/*
 * Copyright (c) 2017 Pantheon Technologies, s.r.o. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.mdsal.binding.dom.codec.osgi.impl;

import static com.google.common.base.Preconditions.checkNotNull;

import javax.annotation.concurrent.GuardedBy;
import org.opendaylight.mdsal.binding.generator.api.ModuleInfoRegistry;
import org.opendaylight.yangtools.concepts.ObjectRegistration;
import org.opendaylight.yangtools.yang.binding.YangModuleInfo;
import org.opendaylight.yangtools.yang.model.api.SchemaContext;
import org.opendaylight.yangtools.yang.model.api.SchemaContextProvider;
import org.osgi.framework.ServiceRegistration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Update SchemaContext service in Service Registry each time new YangModuleInfo is added or removed.
 */
final class OsgiModuleInfoRegistry implements ModuleInfoRegistry {
    private static final Logger LOG = LoggerFactory.getLogger(OsgiModuleInfoRegistry.class);

    private final SimpleBindingRuntimeContextService runtimeContext;
    private final SchemaContextProvider schemaContextProvider;
    private final ModuleInfoRegistry moduleInfoRegistry;

    @GuardedBy("this")
    private ServiceRegistration<?> registration;
    @GuardedBy("this")
    private long generation;

    OsgiModuleInfoRegistry(final ModuleInfoRegistry moduleInfoRegistry,
        final SchemaContextProvider schemaContextProvider, final SimpleBindingRuntimeContextService runtimeContext) {

        this.moduleInfoRegistry = checkNotNull(moduleInfoRegistry);
        this.schemaContextProvider = checkNotNull(schemaContextProvider);
        this.runtimeContext = checkNotNull(runtimeContext);
    }

    @SuppressWarnings("checkstyle:illegalCatch")
    synchronized void updateService() {
        final SchemaContext context;
        try {
            context = schemaContextProvider.getSchemaContext();
        } catch (final RuntimeException e) {
            // The ModuleInfoBackedContext throws a RuntimeException if it can't create the schema context.
            LOG.error("Error updating the schema context", e);
            return;
        }

        try {
            runtimeContext.updateBindingRuntimeContext(context);
        } catch (final RuntimeException e) {
            LOG.error("Error updating binding runtime context", e);
            return;
        }
    }

    @Override
    public ObjectRegistration<YangModuleInfo> registerModuleInfo(final YangModuleInfo yangModuleInfo) {
        return new ObjectRegistrationWrapper(moduleInfoRegistry.registerModuleInfo(yangModuleInfo));
    }

    private class ObjectRegistrationWrapper implements ObjectRegistration<YangModuleInfo> {
        private final ObjectRegistration<YangModuleInfo> inner;

        ObjectRegistrationWrapper(final ObjectRegistration<YangModuleInfo> inner) {
            this.inner = checkNotNull(inner);
        }

        @Override
        public YangModuleInfo getInstance() {
            return inner.getInstance();
        }

        @Override
        @SuppressWarnings("checkstyle:illegalCatch")
        public void close() {
            try {
                inner.close();
            } finally {
                // send modify event when a bundle disappears
                updateService();
            }
        }

        @Override
        public String toString() {
            return inner.toString();
        }
    }
}