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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package jdk.jfr;

import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.Objects;

import jdk.jfr.internal.PlatformEventType;
import jdk.jfr.internal.PlatformRecorder;
import jdk.jfr.internal.PlatformRecording;
import jdk.jfr.internal.PrivateAccess;
import jdk.jfr.internal.Type;
import jdk.jfr.internal.management.EventSettingsModifier;

/**
 * Convenience class for applying event settings to a recording.
 * <p>
 * An {@code EventSettings} object for a recording can be obtained by invoking
 * the {@link Recording#enable(String)} method which is configured using method
 * chaining.
 * <p>
 * The following example shows how to use the {@code EventSettings} class.
 *
 * {@snippet class="Snippets" region="EventSettingOverview"}
 *
 * @since 9
 */
public abstract class EventSettings {

    // Purpose of InternalAccess is to give classes in jdk.jfr.internal
    // access to package private methods in this package (jdk.jfr).
    //
    // The initialization could be done in any class in this package,
    // but this one was chosen because it is lightweight.
    static {
        PrivateAccess.setPrivateAccess(new InternalAccess());
    }

    private static final class InternalAccess extends PrivateAccess {

        @Override
        public Type getType(Object o) {
            if (o instanceof AnnotationElement ae) {
                return ae.getType();
            }
            if (o instanceof EventType et) {
                return et.getType();
            }
            if (o instanceof ValueDescriptor vd) {
                return vd.getType();
            }
            if (o instanceof SettingDescriptor sd) {
                return sd.getType();
            }
            throw new Error("Unknown type " + o.getClass());
        }

        @Override
        public Configuration newConfiguration(String name, String label, String description, String provider, Map<String, String> settings, String contents) {
            return new Configuration(name, label, description, provider, settings, contents);
        }

        @Override
        public EventType newEventType(PlatformEventType platformEventType) {
            return new EventType(platformEventType);
        }

        @Override
        public AnnotationElement newAnnotation(Type annotationType, List<Object> values, boolean boot) {
            return new AnnotationElement(annotationType, values, boot);
        }

        @Override
        public ValueDescriptor newValueDescriptor(String name, Type fieldType, List<AnnotationElement> annos, int dimension, boolean constantPool, String fieldName) {
            return new ValueDescriptor(fieldType, name, annos, dimension, constantPool, fieldName);
        }

        @Override
        public PlatformRecording getPlatformRecording(Recording r) {
            return r.getInternal();
        }

        @Override
        public PlatformEventType getPlatformEventType(EventType eventType) {
            return eventType.getPlatformEventType();
        }

        @Override
        public boolean isConstantPool(ValueDescriptor v) {
            return v.isConstantPool();
        }

        @Override
        public void setAnnotations(ValueDescriptor v, List<AnnotationElement> a) {
            v.setAnnotations(a);
        }

        @Override
        public void setAnnotations(SettingDescriptor s, List<AnnotationElement> a) {
           s.setAnnotations(a);
        }

        @Override
        public String getFieldName(ValueDescriptor v) {
            return v.getJavaFieldName();
        }

        @Override
        public ValueDescriptor newValueDescriptor(Class<?> type, String name) {
            return new ValueDescriptor(type, name, List.of(), true);
        }

        @Override
        public SettingDescriptor newSettingDescriptor(Type type, String name, String defaultValue, List<AnnotationElement> annotations) {
            return new SettingDescriptor(type, name, defaultValue, annotations);
        }

        @Override
        public boolean isUnsigned(ValueDescriptor v) {
            return v.isUnsigned();
        }

        @Override
        public PlatformRecorder getPlatformRecorder() {
            return FlightRecorder.getFlightRecorder().getInternal();
        }

        @Override
        public EventSettings newEventSettings(EventSettingsModifier esm) {
            return new EventSettings.DelegatedEventSettings(esm);
        }

        @Override
        public boolean isVisible(EventType t) {
            return t.isVisible();
        }
    }

    // Used to provide EventSettings for jdk.management.jfr module
    static class DelegatedEventSettings extends EventSettings {
        private final EventSettingsModifier delegate;

        DelegatedEventSettings(EventSettingsModifier modifier) {
            this.delegate = modifier;
        }

        @Override
        public EventSettings with(String name, String value) {
            Objects.requireNonNull(name, "name");
            Objects.requireNonNull(value, "value");
            delegate.with(name, value);
            return this;
        }

        @Override
        Map<String, String> toMap() {
            return delegate.toMap();
        }
    }

    // package private
    EventSettings() {
    }

    /**
     * Enables stack traces for the event that is associated with this event setting.
     * <p>
     * Equivalent to invoking the {@code with("stackTrace", "true")} method.
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public final EventSettings withStackTrace() {
        return with(StackTrace.NAME, "true");
    }

    /**
     * Disables stack traces for the event that is associated with this event setting.
     * <p>
     * Equivalent to invoking the {@code with("stackTrace", "false")} method.
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public final EventSettings withoutStackTrace() {
        return with(StackTrace.NAME, "false");
    }

    /**
     * Specifies that a threshold is not used.
     * <p>
     * This is a convenience method, equivalent to invoking the
     * {@code with("threshold", "0 s")} method.
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public final EventSettings withoutThreshold() {
        return with(Threshold.NAME, "0 s");
    }

    /**
     * Sets the interval for the event that is associated with this event setting.
     *
     * @param duration the duration, not {@code null}
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public final EventSettings withPeriod(Duration duration) {
        Objects.requireNonNull(duration, "duration");
        return with(Period.NAME, duration.toNanos() + " ns");
    }

    /**
     * Sets the threshold for the event that is associated with this event setting.
     *
     * @param duration the duration, or {@code null} if no duration is used
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public final EventSettings withThreshold(Duration duration) {
        if (duration == null) {
            return with(Threshold.NAME, "0 ns");
        } else {
            return with(Threshold.NAME, duration.toNanos() + " ns");
        }
    }

    /**
     * Sets a setting value for the event that is associated with this event setting.
     *
     * @param name the name of the setting (for example, {@code "threshold"})
     *
     * @param value the value to set (for example {@code "20 ms"} not
     *        {@code null})
     *
     * @return event settings object for further configuration, not {@code null}
     */
    public abstract EventSettings with(String name, String value);

    /**
     * Creates a settings {@code Map} for the event that is associated with this
     * event setting.
     *
     * @return a settings {@code Map}, not {@code null}
     */
    abstract Map<String, String> toMap();
}