using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using TriangleNet.Geometry;

namespace TriangleNet.IO
{
	public class TriangleReader
	{
		private static NumberFormatInfo nfi = NumberFormatInfo.InvariantInfo;

		private int startIndex;

		public static bool IsNullOrWhiteSpace(string value)
		{
			if (value == null)
			{
				return true;
			}
			return string.IsNullOrEmpty(value.Trim());
		}

		private bool TryReadLine(StreamReader reader, out string[] token)
		{
			token = null;
			if (reader.EndOfStream)
			{
				return false;
			}
			string text = reader.ReadLine().Trim();
			while (IsNullOrWhiteSpace(text) || text.StartsWith("#"))
			{
				if (reader.EndOfStream)
				{
					return false;
				}
				text = reader.ReadLine().Trim();
			}
			token = text.Split(new char[2] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
			return true;
		}

		private void ReadVertex(List<Vertex> data, int index, string[] line, int attributes, int marks)
		{
			double x = double.Parse(line[1], nfi);
			double y = double.Parse(line[2], nfi);
			Vertex vertex = new Vertex(x, y);
			if (marks > 0 && line.Length > 3 + attributes)
			{
				vertex.Label = int.Parse(line[3 + attributes]);
			}
			_ = 0;
			data.Add(vertex);
		}

		public void Read(string filename, out Polygon polygon)
		{
			polygon = null;
			string text = Path.ChangeExtension(filename, ".poly");
			if (File.Exists(text))
			{
				polygon = ReadPolyFile(text);
				return;
			}
			text = Path.ChangeExtension(filename, ".node");
			polygon = ReadNodeFile(text);
		}

		public void Read(string filename, out Polygon geometry, out List<ITriangle> triangles)
		{
			triangles = null;
			Read(filename, out geometry);
			string text = Path.ChangeExtension(filename, ".ele");
			if (File.Exists(text) && geometry != null)
			{
				triangles = ReadEleFile(text);
			}
		}

		public IPolygon Read(string filename)
		{
			Polygon polygon = null;
			Read(filename, out polygon);
			return polygon;
		}

		public Polygon ReadNodeFile(string nodefilename)
		{
			return ReadNodeFile(nodefilename, readElements: false);
		}

		public Polygon ReadNodeFile(string nodefilename, bool readElements)
		{
			startIndex = 0;
			int num = 0;
			int attributes = 0;
			int marks = 0;
			Polygon polygon;
			using (StreamReader reader = new StreamReader(nodefilename))
			{
				if (!TryReadLine(reader, out var token))
				{
					throw new Exception("Can't read input file.");
				}
				num = int.Parse(token[0]);
				if (num < 3)
				{
					throw new Exception("Input must have at least three input vertices.");
				}
				if (token.Length > 1 && int.Parse(token[1]) != 2)
				{
					throw new Exception("Triangle only works with two-dimensional meshes.");
				}
				if (token.Length > 2)
				{
					attributes = int.Parse(token[2]);
				}
				if (token.Length > 3)
				{
					marks = int.Parse(token[3]);
				}
				polygon = new Polygon(num);
				if (num > 0)
				{
					for (int i = 0; i < num; i++)
					{
						if (!TryReadLine(reader, out token))
						{
							throw new Exception("Can't read input file (vertices).");
						}
						if (token.Length < 3)
						{
							throw new Exception("Invalid vertex.");
						}
						if (i == 0)
						{
							startIndex = int.Parse(token[0], nfi);
						}
						ReadVertex(polygon.Points, i, token, attributes, marks);
					}
				}
			}
			if (readElements)
			{
				string text = Path.ChangeExtension(nodefilename, ".ele");
				if (File.Exists(text))
				{
					ReadEleFile(text, readArea: true);
				}
			}
			return polygon;
		}

		public Polygon ReadPolyFile(string polyfilename)
		{
			return ReadPolyFile(polyfilename, readElements: false, readArea: false);
		}

		public Polygon ReadPolyFile(string polyfilename, bool readElements)
		{
			return ReadPolyFile(polyfilename, readElements, readArea: false);
		}

