package eu.dnetlib.dhp.actionmanager.migration;

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;
import java.util.stream.Collectors;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.tools.DistCp;
import org.apache.hadoop.tools.DistCpOptions;
import org.apache.hadoop.util.ToolRunner;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Splitter;
import com.google.common.collect.Lists;

import eu.dnetlib.dhp.application.ArgumentApplicationParser;
import eu.dnetlib.dhp.utils.ISLookupClientFactory;
import eu.dnetlib.enabling.is.lookup.rmi.ISLookUpException;
import eu.dnetlib.enabling.is.lookup.rmi.ISLookUpService;

public class MigrateActionSet {

	private static final Logger log = LoggerFactory.getLogger(MigrateActionSet.class);

	private static final String SEPARATOR = "/";
	private static final String TARGET_PATHS = "target_paths";
	private static final String RAWSET_PREFIX = "rawset_";

	public static void main(String[] args) throws Exception {
		final ArgumentApplicationParser parser = new ArgumentApplicationParser(
			IOUtils
				.toString(
					MigrateActionSet.class
						.getResourceAsStream(
							"/eu/dnetlib/dhp/actionmanager/migration/migrate_actionsets_parameters.json")));
		parser.parseArgument(args);

		new MigrateActionSet().run(parser);
	}

	private void run(ArgumentApplicationParser parser) throws Exception {

		final String isLookupUrl = parser.get("isLookupUrl");
		final String sourceNN = parser.get("sourceNameNode");
		final String targetNN = parser.get("targetNameNode");
		final String workDir = parser.get("workingDirectory");
		final Integer distcp_num_maps = Integer.parseInt(parser.get("distcp_num_maps"));

		final String distcp_memory_mb = parser.get("distcp_memory_mb");
		final String distcp_task_timeout = parser.get("distcp_task_timeout");

		final String transform_only_s = parser.get("transform_only");

		log.info("transform only param: {}", transform_only_s);

		final Boolean transformOnly = Boolean.valueOf(parser.get("transform_only"));

		log.info("transform only: {}", transformOnly);

		ISLookUpService isLookUp = ISLookupClientFactory.getLookUpService(isLookupUrl);

		Configuration conf = getConfiguration(distcp_task_timeout, distcp_memory_mb, distcp_num_maps);
		FileSystem targetFS = FileSystem.get(conf);

		Configuration sourceConf = getConfiguration(distcp_task_timeout, distcp_memory_mb, distcp_num_maps);
		sourceConf.set(FileSystem.FS_DEFAULT_NAME_KEY, sourceNN);
		FileSystem sourceFS = FileSystem.get(sourceConf);

		Properties props = new Properties();

		List<Path> targetPaths = new ArrayList<>();

		final List<Path> sourcePaths = getSourcePaths(sourceNN, isLookUp);
		log
			.info(
				"paths to process:\n{}", sourcePaths
					.stream()
					.map(p -> p.toString())
					.collect(Collectors.joining("\n")));

		for (Path source : sourcePaths) {

			if (!sourceFS.exists(source)) {
				log.warn("skipping unexisting path: {}", source);
			} else {

				LinkedList<String> pathQ = Lists.newLinkedList(Splitter.on(SEPARATOR).split(source.toUri().getPath()));

				final String rawSet = pathQ.pollLast();
				log.info("got RAWSET: {}", rawSet);

				if (StringUtils.isNotBlank(rawSet) && rawSet.startsWith(RAWSET_PREFIX)) {

					final String actionSetDirectory = pathQ.pollLast();

					final Path targetPath = new Path(
						targetNN + workDir + SEPARATOR + actionSetDirectory + SEPARATOR + rawSet);

					log.info("using TARGET PATH: {}", targetPath);

					if (!transformOnly) {
						if (targetFS.exists(targetPath)) {
							targetFS.delete(targetPath, true);
						}
						runDistcp(
							distcp_num_maps, distcp_memory_mb, distcp_task_timeout, conf, source, targetPath);
					}

					targetPaths.add(targetPath);
				}
			}
		}

		final String targetPathsCsv = targetPaths.stream().map(p -> p.toString()).collect(Collectors.joining(","));
		props.setProperty(TARGET_PATHS, targetPathsCsv);
		File file = new File(System.getProperty("oozie.action.output.properties"));

		try (OutputStream os = new FileOutputStream(file)) {
			props.store(os, "");
		}
		System.out.println(file.getAbsolutePath());
	}

	private void runDistcp(
		Integer distcp_num_maps,
		String distcp_memory_mb,
		String distcp_task_timeout,
		Configuration conf,
		Path source,
		Path targetPath)
		throws Exception {

		final DistCpOptions op = new DistCpOptions(source, targetPath);
		op.setMaxMaps(distcp_num_maps);
		op.preserve(DistCpOptions.FileAttribute.BLOCKSIZE);
		op.preserve(DistCpOptions.FileAttribute.REPLICATION);
		op.preserve(DistCpOptions.FileAttribute.CHECKSUMTYPE);

		int res = ToolRunner
			.run(
				new DistCp(conf, op),
				new String[] {
					"-Dmapred.task.timeout=" + distcp_task_timeout,
					"-Dmapreduce.map.memory.mb=" + distcp_memory_mb,
					"-pb",
					"-m " + distcp_num_maps,
					source.toString(),
					targetPath.toString()
				});

		if (res != 0) {
			throw new RuntimeException(String.format("distcp exited with code %s", res));
		}
	}

	private Configuration getConfiguration(
		String distcp_task_timeout, String distcp_memory_mb, Integer distcp_num_maps) {
		final Configuration conf = new Configuration();
		conf.set("dfs.webhdfs.socket.connect-timeout", distcp_task_timeout);
		conf.set("dfs.webhdfs.socket.read-timeout", distcp_task_timeout);
		conf.set("dfs.http.client.retry.policy.enabled", "true");
		conf.set("mapred.task.timeout", distcp_task_timeout);
		conf.set("mapreduce.map.memory.mb", distcp_memory_mb);
		conf.set("mapred.map.tasks", String.valueOf(distcp_num_maps));
		return conf;
	}

	private List<Path> getSourcePaths(String sourceNN, ISLookUpService isLookUp)
		throws ISLookUpException {
		String XQUERY = "distinct-values(\n"
			+ "let $basePath := collection('/db/DRIVER/ServiceResources/ActionManagerServiceResourceType')//SERVICE_PROPERTIES/PROPERTY[@key = 'basePath']/@value/string()\n"
			+ "for $x in collection('/db/DRIVER/ActionManagerSetDSResources/ActionManagerSetDSResourceType') \n"
			+ "let $setDir := $x//SET/@directory/string()\n"
			+ "let $rawSet := $x//RAW_SETS/LATEST/@id/string()\n"
			+ "return concat($basePath, '/', $setDir, '/', $rawSet))";

		log.info(String.format("running xquery:\n%s", XQUERY));
		return isLookUp
			.quickSearchProfile(XQUERY)
			.stream()
			.map(p -> sourceNN + p)
			.map(Path::new)
			.collect(Collectors.toList());
	}
}