#region Copyright & License Information
/*
 * Copyright 2007-2022 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.Collections.Generic;
using System.Linq;
using OpenRA.Graphics;
using OpenRA.Mods.Common.Graphics;
using OpenRA.Mods.Common.Orders;
using OpenRA.Primitives;

namespace OpenRA.Mods.Common.Traits
{
	[Desc("Creates a building placement preview based on the map editor actor preview.")]
	public class ActorPreviewPlaceBuildingPreviewInfo : FootprintPlaceBuildingPreviewInfo
	{
		[Desc("Enable the building's idle animation.")]
		public readonly bool Animated = true;

		[Desc("Custom opacity to apply to the actor preview.")]
		public readonly float PreviewAlpha = 1f;

		[Desc("Footprint types to draw underneath the actor preview.")]
		public readonly PlaceBuildingCellType FootprintUnderPreview = PlaceBuildingCellType.Valid | PlaceBuildingCellType.LineBuild;

		[Desc("Footprint types to draw above the actor preview.")]
		public readonly PlaceBuildingCellType FootprintOverPreview = PlaceBuildingCellType.Invalid;

		protected override IPlaceBuildingPreview CreatePreview(WorldRenderer wr, ActorInfo ai, TypeDictionary init)
		{
			return new ActorPreviewPlaceBuildingPreviewPreview(wr, ai, this, init);
		}

		public override object Create(ActorInitializer init)
		{
			return new ActorPreviewPlaceBuildingPreview();
		}
	}

	public class ActorPreviewPlaceBuildingPreview { }

	public class ActorPreviewPlaceBuildingPreviewPreview : FootprintPlaceBuildingPreviewPreview
	{
		readonly ActorPreviewPlaceBuildingPreviewInfo info;
		readonly IActorPreview[] preview;

		public ActorPreviewPlaceBuildingPreviewPreview(WorldRenderer wr, ActorInfo ai, ActorPreviewPlaceBuildingPreviewInfo info, TypeDictionary init)
			: base(wr, ai, info)
		{
			this.info = info;
			var previewInit = new ActorPreviewInitializer(ActorInfo, wr, init);
			preview = ActorInfo.TraitInfos<IRenderActorPreviewInfo>()
				.SelectMany(rpi => rpi.RenderPreview(previewInit))
				.ToArray();
		}

		protected override void TickInner()
		{
			if (!info.Animated)
				return;

			foreach (var p in preview)
				p.Tick();
		}

		protected override IEnumerable<IRenderable> RenderInner(WorldRenderer wr, CPos topLeft, Dictionary<CPos, PlaceBuildingCellType> footprint)
		{
			var centerPosition = wr.World.Map.CenterOfCell(topLeft) + CenterOffset;
			var previewRenderables = preview
				.SelectMany(p => p.Render(wr, centerPosition));

			if (info.FootprintUnderPreview != PlaceBuildingCellType.None)
				foreach (var r in RenderFootprint(wr, topLeft, footprint, info.FootprintUnderPreview))
					yield return r;

			foreach (var r in previewRenderables.OrderBy(WorldRenderer.RenderableZPositionComparisonKey))
			{
				if (info.PreviewAlpha < 1f && r is IModifyableRenderable mr)
					yield return mr.WithAlpha(mr.Alpha * info.PreviewAlpha);
				else
					yield return r;
			}

			if (info.FootprintOverPreview != PlaceBuildingCellType.None)
				foreach (var r in RenderFootprint(wr, topLeft, footprint, info.FootprintOverPreview))
					yield return r;
		}
	}
}