		public Polygon ReadPolyFile(string polyfilename, bool readElements, bool readArea)
		{
			startIndex = 0;
			int num = 0;
			int attributes = 0;
			int marks = 0;
			Polygon polygon;
			using (StreamReader reader = new StreamReader(polyfilename))
			{
				if (!TryReadLine(reader, out var token))
				{
					throw new Exception("Can't read input file.");
				}
				num = int.Parse(token[0]);
				if (token.Length > 1 && int.Parse(token[1]) != 2)
				{
					throw new Exception("Triangle only works with two-dimensional meshes.");
				}
				if (token.Length > 2)
				{
					attributes = int.Parse(token[2]);
				}
				if (token.Length > 3)
				{
					marks = int.Parse(token[3]);
				}
				if (num > 0)
				{
					polygon = new Polygon(num);
					for (int i = 0; i < num; i++)
					{
						if (!TryReadLine(reader, out token))
						{
							throw new Exception("Can't read input file (vertices).");
						}
						if (token.Length < 3)
						{
							throw new Exception("Invalid vertex.");
						}
						if (i == 0)
						{
							startIndex = int.Parse(token[0], nfi);
						}
						ReadVertex(polygon.Points, i, token, attributes, marks);
					}
				}
				else
				{
					polygon = ReadNodeFile(Path.ChangeExtension(polyfilename, ".node"));
					num = polygon.Points.Count;
				}
				List<Vertex> points = polygon.Points;
				if (points.Count == 0)
				{
					throw new Exception("No nodes available.");
				}
				if (!TryReadLine(reader, out token))
				{
					throw new Exception("Can't read input file (segments).");
				}
				int num2 = int.Parse(token[0]);
				int num3 = 0;
				if (token.Length > 1)
				{
					num3 = int.Parse(token[1]);
				}
				for (int j = 0; j < num2; j++)
				{
					if (!TryReadLine(reader, out token))
					{
						throw new Exception("Can't read input file (segments).");
					}
					if (token.Length < 3)
					{
						throw new Exception("Segment has no endpoints.");
					}
					int num4 = int.Parse(token[1]) - startIndex;
					int num5 = int.Parse(token[2]) - startIndex;
					int label = 0;
					if (num3 > 0 && token.Length > 3)
					{
						label = int.Parse(token[3]);
					}
					if (num4 < 0 || num4 >= num)
					{
						if (Log.Verbose)
						{
							Log.Instance.Warning("Invalid first endpoint of segment.", "MeshReader.ReadPolyfile()");
						}
					}
					else if (num5 < 0 || num5 >= num)
					{
						if (Log.Verbose)
						{
							Log.Instance.Warning("Invalid second endpoint of segment.", "MeshReader.ReadPolyfile()");
						}
					}
					else
					{
						polygon.Add(new Segment(points[num4], points[num5], label));
					}
				}
				if (!TryReadLine(reader, out token))
				{
					throw new Exception("Can't read input file (holes).");
				}
				int num6 = int.Parse(token[0]);
				if (num6 > 0)
				{
					for (int k = 0; k < num6; k++)
					{
						if (!TryReadLine(reader, out token))
						{
							throw new Exception("Can't read input file (holes).");
						}
						if (token.Length < 3)
						{
							throw new Exception("Invalid hole.");
						}
						polygon.Holes.Add(new Point(double.Parse(token[1], nfi), double.Parse(token[2], nfi)));
					}
				}
				if (TryReadLine(reader, out token))
				{
					int num7 = int.Parse(token[0]);
					if (num7 > 0)
					{
						for (int l = 0; l < num7; l++)
						{
							if (!TryReadLine(reader, out token))
							{
								throw new Exception("Can't read input file (region).");
							}
							if (token.Length < 4)
							{
								throw new Exception("Invalid region attributes.");
							}
							if (!int.TryParse(token[3], out var result))
							{
								result = l;
							}
							double result2 = 0.0;
							if (token.Length > 4)
							{
								double.TryParse(token[4], NumberStyles.Number, nfi, out result2);
							}
							polygon.Regions.Add(new RegionPointer(double.Parse(token[1], nfi), double.Parse(token[2], nfi), result, result2));
						}
					}
				}
			}
			if (readElements)
			{
				string text = Path.ChangeExtension(polyfilename, ".ele");
				if (File.Exists(text))
				{
					ReadEleFile(text, readArea);
				}
			}
			return polygon;
		}

