/*

 * Copyright (c) 2019, 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

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 */

package jdk.jfr.internal.consumer;

import java.util.Collection;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

public final class InternalEventFilter {

    public static final InternalEventFilter ACCEPT_ALL = new InternalEventFilter();

    private final Map<String, Long> thresholds = new HashMap<>();

    private boolean acceptAll;

    public static InternalEventFilter merge(Collection<InternalEventFilter> filters) {

        for (InternalEventFilter ef : filters) {

            if (ef.getAcceptAll()) {

                return ACCEPT_ALL;

            }

        }

        if (filters.size() == 1) {

            return filters.iterator().next();

        }

        Set<String> eventNames = new HashSet<>();

        for (InternalEventFilter ef : filters) {

            eventNames.addAll(ef.thresholds.keySet());

        }

        InternalEventFilter result = new InternalEventFilter();

        for (String eventName : eventNames) {

            for (InternalEventFilter ef : filters) {

                Long l = ef.thresholds.get(eventName);

                if (l != null) {

                    result.setThreshold(eventName, l.longValue());

                }

            }

        }

        return result;

    }

    private boolean getAcceptAll() {

        return acceptAll;

    }

    public void setAcceptAll() {

        acceptAll = true;

    }

    public void setThreshold(String eventName, long nanos) {

        Long l = thresholds.get(eventName);

        if (l != null) {

            l = Math.min(l, nanos);

        } else {

            l = nanos;

        }

        thresholds.put(eventName, l);

    }

    public long getThreshold(String eventName) {

        if (acceptAll) {

            return 0;

        }

        Long l = thresholds.get(eventName);

        if (l != null) {

            return l;

        }

        return -1;

    }

    public String toString() {

        if (acceptAll) {

            return "ACCEPT ALL";

        }

        StringBuilder sb = new StringBuilder();

        for (String key : thresholds.keySet().toArray(new String[0])) {

            Long value = thresholds.get(key);

            sb.append(key);

            sb.append(" = ");

            sb.append(value.longValue() / 1_000_000);

            sb.append(" ms");

        }

        return sb.toString();

    }

}