// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespavisit;

import com.yahoo.document.FixedBucketSpaces;
import com.yahoo.document.fieldset.DocIdOnly;
import com.yahoo.document.fieldset.DocumentOnly;
import com.yahoo.document.select.parser.ParseException;
import com.yahoo.documentapi.ProgressToken;
import com.yahoo.documentapi.VisitorControlHandler;
import com.yahoo.documentapi.VisitorParameters;
import com.yahoo.documentapi.VisitorSession;
import com.yahoo.documentapi.messagebus.MessageBusDocumentAccess;
import com.yahoo.documentapi.messagebus.MessageBusParams;
import com.yahoo.documentapi.messagebus.protocol.DocumentProtocol;
import com.yahoo.log.LogSetup;
import com.yahoo.messagebus.StaticThrottlePolicy;
import com.yahoo.vespaclient.ClusterDef;
import com.yahoo.vespaclient.ClusterList;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Option;
import org.apache.commons.cli.Options;

import java.io.IOException;
import java.io.PrintStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * Client using visiting, used by the vespa-visit command line tool.
 *
 * @author Einar M R Rosenvinge
 */
public class VdsVisit {

    private VdsVisitParameters params;
    private MessageBusParams mbparams = new MessageBusParams();
    private VisitorSession session;

    private final VisitorSessionAccessorFactory sessionAccessorFactory;
    private VisitorSessionAccessor sessionAccessor;
    private ShutdownHookRegistrar shutdownHookRegistrar;

    public interface ShutdownHookRegistrar {

        void registerShutdownHook(Thread thread);

    }

    public interface VisitorSessionAccessor {

        VisitorSession createVisitorSession(VisitorParameters params) throws ParseException;
        void shutdown();

    }

    public interface VisitorSessionAccessorFactory {

        VisitorSessionAccessor createVisitorSessionAccessor();

    }

    private static class MessageBusVisitorSessionAccessor implements VisitorSessionAccessor {

        private MessageBusDocumentAccess access;

        private MessageBusVisitorSessionAccessor(MessageBusParams mbparams) {
            access = new MessageBusDocumentAccess(mbparams);
        }
        @Override
        public VisitorSession createVisitorSession(VisitorParameters params) throws ParseException {
            return access.createVisitorSession(params);
        }

        @Override
        public void shutdown() {
            access.shutdown();
        }

    }

    private static class MessageBusVisitorSessionAccessorFactory implements VisitorSessionAccessorFactory {

        MessageBusParams mbparams;

        private MessageBusVisitorSessionAccessorFactory(MessageBusParams mbparams) {
            this.mbparams = mbparams;
        }

        @Override
        public VisitorSessionAccessor createVisitorSessionAccessor() {
            return new MessageBusVisitorSessionAccessor(mbparams);
        }

    }

    private static class JvmRuntimeShutdownHookRegistrar implements ShutdownHookRegistrar {

        @Override
        public void registerShutdownHook(Thread thread) {
            Runtime.getRuntime().addShutdownHook(thread);
        }

    }

    public VdsVisit() {
        this.sessionAccessorFactory = new MessageBusVisitorSessionAccessorFactory(mbparams);
        this.shutdownHookRegistrar = new JvmRuntimeShutdownHookRegistrar();
    }

    public VdsVisit(VisitorSessionAccessorFactory sessionAccessorFactory, ShutdownHookRegistrar shutdownHookRegistrar) {
        this.sessionAccessorFactory = sessionAccessorFactory;
        this.shutdownHookRegistrar = shutdownHookRegistrar;
    }

    public static void main(String args[]) {
        LogSetup.initVespaLogging("vespa-visit");
        VdsVisit vdsVisit = new VdsVisit();

        Options options = createOptions();

        try {
            ArgumentParser parser = new ArgumentParser(options);
            vdsVisit.params = parser.parse(args);
            if (vdsVisit.params == null) {
                vdsVisit.printSyntax(options);
                System.exit(0);
            }
            ClusterList clusterList = new ClusterList("client");
            vdsVisit.params.getVisitorParameters().setRoute(
                    resolveClusterRoute(clusterList, vdsVisit.params.getCluster()));
        } catch (org.apache.commons.cli.ParseException e) {
            System.err.println("Failed to parse arguments. Try --help for syntax. " + e.getMessage());
            System.exit(1);
        } catch (IllegalArgumentException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }

        if (vdsVisit.params.isVerbose()) {
            verbosePrintParameters(vdsVisit.params, System.err);
        }

        try {
            vdsVisit.run();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    private void printSyntax(Options options) {
        HelpFormatter formatter = new HelpFormatter();
        formatter.printHelp("vespa-visit <options>", "Visit documents from Vespa", options , "");
    }

