package org.jboss.windup.reporting.renderer.dot;

import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.jboss.windup.reporting.renderer.GraphWriter;
import org.jboss.windup.reporting.renderer.dot.DotConstants.DotGraphType;

import com.tinkerpop.blueprints.Direction;
import com.tinkerpop.blueprints.Edge;
import com.tinkerpop.blueprints.Graph;
import com.tinkerpop.blueprints.Vertex;

public class DotWriter implements GraphWriter
{

    private final Graph graph;
    private String graphName = "G";
    private String vertexLabelProperty = "label";
    private DotGraphType graphType = DotGraphType.DIGRAPH;
    private String fontSize = "12pt";
    private String edgeLabel = "";

    public DotWriter(Graph graph)
    {
        this.graph = graph;
    }

    public DotWriter(Graph graph, String graphName, String vertexLabelProperty, String edgeLabel,
                DotGraphType graphType, String fontSize)
    {
        this.graph = graph;
        this.graphName = graphName;
        this.fontSize = fontSize;
        this.vertexLabelProperty = vertexLabelProperty;
        this.graphType = graphType;
        this.edgeLabel = edgeLabel;
    }

    @Override
    public void writeGraph(OutputStream os) throws IOException
    {
        writeDot(os);
    }

    private void writeDot(OutputStream os) throws IOException
    {
        writeGraphTag(os);
    }

    private void writeGraphTag(OutputStream os) throws IOException
    {
        String name = this.getDotSafeName(graphName);
        IOUtils.write(graphType.getName() + " " + name + "{" + DotConstants.NL, os);

        writeGraphNodes(os);
        writeGraphEdges(os);

        IOUtils.write("}", os);
    }

    private void writeGraphEdges(OutputStream os) throws IOException
    {
        for (Edge edge : graph.getEdges())
        {
            String label = edgeLabel;
            String source = "" + edge.getVertex(Direction.OUT).getId().toString();
            String target = "" + edge.getVertex(Direction.IN).getId().toString();
            writeGraphEdge(label, source, target, os);
        }
    }

    private void writeGraphEdge(String label, String source, String target, OutputStream os) throws IOException
    {
        final String startTag = getDotSafeName(source) + graphType.getEdge() + getDotSafeName(target);
        final String endTag = DotConstants.END_LINE;

        IOUtils.write(startTag, os);

        if (StringUtils.isNotBlank(label))
        {
            writeOptions(os, new String[] { "label", label }, new String[] { "fontsize", fontSize });
        }

        IOUtils.write(endTag, os);

    }

    private void writeGraphNode(String id, String label, OutputStream os) throws IOException
    {
        final String tag = DotConstants.INDENT + getDotSafeName(id) + "[label = \"" + label + "\", fontsize = \""
                    + fontSize + "\"]" + DotConstants.END_LINE;
        IOUtils.write(tag, os);
    }

    private void writeGraphNodes(OutputStream os) throws IOException
    {

        // iterate the nodes.
        for (Vertex vertex : graph.getVertices())
        {
            String id = "" + vertex.getId().toString();
            String label = vertex.getProperty(vertexLabelProperty);

            if (StringUtils.isBlank(label))
            {
                label = vertex.toString();
            }
            writeGraphNode(id, label, os);
        }

    }

    private void writeOptions(OutputStream os, String[]... options) throws IOException
    {
        Map<String, String> map = new HashMap<String, String>();
        for (String[] option : options)
        {
            String key = option[0];
            String value = option[1];
            map.put(key, value);

        }
        writeOptions(map, os);
    }

    private void writeOptions(Map<String, String> options, OutputStream os) throws IOException
    {
        if (options == null || options.size() == 0)
        {
            return;
        }

        IOUtils.write("[", os);

        StringBuilder builder = new StringBuilder();
        for (String key : options.keySet())
        {
            builder.append(key + "=\"" + options.get(key) + "\", ");
        }
        String tag = builder.toString().trim();
        tag = StringUtils.removeEnd(tag, ",");

        IOUtils.write(tag, os);
        IOUtils.write("]", os);
    }

    private String getDotSafeName(String inName)
    {
        String name = null;
        if (StringUtils.isAlphanumeric(inName))
        {
            name = inName;
        }
        else
        {
            name = "\"" + inName + "\"";
        }

        return name;
    }

}
