/*

 * Copyright (c) 2012, 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.replacements;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import org.graalvm.compiler.core.common.GraalOptions;

/**

 * A counter that can (only) be {@linkplain #inc() incremented} from within a snippet for gathering

 * snippet specific metrics.

 */

public final class SnippetCounter implements Comparable<SnippetCounter> {

    /**

     * A group of related counters.

     */

    public static class Group {

        public interface Factory {

            /**

             * If snippet counters are {@linkplain GraalOptions#SnippetCounters enabled}, creates

             * and registers a {@link Group} with the given name. Otherwise, returns null.

             *

             * @param name name of the counter group

             */

            Group createSnippetCounterGroup(String name);

        }

        public static final Factory NullFactory = new Factory() {

            @Override

            public Group createSnippetCounterGroup(String name) {

                return null;

            }

        };

        final String name;

        final List<SnippetCounter> counters;

        public Group(String name) {

            this.name = name;

            this.counters = new ArrayList<>();

        }

        @Override

        public synchronized String toString() {

            Collections.sort(counters);

            long total = 0;

            int maxNameLen = 0;

            for (SnippetCounter c : counters) {

                total += c.value;

                maxNameLen = Math.max(c.name.length(), maxNameLen);

            }

            StringBuilder buf = new StringBuilder(String.format("Counters: %s%n", name));

            String formatString = "  %" + maxNameLen + "s: %6.2f%%%," + (String.format("%,d", total).length() + 2) + "d  // %s%n";

            for (SnippetCounter c : counters) {

                double percent = total == 0D ? 0D : ((double) (c.value * 100)) / total;

                buf.append(String.format(formatString, c.name, percent, c.value, c.description));

            }

            buf.append(String.format(formatString, "TOTAL", 100.0D, total, ""));

            return buf.toString();

        }

    }

    /**

     * Sorts counters in descending order of their {@linkplain #value() values}.

     */

    @Override

    public int compareTo(SnippetCounter o) {

    }

    private final Group group;

    private final String name;

    private final String description;

    private long value;

    /**

     * Creates a counter.

     *

     * @param group the group to which the counter belongs. If this is null, the newly created

     *            counter is disabled and {@linkplain #inc() incrementing} is a no-op.

     * @param name the name of the counter

     * @param description a brief comment describing the metric represented by the counter

     */

    public SnippetCounter(Group group, String name, String description) {

        this.group = group;

        this.name = name;

        this.description = description;

        if (group != null) {

            List<SnippetCounter> counters = group.counters;

            counters.add(this);

        }

    }

    public Group getGroup() {

        return group;

    }

    /**

     * Increments the value of this counter. This method can only be used in a snippet on a

     * compile-time constant {@link SnippetCounter} object.

     */

    public void inc() {

        if (group != null) {

            SnippetCounterNode.increment(this);

        }

    }

    /**

     * Increments the value of this counter. This method can only be used in a snippet on a

     * compile-time constant {@link SnippetCounter} object.

     */

    public void add(int increment) {

        if (group != null) {

            SnippetCounterNode.add(this, increment);

        }

    }

    /**

     * Gets the value of this counter.

     */

    public long value() {

        return value;

    }

    @Override

    public String toString() {

        if (group != null) {

            return "SnippetCounter-" + group.name + ":" + name;

        }

        return super.toString();

    }

}