/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.codemodel.internal.fmt;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.PrintWriter;

import java.net.URL;

import java.text.ParseException;

import java.util.Iterator;

import java.util.List;

import com.sun.codemodel.internal.JClass;

import com.sun.codemodel.internal.JPackage;

import com.sun.codemodel.internal.JResourceFile;

import com.sun.codemodel.internal.JTypeVar;

/**

 * Statically generated Java soruce file.

 *

 * <p>

 * This {@link JResourceFile} implementation will generate a Java source

 * file by copying the source code from a resource.

 * <p>

 * While copying a resource, we look for a package declaration and

 * replace it with the target package name. This allows the static Java

 * source code to have an arbitrary package declaration.

 * <p>

 * You can also use the getJClass method to obtain a {@link JClass}

 * object that represents the static file. This allows the client code

 * to refer to the class from other CodeModel generated code.

 * <p>

 * Note that because we don't parse the static Java source code,

 * the returned {@link JClass} object doesn't respond to methods like

 * "isInterface" or "_extends",

 *

 * @author

 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)

 */

public final class JStaticJavaFile extends JResourceFile {

    private final JPackage pkg;

    private final String className;

    private final URL source;

    private final JStaticClass clazz;

    private final LineFilter filter;

    public JStaticJavaFile(JPackage _pkg, String className, String _resourceName) {

        this( _pkg, className,

            SecureLoader.getClassClassLoader(JStaticJavaFile.class).getResource(_resourceName), null );

    }

    public JStaticJavaFile(JPackage _pkg, String _className, URL _source, LineFilter _filter ) {

        super(_className+".java");

        if(_source==null)   throw new NullPointerException();

        this.pkg = _pkg;

        this.clazz = new JStaticClass();

        this.className = _className;

        this.source = _source;

        this.filter = _filter;

    }

    /**

     * Returns a class object that represents a statically generated code.

     */

    public final JClass getJClass() {

        return clazz;

    }

    protected boolean isResource() {

        return false;

    }

    protected  void build(OutputStream os) throws IOException {

        InputStream is = source.openStream();

        BufferedReader r = new BufferedReader(new InputStreamReader(is));

        PrintWriter w = new PrintWriter(new BufferedWriter(new OutputStreamWriter(os)));

        LineFilter filter = createLineFilter();

        int lineNumber=1;

        try {

            String line;

            while((line=r.readLine())!=null) {

                line = filter.process(line);

                if(line!=null)

                    w.println(line);

                lineNumber++;

            }

        } catch( ParseException e ) {

            throw new IOException("unable to process "+source+" line:"+lineNumber+"\n"+e.getMessage());

        }

        w.close();

        r.close();

    }

    /**

     * Creates a {@link LineFilter}.

     * <p>

     * A derived class can override this method to process

     * the contents of the source file.

     */

    private LineFilter createLineFilter() {

        // this filter replaces the package declaration.

        LineFilter f = new LineFilter() {

            public String process(String line) {

                if(!line.startsWith("package ")) return line;

                // replace package decl

                if( pkg.isUnnamed() )

                    return null;

                else

                    return "package "+pkg.name()+";";

            }

        };

        if( filter!=null )

            return new ChainFilter(filter,f);

        else

            return f;

    }

    /**

     * Filter that alters the Java source code.

     * <p>

     * By implementing this interface, derived classes

     * can modify the Java source file before it's written out.

     */

    public interface LineFilter {

        /**

         * @param line

         *      a non-null valid String that corresponds to one line.

         *      No '\n' included.

         * @return

         *      null to strip the line off. Otherwise the returned

         *      String will be written out. Do not add '\n' at the end

         *      of this string.

         *

         * @exception ParseException

         *      when for some reason there's an error in the line.

         */

        String process(String line) throws ParseException;

    }

    /**

     * A {@link LineFilter} that combines two {@link LineFilter}s.

     */

    public final static class ChainFilter implements LineFilter {

        private final LineFilter first,second;

        public ChainFilter( LineFilter first, LineFilter second ) {

            this.first=first;

            this.second=second;

        }

        public String process(String line) throws ParseException {

            line = first.process(line);

            if(line==null)  return null;

            return second.process(line);

        }

    }

    private class JStaticClass extends JClass {

        private final JTypeVar[] typeParams;

        JStaticClass() {

            super(pkg.owner());

            // TODO: allow those to be specified

            typeParams = new JTypeVar[0];

        }

        public String name() {

            return className;

        }

        public String fullName() {

            if(pkg.isUnnamed())

                return className;

            else

                return pkg.name()+'.'+className;

        }

        public JPackage _package() {

            return pkg;

        }

        public JClass _extends() {

            throw new UnsupportedOperationException();

        }

        public Iterator<JClass> _implements() {

            throw new UnsupportedOperationException();

        }

        public boolean isInterface() {

            throw new UnsupportedOperationException();

        }

        public boolean isAbstract() {

            throw new UnsupportedOperationException();

        }

        public JTypeVar[] typeParams() {

            return typeParams;

        }

        protected JClass substituteParams(JTypeVar[] variables, List<JClass> bindings) {

            return this;

        }

    };

}