    @SuppressWarnings("AccessStaticViaInstance")
    protected static Options createOptions() {
        Options options = new Options();
        options.addOption("h", "help", false, "Show this syntax page.");

        options.addOption(Option.builder("d")
                .longOpt("datahandler")
                .hasArg(true)
                .argName("target")
                .desc("Send results to the given target.")
                .build());

        options.addOption(Option.builder("s")
                .longOpt("selection")
                .hasArg(true)
                .argName("selection")
                .desc("What documents to visit.")
                .build());

        options.addOption(Option.builder("f")
                .longOpt("from")
                .hasArg(true)
                .argName("timestamp")
                .desc("Only visit from the given timestamp (microseconds).")
                .type(Number.class)
                .build());

        options.addOption(Option.builder("t")
                .longOpt("to")
                .hasArg(true)
                .argName("timestamp")
                .desc("Only visit up to the given timestamp (microseconds).")
                .type(Number.class).build());

        options.addOption(Option.builder("l")
                .longOpt("fieldset")
                .hasArg(true)
                .argName("fieldset")
                .desc("Retrieve the specified fields only (see https://docs.vespa.ai/en/documents.html#fieldsets). Default is [document].")
                .build());

        options.addOption(Option.builder()
                .longOpt("visitinconsistentbuckets")
                .hasArg(false)
                .desc("Don't wait for inconsistent buckets to become consistent.")
                .build());

        options.addOption(Option.builder("m")
                .longOpt("maxpending")
                .hasArg(true)
                .argName("num")
                .desc("Maximum pending messages to data handlers per storage visitor.")
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("maxpendingsuperbuckets")
                .hasArg(true)
                .argName("num")
                .desc("Maximum pending visitor messages from the vespa-visit client. If set, dynamic throttling of visitors will be disabled!")
                .type(Number.class)
                .build());

        options.addOption(Option.builder("b")
                .longOpt("maxbuckets")
                .hasArg(true)
                .argName("num")
                .desc("Maximum buckets per visitor.")
                .type(Number.class)
                .build());

        options.addOption("i", "printids", false, "Display only document identifiers.");

        options.addOption(Option.builder("p")
                .longOpt("progress")
                .hasArg(true)
                .argName("file")
                .desc("Use given file to track progress.")
                .build());

        options.addOption(Option.builder("o")
                .longOpt("timeout")
                .hasArg(true)
                .argName("milliseconds")
                .desc("Time out visitor after given time.")
                .type(Number.class)
                .build());

        options.addOption(Option.builder("u")
                .longOpt("buckettimeout")
                .hasArg(true)
                .argName("milliseconds")
                .desc("Fail visitor if visiting a single bucket takes longer than this (default same as timeout)")
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("visitlibrary")
                .hasArg(true)
                .argName("string")
                .desc("Use the given visitor library.")
                .build());

        options.addOption(Option.builder()
                .longOpt("libraryparam")
                .numberOfArgs(2)
                .argName("key> <val")
                .desc("Give the following parameter to the visitor.")
                .build());

        options.addOption("r", "visitremoves", false, "Include information about removed documents.");

        options.addOption(Option.builder("c")
                .longOpt("cluster")
                .hasArg(true)
                .argName("cluster")
                .desc("Visit the given cluster.")
                .build());

        options.addOption("v", "verbose", false, "Indent XML, show progress and info on STDERR.");

        options.addOption(Option.builder()
                .longOpt("statistics")
                .hasArg(true)
                .argName("args")
                .desc("Use CountVisitor for document statistics. Use comma-separated arguments.")
                .build());

        options.addOption(Option.builder()
                .longOpt("abortonclusterdown")
                .hasArg(false)
                .desc("Abort if cluster is down.")
                .build());

