using Godot;
using KeepersCompound.LGS;
using KeepersCompound.LGS.Database;
using KeepersCompound.LGS.Database.Chunks;
using KeepersCompound.TMV.UI;
using RectpackSharp;
using System;
using System.Collections.Generic;

namespace KeepersCompound;

[Tool]
public partial class Mission : Node3D
{
	[Export(PropertyHint.GlobalFile, "*.mis")]
	public string FileName { get; set; }
	[Export]
	public bool Build = false;
	[Export]
	public bool Clear = false;

	DbFile _file;

	public override void _Ready()
	{
		var missionSelector = GetNode<Control>("%MissionSelector") as MissionSelector;
		missionSelector.LoadMission += (string path) =>
		{
			FileName = path;
			Build = true;
		};
	}

	public override void _Process(double delta)
	{
		if (Build)
		{
			RebuildMap();
			Build = false;
		}
		if (Clear)
		{
			ClearMap();
			Clear = false;
		}
	}

	public override void _Input(InputEvent @event)
	{
		if (@event is InputEventKey keyEvent && keyEvent.Pressed)
		{
			if (keyEvent.Keycode == Key.R)
			{
				Build = true;
			}
		}
	}

	public void ClearMap()
	{
		foreach (var node in GetChildren())
		{
			node.QueueFree();
		}
	}

	public void RebuildMap()
	{
		ClearMap();

		_file = new(FileName);
		var wr = (WorldRep)_file.Chunks["WREXT"];

		foreach (var cell in wr.Cells)
		{
			BuildCellMesh(cell);
		}
	}

	private void BuildCellMesh(WorldRep.Cell cell)
	{
		var numPolys = cell.PolyCount;
		var numRenderPolys = cell.RenderPolyCount;
		var numPortalPolys = cell.PortalPolyCount;

		// There's nothing to render
		if (numRenderPolys == 0 || numPortalPolys >= numPolys)
		{
			return;
		}

		var vertices = new List<Vector3>();
		var normals = new List<Vector3>();
		var indices = new List<int>();
		var lightmapUvs = new List<Vector2>();
		var cellIdxOffset = 0;

		// You'd think these would be the same number, but apparently not
		// I think it's because water counts as a render poly and a portal poly
		var maxPolyIdx = Math.Min(numRenderPolys, numPolys - numPortalPolys);
		var packingRects = new PackingRectangle[maxPolyIdx];
		var rectIdToUvIdxMap = new List<int[]>();
		for (int i = 0; i < maxPolyIdx; i++)
		{
			var poly = cell.Polys[i];
			var meshIdxOffset = vertices.Count;

			var normal = cell.Planes[poly.PlaneId].Normal.ToGodotVec3();
			var numPolyVertices = poly.VertexCount;
			for (var j = 0; j < numPolyVertices; j++)
			{
				var vertex = cell.Vertices[cell.Indices[cellIdxOffset + j]];
				vertices.Add(vertex.ToGodotVec3());
				normals.Add(normal);
			}

			// Simple triangulation. Polys are always convex so we can just do a fan
			for (int j = 1; j < numPolyVertices - 1; j++)
			{
				indices.Add(meshIdxOffset);
				indices.Add(meshIdxOffset + j);
				indices.Add(meshIdxOffset + j + 1);
			}

			// UVs
			var renderPoly = cell.RenderPolys[i];
			var light = cell.LightList[i];
			packingRects[i] = new PackingRectangle(0, 0, light.Width, light.Height, i);
			var uvIdxs = CalcBaseUV(cell, poly, renderPoly, light, lightmapUvs, cellIdxOffset);
			rectIdToUvIdxMap.Add(uvIdxs);

			cellIdxOffset += poly.VertexCount;
		}

		RectanglePacker.Pack(packingRects, out var bounds);
		var image = Image.Create((int)bounds.Width, (int)bounds.Height, false, Image.Format.Rgba8);
		foreach (var rect in packingRects)
		{
			// Build lightmap
			var lightmap = cell.Lightmaps[rect.Id];
			// TODO: Handle animlight layers
			var layers = (uint)lightmap.Pixels.GetLength(0);
			var height = (uint)lightmap.Pixels.GetLength(1);
			var width = (uint)lightmap.Pixels.GetLength(2);
			for (uint y = 0; y < height; y++)
			{
				for (uint x = 0; x < width; x++)
				{
					var rawColour = System.Numerics.Vector4.Zero;
					for (uint l = 0; l < layers; l++)
					{
						rawColour += lightmap.GetPixel(l, x, y);
					}
					var colour = new Color(MathF.Min(rawColour.X, 1.0f), MathF.Min(rawColour.Y, 1.0f), MathF.Min(rawColour.Z, 1.0f), MathF.Min(rawColour.W, 1.0f));
					image.SetPixel((int)(rect.X + x), (int)(rect.Y + y), colour);
				}
			}

			// Transform UVs
			var lmUvIdxs = rectIdToUvIdxMap[rect.Id];
			foreach (var idx in lmUvIdxs)
			{
				var uv = lightmapUvs[idx];
				var u = uv.X;
				var v = uv.Y;

