using System;

namespace ObjReader
{
	/// <summary>
	/// dummy class
	/// </summary>
	class Class1
	{
		/// <summary>
		/// demonstrates usage of the .OBJ reading routine
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			float[][] vertices;
			int[][] faces;
			ReadObj(@"..\..\test.obj", out vertices, out faces);
			int numV = vertices.Length;
			int numF = faces.Length;
			Console.Out.WriteLine("Found " + numV + " Vertices and " + numF + " faces.");
			Console.Out.WriteLine("The first vertex is (" + vertices[0][0] + ", " + vertices[0][1] + ", " + vertices[0][2] + ")." );
			Console.Out.WriteLine("The last vertex is (" + vertices[numV-1][0] + ", " + vertices[numV-1][1] + ", " + vertices[numV-1][2] + ")." );
			Console.Out.Write("The first polygon contains the vertices");
			bool comma = false;
			foreach(int i in faces[0])
			{
				Console.Out.Write((comma?", ":" ") + i);
				comma = true;
			}
			Console.Out.WriteLine(".");
			Console.Out.Write("The last polygon contains the vertices");
			comma = false;
			foreach(int i in faces[numF-1])
			{
				Console.Out.Write((comma?", ":" ") + i);
				comma = true;
			}
			Console.Out.WriteLine(".");
			
			Console.In.ReadLine();
		}

		/// <summary>
		/// reads in an .OBJ file
		/// </summary>
		/// <author>Jörn Loviscach</author>
		/// <param name="file">file name including path</param>
		/// <param name="vertices">vertex positions</param>
		/// <param name="faces">vertex indices for faces</param>
		static private void ReadObj(string file, out float[][] vertices, out int[][] faces)
		{
			System.Collections.Queue vQueue = new System.Collections.Queue();
			System.Collections.Queue fQueue = new System.Collections.Queue();

			System.IO.StreamReader reader = new System.IO.StreamReader(file);
			bool firstObjectStarted = false;
			while(true)
			{
				string line = reader.ReadLine();
				if(line == null)
					break;
				if(line.StartsWith("g")) // an object starts
				{
					if(firstObjectStarted)
					{
						break; // we only want the first object
					}
					firstObjectStarted = true;
					continue;
				}
				if(!firstObjectStarted)
					continue;

				string[] s = line.Split(new char[]{' '}, 50);
				if(s[0].Equals("v"))
				{
					if(s.Length != 1+3)
						throw new Exception("wrong number of components in vertex");
					float[] v = new float[3];
					for(int i = 0; i < 3; i++)
					{
						v[i] = (float)System.Double.Parse(s[i+1], System.Globalization.CultureInfo.InvariantCulture);
					}
					vQueue.Enqueue(v);
				}
				else if(s[0].Equals("f"))
				{
					int n = s.Length - 1; // number of vertices
					int[] f  = new int[n];
					for(int i = 0; i < n; i++)
					{
						string[] fs = s[i+1].Split(new char[]{'/'}, 2);
						if(fs == null)
							throw new Exception("error in face description");
						f[i] = Int32.Parse(fs[0]);
					}
					fQueue.Enqueue(f);
				}
			}
			reader.Close();

			int numVertices = vQueue.Count;
			object[] vArray = vQueue.ToArray();
			vertices = new float[numVertices][];
			for(int i = 0; i < numVertices; i++)
			{
				vertices[i] = (float[])vArray[i];
			}

			int numFaces = fQueue.Count;
			object[] fArray = fQueue.ToArray();
			faces = new int[numFaces][];
			for(int i = 0; i < numFaces; i++)
			{
				int[] f = (int[])fArray[i];
				int n = f.Length;
				faces[i] = new int[n];
				for(int j = 0; j < n; j++)
				{
					faces[i][j] = f[j]-1; // .obj starts vertex numbering at 1, not at 0
					if(faces[i][j] >= numVertices) // jl 2004-04-14: bug corrected
						throw new Exception("vertex index too large");
				}
			}
		}
	}
}