        options.addOption(Option.builder()
                .longOpt("maxtotalhits")
                .hasArg(true)
                .argName("num")
                .desc("Abort visiting when we have received this many total documents. This is only an approximate number, all pending work will be completed and those documents will also be returned.")
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("processtime")
                .hasArg(true)
                .argName("num")
                .desc("Sleep this amount of millisecs before processing message. (Debug option for pretending to be slow client)")
                .type(Number.class)
                .build());
        options.addOption(Option.builder()
                .longOpt("priority")
                .hasArg(true)
                .argName("name")
                .desc("Priority used for each visitor. Defaults to NORMAL_3. " +
                        "Use with care to avoid starving lower prioritized traffic in the cluster")
                .build());

        options.addOption(Option.builder()
                .longOpt("tracelevel")
                .hasArg(true)
                .argName("level")
                .desc("Tracelevel ([0-9]) to use for debugging purposes")
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("skipbucketsonfatalerrors")
                .hasArg(false)
                .desc("Skip visiting super buckets with fatal error codes.")
                .build());

        options.addOption(Option.builder()
                .longOpt("jsonoutput")
                .desc("Output documents as JSON (default format)")
                .hasArg(false)
                .build());

        options.addOption(Option.builder()
                .longOpt("jsonl")
                .desc("Output documents as JSONL (JSON Lines format)")
                .hasArg(false)
                .build());

        options.addOption(Option.builder("x")
              .longOpt("xmloutput")
              .desc("Output documents as XML (deprecated)")
              .hasArg(false)
              .build());

        options.addOption(Option.builder()
                .longOpt("bucketspace")
                .hasArg(true)
                .argName("space")
                .desc(String.format("Bucket space to visit ('%s' or '%s'). If not specified, '%s' is used.",
                        FixedBucketSpaces.defaultSpace(), FixedBucketSpaces.globalSpace(), FixedBucketSpaces.defaultSpace()))
                .build());

        // TODO Vespa 9: replace with --longtensors ?
        options.addOption(Option.builder()
                .longOpt("shorttensors")
                .desc("Output JSON tensors in short form. Will be the default on Vespa 9")
                .hasArg(false)
                .build());

        options.addOption(Option.builder()
                .longOpt("slices")
                .desc("Split the document corpus into this number of independent slices. " +
                      "This lets multiple, concurrent series of visitors advance the same logical " +
                      "visit independently, by specifying a different --sliceid for each.")
                .hasArg(true)
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("sliceid")
                .desc("The slice number of the visit represented by this visitor. " +
                      "This number must be non-negative and less than the number of slices specified for the visit.")
                .hasArg(true)
                .type(Number.class)
                .build());

        options.addOption(Option.builder()
                .longOpt("nullrender")
                .desc("Process documents, but do not render any output. Overrides all other output options. " +
                      "Used to benchmark whether document rendering is the bottleneck when processing documents.")
                .hasArg(false)
                .build());

        return options;
    }

    public static class VdsVisitParameters {

        private VisitorParameters visitorParameters;
        /** If not specified in options, will get form cluster list */
        private String cluster = null;
        private boolean verbose = false;
        private boolean printIdsOnly = false;
        private String statisticsParts = null;
        private boolean abortOnClusterDown = false;
        private int processTime = 0;
        private int fullTimeout = 7 * 24 * 60 * 60 * 1000;
        private boolean jsonOutput = true;
        private boolean jsonLinesOutput = false;
        private boolean tensorShortForm = false; // TODO Vespa 9: change default to true
        private boolean tensorDirectValues = false; // TODO Vespa 9: change default to true
        private boolean nullRender = false;
        private int slices = 1;
        private int sliceId = 0;

        public VisitorParameters getVisitorParameters() {
            return visitorParameters;
        }

        public void setVisitorParameters(VisitorParameters visitorParameters) {
            this.visitorParameters = visitorParameters;
        }

        public String getCluster() {
            return cluster;
        }

        public void setCluster(String cluster) {
            this.cluster = cluster;
        }

        public boolean isVerbose() {
            return verbose;
        }

        public void setVerbose(boolean verbose) {
            this.verbose = verbose;
        }

        public boolean isPrintIdsOnly() {
            return printIdsOnly;
        }

        public void setPrintIdsOnly(boolean printIdsOnly) {
            this.printIdsOnly = printIdsOnly;
        }

        public String getStatisticsParts() {
            return statisticsParts;
        }

        public void setStatisticsParts(String statisticsParts) {
            this.statisticsParts = statisticsParts;
        }

        public boolean getAbortOnClusterDown() {
            return abortOnClusterDown;
        }

