/*
 * Copyright (c) 2023 PANTHEON.tech, 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.restconf.nb.rfc8040.streams;

import static java.util.Objects.requireNonNull;

import java.util.Map;
import java.util.Set;
import javax.servlet.http.HttpServlet;
import javax.ws.rs.core.Application;
import org.eclipse.jdt.annotation.NonNull;
import org.opendaylight.aaa.web.servlet.ServletSupport;
import org.opendaylight.restconf.api.query.PrettyPrintParam;
import org.opendaylight.restconf.nb.rfc8040.ErrorTagMapping;
import org.opendaylight.restconf.server.spi.RestconfStream;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.service.component.annotations.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Auxiliary interface for instantiating JAX-RS streams.
 *
 * @deprecated This componet exists only to support SSE/Websocket delivery. It will be removed when support for
 *             WebSockets is removed.
 */
@Component(factory = DefaultRestconfStreamServletFactory.FACTORY_NAME, service = RestconfStreamServletFactory.class)
@Deprecated(since = "7.0.0", forRemoval = true)
public final class DefaultRestconfStreamServletFactory implements RestconfStreamServletFactory, AutoCloseable {
    private static final Logger LOG = LoggerFactory.getLogger(DefaultRestconfStreamServletFactory.class);

    public static final String FACTORY_NAME =
        "org.opendaylight.restconf.nb.rfc8040.streams.RestconfStreamServletFactory";

    private static final String PROP_STREAM_REGISTRY = ".streamRegistry";
    private static final String PROP_NAME_PREFIX = ".namePrefix";
    private static final String PROP_CORE_POOL_SIZE = ".corePoolSize";
    private static final String PROP_USE_WEBSOCKETS = ".useWebsockets";
    private static final String PROP_STREAMS_CONFIGURATION = ".streamsConfiguration";
    private static final String PROP_RESTCONF = ".restconf";
    private static final String PROP_PRETTY_PRINT = ".prettyPrint";
    private static final String PROP_ERROR_TAG_MAPPING = ".errorTagMapping";

    private final @NonNull String restconf;
    private final @NonNull ErrorTagMapping errorTagMapping;
    private final @NonNull PrettyPrintParam prettyPrint;
    private final RestconfStream.Registry streamRegistry;
    private final ServletSupport servletSupport;

    private final DefaultPingExecutor pingExecutor;
    private final StreamsConfiguration streamsConfiguration;
    private final boolean useWebsockets;

    public DefaultRestconfStreamServletFactory(final ServletSupport servletSupport, final String restconf,
            final RestconfStream.Registry streamRegistry, final StreamsConfiguration streamsConfiguration,
            final ErrorTagMapping errorTagMapping, final PrettyPrintParam prettyPrint, final String namePrefix,
            final int corePoolSize, final boolean useWebsockets) {
        this.servletSupport = requireNonNull(servletSupport);
        this.restconf = requireNonNull(restconf);
        if (restconf.endsWith("/")) {
            throw new IllegalArgumentException("{+restconf} value ends with /");
        }
        this.streamRegistry = requireNonNull(streamRegistry);
        this.streamsConfiguration = requireNonNull(streamsConfiguration);
        this.errorTagMapping = requireNonNull(errorTagMapping);
        this.prettyPrint = requireNonNull(prettyPrint);
        pingExecutor = new DefaultPingExecutor(namePrefix, corePoolSize);
        this.useWebsockets = useWebsockets;
        if (useWebsockets) {
            LOG.warn("""
                RESTCONF event streams use WebSockets instead of Server-Sent Events. This option is will be removed in
                the next major release.""");
        }
    }

    @Activate
    public DefaultRestconfStreamServletFactory(@Reference final ServletSupport servletSupport,
            final Map<String, ?> props) {
        this(servletSupport, (String) props.get(PROP_RESTCONF),
            (RestconfStream.Registry) props.get(PROP_STREAM_REGISTRY),
            (StreamsConfiguration) props.get(PROP_STREAMS_CONFIGURATION),
            (ErrorTagMapping) props.get(PROP_ERROR_TAG_MAPPING),
            (PrettyPrintParam) props.get(PROP_PRETTY_PRINT),
            (String) props.get(PROP_NAME_PREFIX), (int) requireNonNull(props.get(PROP_CORE_POOL_SIZE)),
            (boolean) requireNonNull(props.get(PROP_USE_WEBSOCKETS)));
    }

    @Override
    public String restconf() {
        return restconf;
    }

    @Override
    public HttpServlet newStreamServlet() {
        return useWebsockets ? new WebSocketInitializer(restconf, streamRegistry, pingExecutor, streamsConfiguration)
            : servletSupport.createHttpServletBuilder(
                new Application() {
                    @Override
                    public Set<Object> getSingletons() {
                        return Set.of(new SSEStreamService(streamRegistry, pingExecutor, streamsConfiguration));
                    }
                }).build();
    }

    @Override
    public PrettyPrintParam prettyPrint() {
        return prettyPrint;
    }

    @Override
    public ErrorTagMapping errorTagMapping() {
        return errorTagMapping;
    }

    @Override
    @Deactivate
    public void close() {
        pingExecutor.close();
    }

    public static Map<String, ?> props(final String restconf, final RestconfStream.Registry streamRegistry,
            final ErrorTagMapping errorTagMapping, final PrettyPrintParam prettyPrint, final boolean useSSE,
            final StreamsConfiguration streamsConfiguration, final String namePrefix, final int corePoolSize) {
        return Map.of(
            PROP_RESTCONF, restconf,
            PROP_STREAM_REGISTRY, streamRegistry,
            PROP_ERROR_TAG_MAPPING, errorTagMapping,
            PROP_PRETTY_PRINT, prettyPrint,
            PROP_USE_WEBSOCKETS, !useSSE,
            PROP_STREAMS_CONFIGURATION, streamsConfiguration,
            PROP_NAME_PREFIX, namePrefix,
            PROP_CORE_POOL_SIZE, corePoolSize);
    }
}