				// Clamp uv range to [0..1]
				u %= 1;
				v %= 1;
				if (u < 0) u = Math.Abs(u);
				if (v < 0) v = Math.Abs(v);

				// Transform!
				u = (rect.X + rect.Width * u) / (int)bounds.Width;
				v = (rect.Y + rect.Height * v) / (int)bounds.Height;
				lightmapUvs[idx] = new Vector2(u, v);
			}
		}


		var cellNode = new Node3D();

		var material = new StandardMaterial3D
		{
			AlbedoTexture = ImageTexture.CreateFromImage(image),
			TextureFilter = BaseMaterial3D.TextureFilterEnum.Nearest,
		};

		var arrMesh = new ArrayMesh();
		var arrays = new Godot.Collections.Array();
		arrays.Resize((int)Mesh.ArrayType.Max);
		arrays[(int)Mesh.ArrayType.Vertex] = vertices.ToArray();
		arrays[(int)Mesh.ArrayType.Normal] = normals.ToArray();
		arrays[(int)Mesh.ArrayType.Index] = indices.ToArray();
		arrays[(int)Mesh.ArrayType.TexUV] = lightmapUvs.ToArray();

		arrMesh.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, arrays);
		arrMesh.SurfaceSetMaterial(0, material);

		var meshInstance = new MeshInstance3D
		{
			Mesh = arrMesh,
			CastShadow = GeometryInstance3D.ShadowCastingSetting.On
		};
		cellNode.AddChild(meshInstance);

		var occluder = new ArrayOccluder3D();
		occluder.SetArrays(vertices.ToArray(), indices.ToArray());
		var occluderInstance = new OccluderInstance3D
		{
			Occluder = occluder,
			BakeSimplificationDistance = 0.0f
		};
		cellNode.AddChild(occluderInstance);

		var r = new Random();
		if (r.NextSingle() > 0.9 && cell.SphereRadius > 5.0)
		{
			var light = new OmniLight3D
			{
				Position = cell.SphereCenter.ToGodotVec3(),
				OmniRange = cell.SphereRadius * (r.NextSingle() + 1.0f) * 0.5f,
			};
			// cellNode.AddChild(light);
		}

		AddChild(cellNode);
	}

	private static int[] CalcBaseUV(
		WorldRep.Cell cell,
		WorldRep.Cell.Poly poly,
		WorldRep.Cell.RenderPoly renderPoly,
		WorldRep.Cell.LightmapInfo light,
		List<Vector2> lightmapUvs,
		int cellIdxOffset)
	{
		// TODO: This is slightly hardcoded for ND. Check other stuff at some point. Should be handled in LG side imo
		// TODO: This is a mess lol
		var texU = renderPoly.TextureVectors.Item1.ToGodotVec3();
		var texV = renderPoly.TextureVectors.Item2.ToGodotVec3();

		var uu = texU.Dot(texU);
		var vv = texV.Dot(texV);
		var uv = texU.Dot(texV);
		var lmUScale = 4.0f / light.Width;
		var lmVScale = 4.0f / light.Height;

		var baseU = renderPoly.TextureBases.Item1;
		var baseV = renderPoly.TextureBases.Item2;
		var lmUBase = lmUScale * (baseU + (0.5f - light.Bases.Item1) / 4.0f);
		var lmVBase = lmVScale * (baseV + (0.5f - light.Bases.Item2) / 4.0f);
		var anchor = cell.Vertices[cell.Indices[cellIdxOffset + 0]].ToGodotVec3(); // TODO: This probably shouldn't be hardcoded idx 0

		var uvIdxs = new int[poly.VertexCount];
		if (uv == 0.0)
		{
			var lmUVec = texU * lmUScale / uu;
			var lmVVec = texV * lmVScale / vv;
			for (var i = 0; i < poly.VertexCount; i++)
			{
				uvIdxs[i] = lightmapUvs.Count;

				var v = cell.Vertices[cell.Indices[cellIdxOffset + i]].ToGodotVec3();
				var delta = new Vector3(v.X - anchor.X, v.Y - anchor.Y, v.Z - anchor.Z);
				var lmUV = new Vector2(delta.Dot(lmUVec) + lmUBase, delta.Dot(lmVVec) + lmVBase);
				lightmapUvs.Add(lmUV);
			}
		}
		else
		{
			var denom = 1.0f / (uu * vv - uv * uv);
			var lmUu = uu * lmVScale * denom;
			var lmVv = vv * lmUScale * denom;
			var lmUvu = lmUScale * denom * uv;
			var lmUvv = lmVScale * denom * uv;
			for (var i = 0; i < poly.VertexCount; i++)
			{
				uvIdxs[i] = lightmapUvs.Count;

				var v = cell.Vertices[cell.Indices[cellIdxOffset + i]].ToGodotVec3();
				var delta = new Vector3(v.X - anchor.X, v.Y - anchor.Y, v.Z - anchor.Z);
				var du = delta.Dot(texU);
				var dv = delta.Dot(texV);
				var lmUV = new Vector2(lmUBase + lmVv * du - lmUvu * dv, lmVBase + lmUu * dv - lmUvv * du);
				lightmapUvs.Add(lmUV);
			}
		}

		return uvIdxs;
	}
}