// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.

using System;
using System.Collections.Generic;
using System.IO;
using System.Diagnostics;
using System.Xml;
using System.Xml.Serialization;


namespace UnrealBuildTool
{
	/// <summary>
	/// Represents a color in the displayed graph.  Values are between 0.0 and 1.0 inclusive.
	/// </summary>
	public struct GraphColor
	{
		public float R;
		public float G;
		public float B;
		public float A;
	}


	/// <summary>
	/// A single "node" in a directed graph
	/// </summary>
	public class GraphNode
	{
		/// ID number, unique for all nodes.  This must also be the array index into the main nodes array
		public int Id;

		/// Optional text label for this node
		public string Label;

		// Color of the node
		public GraphColor Color = new GraphColor() { R = 1.0f, G = 1.0f, B = 1.0f, A = 1.0f };

		// Size
		public float Size = 1.0f;

		// Other attributes
		public Dictionary<string,Object> Attributes = new Dictionary<string,Object>( StringComparer.InvariantCultureIgnoreCase );
	}


	/// <summary>
	/// Describes a graph "edge" in a directed graph
	/// </summary>
	public class GraphEdge
	{
		/// ID number, unique for all edges.  This must also be the array index into the main edges array.
		public int Id;

		/// Source node	(directed graph)
		public GraphNode Source;

		/// Target node (directed graph)
		public GraphNode Target;

		/// Optional edge weight
		public double Weight = 1.0f;

		// Edge color
		public GraphColor Color = new GraphColor() { R = 0.0f, G = 0.0f, B = 0.0f, A = 0.25f };

		// Thickness
		public float Thickness = 0.1f;
	}


	/// <summary>
	/// Describes a type of attribute.  This is derived internally from the attribute data on nodes.
	/// </summary>
	class GraphAttribute
	{
		/// Gexf ID for this attribute
		public int ID;

		/// Name of the attribute
		public string Name;

		/// Gexf type name
		public string TypeName;
	}


	public static class GraphVisualization
	{
		/// <summary>
		/// Writes a GEXF graph file for the specified graph nodes and edges
		/// </summary>
		/// <param name="Filename">The file name to write</param>
		/// <param name="Description">The description to include in the graph file's metadata</param>
		/// <param name="GraphNodes">List of all graph nodes.  Index order is important and must match with the individual node Id members!</param>
		/// <param name="GraphEdges">List of all graph edges.  Index order is important and must match with the individual edge Id members!</param>
		public static void WriteGraphFile( string Filename, string Description, List<GraphNode> GraphNodes, List<GraphEdge> GraphEdges )
		{
			var Settings = new XmlWriterSettings();
			Settings.Indent = true;
			Settings.IndentChars = "    ";

			// Figure out all of the custom attribute types we're dealing with
			var AllAttributes = new Dictionary<string, GraphAttribute>( StringComparer.InvariantCultureIgnoreCase );
			int NextAttributeID = 0;
			foreach( var GraphNode in GraphNodes )
			{
				foreach( var AttributeName in GraphNode.Attributes.Keys )
				{
					var AttributeValue = GraphNode.Attributes[ AttributeName ];

					string AttributeTypeName;
					if( AttributeValue.GetType() == typeof(int) )
					{
						AttributeTypeName = "integer";
					}
					else if( AttributeValue.GetType() == typeof(float) )
					{
						AttributeTypeName = "float";
					}
					else if( AttributeValue.GetType() == typeof(double) )
					{
						AttributeTypeName = "double";
					}
					else if( AttributeValue.GetType() == typeof(string) )
					{
						AttributeTypeName = "string";
					}
					else if( AttributeValue.GetType() == typeof(bool) )
					{
						AttributeTypeName = "boolean";
					}
					else
					{
						// No other types supported yet!
						throw new InvalidOperationException( "Unsupported attribute data type encountered on graph node!" );
					}


					GraphAttribute Attribute;
					if( !AllAttributes.TryGetValue( AttributeName, out Attribute ) )
					{
						Attribute = new GraphAttribute();
						Attribute.ID = NextAttributeID++;
						Attribute.Name = AttributeName;
						Attribute.TypeName = AttributeTypeName;

						AllAttributes[ AttributeName ] = Attribute;
					}
					else
					{
						if( !Attribute.TypeName.Equals( AttributeTypeName ) )
						{
							throw new InvalidOperationException( "Multiple graph nodes with the same attribute name but different types encountered!");
						}
					}
				}
			}


			using( var Writer = XmlWriter.Create( Filename, Settings ) )
			{
				// NOTE: The GEXF XML format is defined here:  http://gexf.net/1.2draft/gexf-12draft-primer.pdf

				var GEXFNamespace = "http://www.gexf.net/1.2-draft";
				var SchemaNamespace = "http://www.w3.org/2001/XMLSchema-instance";
				var VizNamespace = "http://www.gexf.net/1.2draft/viz";

				Writer.WriteStartElement( "gexf", GEXFNamespace );
 				Writer.WriteAttributeString( "xmlns", "xsi", null, SchemaNamespace );
 				Writer.WriteAttributeString( "schemaLocation", SchemaNamespace, "http://www.gexf.net/1.2draft http://www.gexf.net/1.2draft/gexf.xsd" );
				Writer.WriteAttributeString( "xmlns", "viz", null, VizNamespace );
 				Writer.WriteAttributeString( "version", "1.2" );

