#region ================== Namespaces

using System;
using System.Collections.Generic;
using CodeImp.DoomBuilder.Geometry;
using CodeImp.DoomBuilder.Map;
using CodeImp.DoomBuilder.Rendering;

#endregion

namespace CodeImp.DoomBuilder.BuilderModes
{
	public class ResultSectorInvalid : ErrorResult
	{
		#region ================== Variables

		private readonly Sector sector;

		#endregion

		#region ================== Properties

		public override int Buttons { get { return 1; } }
		public override string Button1Text { get { return "Dissolve"; } }

		#endregion

		#region ================== Constructor / Destructor
		
		// Constructor
		public ResultSectorInvalid(Sector s)
		{
			// Initialize
			sector = s;
			viewobjects.Add(s);
			hidden = s.IgnoredErrorChecks.Contains(this.GetType()); //mxd
			description = "This sector has invalid geometry (it has less than 3 sidedefs or linedefs, or it's area is 0). This could cause problems with clipping and rendering in the game.";
		}
		
		#endregion
		
		#region ================== Methods

		// This sets if this result is displayed in ErrorCheckForm (mxd)
		internal override void Hide(bool hide) 
		{
			hidden = hide;
			Type t = this.GetType();
			if(hide) sector.IgnoredErrorChecks.Add(t);
			else if(sector.IgnoredErrorChecks.Contains(t)) sector.IgnoredErrorChecks.Remove(t);
		}
		
		// This must return the string that is displayed in the listbox
		public override string ToString() 
		{
			if(sector.Sidedefs != null && sector.Sidedefs.Count > 2)
				return "Area of sector " + sector.Index + " is 0";
			return "Sector " + sector.Index + " has " + (sector.Sidedefs == null ? "no" : sector.Sidedefs.Count.ToString()) + " sidedefs";
		}
		
		// Rendering
		public override void PlotSelection(IRenderer2D renderer)
		{
			renderer.PlotSector(sector, General.Colors.Selection);
		}

		// Fix by merging with surrounding geometry/removing
		public override bool Button1Click(bool batchMode) 
		{
			if(!batchMode) General.Map.UndoRedo.CreateUndo("Invalid sector correction");

			//collect the lines
			List<Linedef> lines = new List<Linedef>();
			foreach(Sidedef side in sector.Sidedefs) 
			{
				if(!lines.Contains(side.Line) && !side.Line.IsDisposed) 
					lines.Add(side.Line);
			}

			//get rid of lines with zero length
			foreach(Linedef line in lines)
				if(line.Length == 0) line.Dispose();

			if(lines.Count == 0) 
			{
				sector.Dispose();
			} 
			else if(lines.Count < 3) //merge with surrounding geometry
			{ 
				bool merged = false;
				foreach(Sidedef side in sector.Sidedefs) 
				{
					if(side.Other != null && side.Other.Sector != null && sector.Index != side.Other.Sector.Index) 
					{
						sector.Join(side.Other.Sector);
						merged = true;
						break;
					}
				}

				if(!merged)
				{
					HashSet<Linedef> sectorlines = new HashSet<Linedef>();
					foreach(Sidedef side in sector.Sidedefs) sectorlines.Add(side.Line);

					if(sectorlines.Count > 0)
					{
						List<LinedefSide> newlines = new List<LinedefSide>(sectorlines.Count);
						foreach(Linedef line in sectorlines)
						{
							if(line.Front != null) newlines.Add(new LinedefSide(line, true));
							if(line.Back != null) newlines.Add(new LinedefSide(line, false));
						}
						
						if(newlines.Count > 0)
						{
							// If invalid sector is inside another one, join them
							Vector2D center = new Vector2D(sector.BBox.X + sector.BBox.Width / 2, sector.BBox.Y + sector.BBox.Height / 2);
							Linedef otherline = General.Map.Map.NearestLinedef(center, sectorlines);
							Sidedef targetside = (otherline.Front ?? otherline.Back);

							if(targetside != null &&
								((otherline.Front != null && otherline.Front.Sector != null && otherline.Front.Sector.BBox.Contains(center.x, center.y)) ||
								otherline.Back != null && otherline.Back.Sector != null && otherline.Back.Sector.BBox.Contains(center.x, center.y)))
							{
								Tools.JoinSector(newlines, targetside);
								merged = true;
							}
						}
					}
					
					//oh well, I don't know what else I can do here...
					if(!merged) sector.Dispose();
				}
			} 
			else //redraw the lines
			{ 
				foreach(Linedef line in lines)
				{
					if(line.IsDisposed) continue;
					DrawnVertex start = new DrawnVertex { pos = line.Start.Position, stitch = true, stitchline = true };
					DrawnVertex end = new DrawnVertex { pos = line.End.Position, stitch = true, stitchline = true };
					Tools.DrawLines(new List<DrawnVertex> { start, end }, false, false);
				}
			}

			General.Map.Map.Update();
			return true;
		}
		
		#endregion
	}
}