/*
 * Copyright (c) 2013, 2014, 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.
 *
 * 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 org.graalvm.compiler.hotspot.debug;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicLong;

import org.graalvm.compiler.core.common.SuppressFBWarnings;
import org.graalvm.compiler.debug.CSVUtil;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.debug.TTY;
import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
import org.graalvm.compiler.nodes.debug.DynamicCounterNode;
import org.graalvm.compiler.options.Option;
import org.graalvm.compiler.options.OptionKey;
import org.graalvm.compiler.options.OptionType;
import org.graalvm.compiler.options.OptionValues;

import jdk.vm.ci.hotspot.HotSpotJVMCIRuntime;

//JaCoCo Exclude

This class contains infrastructure to maintain counters based on DynamicCounterNodes. The infrastructure is enabled by specifying either the GenericDynamicCounters or BenchmarkDynamicCounters option. 
 The counters are kept in a special area allocated for each native JavaThread object, and the number of counters is configured using -XX:JVMCICounterSize=value. -XX:+/-JVMCICountersExcludeCompiler configures whether to exclude compiler threads (defaults to true). The subsystems that use the logging need to have their own options to turn on the counters, and insert DynamicCounterNodes when they're enabled. Counters will be displayed as a rate (per second) if their group name starts with "~", otherwise they will be displayed as a total number. See here for a detailed example of how to use
benchmark counters.
/**
 * This class contains infrastructure to maintain counters based on {@link DynamicCounterNode}s. The
 * infrastructure is enabled by specifying either the GenericDynamicCounters or
 * BenchmarkDynamicCounters option.
 * <p>
 *
 * The counters are kept in a special area allocated for each native JavaThread object, and the
 * number of counters is configured using {@code -XX:JVMCICounterSize=value}.
 * {@code -XX:+/-JVMCICountersExcludeCompiler} configures whether to exclude compiler threads
 * (defaults to true).
 *
 * The subsystems that use the logging need to have their own options to turn on the counters, and
 * insert DynamicCounterNodes when they're enabled.
 *
 * Counters will be displayed as a rate (per second) if their group name starts with "~", otherwise
 * they will be displayed as a total number.
 *
 * See <a href="BenchmarkDynamicCountersHelp.txt">here</a> for a detailed example of how to use
 * benchmark counters.
 */
public class BenchmarkCounters {

    static class Options {

        //@formatter:off
        @Option(help = "Turn on the benchmark counters, and displays the results on VM shutdown", type = OptionType.Debug)
        public static final OptionKey<Boolean> GenericDynamicCounters = new OptionKey<>(false);
        @Option(help = "Turn on the benchmark counters, and displays the results every n milliseconds", type = OptionType.Debug)
        public static final OptionKey<Integer> TimedDynamicCounters = new OptionKey<>(-1);

        @Option(help = "file:doc-files/BenchmarkDynamicCountersHelp.txt", type = OptionType.Debug)
        public static final OptionKey<String> BenchmarkDynamicCounters = new OptionKey<>(null);
        @Option(help = "Use grouping separators for number printing", type = OptionType.Debug)
        public static final OptionKey<Boolean> DynamicCountersPrintGroupSeparator = new OptionKey<>(true);
        @Option(help = "File to which benchmark counters are dumped. A CSV format is used if the file ends with .csv " +
                       "otherwise a more human readable format is used. The fields in the CSV format are: " +
                       "category, group, name, value", type = OptionType.Debug)
        public static final OptionKey<String> BenchmarkCountersFile = new OptionKey<>(null);
        @Option(help = "Dump dynamic counters", type = OptionType.Debug)
        public static final OptionKey<Boolean> BenchmarkCountersDumpDynamic = new OptionKey<>(true);
        @Option(help = "Dump static counters", type = OptionType.Debug)
        public static final OptionKey<Boolean> BenchmarkCountersDumpStatic = new OptionKey<>(false);
        //@formatter:on
    }

    public static boolean enabled = false;

    private static class Counter {
        public final int index;
        public final String group;
        public final AtomicLong staticCounters;

        Counter(int index, String group, AtomicLong staticCounters) {
            this.index = index;
            this.group = group;
            this.staticCounters = staticCounters;
        }
    }

    public static final ConcurrentHashMap<String, Counter> counterMap = new ConcurrentHashMap<>();
    public static long[] delta;

    public static int getIndexConstantIncrement(String name, String group, GraalHotSpotVMConfig config, long increment) {
        Counter counter = getCounter(name, group, config);
        counter.staticCounters.addAndGet(increment);
        return counter.index;
    }

    public static int getIndex(String name, String group, GraalHotSpotVMConfig config) {
        Counter counter = getCounter(name, group, config);
        return counter.index;
    }