        public void setAbortOnClusterDown(boolean abortOnClusterDown) {
            this.abortOnClusterDown = abortOnClusterDown;
        }

        public int getFullTimeout() {
            return fullTimeout;
        }

        public void setFullTimeout(int fullTimeout) {
            this.fullTimeout = fullTimeout;
        }

        public int getProcessTime() {
            return processTime;
        }

        public void setProcessTime(int processTime) {
            this.processTime = processTime;
        }

        public boolean jsonOutput() {
            return jsonOutput;
        }

        public void setJsonOutput(boolean jsonOutput) {
            this.jsonOutput = jsonOutput;
        }

        public boolean jsonLinesOutput() {
            return jsonLinesOutput;
        }

        public void setJsonLinesOutput(boolean jsonLinesOutput) {
            this.jsonLinesOutput = jsonLinesOutput;
        }

        public StdOutVisitorHandler.OutputFormat stdOutHandlerOutputFormat() {
            if (jsonLinesOutput) {
                return StdOutVisitorHandler.OutputFormat.JSONL;
            } else if (jsonOutput) {
                return StdOutVisitorHandler.OutputFormat.JSON;
            } else {
                return StdOutVisitorHandler.OutputFormat.XML;
            }
        }

        public boolean tensorShortForm() {
            return tensorShortForm;
        }

        public void setTensorShortForm(boolean tensorShortForm) {
            this.tensorShortForm = tensorShortForm;
        }

        public boolean tensorDirectValues() {
            return tensorDirectValues;
        }

        public void setTensorDirectValues(boolean tensorDirectValues) {
            this.tensorDirectValues = tensorDirectValues;
        }

        public boolean nullRender() {
            return nullRender;
        }

        public void setNullRender(boolean nullRender) {
            this.nullRender = nullRender;
        }

        public int slices() {
            return slices;
        }

        public void setSlices(int slices) {
            this.slices = slices;
        }

        public int sliceId() {
            return sliceId;
        }

        public void setSliceId(int sliceId) {
            this.sliceId = sliceId;
        }

    }

    private static int optionAsInt(CommandLine cmdLine, String optName) throws org.apache.commons.cli.ParseException {
        return ((Number)cmdLine.getParsedOptionValue(optName)).intValue();
    }

    private static long optionAsLong(CommandLine cmdLine, String optName) throws org.apache.commons.cli.ParseException {
        return ((Number)cmdLine.getParsedOptionValue(optName)).longValue();
    }

    protected static class ArgumentParser {
        private final Options options;

        public ArgumentParser(Options options) {
            this.options = options;
        }

        public VdsVisitParameters parse(String[] args) throws org.apache.commons.cli.ParseException {
            VdsVisitParameters allParams = new VdsVisitParameters();
            VisitorParameters params = new VisitorParameters("");
            CommandLineParser parser = new DefaultParser();
            CommandLine line = parser.parse(options, args);

            if (line.hasOption("h")) {
                return null;
            }
            if (line.hasOption("d")) {
                params.setRemoteDataHandler(line.getOptionValue("d"));
            }
            if (line.hasOption("s")) {
                params.setDocumentSelection(line.getOptionValue("s"));
            }
            if (line.hasOption("bucketspace")) {
                params.setBucketSpace(line.getOptionValue("bucketspace"));
            }
            if (line.hasOption("f")) {
                params.setFromTimestamp(optionAsLong(line, "f"));
            }
            if (line.hasOption("t")) {
                params.setToTimestamp(optionAsLong(line, "t"));
            }
            if (line.hasOption("e")) {
                throw new IllegalArgumentException("Headers only option has been removed.");
            }
            if (line.hasOption("l")) {
                params.fieldSet(line.getOptionValue("l"));
            } else {
                params.fieldSet(DocumentOnly.NAME);
            }
            if (line.hasOption("visitinconsistentbuckets")) {
                params.visitInconsistentBuckets(true);
            }
            if (line.hasOption("m")) {
                params.setMaxPending(optionAsInt(line, "m"));
            }
            if (line.hasOption("b")) {
                params.setMaxBucketsPerVisitor(optionAsInt(line, "b"));
            }
            if (line.hasOption("i")) {
                allParams.setPrintIdsOnly(true);
                params.fieldSet(DocIdOnly.NAME);
            }
            if (line.hasOption("p")) {
                params.setResumeFileName(line.getOptionValue("p"));
            }
            if (line.hasOption("o")) {
                allParams.setFullTimeout(optionAsInt(line, "o"));
                params.setTimeoutMs(allParams.getFullTimeout());
            }
            if (line.hasOption("u")) {
                params.setTimeoutMs(optionAsInt(line, "u"));
            }
            if (line.hasOption("visitlibrary")) {
                params.setVisitorLibrary(line.getOptionValue("visitlibrary"));
            }
            if (line.hasOption("libraryparam")) {
                String key = line.getOptionValues("libraryparam")[0];
                String value = line.getOptionValues("libraryparam")[1];
                params.setLibraryParameter(key, value);
            }
            if (line.hasOption("r")) {
                params.visitRemoves(true);
            }
            if (line.hasOption("c")) {
                allParams.setCluster(line.getOptionValue("c"));
            }

