/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.sling.installer.factories.configuration.impl;

import java.io.IOException;
import java.util.Collection;
import java.util.Dictionary;
import java.util.Hashtable;

import org.apache.sling.installer.api.InstallableResource;
import org.apache.sling.installer.api.tasks.ResourceUpdater;
import org.apache.sling.installer.api.tasks.UpdatableResourceGroup;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceRegistration;
import org.osgi.service.cm.Configuration;
import org.osgi.service.cm.ConfigurationAdmin;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Update handler for updating 1.x to 1.2
 */
public class ConfigUpdateHandler implements ResourceUpdater {

    /** Logger. */
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    /** Configuration admin. */
    private final ConfigurationAdmin configAdmin;

    private final ServicesListener activator;


    public ConfigUpdateHandler(final ConfigurationAdmin configAdmin,
            final ServicesListener activator) {
        this.configAdmin = configAdmin;
        this.activator = activator;
    }

    public ServiceRegistration<?> register(final BundleContext bundleContext) {
        final Hashtable<String, String> props = new Hashtable<>();
        props.put(Constants.SERVICE_DESCRIPTION, "Apache Sling Configuration Install Task Factory Update Handler");
        props.put(Constants.SERVICE_VENDOR, ServicesListener.VENDOR);

        final String [] serviceInterfaces = {
                ResourceUpdater.class.getName()
        };
        return bundleContext.registerService(serviceInterfaces, this, props);
    }

    @Override
    public void update(final Collection<UpdatableResourceGroup> groups) {
        for(final UpdatableResourceGroup group : groups) {
            update(group);
        }
        this.activator.finishedUpdating();
    }

    private void update(final UpdatableResourceGroup group) {
        if ( this.activator.isActive() ) {
            // check if the group handles configurations and has an alias (aka factory config)
            if ( InstallableResource.TYPE_CONFIG.equals(group.getResourceType()) ) {
                if(group.getAlias() == null && group.getId().contains("~") && group.getId().contains("-")){
                    // new format config with ~ as separator, cleanup if duplicate old format config exists
                    this.cleanupDuplicateFactoryConfig(group);
                } else {
                    if (group.getAlias() != null || group.getId().contains("-")) {
                        this.logger.debug("Configuration going under updation is : {} with alias : {}", group.getId(), group.getAlias());
                        this.updateFactoryConfig(group);
                    }
                }
            }
        }
    }

    protected String[] getFactoryPidAndPid(final String alias, final String oldId) {
        String factoryPid;
        String pid;
        if (alias != null) {

            // special case, oldId is prefix of alias
            if (alias.startsWith(oldId)) {
                final int lastDotIndex = oldId.length();
                final String factoryIdString = alias.substring(0, lastDotIndex + 1); // keep it +1 to have last dot
                                                                                     // intact so that we always have
                                                                                     // even dots in the string
                factoryPid = alias.substring(0, getMiddleDotSplitIndex(factoryIdString));
                pid = alias.substring(lastDotIndex + 1);

            } else {
                int pos = 0;
                while (alias.charAt(pos) == oldId.charAt(pos)) {
                    pos++;
                }
                while (alias.charAt(pos - 1) != '.') {
                    pos--;
                }
                factoryPid = alias.substring(0, pos - 1);
                pid = oldId.substring(factoryPid.length() + 1);
            }
        } else {
            // extract factory id for these cases where alias is not available and factoryId and pid need to be separated from the old id string itself
            //format assumption ::: "factory_pid.factory_pid.pid"
            // split pid with lastIndexOf('.') then remove the duplicate factory_pid part from the remaining string using the middle dot split index
            final int lastDotIndex = oldId.lastIndexOf('.');
            final String factoryIdString = oldId.substring(0, lastDotIndex + 1); // keep it +1 to have last dot intact
                                                                                 // so that we always have even dots in
                                                                                 // the string
            factoryPid = oldId.substring(0, getMiddleDotSplitIndex(factoryIdString));
            pid = oldId.substring(lastDotIndex+1);

        }

        return new String[] { factoryPid, pid };
    }

    private int getMiddleDotSplitIndex(final String strId) {

        int dotCount = 0;
        int[] dotIndexArray = new int[strId.length()];

        for (int i=0;i<strId.length();i++)

            if (strId.charAt(i) == '.') {
                dotCount++;
                dotIndexArray[dotCount] = i;
            }

        return dotIndexArray[dotCount/2]; // get the middle dot index
    }

    private void updateFactoryConfig(final UpdatableResourceGroup group) {
        final String alias = group.getAlias();
        final String oldId = group.getId();

        // change group id
        final String[] result = getFactoryPidAndPid(alias, oldId);

        final String factoryPid = result[0];
        final String pid = result[1];

        final String newId = ConfigUtil.getPIDOfFactoryPID(factoryPid, pid);
        group.setId(newId);
        // clear alias
        group.setAlias(null);

        this.logger.debug("Updating factory configuration from {} to {}", oldId, newId);
        try {
            final Configuration cfg = ConfigUtil.getLegacyFactoryConfig(this.configAdmin, factoryPid, alias, pid);
            if ( cfg != null ) {
                // keep existing values / location
                final String location = cfg.getBundleLocation();
                final Dictionary<String, Object> dict = ConfigUtil.cleanConfiguration(cfg.getProperties());
                // delete old factory configuration
                cfg.delete();
                // create new named factory configuration with same properties and bundle location
                final Configuration upCfg = this.configAdmin.getFactoryConfiguration(factoryPid, pid, location);
                upCfg.update(dict);
            }
        } catch ( final IOException | InvalidSyntaxException io) {
            // ignore for now
        }
        group.update();
    }

    private void cleanupDuplicateFactoryConfig(final UpdatableResourceGroup group) {
            final String newPid = group.getId();
            final int indexOfSeparator = newPid.lastIndexOf('~');
            final String pid = newPid.substring(indexOfSeparator+1);
            final String factoryPid = newPid.substring(0,indexOfSeparator);
            try {
                final Configuration cfg = ConfigUtil.getLegacyFactoryConfig(this.configAdmin, factoryPid, null, pid);
                if ( cfg != null ) {
                    this.logger.debug("Duplicate configuration being cleaned up is : {}",cfg.getFactoryPid() + '.' + cfg.getPid());
                    // delete old factory configuration
                    cfg.delete();
                }

        } catch ( final IOException | InvalidSyntaxException io) {
            // ignore for now
        }
    }
}