BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
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.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2007-2011 Nick Sieger 
Copyright (C) 2009 Joseph LaFata 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2007-2011 Nick Sieger <nicksieger@gmail.com>
 * Copyright (C) 2009 Joseph LaFata <joe@quibb.org>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby.management;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.ref.SoftReference;
import java.util.Arrays;
import java.util.stream.Stream;

import com.headius.backport9.stack.StackWalker;
import org.jruby.Ruby;
import org.jruby.RubyException;
import org.jruby.RubyThread;
import org.jruby.exceptions.RaiseException;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.backtrace.BacktraceData;
import org.jruby.runtime.backtrace.TraceType;
import org.jruby.runtime.backtrace.TraceType.Format;
import org.jruby.runtime.backtrace.TraceType.Gather;

public class Runtime implements RuntimeMBean {
    private final SoftReference<Ruby> ruby;

    private static final StackWalker WALKER = ThreadContext.WALKER;

    public Runtime(Ruby ruby) {
        this.ruby = new SoftReference<Ruby>(ruby);
    }

    public int getExceptionCount() {
        return ruby.get().getExceptionCount();
    }

    public int getBacktraceCount() {
        return ruby.get().getBacktraceCount();
    }

    public int getCallerCount() {
        return ruby.get().getCallerCount();
    }

    public String threadDump() {
        return dumpThreads(Gather.NORMAL);
    }
    
    public String rawThreadDump() {
        return dumpThreads(Gather.RAW);
    }
    
    public String fullThreadDump() {
        return dumpThreads(Gather.FULL);
    }


    
Dump all the threads that are known to ruby. We first discover any running
threads and then raise an exception in each thread adding the current thread
and it's context to the backtrace.
Params:
gather – The level of backtrace that get's raised in each thread
Returns:
[String] A string represnetation of the threds that have been dumped with included backtrace./**
     *
     * Dump all the threads that are known to ruby. We first discover any running
     * threads and then raise an exception in each thread adding the current thread
     * and it's context to the backtrace.
     *
     * @param gather The level of backtrace that get's raised in each thread
     * @return [String] A string represnetation of the threds that have been dumped with included backtrace.
     */
    public String dumpThreads(Gather gather) {
        Ruby ruby = this.ruby.get();
        RubyThread[] thrs = ruby.getThreadService().getActiveRubyThreads();
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        
        pw.println("All threads known to Ruby instance " + ruby.hashCode());
        pw.println();
        
        for (RubyThread th : thrs) {
            dumpThread(ruby, th, gather, pw);
        }
        
        return sw.toString();
    }
    
    private static void dumpThread(Ruby ruby, RubyThread th, Gather gather, PrintWriter pw) {
        pw.println("Thread: " + th.getNativeThread().getName());
        pw.println("Stack:");
        ThreadContext tc = th.getContext();
        StringBuilder builder = new StringBuilder();
        if (tc != null) {
            Format.JRUBY.renderBacktrace(
                    WALKER.walk(th.getNativeThread().getStackTrace(), stream -> gather.getBacktraceData(tc, stream)).getBacktrace(ruby),
                    builder,
                    false);
            pw.println(builder);
            builder.setLength(0);
        } else {
            pw.println("    [no longer alive]");
        }
        pw.println();
    }

    public String executeRuby(final String code) {
        final String[] result = new String[1];

        Thread t = new Thread() {

            @Override
            public void run() {
                // IRubyObject oldExc = ruby.get().getGlobalVariables().get("$!"); // Save $!
                try {
                    result[0] = ruby.get().evalScriptlet(code).toString();
                } catch (RaiseException re) {
                    result[0] = ruby.get().getInstanceConfig().getTraceType().printBacktrace(re.getException(), false);
                    // ruby.get().getGlobalVariables().set("$!", oldExc); // Restore $!
                } catch (Throwable t) {
                    StringWriter sw = new StringWriter();
                    t.printStackTrace(new PrintWriter(sw));
                    result[0] = sw.toString();
                }
            }
        };
        t.start();
        try {
            t.join();
        } catch (InterruptedException ie) {
            // ignore
        }

        return result[0];
    }
}