				Writer.WriteStartElement( "meta" );
				{
					Writer.WriteAttributeString( "creator", "UnrealBuildTool" );
					Writer.WriteAttributeString( "description", Description );
				}
				Writer.WriteEndElement();	// meta

				{
					Writer.WriteStartElement( "graph" );
					{
						Writer.WriteAttributeString( "mode", "static" );
						Writer.WriteAttributeString( "defaultedgetype", "directed" );

						if( AllAttributes.Count > 0 )
						{
							Writer.WriteStartElement( "attributes" );
							{
								// @todo: Add support for edge attributes, not just node attributes
								Writer.WriteAttributeString( "class", "node" );	// Node attributes, not edges!

								foreach( var Attribute in AllAttributes.Values )
								{
									Writer.WriteStartElement( "attribute" );
									{
										Writer.WriteAttributeString( "id", Attribute.ID.ToString() );
										Writer.WriteAttributeString( "title", Attribute.Name );
										Writer.WriteAttributeString( "type", Attribute.TypeName );
									}
									Writer.WriteEndElement();	// attribute
								}

								// @todo: Add support for attribute type default values
							}
							Writer.WriteEndElement();	// attributes

						}

						Writer.WriteStartElement( "nodes" );
						{
							foreach( var GraphNode in GraphNodes )
							{
								Writer.WriteStartElement( "node" );
								{
									Writer.WriteAttributeString( "id", GraphNode.Id.ToString() );
									Writer.WriteAttributeString( "label", GraphNode.Label );
									
									Writer.WriteStartElement( "color", VizNamespace );
									{
										Writer.WriteAttributeString( "r", ((int)( GraphNode.Color.R * 255.0f )).ToString() );
										Writer.WriteAttributeString( "g", ((int)( GraphNode.Color.G * 255.0f )).ToString() );
										Writer.WriteAttributeString( "b", ((int)( GraphNode.Color.B * 255.0f )).ToString() );
										Writer.WriteAttributeString( "a", GraphNode.Color.A.ToString() );
									}
									Writer.WriteEndElement();	// viz:color

									Writer.WriteStartElement( "size", VizNamespace );
									{
										Writer.WriteAttributeString( "value", GraphNode.Size.ToString() );
									}
									Writer.WriteEndElement();	// viz:size

									Writer.WriteStartElement( "shape", VizNamespace );
									{
										// NOTE: Valid shapes are:  disc, square, triangle, diamond, image
										Writer.WriteAttributeString( "value", "disc" );
									}
									Writer.WriteEndElement();	// viz:shape

									if( GraphNode.Attributes.Count > 0 )
									{
										Writer.WriteStartElement( "attvalues" );
										{
											foreach( var AttributeHashEntry in GraphNode.Attributes )
											{
												var AttributeName = AttributeHashEntry.Key;
												var AttributeValue = AttributeHashEntry.Value;

												var Attribute = AllAttributes[ AttributeName ];

												Writer.WriteStartElement( "attvalue" );
												{ 
													Writer.WriteAttributeString( "for", Attribute.ID.ToString() );
													Writer.WriteAttributeString( "value", AttributeValue.ToString() );
												}
												Writer.WriteEndElement();
											}
										}
										Writer.WriteEndElement();	// attvalues
									}
								}
								Writer.WriteEndElement();	// node
							}
						}
						Writer.WriteEndElement();	// nodes

	
						Writer.WriteStartElement( "edges" );
						{
							foreach( var GraphEdge in GraphEdges )
							{
								Writer.WriteStartElement( "edge" );
								{
									Writer.WriteAttributeString( "id", GraphEdge.Id.ToString() );
									Writer.WriteAttributeString( "source", GraphEdge.Source.Id.ToString() );
									Writer.WriteAttributeString( "target", GraphEdge.Target.Id.ToString() );
									Writer.WriteAttributeString( "weight", GraphEdge.Weight.ToString() );

									Writer.WriteStartElement( "color", VizNamespace );
									{
										Writer.WriteAttributeString( "r", ((int)( GraphEdge.Color.R * 255.0f )).ToString() );
										Writer.WriteAttributeString( "g", ((int)( GraphEdge.Color.G * 255.0f )).ToString() );
										Writer.WriteAttributeString( "b", ((int)( GraphEdge.Color.B * 255.0f )).ToString() );
										Writer.WriteAttributeString( "a", GraphEdge.Color.A.ToString() );
									}
									Writer.WriteEndElement();	// viz:color

									Writer.WriteStartElement( "thickness", VizNamespace );
									{
										Writer.WriteAttributeString( "value", GraphEdge.Thickness.ToString() );
									}
									Writer.WriteEndElement();	// viz:thickness

									Writer.WriteStartElement( "shape", VizNamespace );
									{
										// NOTE: Valid shapes are:  solid, dotted, dashed, double
										Writer.WriteAttributeString( "value", "solid" );
									}
									Writer.WriteEndElement();	// viz:shape
								}
								Writer.WriteEndElement();	// edge
							}
						}
						Writer.WriteEndElement();	// nodes
					}

					Writer.WriteEndElement();	// graph
				}
				Writer.WriteEndElement();	// gexf

				Writer.Flush();
			}
		}
	}

}