/*
 * (C) Copyright 2006-2018 Nuxeo (http://nuxeo.com/) and others.
 *
 * Licensed 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.
 *
 * Contributors:
 *     Nuxeo - initial API and implementation
 */
package org.nuxeo.runtime.model.impl;

import static java.nio.charset.StandardCharsets.UTF_8;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.IOUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.nuxeo.runtime.RuntimeService;
import org.nuxeo.runtime.RuntimeServiceException;
import org.nuxeo.runtime.api.Framework;
import org.nuxeo.runtime.model.ComponentManager;
import org.nuxeo.runtime.model.ComponentName;
import org.nuxeo.runtime.model.RegistrationInfo;
import org.nuxeo.runtime.model.RuntimeContext;
import org.nuxeo.runtime.model.StreamRef;
import org.nuxeo.runtime.model.URLStreamRef;
import org.nuxeo.runtime.osgi.OSGiRuntimeActivator;
import org.nuxeo.runtime.osgi.OSGiRuntimeContext;
import org.osgi.framework.Bundle;

/**
 * New behavior @since 9.2 As the runtime lifecycle changed there make no sense to unregister components by their own.
 * <p />
 * The component registry is either reset to a clean state or shutdown.
 * <p />
 * So methods like unregister by location used in tests make no sense. These methods are preserved yet for compatibility
 * with some tests but may be removed in future.
 * <p />
 * Also when a context is destroyed we unregister all the components the context deployed.
 * <p />
 * This is also deprecated since the unregister component is deprecated too.
 * <p />
 * The code inside destroy method was removed too since the deployedFiles map was removed.
 * <p />
 * This map posed problems with the registry snapshot approaches since it was not kept in sync with the registry.
 * <p />
 * <p />
 * If unregistering components will be removed completely don't forget to remove
 * {@link ComponentManager#unregisterByLocation(String)} and the {@link ComponentRegistry#deployedFiles}.
 * <p />
 * <p />
 * Features like studio or IDE which needs unregistering components must use their own mechanism.
 *
 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
 */
public class DefaultRuntimeContext implements RuntimeContext {

    private static final Logger log = LogManager.getLogger(DefaultRuntimeContext.class);

    protected RuntimeService runtime;

    /**
     * The list of component names deployed by this context.
     *
     * @since 9.2
     */
    protected List<ComponentName> components;

    protected final ComponentDescriptorReader reader;

    public DefaultRuntimeContext() {
        this(Framework.getRuntime());
    }

    public DefaultRuntimeContext(RuntimeService runtime) {
        this.runtime = runtime;
        this.components = new ArrayList<>();
        reader = new ComponentDescriptorReader();
    }

    public void setRuntime(RuntimeService runtime) {
        this.runtime = runtime;
    }

    @Override
    public RuntimeService getRuntime() {
        return runtime;
    }

    @Override
    public ComponentName[] getComponents() {
        return components.toArray(new ComponentName[0]);
    }

    @Override
    public URL getResource(String name) {
        return Thread.currentThread().getContextClassLoader().getResource(name);
    }

    @Override
    public URL getLocalResource(String name) {
        return Thread.currentThread().getContextClassLoader().getResource(name);
    }

    @Override
    public Class<?> loadClass(String className) throws ClassNotFoundException {
        return Thread.currentThread().getContextClassLoader().loadClass(className);
    }

    @Override
    public RegistrationInfo deploy(URL url) throws IOException {
        return deploy(new URLStreamRef(url));
    }

    @Override
    public RegistrationInfo deploy(StreamRef ref) throws IOException {
        String name = ref.getId();
        RegistrationInfoImpl ri = createRegistrationInfo(ref);
        if (ri == null || ri.name == null) {
            // not parsed correctly, e.g., faces-config.xml
            return null;
        }
        log.debug("Deploying component from url {}", name);
        ri.sourceId = name;
        ri.context = this;
        ri.xmlFileUrl = ref.asURL();
        if (ri.getBundle() != null) {
            // this is an external component XML.
            // should use the real owner bundle as the context.
            Bundle bundle = OSGiRuntimeActivator.getInstance().getBundle(ri.getBundle());
            if (bundle != null) {
                ri.context = new OSGiRuntimeContext(bundle);
            }
        }
        runtime.getComponentManager().register(ri);
        components.add(ri.name);
        return ri;
    }

    @Override
    public void undeploy(URL url) {
        runtime.getComponentManager().unregisterByLocation(url.toString());
    }

    @Override
    public void undeploy(StreamRef ref) {
        runtime.getComponentManager().unregisterByLocation(ref.getId());
    }

    @Override
    public boolean isDeployed(URL url) {
        return runtime.getComponentManager().hasComponentFromLocation(url.toString());
    }

    @Override
    public boolean isDeployed(StreamRef ref) {
        return runtime.getComponentManager().hasComponentFromLocation(ref.getId());
    }

    @Override
    public RegistrationInfo deploy(String location) {
        URL url = getLocalResource(location);
        if (url == null) {
            throw new IllegalArgumentException("No local resources was found with this name: " + location);
        }
        try {
            return deploy(url);
        } catch (IOException e) {
            throw new RuntimeServiceException("Cannot deploy: " + location, e);
        }
    }

    @Override
    public void undeploy(String location) {
        URL url = getLocalResource(location);
        if (url == null) {
            throw new IllegalArgumentException("No local resources was found with this name: " + location);
        }
        undeploy(url);
    }

    @Override
    public boolean isDeployed(String location) {
        URL url = getLocalResource(location);
        if (url != null) {
            return isDeployed(url);
        } else {
            log.warn("No local resources was found with this name: {}", location);
            return false;
        }
    }

    @Override
    public void destroy() {
        ComponentManager mgr = runtime.getComponentManager();
        for (ComponentName cname : components) {
            mgr.unregister(cname);
        }
    }

    @Override
    public Bundle getBundle() {
        return null;
    }

    public RegistrationInfoImpl createRegistrationInfo(StreamRef ref) throws IOException {
        String source;
        try (InputStream stream = ref.getStream()) {
            source = IOUtils.toString(stream, UTF_8);
        }
        String expanded = Framework.expandVars(source);
        try (InputStream in = new ByteArrayInputStream(expanded.getBytes())) {
            return createRegistrationInfo(in);
        }
    }

    public RegistrationInfoImpl createRegistrationInfo(InputStream in) throws IOException {
        return reader.read(this, in);
    }

}