/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2024, Arnaud Roques
 *
 * Project Info:  https://plantuml.com
 * 
 * If you like this project or if you find it useful, you can support us at:
 * 
 * https://plantuml.com/patreon (only 1$ per month!)
 * https://plantuml.com/paypal
 * 
 * This file is part of PlantUML.
 *
 * PlantUML is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PlantUML distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
 * License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 *
 * Original Author:  Arnaud Roques
 *
 */
package net.sourceforge.plantuml.directdot;

import java.util.regex.Pattern;
import java.util.regex.Matcher;

import net.sourceforge.plantuml.command.PSystemBasicFactory;
import net.sourceforge.plantuml.core.DiagramType;
import net.sourceforge.plantuml.core.UmlSource;
import net.sourceforge.plantuml.preproc.PreprocessingArtifact;
import net.sourceforge.plantuml.skin.UmlDiagramType;

public class PSystemDotFactory extends PSystemBasicFactory<PSystemDot> {

	private StringBuilder data;
	private static final Pattern GRAPHVIZ_DOT_HEADER_PATTERN = Pattern.compile(
		  "\\s*"                            // optional leading whitespace
		+ "(strict\\s+)?"                   // optional 'strict'
		+ "(di)?"                           // optional 'di'
		+ "graph\\s+"                       // 'graph' keyword
		+ "("
		+     "[_\\p{L}][_\\p{L}\\p{N}]*"   // identifier
		+   "|"
		+     "-?(?:\\.[0-9]+|[0-9]+(?:\\.[0-9]*)?)" // number
		+   "|"
		+     "\"([^\"\\\\]|\\\\\")*\""     // quoted string
		+ ")?"
		+ "\\s*\\{\\s*"                     // opening brace
	);

	public PSystemDotFactory(DiagramType diagramType) {
		super(diagramType);
	}

	@Override
	public PSystemDot initDiagram(UmlSource source, String startLine, PreprocessingArtifact preprocessing) {
		data = null;
		return null;
	}

	@Override
	public PSystemDot executeLine(UmlSource source, PSystemDot system, String line, PreprocessingArtifact preprocessing) {
		if (system == null && isGraphvizDotHeader(line)) {
			data = new StringBuilder(line);
			data.append("\n");
			return new PSystemDot(source, data.toString(), preprocessing);
		}
		if (data == null || system == null)
			return null;

		data.append(line);
		data.append("\n");
		return new PSystemDot(source, data.toString(), preprocessing);
	}

    private boolean isGraphvizDotHeader(String line) {
        Matcher matcher = GRAPHVIZ_DOT_HEADER_PATTERN.matcher(line);
        return matcher.matches();
    }

	@Override
	public UmlDiagramType getUmlDiagramType() {
		return null;
	}

}
