/*

 * Copyright (c) 2013, 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.options;

import java.util.Formatter;

/**

 * A key for an option. The value for an option is obtained from an {@link OptionValues} object.

 */

public class OptionKey<T> {

    private final T defaultValue;

    private OptionDescriptor descriptor;

    public OptionKey(T defaultValue) {

        this.defaultValue = defaultValue;

    }

    /**

     * Sets the descriptor for this option.

     */

    public final void setDescriptor(OptionDescriptor descriptor) {

        assert this.descriptor == null : "Overwriting existing descriptor";

        this.descriptor = descriptor;

    }

    /**

     * Returns the descriptor for this option, if it has been set by

     * {@link #setDescriptor(OptionDescriptor)}.

     */

    public final OptionDescriptor getDescriptor() {

        return descriptor;

    }

    /**

     * Checks that a descriptor exists for this key after triggering loading of descriptors.

     */

    protected boolean checkDescriptorExists() {

        OptionKey.Lazy.init();

        if (descriptor == null) {

            Formatter buf = new Formatter();

            buf.format("Could not find a descriptor for an option key. The most likely cause is " +

                            "a dependency on the %s annotation without a dependency on the " +

                            "org.graalvm.compiler.options.processor.OptionProcessor annotation processor.", Option.class.getName());

            StackTraceElement[] stackTrace = new Exception().getStackTrace();

            if (stackTrace.length > 2 &&

                            stackTrace[1].getClassName().equals(OptionKey.class.getName()) &&

                            stackTrace[1].getMethodName().equals("getValue")) {

                String caller = stackTrace[2].getClassName();

                buf.format(" In suite.py, add GRAAL_OPTIONS_PROCESSOR to the \"annotationProcessors\" attribute of the project " +

                                "containing %s.", caller);

            }

            throw new AssertionError(buf.toString());

        }

        return true;

    }

    /**

     * Mechanism for lazily loading all available options which has the side effect of assigning

     * names to the options.

     */

    static class Lazy {

        static {

            for (OptionDescriptors opts : OptionsParser.getOptionsLoader()) {

                for (OptionDescriptor desc : opts) {

                    desc.getName();

                }

            }

        }

        static void init() {

            /* Running the static class initializer does all the initialization. */

        }

    }

    /**

     * Gets the name of this option. The name for an option value with a null

     * {@linkplain #setDescriptor(OptionDescriptor) descriptor} is the value of

     * {@link Object#toString()}.

     */

    public final String getName() {

        if (descriptor == null) {

            // Trigger initialization of OptionsLoader to ensure all option values have

            // a descriptor which is required for them to have meaningful names.

            Lazy.init();

        }

        return descriptor == null ? super.toString() : descriptor.getName();

    }

    @Override

    public String toString() {

        return getName();

    }

    /**

     * The initial value specified in source code.

     */

    public final T getDefaultValue() {

        return defaultValue;

    }

    /**

     * Returns true if the option has been set in any way. Note that this doesn't mean that the

     * current value is different than the default.

     */

    public boolean hasBeenSet(OptionValues values) {

        return values.containsKey(this);

    }

    /**

     * Gets the value of this option in {@code values}.

     */

    public T getValue(OptionValues values) {

        assert checkDescriptorExists();

        return values.get(this);

    }

    /**

     * Sets the value of this option in a given map. The

     * {@link #onValueUpdate(EconomicMap, Object, Object)} method is called once the value is set.

     *

     * @param values map of option values

     * @param v the value to set for this key in {@code map}

     */

    @SuppressWarnings("unchecked")

    public void update(EconomicMap<OptionKey<?>, Object> values, Object v) {

        T oldValue = (T) values.put(this, v);

        onValueUpdate(values, oldValue, (T) v);

    }

    /**

     * Sets the value of this option in a given map if it doesn't already have a value. The

     * {@link #onValueUpdate(EconomicMap, Object, Object)} method is called once the value is set.

     *

     * @param values map of option values

     * @param v the value to set for this key in {@code map}

     */

    @SuppressWarnings("unchecked")

    public void putIfAbsent(EconomicMap<OptionKey<?>, Object> values, Object v) {

        if (!values.containsKey(this)) {

            T oldValue = (T) values.put(this, v);

            onValueUpdate(values, oldValue, (T) v);

        }

    }

    /**

     * Notifies this object when a value associated with this key is set or updated in

     * {@code values}.

     *

     * @param values

     * @param oldValue

     * @param newValue

     */

    protected void onValueUpdate(EconomicMap<OptionKey<?>, Object> values, T oldValue, T newValue) {

    }

}