/*
 * Copyright (c) 2014, 2015, Dynatrace and/or its affiliates. All rights reserved.
 * 
 * This file is part of the Lock Contention Tracing Subsystem for the HotSpot
 * Virtual Machine, which is developed at Christian Doppler Laboratory on
 * Monitoring and Evolution of Very-Large-Scale Software Systems. Please
 * contact us at <http://mevss.jku.at/> if you need additional information
 * or have any questions.
 *
 * 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.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 */ 
package sun.evtracing.processing;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintStream;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import sun.evtracing.parser.GlobalSequenceOrderedEvent;
import sun.evtracing.parser.GroupEvent;
import sun.evtracing.parser.ThreadExitEvent;
import sun.evtracing.parser.ThreadNameChangeEvent;
import sun.evtracing.parser.ThreadParkBeginEvent;
import sun.evtracing.parser.ThreadParkEndEvent;
import sun.evtracing.parser.ThreadStartEvent;
import sun.evtracing.parser.ThreadState;
import sun.evtracing.parser.ThreadStateChangeEvent;
import sun.evtracing.parser.VMEndEvent;
import sun.evtracing.parser.metadata.JavaStack;

public class TraceEventJsonWriter extends AbstractTraceEventHandler {
	private class ThreadData {
		private long stateChangeTime = -1;
		private ThreadState state;
		private final Deque<List<GlobalSequenceOrderedEvent>> nestingStack = new ArrayDeque<>();

		public long stateChangeTime() {
			assert stateChangeTime > 0;
			return stateChangeTime;
		}

		public ThreadState state() {
			return state;
		}

		public void setThreadState(long time, ThreadState ts) {
			this.stateChangeTime = time;
			this.state = ts;
		}

		public void resetThreadState() {
			setThreadState(-1, null);
		}

		public int nestingLevel() {
			return nestingStack.size();
		}

		public void addParkBeginEvent(ThreadParkBeginEvent event) {
			int currentLevel = nestingStack.size();
			assert event.nestingLevel() >= currentLevel;
			if (event.nestingLevel() > currentLevel) {
				for (int i = currentLevel; i < event.nestingLevel() - 1; i++) {
					nestingStack.push(new ArrayList<>());
				}
				List<GlobalSequenceOrderedEvent> events = new ArrayList<>();
				events.add(event);
				nestingStack.push(events);
			} else if (event.nestingLevel() == currentLevel) {
				addParkEvent(event);
			}
		}

		public void addParkEndEvent(ThreadParkEndEvent event) {
			addParkEvent(event);
		}

		public void addParkEvent(GlobalSequenceOrderedEvent event) {
			if (nestingLevel() > 0) {
				nestingStack.peek().add(event);
			} else {
				event.accept(parkHandler);
			}
		}

		public long nestingFirstSeen() {
			return nestingStack.peek().get(0).timestamp();
		}

		public void popNestingLevel() {
			List<GlobalSequenceOrderedEvent> events = nestingStack.pop();
			if (nestingLevel() > 0) {
				nestingStack.peek().addAll(events);
			} else {
				events.forEach(e -> e.accept(parkHandler));
			}
		}
	}

	private PrintStream ps;
	private final Map<Long, ThreadData> threadData = new HashMap<>();
	private final TraceEventHandler parkHandler = new AbstractTraceEventHandler() {
		@Override
		public void threadParkBegin(ThreadParkBeginEvent event) {
			String name = event.clazz().metadata().prettyName(true);
			JavaStack jstack = event.stack().metadata();
			String stack;
			if (jstack.isSet()) {
				stack = StreamSupport.stream(jstack.spliterator(), false)
							.map(frame -> "\"" + (frame.method().isSet() ? frame.method().prettyDescriptor(true) : "(unknown)") + "\"")
							.collect(Collectors.joining(","));
			} else {
				stack = "";
			}
			ps.printf(",\n{\"name\":\"%s\",\"cat\":\"park\",\"ph\":\"B\",\"ts\":%d,\"pid\":1,\"tid\":%d,\"args\":{\"Arg isAbsolute\":%s,\"Arg time\":%d,\"Identity Hash Code\":\"%s\",\"Stack\":[%s],\"Nesting Level\":%d,\"Seq Begin\":%d}}", name, event.timestamp() / 1000, event.thread().identifier(), event.isAbsolute(), event.parkTime(), Integer.toHexString(event.blockerObject()), stack, event.nestingLevel(), event.sequenceNumber());
		}