    @SuppressFBWarnings(value = "AT_OPERATION_SEQUENCE_ON_CONCURRENT_ABSTRACTION", justification = "concurrent abstraction calls are in synchronized block")
    private static Counter getCounter(String name, String group, GraalHotSpotVMConfig config) throws GraalError {
        if (!enabled) {
            throw new GraalError("cannot access count index when counters are not enabled: " + group + ", " + name);
        }
        String nameGroup = name + "#" + group;
        Counter counter = counterMap.get(nameGroup);
        if (counter == null) {
            synchronized (BenchmarkCounters.class) {
                counter = counterMap.get(nameGroup);
                if (counter == null) {
                    counter = new Counter(counterMap.size(), group, new AtomicLong());
                    counterMap.put(nameGroup, counter);
                }
            }
        }
        assert counter.group.equals(group) : "mismatching groups: " + counter.group + " vs. " + group;
        int countersSize = config.jvmciCountersSize;
        if (counter.index >= countersSize) {
            throw new GraalError("too many counters, reduce number of counters or increase -XX:JVMCICounterSize=... (current value: " + countersSize + ")");
        }
        return counter;
    }

    private static synchronized void dump(OptionValues options, PrintStream out, double seconds, long[] counters, int maxRows) {
        if (!counterMap.isEmpty()) {
            try (Dumper dumper = Dumper.getDumper(options, out, counterMap.size(), seconds, maxRows)) {
                TreeSet<String> set = new TreeSet<>();
                counterMap.forEach((nameGroup, counter) -> set.add(counter.group));
                for (String group : set) {
                    if (group != null) {
                        if (Options.BenchmarkCountersDumpStatic.getValue(options)) {
                            dumper.dumpCounters(true, group, collectStaticCounters(), counterMap.entrySet(), options);
                        }
                        if (Options.BenchmarkCountersDumpDynamic.getValue(options)) {
                            dumper.dumpCounters(false, group, collectDynamicCounters(counters), counterMap.entrySet(), options);
                        }
                    }
                }
            }

            clear(counters);
        }
    }

    private static synchronized long[] collectDynamicCounters(long[] counters) {
        long[] array = counters.clone();
        for (int i = 0; i < array.length; i++) {
            array[i] -= delta[i];
        }
        return array;
    }

    private static synchronized long[] collectStaticCounters() {
        long[] array = new long[counterMap.size()];
        for (Counter counter : counterMap.values()) {
            array[counter.index] = counter.staticCounters.get();
        }
        return array;
    }

    private static synchronized void clear(long[] counters) {
        delta = counters;
    }

    private static boolean shouldDumpComputerReadable(OptionValues options) {
        String dumpFile = Options.BenchmarkCountersFile.getValue(options);
        return dumpFile != null && (dumpFile.endsWith(".csv") || dumpFile.endsWith(".CSV"));
    }

    private abstract static class Dumper implements AutoCloseable {
        public static Dumper getDumper(OptionValues options, PrintStream out, int counterSize, double second, int maxRows) {
            Dumper dumper = shouldDumpComputerReadable(options) ? new ComputerReadableDumper(out) : new HumanReadableDumper(out, second, maxRows);
            dumper.start(counterSize);
            return dumper;
        }

        protected final PrintStream out;

        private Dumper(PrintStream out) {
            this.out = out;
        }

        protected abstract void start(int size);

        public abstract void dumpCounters(boolean staticCounter, String group, long[] array, Set<Entry<String, Counter>> counterEntrySet, OptionValues options);

        @Override
        public abstract void close();

    }

    private static String getName(String nameGroup, String group) {
        return nameGroup.substring(0, nameGroup.length() - group.length() - 1);
    }

    private static long percentage(long counter, long sum) {
        return (counter * 200 + 1) / sum / 2;
    }

    private static class HumanReadableDumper extends Dumper {
        private final double seconds;
        private final int maxRows;

        HumanReadableDumper(PrintStream out, double seconds, int maxRows) {
            super(out);
            this.seconds = seconds;
            this.maxRows = maxRows;
        }

