/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.myfaces.extensions.scripting.core.engine.compiler;

import org.apache.myfaces.extensions.scripting.core.api.Configuration;
import org.apache.myfaces.extensions.scripting.core.api.WeavingContext;
import org.apache.myfaces.extensions.scripting.core.common.util.ClassLoaderUtils;
import org.apache.myfaces.extensions.scripting.core.common.util.FileUtils;
import org.apache.myfaces.extensions.scripting.core.engine.api.CompilationMessage;
import org.apache.myfaces.extensions.scripting.core.engine.api.CompilationResult;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

import static org.apache.myfaces.extensions.scripting.core.api.ScriptingConst.ENGINE_TYPE_JSF_JRUBY;
import static org.apache.myfaces.extensions.scripting.core.engine.api.CompilerConst.JRUBY_WILDARD;

/**
 * @author Werner Punz (latest modification by $Author$)
 * @version $Revision$ $Date$
 *          <p>&nbsp;</p>
 *          A compiler for jruby which uses ruby and the standard JSR 223
 *          for compiling classes into java classes
 */

public class JRubyCompiler implements org.apache.myfaces.extensions.scripting.core.engine.api.Compiler
{

    private static final String ENGINE_JRUBY = "jruby";

    private static  Logger logger = Logger.getLogger(JRubyCompiler.class.getName());

    @Override
    public CompilationResult compile(File sourcePath, File targetPath, ClassLoader classLoader)
    {
        targetPath.mkdirs();
        List<String> sources = getSourceFiles();
        return compile(sourcePath, targetPath, sources);
    }

    public CompilationResult compile(File sourcePath, File targetPath, List<String> sources)
    {
        targetPath.mkdirs();

        String classPath = ClassLoaderUtils.buildClasspath(ClassLoaderUtils.getDefaultClassLoader());
        //capturing stdout technique from http://thinkingdigitally.com/archive/capturing-output-from-puts-in-ruby/
        StringBuilder commandString = new StringBuilder();
        commandString.append("require 'jruby/jrubyc'\n");
        commandString.append("require 'stringio' \n");
        commandString.append("module Kernel\n");
        commandString.append("  def capture_stdout\n");
        commandString.append("    out = StringIO.new\n");
        commandString.append("    $stdout = out\n");
        commandString.append("    yield\n");
        commandString.append("    return out\n");
        commandString.append("  ensure\n");
        commandString.append("    $stdout = STDOUT\n");
        commandString.append("  end\n");
        commandString.append("end\n");
        commandString.append("out = capture_stdout do\n");
        commandString.append("  options = Array.new \n");
        commandString.append("  options << '-d" + sourcePath.getAbsolutePath().replaceAll("\\s", "\\\\ ") + "'\n");
        commandString.append("  options<< '--javac' \n");
        commandString.append("  options<< '-t" + targetPath.getAbsolutePath().replaceAll("\\s", "\\\\ ") + "'\n");
        commandString.append("  options<< '-c" + classPath.replaceAll("\\s", "\\\\ ") + "'\n");
        for (String singleSource : sources)
        {
            commandString.append("  options<< '" + singleSource.replaceAll("\\s", "\\\\ ") + "'\n");
        }
        commandString.append("  $status = JRuby::Compiler::compile_argv(options) \n");
        commandString.append("end\n");
        commandString.append("$finalOut = out.string\n");

        //commandString.append("options<< '" + sources + "'\n");
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName(ENGINE_JRUBY);
        if(engine == null) {
            logger.info("[EXT-SCRIPT] jruby not present compiler deactivated");
            return new CompilationResult("No Errors");
        }
        try
        {
            //See: http://stackoverflow.com/questions/4183408/redirect-stdout-to-a-string-in-java
            engine.eval(commandString.toString());
            Long status = (Long) engine.get("status");
            String compilerOutput = (String) engine.get("finalOut");
            if (status.equals(0L))
            {
                CompilationResult result = new CompilationResult("No Errors");
                logger.info("No Compilation errors");
                return result;
            } else
            {
                CompilationResult result = new CompilationResult("Errors");
                result.registerError(new CompilationMessage(status, compilerOutput));
                logger.info(compilerOutput);
                return result;
            }
        }
        catch (ScriptException e)
        {
            e.printStackTrace();
        }

        return null;
    }

    private List<String> getSourceFiles()
    {
        WeavingContext context = WeavingContext.getInstance();
        Configuration configuration = context.getConfiguration();
        List<File> sourceFiles = FileUtils.fetchSourceFiles(configuration.getWhitelistedSourceDirs
                (ENGINE_TYPE_JSF_JRUBY), JRUBY_WILDARD);
        StringBuilder sources = new StringBuilder(sourceFiles.size() * 30);
        List<String> sourcesStr = new ArrayList<String>(sourceFiles.size());
        for (File sourceFile : sourceFiles)
        {
            sourcesStr.add(sourceFile.getAbsolutePath());
            //sources.append(" ");
        }
        return sourcesStr;
    }

}