/*
 * Copyright (C) 2011 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.javac;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;

import com.sun.tools.javac.main.JavaCompiler;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.util.Context;

public class CommentCatcher {
	private final JavaCompiler compiler;
	private final Map<JCCompilationUnit, List<Comment>> commentsMap;
	
	public static CommentCatcher create(Context context) {
		registerCommentsCollectingScannerFactory(context);
		JavaCompiler compiler = new JavaCompiler(context);
		
		Map<JCCompilationUnit, List<Comment>> commentsMap = new WeakHashMap<JCCompilationUnit, List<Comment>>();
		setInCompiler(compiler, context, commentsMap);
		
		compiler.keepComments = true;
		compiler.genEndPos = true;
		
		return new CommentCatcher(compiler, commentsMap);
	}
	
	private CommentCatcher(JavaCompiler compiler, Map<JCCompilationUnit, List<Comment>> commentsMap) {
		this.compiler = compiler;
		this.commentsMap = commentsMap;
	}
	
	public JavaCompiler getCompiler() {
		return compiler;
	}
	
	public List<Comment> getComments(JCCompilationUnit ast) {
		List<Comment> list = commentsMap.get(ast);
		return list == null ? Collections.<Comment>emptyList() : list;
	}
	
	private static void registerCommentsCollectingScannerFactory(Context context) {
		try {
			if (JavaCompiler.version().startsWith("1.6")) {
				Class.forName("lombok.javac.java6.CommentCollectingScannerFactory").getMethod("preRegister", Context.class).invoke(null, context);
			} else {
				Class.forName("lombok.javac.java7.CommentCollectingScannerFactory").getMethod("preRegister", Context.class).invoke(null, context);
			}
		} catch (Exception e) {
			if (e instanceof RuntimeException) throw (RuntimeException)e;
			throw new RuntimeException(e);
		}
	}
	
	private static void setInCompiler(JavaCompiler compiler, Context context, Map<JCCompilationUnit, List<Comment>> commentsMap) {
		
		try {
			if (JavaCompiler.version().startsWith("1.6")) {
				Class<?> parserFactory = Class.forName("lombok.javac.java6.CommentCollectingParserFactory");
				parserFactory.getMethod("setInCompiler",JavaCompiler.class, Context.class, Map.class).invoke(null, compiler, context, commentsMap);
			} else {
				Class<?> parserFactory = Class.forName("lombok.javac.java7.CommentCollectingParserFactory");
				parserFactory.getMethod("setInCompiler",JavaCompiler.class, Context.class, Map.class).invoke(null, compiler, context, commentsMap);
			}
		} catch (Exception e) {
			if (e instanceof RuntimeException) throw (RuntimeException)e;
			throw new RuntimeException(e);
		}
	}
	
}