/*

 * Copyright (c) 2014, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.util.Map;

import java.util.function.BiFunction;

import java.util.function.Function;

/**

 * BundlerParamInfo<T>

 *

 * A BundlerParamInfo encapsulates an individual bundler parameter of type <T>.

 */

class BundlerParamInfo<T> {

    /**

     * The command line and hashmap name of the parameter

     */

    String id;

    /**

     * Type of the parameter

     */

    Class<T> valueType;

    /**

     * Indicates if value was set using default value function

     */

    boolean isDefaultValue;

    /**

     * If the value is not set, and no fallback value is found,

     * the parameter uses the value returned by the producer.

     */

    Function<Map<String, ? super Object>, T> defaultValueFunction;

    /**

     * An optional string converter for command line arguments.

     */

    BiFunction<String, Map<String, ? super Object>, T> stringConverter;

    String getID() {

        return id;

    }

    Class<T> getValueType() {

        return valueType;

    }

    boolean getIsDefaultValue() {

        return isDefaultValue;

    }

    Function<Map<String, ? super Object>, T> getDefaultValueFunction() {

        return defaultValueFunction;

    }

    BiFunction<String, Map<String, ? super Object>,T>

            getStringConverter() {

        return stringConverter;

    }

    @SuppressWarnings("unchecked")

    final T fetchFrom(Map<String, ? super Object> params) {

        return fetchFrom(params, true);

    }

    @SuppressWarnings("unchecked")

    final T fetchFrom(Map<String, ? super Object> params,

            boolean invokeDefault) {

        Object o = params.get(getID());

        if (o instanceof String && getStringConverter() != null) {

            return getStringConverter().apply((String)o, params);

        }

        Class<T> klass = getValueType();

        if (klass.isInstance(o)) {

            return (T) o;

        }

        if (o != null) {

            throw new IllegalArgumentException("Param " + getID()

                    + " should be of type " + getValueType()

                    + " but is a " + o.getClass());

        }

        if (params.containsKey(getID())) {

            // explicit nulls are allowed

            return null;

        }

        if (invokeDefault && (getDefaultValueFunction() != null)) {

            T result =  getDefaultValueFunction().apply(params);

            if (result != null) {

                params.put(getID(), result);

                isDefaultValue = true;

            }

            return result;

        }

        // ultimate fallback

        return null;

    }

}