/*
 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
 * 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.tools.sjavac;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Locale;

Utility class only for sjavac logging.
Logging in sjavac has special requirements when running in server/client
mode. Most of the log messages is generated server-side, but the server
is typically spawned by the client in the background, so the user usually
does not see the server stdout/stderr. For this reason log messages needs
to relayed back to the client that performed the request that generated the
log message. To support this use case this class maintains a per-thread log
instance so that each connected client can have its own instance that
relays messages back to the requesting client.
On the client-side (or when running sjavac without server-mode) there will
typically just be one Log instance.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 * Utility class only for sjavac logging.
 *
 * Logging in sjavac has special requirements when running in server/client
 * mode. Most of the log messages is generated server-side, but the server
 * is typically spawned by the client in the background, so the user usually
 * does not see the server stdout/stderr. For this reason log messages needs
 * to relayed back to the client that performed the request that generated the
 * log message. To support this use case this class maintains a per-thread log
 * instance so that each connected client can have its own instance that
 * relays messages back to the requesting client.
 *
 * On the client-side (or when running sjavac without server-mode) there will
 * typically just be one Log instance.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class Log {

    public enum Level {
        ERROR,
        WARN,
        INFO,
        DEBUG,
        TRACE;
    }

    private static Log stdOutErr = new Log(new PrintWriter(System.out), new PrintWriter(System.err));
    private static ThreadLocal<Log> loggers = new ThreadLocal<>();

    protected PrintWriter err; // Used for error and warning messages
    protected PrintWriter out; // Used for other messages
    protected Level level = Level.INFO;

    public Log(Writer out, Writer err) {
        this.out = out == null ? null : new PrintWriter(out, true);
        this.err = err == null ? null : new PrintWriter(err, true);
    }

    public static void setLogForCurrentThread(Log log) {
        loggers.set(log);
    }

    public static void setLogLevel(String l) {
        setLogLevel(Level.valueOf(l.toUpperCase(Locale.US)));
    }

    public static void setLogLevel(Level l) {
        get().level = l;
    }

    static public void trace(String msg) {
        log(Level.TRACE, msg);
    }

    static public void debug(String msg) {
        log(Level.DEBUG, msg);
    }

    static public void info(String msg) {
        log(Level.INFO, msg);
    }

    static public void warn(String msg) {
        log(Level.WARN, msg);
    }

    static public void error(String msg) {
        log(Level.ERROR, msg);
    }

    static public void error(Throwable t) {
        log(Level.ERROR, t);
    }

    static public void log(Level l, String msg) {
        get().printLogMsg(l, msg);
    }

    public static void debug(Throwable t) {
        log(Level.DEBUG, t);
    }

    public static void log(Level l, Throwable t) {
        StringWriter sw = new StringWriter();
        t.printStackTrace(new PrintWriter(sw, true));
        log(l, sw.toString());
    }

    static public boolean isDebugging() {
        return get().isLevelLogged(Level.DEBUG);
    }

    protected boolean isLevelLogged(Level l) {
        return l.ordinal() <= level.ordinal();
    }

    public static Log get() {
        Log log = loggers.get();
        return log != null ? log : stdOutErr;
    }

    protected void printLogMsg(Level msgLevel, String msg) {
        if (isLevelLogged(msgLevel)) {
            PrintWriter pw = msgLevel.ordinal() <= Level.WARN.ordinal() ? err : out;
            pw.println(msg);
        }
    }
}