/*
 * [The "BSD licence"]
 * Copyright (c) 2005-2008 Terence Parr
 * All rights reserved.
 *
 * Conversion to C#:
 * Copyright (c) 2008 Sam Harwell, Pixel Mine, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

namespace Antlr.Runtime.Tree
{
    using System.Collections.Generic;
    using StringBuilder = System.Text.StringBuilder;

    /** A utility class to generate DOT diagrams (graphviz) from
     *  arbitrary trees.  You can pass in your own templates and
     *  can pass in any kind of tree or use Tree interface method.
     *  I wanted this separator so that you don't have to include
     *  ST just to use the org.antlr.runtime.tree.* package.
     *  This is a set of non-static methods so you can subclass
     *  to override.  For example, here is an invocation:
     *
     *      CharStream input = new ANTLRInputStream(System.in);
     *      TLexer lex = new TLexer(input);
     *      CommonTokenStream tokens = new CommonTokenStream(lex);
     *      TParser parser = new TParser(tokens);
     *      TParser.e_return r = parser.e();
     *      Tree t = (Tree)r.tree;
     *      System.out.println(t.toStringTree());
     *      DOTTreeGenerator gen = new DOTTreeGenerator();
     *      StringTemplate st = gen.toDOT(t);
     *      System.out.println(st);
     */
    public class DotTreeGenerator
    {
        readonly string[] HeaderLines =
            {
                "digraph {",
                "",
                "\tordering=out;",
                "\tranksep=.4;",
                "\tbgcolor=\"lightgrey\"; node [shape=box, fixedsize=false, fontsize=12, fontname=\"Helvetica-bold\", fontcolor=\"blue\"",
                "\t\twidth=.25, height=.25, color=\"black\", fillcolor=\"white\", style=\"filled, solid, bold\"];",
                "\tedge [arrowsize=.5, color=\"black\", style=\"bold\"]",
                ""
            };
        const string Footer = "}";
        const string NodeFormat = "  {0} [label=\"{1}\"];";
        const string EdgeFormat = "  {0} -> {1} // \"{2}\" -> \"{3}\"";

        /** Track node to number mapping so we can get proper node name back */
        Dictionary<object, int> nodeToNumberMap = new Dictionary<object, int>();

        /** Track node number so we can get unique node names */
        int nodeNumber = 0;

        /** Generate DOT (graphviz) for a whole tree not just a node.
         *  For example, 3+4*5 should generate:
         *
         * digraph {
         *   node [shape=plaintext, fixedsize=true, fontsize=11, fontname="Courier",
         *         width=.4, height=.2];
         *   edge [arrowsize=.7]
         *   "+"->3
         *   "+"->"*"
         *   "*"->4
         *   "*"->5
         * }
         *
         * Takes a Tree interface object.
         */
        public virtual string ToDot( object tree, ITreeAdaptor adaptor )
        {
            StringBuilder builder = new StringBuilder();
            foreach ( string line in HeaderLines )
                builder.AppendLine( line );

            nodeNumber = 0;
            var nodes = DefineNodes( tree, adaptor );
            nodeNumber = 0;
            var edges = DefineEdges( tree, adaptor );

            foreach ( var s in nodes )
                builder.AppendLine( s );

            builder.AppendLine();

            foreach ( var s in edges )
                builder.AppendLine( s );

            builder.AppendLine();

            builder.AppendLine( Footer );
            return builder.ToString();
        }

        public virtual string ToDot( ITree tree )
        {
            return ToDot( tree, new CommonTreeAdaptor() );
        }
        protected virtual IEnumerable<string> DefineNodes( object tree, ITreeAdaptor adaptor )
        {
            if ( tree == null )
                yield break;

            int n = adaptor.GetChildCount( tree );
            if ( n == 0 )
            {
                // must have already dumped as child from previous
                // invocation; do nothing
                yield break;
            }

            // define parent node
            yield return GetNodeText( adaptor, tree );

            // for each child, do a "<unique-name> [label=text]" node def
            for ( int i = 0; i < n; i++ )
            {
                object child = adaptor.GetChild( tree, i );
                yield return GetNodeText( adaptor, child );
                foreach ( var t in DefineNodes( child, adaptor ) )
                    yield return t;
            }
        }

        protected virtual IEnumerable<string> DefineEdges( object tree, ITreeAdaptor adaptor )
        {
            if ( tree == null )
                yield break;

            int n = adaptor.GetChildCount( tree );
            if ( n == 0 )
            {
                // must have already dumped as child from previous
                // invocation; do nothing
                yield break;
            }

            string parentName = "n" + GetNodeNumber( tree );

            // for each child, do a parent -> child edge using unique node names
            string parentText = adaptor.GetNodeText( tree );
            for ( int i = 0; i < n; i++ )
            {
                object child = adaptor.GetChild( tree, i );
                string childText = adaptor.GetNodeText(child);
                string childName = "n" + GetNodeNumber( child );
                yield return string.Format( EdgeFormat, parentName, childName, FixString( parentText ), FixString( childText ) );
                foreach ( var t in DefineEdges( child, adaptor ) )
                    yield return t;
            }
        }

        protected virtual string GetNodeText( ITreeAdaptor adaptor, object t )
        {
            string text = adaptor.GetNodeText(t);
            string uniqueName = "n" + GetNodeNumber( t );
            return string.Format( NodeFormat, uniqueName, FixString( text ) );
        }

        protected virtual int GetNodeNumber( object t )
        {
            int i;
            if ( nodeToNumberMap.TryGetValue( t, out i ) )
            {
                return i;
            }
            else
            {
                nodeToNumberMap[t] = nodeNumber;
                nodeNumber++;
                return nodeNumber - 1;
            }
        }

        protected virtual string FixString( string text )
        {
            if ( text != null )
            {
                text = System.Text.RegularExpressions.Regex.Replace( text, "\"", "\\\\\"" );
                text = System.Text.RegularExpressions.Regex.Replace( text, "\\t", "    " );
                text = System.Text.RegularExpressions.Regex.Replace( text, "\\n", "\\\\n" );
                text = System.Text.RegularExpressions.Regex.Replace( text, "\\r", "\\\\r" );

                if ( text.Length > 20 )
                    text = text.Substring( 0, 8 ) + "..." + text.Substring( text.Length - 8 );
            }

            return text;
        }
    }
}