else if (!hasPlayedSound && time > 0)
											{
												Sound.PlayToPlayer(order.Player, Info.BlockedAudio);
												hasPlayedSound = true;
											}
										}
									})));
					}
					break;
				}
			case "PauseProduction":
				{
					if( Queue.Count > 0 && Queue[0].Item == order.TargetString )
						Queue[0].Paused = ( order.TargetLocation.X != 0 );
					break;
				}
			case "CancelProduction":
				{
					CancelProduction(order.TargetString,order.TargetLocation.X);
					break;
				}
			}
		}
		
		public int GetBuildTime(String unitString)
		{
			var unit = Rules.Info[unitString];
			if (unit == null || ! unit.Traits.Contains<BuildableInfo>())
				return 0;
			
			if (self.World.LobbyInfo.GlobalSettings.AllowCheats && self.Owner.PlayerActor.Trait<DeveloperMode>().FastBuild) return 0;
			var cost = unit.Traits.Contains<ValuedInfo>() ? unit.Traits.Get<ValuedInfo>().Cost : 0;
			var time = cost
				* Info.BuildSpeed
				* (25 * 60) /* frames per min */				/* todo: build acceleration, if we do that */
				 / 1000;
			return (int) time;
		}

		protected void CancelProduction(string itemName, int numberToCancel)
		{
			for (var i = 0; i < numberToCancel; i++)
				CancelProductionInner(itemName);
		}

		void CancelProductionInner(string itemName)
		{
			var lastIndex = Queue.FindLastIndex(a => a.Item == itemName);

			if (lastIndex > 0)
				Queue.RemoveAt(lastIndex);
			else if (lastIndex == 0)
			{
				var item = Queue[0];
				playerResources.GiveCash(item.TotalCost - item.RemainingCost);	// refund what has been paid
				FinishProduction();
			}
		}

		public void FinishProduction()
		{
			if (Queue.Count == 0) return;
			Queue.RemoveAt(0);
		}

		protected void BeginProduction( ProductionItem item )
		{
			Queue.Add(item);
		}

		protected static bool IsDisabledBuilding(Actor a)
		{
			return a.TraitsImplementing<IDisable>().Any(d => d.Disabled);
		}

		// Builds a unit from the actor that holds this queue (1 queue per building)
		// Returns false if the unit can't be built
		protected virtual bool BuildUnit( string name )
		{			
			// Cannot produce if i'm dead
			if (!self.IsInWorld || self.IsDead())
			{
				CancelProduction(name, 1);
				return true;
			}
			
			var sp = self.TraitsImplementing<Production>().FirstOrDefault(p => p.Info.Produces.Contains(Info.Type));
			if (sp != null && !IsDisabledBuilding(self) && sp.Produce(self, Rules.Info[ name ]))
			{
				FinishProduction();
				return true;
			}
			return false;
		}
	}

	public class ProductionState
	{
		public bool Visible = false;
		public bool Buildable = false;
		public bool Sticky = false;
	}
	
	public class ProductionItem
	{
		public readonly string Item;
		public readonly ProductionQueue Queue;
		public readonly int TotalTime;
		public readonly int TotalCost;
		public int RemainingTime { get; private set; }
		public int RemainingCost { get; private set; }

		public bool Paused = false, Done = false;
		public Action OnComplete;
		public int slowdown = 0;

		public ProductionItem(ProductionQueue queue, string item, int time, int cost, Action onComplete)
		{
			if (time <= 0) time = 1;
			Item = item;
			RemainingTime = TotalTime = time;
			RemainingCost = TotalCost = cost;
			OnComplete = onComplete;
			Queue = queue;

			//Log.Write("debug", "new ProductionItem: {0} time={1} cost={2}", item, time, cost);
		}

		public void Tick(PlayerResources pr, PowerManager pm)
		{
			if (Done)
			{
				if (OnComplete != null) OnComplete();
				return;
			}

			if (Paused) return;

			if (pm.PowerState != PowerState.Normal)
			{
				if (--slowdown <= 0)
					slowdown = Queue.Info.LowPowerSlowdown; 
				else
					return;
			}

			var costThisFrame = RemainingCost / RemainingTime;
			if (costThisFrame != 0 && !pr.TakeCash(costThisFrame)) return;
			RemainingCost -= costThisFrame;
			RemainingTime -= 1;
			if (RemainingTime > 0) return;

			Done = true;
		}
	}
}