		@Override
		public void threadParkEnd(ThreadParkEndEvent event) {
			ps.printf(",\n{\"ph\":\"E\",\"ts\":%d,\"pid\":1,\"tid\":%d,\"args\":{\"Seq Unpark\":%d,\"Seq End\":%d,\"Return Code\":\"%s\"}}", event.timestamp() / 1000, event.thread().identifier(), event.unparkSequenceNumber(), event.sequenceNumber(), event.parkReturnCode().name());
		}
	};

	public TraceEventJsonWriter(File file) throws FileNotFoundException {
		ps = new PrintStream(file);
		ps.println("[");
		ps.print("{\"name\":\"process_name\",\"ph\":\"M\",\"pid\":1,\"args\":{\"name\":\"java\"}}");
	}

	private ThreadData getOrCreateThreadData(long thread) {
		return threadData.computeIfAbsent(thread, t -> new ThreadData());
	}

	@Override
	public void threadStart(ThreadStartEvent event) {
		ps.printf(",\n{\"name\":\"thread_name\",\"ph\":\"M\",\"pid\":1,\"tid\":%d,\"args\":{\"name\":\"%s\"}}", event.thread().identifier(), event.name());
	}

	@Override
	public void threadNameChange(ThreadNameChangeEvent event) {
		ps.printf(",\n{\"name\":\"thread_name\",\"ph\":\"M\",\"pid\":1,\"tid\":%d,\"args\":{\"name\":\"%s\"}}", event.affectedThread().identifier(), event.newName());
	}

	@Override
	public void threadStateChange(ThreadStateChangeEvent event) {
		ThreadData td = getOrCreateThreadData(event.affectedThread().identifier());
		if (td.state() != null) {
			printThreadState(event.timestamp(), event.affectedThread().identifier(), td);
		}
		if (!event.newState().toThreadState().equals(Thread.State.TERMINATED)) {
			td.setThreadState(event.timestamp(), event.newState());
		}
	}

	private void printThreadState(long time, long thread, ThreadData threadData) {
		long startTime = threadData.stateChangeTime() / 1000;
		long endTime = time / 1000;
		if (endTime - startTime > 0) {
			ps.printf(",\n{\"name\":\"%s\",\"cat\":\"state\",\"ph\":\"B\",\"ts\":%d,\"pid\":1,\"tid\":%d}", threadData.state().toString(), startTime, thread);
			ps.printf(",\n{\"cat\":\"state\",\"ph\":\"E\",\"ts\":%d,\"pid\":1,\"tid\":%d}", endTime, thread);
		}
	}

	@Override
	public void threadExit(ThreadExitEvent event) {
		ThreadData td = getOrCreateThreadData(event.thread().identifier());
		if (td.state() != null) {
			printThreadState(event.timestamp(), event.thread().identifier(), td);
			td.resetThreadState();
		}
	}

	@Override
	public void endVM(VMEndEvent event) {
		ps.println("\n]");
		ps.close();
	}

	@Override
	public void threadParkBegin(ThreadParkBeginEvent event) {
		ThreadData td = getOrCreateThreadData(event.thread().identifier());
		td.addParkBeginEvent(event);
	}

	@Override
	public void threadParkEnd(ThreadParkEndEvent event) {
		ThreadData td = getOrCreateThreadData(event.thread().identifier());
		td.addParkEndEvent(event);
	}

	@Override
	public void group(GroupEvent event) {
		ThreadData td = getOrCreateThreadData(event.thread().identifier());
		int nestingLevel = td.nestingLevel();
		if (nestingLevel > 0) {
			String name = event.clazz().metadata().prettyName(true);
			long startTime = td.nestingFirstSeen();
			ps.printf(",\n{\"name\":\"%s\",\"cat\":\"group\",\"ph\":\"X\",\"ts\":%d,\"dur\":%d,\"pid\":1,\"tid\":%d,\"args\":{\"Identity Hash Code\":\"%s\",\"Nesting Level\":%d,\"Seq Begin Reference\":%d,\"Seq End\":%d}}", name, startTime / 1000, (event.timestamp() - startTime) / 1000, event.thread().identifier(), Integer.toHexString(event.obj()), nestingLevel, event.sequenceBeginReference(), event.sequenceNumber());
			td.popNestingLevel();
		}
	}

}