        @Override
        public void start(int size) {
            out.println("====== dynamic counters (" + size + " in total) ======");
        }

        @Override
        public void close() {
            out.println("============================");
        }

        @Override
        public void dumpCounters(boolean staticCounter, String group, long[] array, Set<Entry<String, Counter>> counterEntrySet, OptionValues options) {
            // sort the counters by putting them into a sorted map
            TreeMap<Long, String> sorted = new TreeMap<>();
            long sum = 0;
            for (Map.Entry<String, Counter> entry : counterEntrySet) {
                Counter counter = entry.getValue();
                int index = counter.index;
                if (counter.group.equals(group)) {
                    sum += array[index];
                    sorted.put(array[index] * array.length + index, getName(entry.getKey(), group));
                }
            }

            if (sum > 0) {
                long cutoff = sorted.size() < 10 ? 1 : Math.max(1, sum / 100);
                int cnt = sorted.size();

                // remove everything below cutoff and keep at most maxRows
                Iterator<Map.Entry<Long, String>> iter = sorted.entrySet().iterator();
                while (iter.hasNext()) {
                    Map.Entry<Long, String> entry = iter.next();
                    long counter = entry.getKey() / array.length;
                    if (counter < cutoff || cnt > maxRows) {
                        iter.remove();
                    }
                    cnt--;
                }

                String numFmt = Options.DynamicCountersPrintGroupSeparator.getValue(options) ? "%,19d" : "%19d";
                if (staticCounter) {
                    out.println("=========== " + group + " (static counters):");
                    for (Map.Entry<Long, String> entry : sorted.entrySet()) {
                        long counter = entry.getKey() / array.length;
                        out.format(Locale.US, numFmt + " %3d%%  %s\n", counter, percentage(counter, sum), entry.getValue());
                    }
                    out.format(Locale.US, numFmt + " total\n", sum);
                } else {
                    if (group.startsWith("~")) {
                        out.println("=========== " + group + " (dynamic counters), time = " + seconds + " s:");
                        for (Map.Entry<Long, String> entry : sorted.entrySet()) {
                            long counter = entry.getKey() / array.length;
                            out.format(Locale.US, numFmt + "/s %3d%%  %s\n", (long) (counter / seconds), percentage(counter, sum), entry.getValue());
                        }
                        out.format(Locale.US, numFmt + "/s total\n", (long) (sum / seconds));
                    } else {
                        out.println("=========== " + group + " (dynamic counters):");
                        for (Map.Entry<Long, String> entry : sorted.entrySet()) {
                            long counter = entry.getKey() / array.length;
                            out.format(Locale.US, numFmt + " %3d%%  %s\n", counter, percentage(counter, sum), entry.getValue());
                        }
                        out.format(Locale.US, numFmt + " total\n", sum);
                    }
                }
            }
        }
    }

    private static final String CSV_FMT = CSVUtil.buildFormatString("%s", "%s", "%s", "%d");

    private static class ComputerReadableDumper extends Dumper {

        ComputerReadableDumper(PrintStream out) {
            super(out);
        }

        @Override
        public void start(int size) {
            // do nothing
        }

        @Override
        public void close() {
            // do nothing
        }

        @Override
        public void dumpCounters(boolean staticCounter, String group, long[] array, Set<Entry<String, Counter>> counterEntrySet, OptionValues options) {
            String category = staticCounter ? "static counters" : "dynamic counters";
            for (Map.Entry<String, Counter> entry : counterEntrySet) {
                Counter counter = entry.getValue();
                if (counter.group.equals(group)) {
                    String name = getName(entry.getKey(), group);
                    int index = counter.index;
                    long value = array[index];
                    CSVUtil.Escape.println(out, CSV_FMT, category, group, name, value);
                }
            }
        }
    }

    private abstract static class CallbackOutputStream extends OutputStream {

        protected final PrintStream delegate;
        private final byte[][] patterns;
        private final int[] positions;

        CallbackOutputStream(PrintStream delegate, String... patterns) {
            this.delegate = delegate;
            this.positions = new int[patterns.length];
            this.patterns = new byte[patterns.length][];
            for (int i = 0; i < patterns.length; i++) {
                this.patterns[i] = patterns[i].getBytes();
            }
        }

        protected abstract void patternFound(int index);