		public List<ITriangle> ReadEleFile(string elefilename)
		{
			return ReadEleFile(elefilename, readArea: false);
		}

		private List<ITriangle> ReadEleFile(string elefilename, bool readArea)
		{
			int num = 0;
			int num2 = 0;
			List<ITriangle> list;
			using (StreamReader reader = new StreamReader(elefilename))
			{
				bool flag = false;
				if (!TryReadLine(reader, out var token))
				{
					throw new Exception("Can't read input file (elements).");
				}
				num = int.Parse(token[0]);
				num2 = 0;
				if (token.Length > 2)
				{
					num2 = int.Parse(token[2]);
					flag = true;
				}
				if (num2 > 1)
				{
					Log.Instance.Warning("Triangle attributes not supported.", "FileReader.Read");
				}
				list = new List<ITriangle>(num);
				for (int i = 0; i < num; i++)
				{
					if (!TryReadLine(reader, out token))
					{
						throw new Exception("Can't read input file (elements).");
					}
					if (token.Length < 4)
					{
						throw new Exception("Triangle has no nodes.");
					}
					InputTriangle inputTriangle = new InputTriangle(int.Parse(token[1]) - startIndex, int.Parse(token[2]) - startIndex, int.Parse(token[3]) - startIndex);
					if (num2 > 0 && flag)
					{
						int result = 0;
						flag = int.TryParse(token[4], out result);
						inputTriangle.label = result;
					}
					list.Add(inputTriangle);
				}
			}
			if (readArea)
			{
				string text = Path.ChangeExtension(elefilename, ".area");
				if (File.Exists(text))
				{
					ReadAreaFile(text, num);
				}
			}
			return list;
		}

		private double[] ReadAreaFile(string areafilename, int intriangles)
		{
			double[] array = null;
			using StreamReader reader = new StreamReader(areafilename);
			if (!TryReadLine(reader, out var token))
			{
				throw new Exception("Can't read input file (area).");
			}
			if (int.Parse(token[0]) != intriangles)
			{
				Log.Instance.Warning("Number of area constraints doesn't match number of triangles.", "ReadAreaFile()");
				return null;
			}
			array = new double[intriangles];
			for (int i = 0; i < intriangles; i++)
			{
				if (!TryReadLine(reader, out token))
				{
					throw new Exception("Can't read input file (area).");
				}
				if (token.Length != 2)
				{
					throw new Exception("Triangle has no nodes.");
				}
				array[i] = double.Parse(token[1], nfi);
			}
			return array;
		}

		public List<Edge> ReadEdgeFile(string edgeFile, int invertices)
		{
			List<Edge> list = null;
			startIndex = 0;
			using StreamReader reader = new StreamReader(edgeFile);
			if (!TryReadLine(reader, out var token))
			{
				throw new Exception("Can't read input file (segments).");
			}
			int num = int.Parse(token[0]);
			int num2 = 0;
			if (token.Length > 1)
			{
				num2 = int.Parse(token[1]);
			}
			if (num > 0)
			{
				list = new List<Edge>(num);
			}
			for (int i = 0; i < num; i++)
			{
				if (!TryReadLine(reader, out token))
				{
					throw new Exception("Can't read input file (segments).");
				}
				if (token.Length < 3)
				{
					throw new Exception("Segment has no endpoints.");
				}
				int num3 = int.Parse(token[1]) - startIndex;
				int num4 = int.Parse(token[2]) - startIndex;
				int label = 0;
				if (num2 > 0 && token.Length > 3)
				{
					label = int.Parse(token[3]);
				}
				if (num3 < 0 || num3 >= invertices)
				{
					if (Log.Verbose)
					{
						Log.Instance.Warning("Invalid first endpoint of segment.", "MeshReader.ReadPolyfile()");
					}
				}
				else if (num4 < 0 || num4 >= invertices)
				{
					if (Log.Verbose)
					{
						Log.Instance.Warning("Invalid second endpoint of segment.", "MeshReader.ReadPolyfile()");
					}
				}
				else
				{
					list.Add(new Edge(num3, num4, label));
				}
			}
			return list;
		}
	}
}