            if (line.hasOption("v")) {
                allParams.setVerbose(true);
            }

            if (line.hasOption("statistics")) {
                allParams.setStatisticsParts(line.getOptionValue("statistics"));
                params.fieldSet(DocIdOnly.NAME);
                params.setVisitorLibrary("CountVisitor");
            }

            if (line.hasOption("abortonclusterdown")) {
                allParams.setAbortOnClusterDown(true);
            }
            if (line.hasOption("processtime")) {
                allParams.setProcessTime(optionAsInt(line, "processtime"));
            }
            if (line.hasOption("maxtotalhits")) {
                params.setMaxTotalHits(optionAsLong(line, "maxtotalhits"));
            }
            if (line.hasOption("tracelevel")) {
                params.setTraceLevel(optionAsInt(line, "tracelevel"));
            }
            if (line.hasOption("priority")) {
                try {
                    DocumentProtocol.Priority priority = DocumentProtocol.getPriorityByName(
                            line.getOptionValue("priority"));
                    params.setPriority(priority);
                } catch (IllegalArgumentException e) {
                    throw new IllegalArgumentException("Unknown priority name");
                }
            } else {
                // Let bulk visitor jobs have a low priority by default to avoid stalling concurrent
                // (real time) write and read operations.
                params.setPriority(DocumentProtocol.Priority.LOW_1);
            }
            if (line.hasOption("skipbucketsonfatalerrors")) {
                params.skipBucketsOnFatalErrors(true);
            }
            if (line.hasOption("maxpendingsuperbuckets")) {
                StaticThrottlePolicy throttlePolicy = new StaticThrottlePolicy();
                throttlePolicy.setMaxPendingCount(optionAsInt(line, "maxpendingsuperbuckets"));
                params.setThrottlePolicy(throttlePolicy);
            }
            if (line.hasOption("shorttensors")) {
                allParams.setTensorShortForm(true);
            }
            if (line.hasOption("tensorvalues")) {
                allParams.setTensorDirectValues(true);
            }
            if (line.hasOption("nullrender")) {
                allParams.setNullRender(true);
            }
            if (line.hasOption("slices") != line.hasOption("sliceid")) {
                throw new IllegalArgumentException("Both --slices and --sliceid must be specified when visiting with slicing");
            }
            if (line.hasOption("slices")) {
                allParams.setSlices(optionAsInt(line, "slices"));
                allParams.setSliceId(optionAsInt(line, "sliceid"));
            }

            boolean jsonOutput = line.hasOption("jsonoutput");
            boolean jsonl      = line.hasOption("jsonl");
            boolean xmlOutput  = line.hasOption("xmloutput");
            if ((jsonOutput || jsonl) && xmlOutput) {
                throw new IllegalArgumentException("Cannot combine both XML and JSON output");
            } else if (jsonOutput && jsonl) {
                throw new IllegalArgumentException("Cannot combine both JSON and JSONL output");
            }
            if (jsonl) {
                allParams.setJsonLinesOutput(true);
            } else {
                allParams.setJsonOutput(!xmlOutput);
            }

            if (allParams.slices() != 1 || allParams.sliceId() != 0) {
                if ((allParams.slices() < 1) || (allParams.sliceId() < 0) || (allParams.sliceId() >= allParams.slices())) {
                    throw new IllegalArgumentException("--slices must be greater than 0 and --sliceid must be in the " +
                                                       "range [0, the value provided for --slices)");
                }
                params.slice(allParams.slices(), allParams.sliceId());
            }

            allParams.setVisitorParameters(params);
            return allParams;
        }
    }

