/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed 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 io.undertow.servlet.spec;

import java.io.OutputStream;
import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Locale;

import sun.misc.Unsafe;

/**
 * @author Stuart Douglas
 */
public final class ServletPrintWriterDelegate extends PrintWriter {
    private ServletPrintWriterDelegate() {
        super((OutputStream) null);
    }

    private static final sun.misc.Unsafe UNSAFE;

    static {
        UNSAFE = getUnsafe();
    }

    public static ServletPrintWriterDelegate newInstance(final ServletPrintWriter servletPrintWriter) {
        final ServletPrintWriterDelegate delegate;
        if (System.getSecurityManager() == null) {
            try {
                delegate = (ServletPrintWriterDelegate) UNSAFE.allocateInstance(ServletPrintWriterDelegate.class);
            } catch (InstantiationException e) {
                throw new RuntimeException(e);
            }
        } else {
            delegate = AccessController.doPrivileged(new PrivilegedAction<ServletPrintWriterDelegate>() {
                @Override
                public ServletPrintWriterDelegate run() {
                    try {
                        return  (ServletPrintWriterDelegate) UNSAFE.allocateInstance(ServletPrintWriterDelegate.class);
                    } catch (InstantiationException e) {
                        throw new RuntimeException(e);
                    }
                }
            });
        }
        delegate.setServletPrintWriter(servletPrintWriter);
        return delegate;
    }

    private ServletPrintWriter servletPrintWriter;

    public void setServletPrintWriter(final ServletPrintWriter servletPrintWriter) {
        this.servletPrintWriter = servletPrintWriter;
    }

    @Override
    public void flush() {
        servletPrintWriter.flush();
    }

    @Override
    public void close() {
        servletPrintWriter.close();
    }

    @Override
    public boolean checkError() {
        return servletPrintWriter.checkError();
    }

    @Override
    public void write(final int c) {
        servletPrintWriter.write(c);
    }

    @Override
    public void write(final char[] buf, final int off, final int len) {
        servletPrintWriter.write(buf, off, len);
    }

    @Override
    public void write(final char[] buf) {
        servletPrintWriter.write(buf);
    }

    @Override
    public void write(final String s, final int off, final int len) {
        servletPrintWriter.write(s, off, len);
    }

    @Override
    public void write(final String s) {
        servletPrintWriter.write(s == null ? "null" : s);
    }

    @Override
    public void print(final boolean b) {
        servletPrintWriter.print(b);
    }

    @Override
    public void print(final char c) {
        servletPrintWriter.print(c);
    }

    @Override
    public void print(final int i) {
        servletPrintWriter.print(i);
    }

    @Override
    public void print(final long l) {
        servletPrintWriter.print(l);
    }

    @Override
    public void print(final float f) {
        servletPrintWriter.print(f);
    }

    @Override
    public void print(final double d) {
        servletPrintWriter.print(d);
    }

    @Override
    public void print(final char[] s) {
        servletPrintWriter.print(s);
    }

    @Override
    public void print(final String s) {
        servletPrintWriter.print(s);
    }

    @Override
    public void print(final Object obj) {
        servletPrintWriter.print(obj);
    }

    @Override
    public void println() {
        servletPrintWriter.println();
    }

    @Override
    public void println(final boolean x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final char x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final int x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final long x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final float x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final double x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final char[] x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final String x) {
        servletPrintWriter.println(x);
    }

    @Override
    public void println(final Object x) {
        servletPrintWriter.println(x);
    }

    @Override
    public PrintWriter printf(final String format, final Object... args) {
        servletPrintWriter.printf(format, args);
        return this;
    }

    @Override
    public PrintWriter printf(final Locale l, final String format, final Object... args) {
        servletPrintWriter.printf(l, format, args);
        return this;
    }

    @Override
    public PrintWriter format(final String format, final Object... args) {
        servletPrintWriter.format(format, args);
        return this;
    }

    @Override
    public PrintWriter format(final Locale l, final String format, final Object... args) {
        servletPrintWriter.format(l, format, args);
        return this;
    }

    @Override
    public PrintWriter append(final CharSequence csq) {
        servletPrintWriter.append(csq);
        return this;
    }

    @Override
    public PrintWriter append(final CharSequence csq, final int start, final int end) {
        servletPrintWriter.append(csq, start, end);
        return this;
    }

    @Override
    public PrintWriter append(final char c) {
        servletPrintWriter.append(c);
        return this;
    }

    private static Unsafe getUnsafe() {
        if (System.getSecurityManager() != null) {
            return AccessController.doPrivileged(new PrivilegedAction<Unsafe>() {
                public Unsafe run() {
                    return getUnsafe0();
                }
            });
        }
        return getUnsafe0();
    }

    private static Unsafe getUnsafe0()  {
        try {
            Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
            theUnsafe.setAccessible(true);
            return (Unsafe) theUnsafe.get(null);
        } catch (Throwable t) {
            throw new RuntimeException("JDK did not allow accessing unsafe", t);
        }
    }
}