#region Copyright & License Information
/*
 * Copyright 2007-2017 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.Drawing;
using System.Linq;
using OpenRA.Graphics;
using OpenRA.Mods.Common.Orders;
using OpenRA.Mods.Common.Traits;
using OpenRA.Orders;
using OpenRA.Primitives;
using OpenRA.Widgets;

namespace OpenRA.Mods.Common.Widgets
{
	/// <summary> Contains all functions that are unit-specific. </summary>
	public class CommandBarLogic : ChromeLogic
	{
		readonly World world;

		int selectionHash;
		Actor[] selectedActors = { };
		bool attackMoveDisabled = true;
		bool forceMoveDisabled = true;
		bool forceAttackDisabled = true;
		bool guardDisabled = true;
		bool scatterDisabled = true;

		int deployHighlighted;
		int scatterHighlighted;
		int stopHighlighted;

		TraitPair<IIssueDeployOrder>[] selectedDeploys = { };

		[ObjectCreator.UseCtor]
		public CommandBarLogic(Widget widget, World world)
		{
			this.world = world;
			var ks = Game.Settings.Keys;

			var attackMoveButton = widget.GetOrNull<ButtonWidget>("ATTACK_MOVE");
			if (attackMoveButton != null)
			{
				BindButtonIcon(attackMoveButton);

				attackMoveButton.GetKey = _ => ks.AttackMoveKey;
				attackMoveButton.IsDisabled = () => { UpdateStateIfNecessary(); return attackMoveDisabled; };
				attackMoveButton.IsHighlighted = () => world.OrderGenerator is GenericSelectTarget
					&& ((GenericSelectTarget)world.OrderGenerator).OrderName == "AttackMove";

				attackMoveButton.OnClick = () =>
				{
					if (attackMoveButton.IsHighlighted())
						world.CancelInputMode();
					else
						world.OrderGenerator = new GenericSelectTarget(selectedActors,
							"AttackMove", "attackmove", Game.Settings.Game.MouseButtonPreference.Action);
				};
			}

			var forceMoveButton = widget.GetOrNull<ButtonWidget>("FORCE_MOVE");
			if (forceMoveButton != null)
			{
				BindButtonIcon(forceMoveButton);

				forceMoveButton.IsDisabled = () => { UpdateStateIfNecessary(); return forceMoveDisabled; };
				forceMoveButton.IsHighlighted = () => !forceMoveButton.IsDisabled() && IsForceModifiersActive(Modifiers.Alt);
				forceMoveButton.OnClick = () =>
				{
					if (forceMoveButton.IsHighlighted())
						world.CancelInputMode();
					else
						world.OrderGenerator = new ForceModifiersOrderGenerator(Modifiers.Alt, true);
				};
			}

			var forceAttackButton = widget.GetOrNull<ButtonWidget>("FORCE_ATTACK");
			if (forceAttackButton != null)
			{
				BindButtonIcon(forceAttackButton);

				forceAttackButton.IsDisabled = () => { UpdateStateIfNecessary(); return forceAttackDisabled; };
				forceAttackButton.IsHighlighted = () => !forceAttackButton.IsDisabled() && IsForceModifiersActive(Modifiers.Ctrl);
				forceAttackButton.OnClick = () =>
				{
					if (forceAttackButton.IsHighlighted())
						world.CancelInputMode();
					else
						world.OrderGenerator = new ForceModifiersOrderGenerator(Modifiers.Ctrl, true);
				};
			}

			var guardButton = widget.GetOrNull<ButtonWidget>("GUARD");
			if (guardButton != null)
			{
				BindButtonIcon(guardButton);

				guardButton.GetKey = _ => ks.GuardKey;
				guardButton.IsDisabled = () => { UpdateStateIfNecessary(); return guardDisabled; };
				guardButton.IsHighlighted = () => world.OrderGenerator is GenericSelectTarget
					&& ((GenericSelectTarget)world.OrderGenerator).OrderName == "Guard";

				guardButton.OnClick = () =>
				{
					if (guardButton.IsHighlighted())
						world.CancelInputMode();
					else
						world.OrderGenerator = new GuardOrderGenerator(selectedActors,
							"Guard", "guard", Game.Settings.Game.MouseButtonPreference.Action);
				};
			}

			var scatterButton = widget.GetOrNull<ButtonWidget>("SCATTER");
			if (scatterButton != null)
			{
				BindButtonIcon(scatterButton);

				scatterButton.GetKey = _ => ks.ScatterKey;
				scatterButton.IsDisabled = () => { UpdateStateIfNecessary(); return scatterDisabled; };
				scatterButton.IsHighlighted = () => scatterHighlighted > 0;
				scatterButton.OnClick = () => PerformKeyboardOrderOnSelection(a => new Order("Scatter", a, false));
				scatterButton.OnKeyPress = ki => { scatterHighlighted = 2; scatterButton.OnClick(); };
			}

