using System;
using System.Diagnostics;
using System.IO;
using HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration.GrammarEnumeration;
using HeuristicLab.Common;
using HeuristicLab.Core;

namespace HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration {
  class SearchGraphVisualizer : Item, IGrammarEnumerationAnalyzer {
    private readonly string dotFileName = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + @"\searchgraph.dot";

    private TextWriterTraceListener dotFileTrace;

    public SearchGraphVisualizer() { }

    protected SearchGraphVisualizer(SearchGraphVisualizer original, Cloner cloner) : base(original, cloner) { }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new SearchGraphVisualizer(this, cloner);
    }

    public void Register(GrammarEnumerationAlgorithm algorithm) {
      algorithm.Started += GrammarEnumerationAlgorithmOnStarted;
      algorithm.Stopped += GrammarEnumerationAlgorithmOnStopped;
      algorithm.ExceptionOccurred += GrammarEnumerationAlgorithmOnStopped;

      algorithm.PhraseFetched += PhraseFetched;
      algorithm.PhraseDerived += PhraseDerived;
      algorithm.SentenceGenerated += SentenceGenerated;
    }

    public void Deregister(GrammarEnumerationAlgorithm algorithm) {
      algorithm.Started -= GrammarEnumerationAlgorithmOnStarted;
      algorithm.Stopped -= GrammarEnumerationAlgorithmOnStopped;
      algorithm.ExceptionOccurred -= GrammarEnumerationAlgorithmOnStopped;

      algorithm.PhraseFetched -= PhraseFetched;
      algorithm.PhraseDerived -= PhraseDerived;
      algorithm.SentenceGenerated -= SentenceGenerated;
    }

    private void GrammarEnumerationAlgorithmOnStarted(object sender, EventArgs eventArgs) {
      dotFileTrace = new TextWriterTraceListener(new FileStream(dotFileName, FileMode.Create));
      ((StreamWriter)dotFileTrace.Writer).AutoFlush = true;
      dotFileTrace.WriteLine("digraph searchgraph { pad=0.02; nodesep=0.3; ranksep=0.02;ratio=0.5625;");
    }

    private void GrammarEnumerationAlgorithmOnStopped(object sender, EventArgs eventArgs) {
      try {
        var alg = (GrammarEnumerationAlgorithm)sender;
        var phrase0 = new SymbolString(new[] { alg.Grammar.StartSymbol });
        var phrase0Hash = alg.Grammar.Hasher.CalcHashCode(phrase0);

        dotFileTrace.WriteLine($"{phrase0Hash} [label=\"{phrase0}\", shape=doublecircle]; }}");
        dotFileTrace.Flush();
      } catch (Exception) {
        dotFileTrace.Close();
        throw;
      }
    }

    private void PhraseFetched(object sender, PhraseEventArgs phraseEventArgs) {
      dotFileTrace.WriteLine($"{phraseEventArgs.Hash} [label=\"{phraseEventArgs.Phrase}\"];");
    }

    private void PhraseDerived(object sender, PhraseAddedEventArgs args) {
      dotFileTrace.WriteLine($"{args.ParentHash} -> {args.NewHash} [label=\"{args.ExpandedSymbol.StringRepresentation} + → {args.ExpandedProduction}\"];");
    }

    private void SentenceGenerated(object sender, PhraseAddedEventArgs args) {
      var alg = (GrammarEnumerationAlgorithm)sender;
      dotFileTrace.WriteLine($"{args.NewHash} [label=\"{alg.Grammar.ToInfixString(args.NewPhrase)}\", style=\"filled\", fillcolor=\"#f79423\", color=\"#f79423\"];");
    }
  }
}