/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2014, Arnaud Roques
 *
 * Project Info:  http://plantuml.sourceforge.net
 * 
 * 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.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * Original Author:  Arnaud Roques
 * 
 * Revision $Revision: 17341 $
 *
 */
package net.sourceforge.plantuml.preproc;

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

import net.sourceforge.plantuml.CharSequence2;
import net.sourceforge.plantuml.CharSequence2Impl;
import net.sourceforge.plantuml.StringUtils;
import net.sourceforge.plantuml.command.regex.MyPattern;
import net.sourceforge.plantuml.utils.StartUtils;

public class Preprocessor implements ReadLine {

	private static final String ID = "[A-Za-z_][A-Za-z_0-9]*";
	private static final String ARG = "(?:\\(" + ID + "(?:," + ID + ")*?\\))?";
	private static final Pattern definePattern = MyPattern.cmpile("^[%s]*!define[%s]+(" + ID + ARG + ")"
			+ "(?:[%s]+(.*))?$");
	private static final Pattern undefPattern = MyPattern.cmpile("^[%s]*!undef[%s]+(" + ID + ")$");
	private static final Pattern definelongPattern = MyPattern.cmpile("^[%s]*!definelong[%s]+(" + ID + ARG + ")");
	private static final Pattern enddefinelongPattern = MyPattern.cmpile("^[%s]*!enddefinelong[%s]*$");

	private final Defines defines;
	private final PreprocessorInclude rawSource;
	private final ReadLineInsertable source;

	public Preprocessor(ReadLine reader, String charset, Defines defines, File newCurrentDir) {
		this.defines = defines;
		this.defines.saveState();
		this.rawSource = new PreprocessorInclude(reader, defines, charset, newCurrentDir);
		this.source = new ReadLineInsertable(new IfManager(rawSource, defines));
	}

	public CharSequence2 readLine() throws IOException {
		final CharSequence2 s = source.readLine();
		if (s == null) {
			return null;
		}
		if (StartUtils.isArobaseStartDiagram(s)) {
			this.defines.restoreState();
		}

		Matcher m = definePattern.matcher(s);
		if (m.find()) {
			return manageDefine(m);
		}

		m = definelongPattern.matcher(s);
		if (m.find()) {
			return manageDefineLong(m);
		}

		m = undefPattern.matcher(s);
		if (m.find()) {
			return manageUndef(m);
		}

		if (ignoreDefineDuringSeveralLines > 0) {
			ignoreDefineDuringSeveralLines--;
			return s;
		}

		final List<String> result = defines.applyDefines(s.toString2());
		if (result.size() > 1) {
			ignoreDefineDuringSeveralLines = result.size() - 2;
			source.insert(result.subList(1, result.size() - 1), s.getLocation());
		}
		return new CharSequence2Impl(result.get(0), s.getLocation());
	}

	private int ignoreDefineDuringSeveralLines = 0;

	private CharSequence2 manageUndef(Matcher m) throws IOException {
		defines.undefine(m.group(1));
		return this.readLine();
	}

	private CharSequence2 manageDefineLong(Matcher m) throws IOException {
		final String group1 = m.group(1);
		final List<String> def = new ArrayList<String>();
		while (true) {
			final CharSequence2 read = this.readLine();
			if (read == null) {
				return null;
			}
			def.add(read.toString2());
			if (enddefinelongPattern.matcher(read).find()) {
				defines.define(group1, def);
				return this.readLine();
			}
		}
	}

	private CharSequence2 manageDefine(Matcher m) throws IOException {
		final String group1 = m.group(1);
		final String group2 = m.group(2);
		if (group2 == null) {
			defines.define(group1, null);
		} else {
			final List<String> strings = defines.applyDefines(group2);
			if (strings.size() > 1) {
				throw new UnsupportedOperationException();
			}
			final StringBuilder value = new StringBuilder(strings.get(0));
			while (StringUtils.endsWithBackslash(value.toString())) {
				value.setLength(value.length() - 1);
				final CharSequence2 read = this.readLine();
				value.append(read.toString2());
			}
			final List<String> li = new ArrayList<String>();
			li.add(value.toString());
			defines.define(group1, li);
		}
		return this.readLine();
	}

	public int getLineNumber() {
		return rawSource.getLineNumber();
	}

	public void close() throws IOException {
		rawSource.close();
	}

	public Set<FileWithSuffix> getFilesUsed() {
		return Collections.unmodifiableSet(rawSource.getFilesUsedGlobal());
	}

}