        @Override
        public void write(int b) throws IOException {
            try {
                delegate.write(b);
                for (int i = 0; i < patterns.length; i++) {
                    int j = positions[i];
                    byte[] cs = patterns[i];
                    byte patternChar = cs[j];
                    if (patternChar == '~' && Character.isDigit(b)) {
                        // nothing to do...
                    } else {
                        if (patternChar == '~') {
                            patternChar = cs[++positions[i]];
                        }
                        if (b == patternChar) {
                            positions[i]++;
                        } else {
                            positions[i] = 0;
                        }
                    }
                    if (positions[i] == patterns[i].length) {
                        positions[i] = 0;
                        patternFound(i);
                    }
                }
            } catch (RuntimeException e) {
                e.printStackTrace(delegate);
                throw e;
            }
        }
    }

    public static void initialize(final HotSpotJVMCIRuntime jvmciRuntime, OptionValues options) {
        final class BenchmarkCountersOutputStream extends CallbackOutputStream {

            private long startTime;
            private boolean running;
            private boolean waitingForEnd;

            private BenchmarkCountersOutputStream(PrintStream delegate, String start, String end) {
                super(delegate, new String[]{"\n", end, start});
            }

            @Override
            protected void patternFound(int index) {
                switch (index) {
                    case 2:
                        startTime = System.nanoTime();
                        BenchmarkCounters.clear(jvmciRuntime.collectCounters());
                        running = true;
                        break;
                    case 1:
                        if (running) {
                            waitingForEnd = true;
                        }
                        break;
                    case 0:
                        if (waitingForEnd) {
                            waitingForEnd = false;
                            running = false;
                            BenchmarkCounters.dump(options, getPrintStream(options), (System.nanoTime() - startTime) / 1000000000d, jvmciRuntime.collectCounters(), 100);
                        }
                        break;
                }
            }
        }

        if (Options.BenchmarkDynamicCounters.getValue(options) != null) {
            String[] arguments = Options.BenchmarkDynamicCounters.getValue(options).split(",");
            if (arguments.length == 0 || (arguments.length % 3) != 0) {
                throw new GraalError("invalid arguments to BenchmarkDynamicCounters: (err|out),start,end,(err|out),start,end,... (~ matches multiple digits)");
            }
            for (int i = 0; i < arguments.length; i += 3) {
                if (arguments[i].equals("err")) {
                    System.setErr(new PrintStream(new BenchmarkCountersOutputStream(System.err, arguments[i + 1], arguments[i + 2])));
                } else if (arguments[i].equals("out")) {
                    System.setOut(new PrintStream(new BenchmarkCountersOutputStream(System.out, arguments[i + 1], arguments[i + 2])));
                } else {
                    throw new GraalError("invalid arguments to BenchmarkDynamicCounters: err|out");
                }
            }
            enabled = true;
        }
        if (Options.GenericDynamicCounters.getValue(options)) {
            enabled = true;
        }
        if (Options.TimedDynamicCounters.getValue(options) > 0) {
            Thread thread = new Thread() {
                long lastTime = System.nanoTime();
                PrintStream out = getPrintStream(options);

                @Override
                public void run() {
                    while (true) {
                        try {
                            Thread.sleep(Options.TimedDynamicCounters.getValue(options));
                        } catch (InterruptedException e) {
                        }
                        long time = System.nanoTime();
                        dump(options, out, (time - lastTime) / 1000000000d, jvmciRuntime.collectCounters(), 10);
                        lastTime = time;
                    }
                }
            };
            thread.setDaemon(true);
            thread.setPriority(Thread.MAX_PRIORITY);
            thread.start();
            enabled = true;
        }
        if (enabled) {
            clear(jvmciRuntime.collectCounters());
        }
    }

    public static void shutdown(HotSpotJVMCIRuntime jvmciRuntime, OptionValues options, long compilerStartTime) {
        if (Options.GenericDynamicCounters.getValue(options)) {
            dump(options, getPrintStream(options), (System.nanoTime() - compilerStartTime) / 1000000000d, jvmciRuntime.collectCounters(), 100);
        }
    }

    private static PrintStream getPrintStream(OptionValues options) {
        if (Options.BenchmarkCountersFile.getValue(options) != null) {
            try {

                File file = new File(Options.BenchmarkCountersFile.getValue(options));
                TTY.println("Writing benchmark counters to '%s'", file.getAbsolutePath());
                return new PrintStream(file);
            } catch (IOException e) {
                TTY.out().println(e.getMessage());
                TTY.out().println("Fallback to default");
            }
        }
        return TTY.out;
    }
}