/*
 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, version 2.0, as published by the
 * Free Software Foundation.
 *
 * This program is also distributed with certain software (including but not
 * limited to OpenSSL) that is licensed under separate terms, as designated in a
 * particular file or component or in included license documentation. The
 * authors of MySQL hereby grant you an additional permission to link the
 * program and your derivative works with the separately licensed software that
 * they have included with MySQL.
 *
 * Without limiting anything contained in the foregoing, this file, which is
 * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
 * version 1.0, a copy of which can be found at
 * http://oss.oracle.com/licenses/universal-foss-exception.
 *
 * This program 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 2.0,
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */

package com.mysql.cj.conf;

import java.io.Serializable;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import javax.naming.RefAddr;
import javax.naming.Reference;

import com.mysql.cj.Messages;
import com.mysql.cj.exceptions.ExceptionFactory;
import com.mysql.cj.exceptions.ExceptionInterceptor;
import com.mysql.cj.exceptions.PropertyNotModifiableException;

public abstract class AbstractRuntimeProperty<T> implements RuntimeProperty<T>, Serializable {

    private static final long serialVersionUID = -3424722534876438236L;

    private PropertyDefinition<T> propertyDefinition;

    protected T value;

    protected T initialValue;

    protected boolean wasExplicitlySet = false;

    private List<WeakReference<RuntimePropertyListener>> listeners;

    public AbstractRuntimeProperty() {
    }

    protected AbstractRuntimeProperty(PropertyDefinition<T> propertyDefinition) {
        this.propertyDefinition = propertyDefinition;
        this.value = propertyDefinition.getDefaultValue();
        this.initialValue = propertyDefinition.getDefaultValue();
    }

    @Override
    public PropertyDefinition<T> getPropertyDefinition() {
        return this.propertyDefinition;
    }

    @Override
    public void initializeFrom(Properties extractFrom, ExceptionInterceptor exceptionInterceptor) {
        String name = getPropertyDefinition().getName();
        if (extractFrom.containsKey(name)) {
            String extractedValue = (String) extractFrom.remove(name);
            if (extractedValue != null) {
                setValueInternal(extractedValue, exceptionInterceptor);
                this.initialValue = this.value;
            }
        }
    }

    @Override
    public void initializeFrom(Reference ref, ExceptionInterceptor exceptionInterceptor) {
        RefAddr refAddr = ref.get(getPropertyDefinition().getName());
        if (refAddr != null) {
            String refContentAsString = (String) refAddr.getContent();
            if (refContentAsString != null) {
                setValueInternal(refContentAsString, exceptionInterceptor);
                this.initialValue = this.value;
            }
        }
    }

    @Override
    public void resetValue() {
        this.value = this.initialValue;
        invokeListeners();
    }

    public boolean isExplicitlySet() {
        return this.wasExplicitlySet;
    }

    @Override
    public void addListener(RuntimePropertyListener l) {
        if (this.listeners == null) {
            this.listeners = new ArrayList<>();
        }

        boolean found = false;
        for (WeakReference<RuntimePropertyListener> weakReference : this.listeners) {
            if (l.equals(weakReference.get())) {
                found = true;
                break;
            }
        }
        if (!found) {
            this.listeners.add(new WeakReference<>(l));
        }
    }

    @Override
    public void removeListener(RuntimePropertyListener listener) {
        if (this.listeners != null) {
            for (WeakReference<RuntimePropertyListener> wr : this.listeners) {
                RuntimePropertyListener l = wr.get();
                if (l.equals(listener)) {
                    this.listeners.remove(wr);
                    break;
                }
            }
        }
    }

    protected void invokeListeners() {
        if (this.listeners != null) {
            for (WeakReference<RuntimePropertyListener> wr : this.listeners) {
                RuntimePropertyListener l = wr.get();
                if (l != null) {
                    l.handlePropertyChange(this);
                } else {
                    this.listeners.remove(wr);
                }
            }
        }
    }

    @Override
    public T getValue() {
        return this.value;
    }

    @Override
    public T getInitialValue() {
        return this.initialValue;
    }

    @Override
    public String getStringValue() {
        return this.value == null ? null : this.value.toString();
    }

    /**
     * Set the value of a property from a string value.
     * It involves the {@link PropertyDefinition#parseObject(String, ExceptionInterceptor)} to validate and parse the string.
     * 
     * @param value
     *            value
     * @param exceptionInterceptor
     *            exception interceptor
     */
    public void setValueInternal(String value, ExceptionInterceptor exceptionInterceptor) {
        setValueInternal(getPropertyDefinition().parseObject(value, exceptionInterceptor), value, exceptionInterceptor);
    }

    /**
     * Internal method for setting property value; ignoring the RUNTIME_NOT_MODIFIABLE flag.
     * 
     * @param value
     *            value
     * @param valueAsString
     *            value represented by String
     * @param exceptionInterceptor
     *            exception interceptor
     */
    public void setValueInternal(T value, String valueAsString, ExceptionInterceptor exceptionInterceptor) {
        if (getPropertyDefinition().isRangeBased()) {
            checkRange(value, valueAsString, exceptionInterceptor);
        }
        this.value = value;
        this.wasExplicitlySet = true;
    }

    /**
     * For range-based property, checks that value fit into range given by PropertyDefinition.
     * 
     * @param val
     *            value
     * @param valueAsString
     *            value represented by String
     * @param exceptionInterceptor
     *            exception interceptor
     */
    protected void checkRange(T val, String valueAsString, ExceptionInterceptor exceptionInterceptor) {
        // no-op for not range-based properties
    }

    @Override
    public void setValue(T value) {
        setValue(value, null);
    }

    @Override
    public void setValue(T value, ExceptionInterceptor exceptionInterceptor) {
        if (getPropertyDefinition().isRuntimeModifiable()) {
            setValueInternal(value, null, exceptionInterceptor);
            invokeListeners();
        } else {
            throw ExceptionFactory.createException(PropertyNotModifiableException.class,
                    Messages.getString("ConnectionProperties.dynamicChangeIsNotAllowed", new Object[] { "'" + getPropertyDefinition().getName() + "'" }));
        }
    }
}