using System;
using System.IO;
using System.Collections.Generic;
using NW4RTools.Models;

namespace NW4RTools {
	public class ObjWriter {
		public static void WriteModel(TextWriter tw, ResFile file, string modelName) {
			new ObjWriter(file).SaveModel(tw, modelName);
		}



		ResFile CurrentFile;
		Models.Model CurrentModel;
		TextWriter Output;

		private ObjWriter(ResFile file) {
			CurrentFile = file;
		}

		Dictionary<Models.VertexPosData, int> VtxPosOffsets;
		Dictionary<Models.VertexNrmData, int> VtxNrmOffsets;
		Dictionary<Models.VertexTexCoordData, int> VtxTexCoordOffsets;

		public void SaveModel(TextWriter tw, string modelName) {
			Output = tw;
			CurrentModel = CurrentFile.GetGroup<Model>("3DModels(NW4R)")[modelName];

			Output.WriteLine("# {0} exported by Treeki's NW4RTools", modelName);
			Output.WriteLine("# {0}", DateTime.Now);
			Output.WriteLine();

			// Write vertex data pool
			int Offset;
			
			VtxPosOffsets = new Dictionary<VertexPosData, int>();
			Offset = 1;
			foreach (var kv in CurrentModel.VtxPosData) {
				VtxPosOffsets[kv.Value] = Offset;
				Output.WriteLine("# Vertex Positions: {0} [offset {1}]", kv.Key, Offset);
				
				for (int i = 0; i < kv.Value.EntryCount; i++) {
					float[] v = kv.Value.GetEntry(i);
					Output.WriteLine("v {0} {1} {2}", v[0], v[1], v[2]);
				}
				
				Offset += kv.Value.EntryCount;
			}
			
			VtxNrmOffsets = new Dictionary<VertexNrmData, int>();
			Offset = 1;
			foreach (var kv in CurrentModel.VtxNrmData) {
				VtxNrmOffsets[kv.Value] = Offset;
				Output.WriteLine("# Vertex Normals: {0} [offset {1}]", kv.Key, Offset);
				
				for (int i = 0; i < kv.Value.EntryCount; i++) {
					float[] v = kv.Value.GetEntry(i);
					Output.WriteLine("vn {0} {1} {2}", v[0], v[1], v[2]);
				}
				
				Offset += kv.Value.EntryCount;
			}
			
			VtxTexCoordOffsets = new Dictionary<VertexTexCoordData, int>();
			Offset = 1;
			foreach (var kv in CurrentModel.VtxTexCoordData) {
				VtxTexCoordOffsets[kv.Value] = Offset;
				Output.WriteLine("# Vertex TexCoords: {0} [offset {1}]", kv.Key, Offset);
				
				for (int i = 0; i < kv.Value.EntryCount; i++) {
					float[] v = kv.Value.GetEntry(i);
					Output.WriteLine("vt {0} {1}", v[0], v[1]);
				}
				
				Offset += kv.Value.EntryCount;
			}

			Output.WriteLine();

			// Write shapes
			// TODO: replace with something using the Bytecode
			foreach (var kv in CurrentModel.Shapes) {
				Output.WriteLine("g {0}", kv.Key);

				WriteShape(kv.Value);

				Output.WriteLine();
			}

			Output.Flush();
		}


		private void WriteShape(Models.Shape shape) {
			// parse the DisplayList

			int posOffset = VtxPosOffsets[shape.PosData];
			int nrmOffset = shape.NrmData == null ? -1 : VtxNrmOffsets[shape.NrmData];
			int tcOffset = shape.TexCoordData[0] == null ? -1 : VtxTexCoordOffsets[shape.TexCoordData[0]];
			// TODO: Better DisplayList parsing, in a similar fashion to ByteCode
			var dl = new InputStream(shape.DisplayList2);

			while (true) {
				if (dl.AtEnd)
					break;

				byte cmd = dl.ReadByte();
				PrimitiveType prim = (PrimitiveType)cmd;
				int vtxCount = dl.ReadUInt16();
				Output.WriteLine("# Primitive: {0} ({1} vertices)", prim, vtxCount);

				// I wonder if INDEX8 is ever used here?
				// Going with INDEX16 for now.

				switch (prim) {
				case PrimitiveType.TriangleStrip:
					// De-stripify it!


					break;

				default:
					throw new NotImplementedException();
				}
			}
		}
	}
}