    // For unit testing only
    protected void setVdsVisitParameters(VdsVisitParameters vdsVisitParameters) {
        this.params = vdsVisitParameters;
    }

    protected static String resolveClusterRoute(ClusterList clusters, String wantedCluster) {
        if (clusters.getStorageClusters().size() == 0) {
            throw new IllegalArgumentException("Your Vespa cluster does not have any content clusters " +
                                               "declared. Visiting feature is not available.");
        }

        ClusterDef found = null;

        String names = clusters.getStorageClusters()
                               .stream().map(c -> "'" + c.getName() + "'")
                               .collect(Collectors.joining(", "));
        if (wantedCluster != null) {
            for (ClusterDef c : clusters.getStorageClusters()) {
                if (c.getName().equals(wantedCluster)) {
                    found = c;
                }
            }
            if (found == null) {
                throw new IllegalArgumentException("Your vespa cluster contains the content clusters " +
                                                   names + ", not '" + wantedCluster +
                                                   "'. Please select a valid vespa cluster.");
            }
        } else if (clusters.getStorageClusters().size() == 1) {
            found = clusters.getStorageClusters().get(0);
        } else {
            throw new IllegalArgumentException("Your vespa cluster contains the content clusters " +
                                               names + ". Please use the -c option to select one of them as a target for visiting.");
        }

        return found.getRoute();
    }

    protected static void verbosePrintParameters(VdsVisitParameters vdsParams, PrintStream out) {
        VisitorParameters params = vdsParams.getVisitorParameters();
        if (params.getTimeoutMs() != -1) {
            out.println("Time out visitor after " + params.getTimeoutMs() + " ms.");
        }
        if (params.getDocumentSelection() == null || params.getDocumentSelection().equals("")) {
            out.println("Visiting all documents");
        } else {
            out.println("Visiting documents matching: " + params.getDocumentSelection());
        }
        out.println(String.format("Visiting bucket space: %s", params.getBucketSpace()));
        if (params.getFromTimestamp() != 0 && params.getToTimestamp() != 0) {
            out.println("Visiting in the inclusive timestamp range "
                               + params.getFromTimestamp() + " - " + params.getToTimestamp() + ".");
        } else if (params.getFromTimestamp() != 0) {
            out.println("Visiting from and including timestamp " + params.getFromTimestamp() + ".");
        } else if (params.getToTimestamp() != 0) {
            out.println("Visiting to and including timestamp " + params.getToTimestamp() + ".");
        }
        out.println("Visiting field set " + params.fieldSet() + ".");
        if (params.visitInconsistentBuckets()) {
            out.println("Visiting inconsistent buckets.");
        }
        if (params.visitRemoves()) {
            out.println("Including remove entries.");
        }
        if (params.getResumeFileName() != null && !"".equals(params.getResumeFileName())) {
            out.println("Tracking progress in file: " + params.getResumeFileName());
        }
        if (vdsParams.isPrintIdsOnly()) {
            out.println("Only showing document identifiers.");
        }
        out.println("Let visitor have maximum " + params.getMaxPending() + " replies pending on data handlers per storage node visitor.");
        out.println("Visit maximum " + params.getMaxBucketsPerVisitor() + " buckets per visitor.");
        if (params.getRemoteDataHandler() != null) {
            out.println("Sending data to data handler at: " + params.getRemoteDataHandler());
        }
        if (params.getRoute() != null) {
            out.println("Visiting cluster '" + params.getRoute() + "'.");
        }
        if (params.getVisitorLibrary() != null) {
            out.println("Using visitor library '" + params.getVisitorLibrary() + "'.");
        }
        if (params.getLibraryParameters().size() > 0) {
            out.println("Adding the following library specific parameters:");
            for (Map.Entry<String, byte[]> entry : params.getLibraryParameters().entrySet()) {
                out.println("  " + entry.getKey() + " = " +
                            new String(entry.getValue(), StandardCharsets.UTF_8));
            }
        }
        if (params.getPriority() != DocumentProtocol.Priority.NORMAL_3) {
            out.println("Visitor priority " + params.getPriority().name());
        }
        if (params.skipBucketsOnFatalErrors()) {
            out.println("Skip visiting super buckets with fatal errors.");
        }
        if (params.getSlices() > 1) {
            out.format("Visiting slice %d out of %s slices\n", params.getSliceId(), params.getSlices());
        }
    }