			var deployButton = widget.GetOrNull<ButtonWidget>("DEPLOY");
			if (deployButton != null)
			{
				BindButtonIcon(deployButton);

				deployButton.GetKey = _ => ks.DeployKey;
				deployButton.IsDisabled = () => { UpdateStateIfNecessary(); return !selectedDeploys.Any(Exts.IsTraitEnabled); };
				deployButton.IsHighlighted = () => deployHighlighted > 0;
				deployButton.OnClick = PerformDeployOrderOnSelection;
				deployButton.OnKeyPress = ki => { deployHighlighted = 2; deployButton.OnClick(); };
			}

			var stopButton = widget.GetOrNull<ButtonWidget>("STOP");
			if (stopButton != null)
			{
				BindButtonIcon(stopButton);

				stopButton.GetKey = _ => ks.StopKey;
				stopButton.IsDisabled = () => { UpdateStateIfNecessary(); return !selectedActors.Any(); };
				stopButton.IsHighlighted = () => stopHighlighted > 0;
				stopButton.OnClick = () => PerformKeyboardOrderOnSelection(a => new Order("Stop", a, false));
				stopButton.OnKeyPress = ki => { stopHighlighted = 2; stopButton.OnClick(); };
			}

			var queueOrdersButton = widget.GetOrNull<ButtonWidget>("QUEUE_ORDERS");
			if (queueOrdersButton != null)
			{
				BindButtonIcon(queueOrdersButton);

				queueOrdersButton.IsDisabled = () => { UpdateStateIfNecessary(); return !selectedActors.Any(); };
				queueOrdersButton.IsHighlighted = () => !queueOrdersButton.IsDisabled() && IsForceModifiersActive(Modifiers.Shift);
				queueOrdersButton.OnClick = () =>
				{
					if (queueOrdersButton.IsHighlighted())
						world.CancelInputMode();
					else
						world.OrderGenerator = new ForceModifiersOrderGenerator(Modifiers.Shift, false);
				};
			}
		}

		public override void Tick()
		{
			if (deployHighlighted > 0)
				deployHighlighted--;

			if (scatterHighlighted > 0)
				scatterHighlighted--;

			if (stopHighlighted > 0)
				stopHighlighted--;

			base.Tick();
		}

		void BindButtonIcon(ButtonWidget button)
		{
			var icon = button.Get<ImageWidget>("ICON");
			icon.GetImageName = () => button.IsDisabled() ? icon.ImageName + "-disabled" : icon.ImageName;
		}

		bool IsForceModifiersActive(Modifiers modifiers)
		{
			var fmog = world.OrderGenerator as ForceModifiersOrderGenerator;
			if (fmog != null && fmog.Modifiers.HasFlag(modifiers))
				return true;

			var uog = world.OrderGenerator as UnitOrderGenerator;
			if (uog != null && Game.GetModifierKeys().HasFlag(modifiers))
				return true;

			return false;
		}

		void UpdateStateIfNecessary()
		{
			if (selectionHash == world.Selection.Hash)
				return;

			selectedActors = world.Selection.Actors
				.Where(a => a.Owner == world.LocalPlayer && a.IsInWorld)
				.ToArray();

			attackMoveDisabled = !selectedActors.Any(a => a.Info.HasTraitInfo<AttackMoveInfo>() && a.Info.HasTraitInfo<AutoTargetInfo>());
			guardDisabled = !selectedActors.Any(a => a.Info.HasTraitInfo<GuardInfo>() && a.Info.HasTraitInfo<AutoTargetInfo>());
			forceMoveDisabled = !selectedActors.Any(a => a.Info.HasTraitInfo<MobileInfo>() || a.Info.HasTraitInfo<AircraftInfo>());
			forceAttackDisabled = !selectedActors.Any(a => a.Info.HasTraitInfo<AttackBaseInfo>());
			scatterDisabled = !selectedActors.Any(a => a.Info.HasTraitInfo<MobileInfo>());

			selectedDeploys = selectedActors
				.SelectMany(a => a.TraitsImplementing<IIssueDeployOrder>()
					.Select(d => new TraitPair<IIssueDeployOrder>(a, d)))
				.ToArray();

			selectionHash = world.Selection.Hash;
		}

		void PerformKeyboardOrderOnSelection(Func<Actor, Order> f)
		{
			UpdateStateIfNecessary();

			var orders = selectedActors
				.Select(f)
				.ToArray();

			foreach (var o in orders)
				world.IssueOrder(o);

			world.PlayVoiceForOrders(orders);
		}

		void PerformDeployOrderOnSelection()
		{
			UpdateStateIfNecessary();

			var orders = selectedDeploys
				.Where(Exts.IsTraitEnabled)
				.Select(d => d.Trait.IssueDeployOrder(d.Actor))
				.ToArray();

			foreach (var o in orders)
				world.IssueOrder(o);

			world.PlayVoiceForOrders(orders);
		}
	}
}