/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2020, Arnaud Roques
 *
 * Project Info:  http://plantuml.com
 * 
 * If you like this project or if you find it useful, you can support us at:
 * 
 * http://plantuml.com/patreon (only 1$ per month!)
 * http://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.cucadiagram.dot;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.sourceforge.plantuml.ISkinParam;
import net.sourceforge.plantuml.Log;
import net.sourceforge.plantuml.StringUtils;
import net.sourceforge.plantuml.vizjs.GraphvizJs;
import net.sourceforge.plantuml.vizjs.VizJsEngine;

public class GraphvizUtils {

	public static final String VIZJS = "vizjs";
	private static int DOT_VERSION_LIMIT = 226;

	private static boolean isWindows() {
		return File.separatorChar == '\\';
	}

	private static String dotExecutable;

	public static final String getDotExecutableForTest() {
		return dotExecutable;
	}

	public static final void setDotExecutable(String value) {
		dotExecutable = value == null ? null : value.trim();
	}

	public static Graphviz create(ISkinParam skinParam, String dotString, String... type) {
		if (useVizJs(skinParam)) {
			Log.info("Using " + VIZJS);
			return new GraphvizJs(dotString);
		}
		final AbstractGraphviz result;
		if (isWindows()) {
			result = new GraphvizWindows(skinParam, dotString, type);
		} else {
			result = new GraphvizLinux(skinParam, dotString, type);
		}
		if (result.getExeState() != ExeState.OK && VizJsEngine.isOk()) {
			Log.info("Error with file " + result.getDotExe() + ": " + result.getExeState().getTextMessage());
			Log.info("Using " + VIZJS);
			return new GraphvizJs(dotString);
		}
		return result;
	}

	private static boolean useVizJs(ISkinParam skinParam) {
		if (skinParam != null && skinParam.isUseVizJs() && VizJsEngine.isOk()) {
			return true;
		}
		if (VIZJS.equalsIgnoreCase(getenvGraphvizDot()) && VizJsEngine.isOk()) {
			return true;
		}
		return false;
	}

	static public File getDotExe() {
		return create(null, "png").getDotExe();
	}

	public static String getenvGraphvizDot() {
		if (StringUtils.isNotEmpty(dotExecutable)) {
			return StringUtils.eventuallyRemoveStartingAndEndingDoubleQuote(dotExecutable);
		}
		final String env = System.getProperty("GRAPHVIZ_DOT");
		if (StringUtils.isNotEmpty(env)) {
			return StringUtils.eventuallyRemoveStartingAndEndingDoubleQuote(env);
		}
		final String getenv = System.getenv("GRAPHVIZ_DOT");
		if (StringUtils.isNotEmpty(getenv)) {
			return StringUtils.eventuallyRemoveStartingAndEndingDoubleQuote(getenv);
		}
		return null;
	}

	private static final ThreadLocal<Integer> limitSize = new ThreadLocal<Integer>();

	public static void removeLocalLimitSize() {
		limitSize.remove();
	}

	public static void setLocalImageLimit(int value) {
		limitSize.set(value);
	}

	public static int getenvImageLimit() {
		final Integer local = limitSize.get();
		if (local != null) {
			return local;
		}
		final String env = getenv("PLANTUML_LIMIT_SIZE");
		if (StringUtils.isNotEmpty(env) && env.matches("\\d+")) {
			return Integer.parseInt(env);
		}
		return 4096;
	}

	public static String getenvDefaultConfigFilename() {
		return getenv("PLANTUML_DEFAULT_CONFIG_FILENAME");
	}

	public static String getenvLogData() {
		return getenv("PLANTUML_LOGDATA");
	}

	public static String getenv(String name) {
		final String env = System.getProperty(name);
		if (StringUtils.isNotEmpty(env)) {
			return env;
		}
		return System.getenv(name);
	}

	private static String dotVersion = null;

	public static String dotVersion() throws IOException, InterruptedException {
		if (dotVersion == null) {
			final File dotExe = GraphvizUtils.getDotExe();
			final ExeState exeState = ExeState.checkFile(dotExe);
			if (exeState == ExeState.OK) {
				dotVersion = create(null, "png").dotVersion();
			} else {
				dotVersion = "Error:" + exeState.getTextMessage(dotExe);
			}
		}
		return dotVersion;
	}

	public static int retrieveVersion(String s) {
		if (s == null) {
			return -1;
		}
		final Pattern p = Pattern.compile("\\s([12].\\d\\d)\\D");
		final Matcher m = p.matcher(s);
		if (m.find() == false) {
			return -1;
		}
		return Integer.parseInt(m.group(1).replaceAll("\\.", ""));
	}

	public static int getDotVersion() throws IOException, InterruptedException {
		return retrieveVersion(dotVersion());
	}

	static public int addDotStatus(List<String> result, boolean withRichText) {
		String red = "";
		String bold = "";
		if (withRichText) {
			red = "<b><color:red>";
			bold = "<b>";
		}

		int error = 0;

		if (useVizJs(null)) {
			result.add("VizJs library is used!");
			try {
				final String err = getTestCreateSimpleFile();
				if (err == null) {
					result.add(bold + "Installation seems OK. File generation OK");
				} else {
					result.add(red + err);
				}
			} catch (Exception e) {
				result.add(red + e.toString());
				e.printStackTrace();
				error = -1;
			}
			return error;
		}

		final String ent = GraphvizUtils.getenvGraphvizDot();
		if (ent == null) {
			result.add("The environment variable GRAPHVIZ_DOT has not been set");
		} else {
			result.add("The environment variable GRAPHVIZ_DOT has been set to " + ent);
		}
		final File dotExe = GraphvizUtils.getDotExe();
		result.add("Dot executable is " + dotExe);

		final ExeState exeState = ExeState.checkFile(dotExe);

		if (exeState == ExeState.OK) {
			try {
				final String version = GraphvizUtils.dotVersion();
				result.add("Dot version: " + version);
				final int v = GraphvizUtils.getDotVersion();
				if (v == -1) {
					result.add("Warning : cannot determine dot version");
					error = -2;
				} else if (v < DOT_VERSION_LIMIT) {
					result.add(bold + "Warning : Your dot installation seems old");
					result.add(bold + "Some diagrams may have issues");
					error = -3;
				} else {
					final String err = getTestCreateSimpleFile();
					if (err == null) {
						result.add(bold + "Installation seems OK. File generation OK");
					} else {
						result.add(red + err);
						error = -4;
					}
				}
			} catch (Exception e) {
				result.add(red + e.toString());
				e.printStackTrace();
				error = -5;
			}
		} else {
			result.add(red + "Error: " + exeState.getTextMessage());
			result.add("Error: only sequence diagrams will be generated");
			error = -6;
		}

		return error;
	}

	static String getTestCreateSimpleFile() throws IOException {
		final Graphviz graphviz2 = GraphvizUtils.create(null, "digraph foo { test; }", "svg");
		final ByteArrayOutputStream baos = new ByteArrayOutputStream();
		final ProcessState state = graphviz2.createFile3(baos);
		if (state.differs(ProcessState.TERMINATED_OK())) {
			return "Error: timeout " + state;
		}

		final byte data[] = baos.toByteArray();

		if (data.length == 0) {
			return "Error: dot generates empty file. Check you dot installation.";
		}
		final String s = new String(data);
		if (s.indexOf("<svg") == -1) {
			return "Error: dot generates unreadable SVG file. Check you dot installation.";
		}
		return null;
	}

}