    private void onDocumentSelectionException(Exception e) {
        System.err.println("Illegal document selection string '" +
                params.getVisitorParameters().getDocumentSelection() + "'.\n");
        System.exit(1);
    }

    private void onIllegalArgumentException(Exception e) {
        System.err.println("Illegal arguments : \n");
        System.err.println(e.getMessage());
        System.exit(1);
    }

    public void run() {
        System.exit(doRun());
    }

    protected int doRun() {
        VisitorParameters visitorParameters = params.getVisitorParameters();
        // If progress file already exists, create resume token from it
        if (visitorParameters.getResumeFileName() != null &&
            !"".equals(visitorParameters.getResumeFileName()))
        {
            try {
                var progressFileContents = Files.readString(Path.of(visitorParameters.getResumeFileName()));
                visitorParameters.setResumeToken(new ProgressToken(progressFileContents));

                if (params.isVerbose()) {
                    System.err.format("Resuming visitor already %.1f %% finished.\n",
                            visitorParameters.getResumeToken().percentFinished());
                }
            } catch (NoSuchFileException e) {
                // Ignore; file has not been created yet but will be shortly.
            } catch (IOException e) {
                System.err.println("Could not open progress file: " + visitorParameters.getResumeFileName());
                e.printStackTrace(System.err);
                return 1;
            }
        }

        initShutdownHook();
        sessionAccessor = sessionAccessorFactory.createVisitorSessionAccessor();

        VdsVisitHandler handler;

        var handlerParams = new StdOutVisitorHandler.Params();
        handlerParams.printIds             = params.isPrintIdsOnly();
        handlerParams.indentXml            = params.isVerbose();
        handlerParams.showProgress         = params.isVerbose();
        handlerParams.showStatistics       = params.isVerbose();
        handlerParams.doStatistics         = params.getStatisticsParts() != null;
        handlerParams.abortOnClusterDown   = params.getAbortOnClusterDown();
        handlerParams.processTimeMilliSecs = params.getProcessTime();
        handlerParams.outputFormat         = params.stdOutHandlerOutputFormat();
        handlerParams.tensorShortForm      = params.tensorShortForm();
        handlerParams.tensorDirectValues   = params.tensorDirectValues();
        handlerParams.nullRender           = params.nullRender();
        handler = new StdOutVisitorHandler(handlerParams);

        if (visitorParameters.getResumeFileName() != null) {
            handler.setProgressFileName(visitorParameters.getResumeFileName());
        }

        visitorParameters.setControlHandler(handler.getControlHandler());
        if (visitorParameters.getRemoteDataHandler() == null) {
            visitorParameters.setLocalDataHandler(handler.getDataHandler());
        }

        if (params.getStatisticsParts() != null) {
            String[] parts = params.getStatisticsParts().split(",");
            for (String s : parts) {
                visitorParameters.setLibraryParameter(s, "true");
            }
        }

        try {
            session = sessionAccessor.createVisitorSession(visitorParameters);
            while (true) {
                try {
                    if (session.waitUntilDone(params.getFullTimeout())) break;
                } catch (InterruptedException e) {}
            }

            if (visitorParameters.getTraceLevel() > 0) {
                System.out.println(session.getTrace().toString());
            }
        } catch (ParseException e) {
            onDocumentSelectionException(e);
        } catch (IllegalArgumentException e) {
            onIllegalArgumentException(e);
        } catch (Exception e) {
            System.err.println("Document selection string was: " + visitorParameters.getDocumentSelection());
            System.err.println("Caught unexpected exception: ");
            e.printStackTrace(System.err);
            return 1;
        }
        if (visitorParameters.getControlHandler().getResult().code
                == VisitorControlHandler.CompletionCode.SUCCESS)
        {
            return 0;
        } else {
            return 1;
        }
    }

    private void initShutdownHook() {
        shutdownHookRegistrar.registerShutdownHook(new CleanUpThread());
    }

    class CleanUpThread extends Thread {
        public void run() {
            try {
                if (session != null) {
                    session.destroy();
                }
            } catch (IllegalStateException ise) {
                //ignore this
            }
            try {
                if (sessionAccessor != null) {
                    sessionAccessor.shutdown();
                }
            } catch (IllegalStateException ise) {
                //ignore this too
            }
        }
    }
}