/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

package org.apache.kylin.cube.upgrade.common;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.NavigableSet;

import org.apache.kylin.common.persistence.ResourceStore;
import org.apache.kylin.common.util.HadoopUtil;
import org.apache.kylin.metadata.MetadataConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.collect.Lists;

import io.kyligence.kap.guava20.shaded.common.io.ByteSource;

/**
 * After upgrade a metadata store to current version,
 * we'll label every RootPersistentEntity's version as KylinVersion.getCurrentVersion()
 */
public class MetadataVersionRefresher {

    private static final Logger logger = LoggerFactory.getLogger(MetadataVersionRefresher.class);

    private ResourceStore store;
    private String version;

    public MetadataVersionRefresher(ResourceStore resourceStore, String version) {
        this.store = resourceStore;
        this.version = version;

    }

    public void refresh() throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(SerializationFeature.INDENT_OUTPUT, true);

        List<String> all = Lists.newArrayList();
        collectFiles(this.store, "/", all);

        for (String path : all) {
            if (path.endsWith(MetadataConstants.FILE_SURFIX) && !(path.startsWith(HadoopUtil.DICT_STORAGE_ROOT)
                    || path.startsWith(HadoopUtil.SNAPSHOT_STORAGE_ROOT))) {
                logger.info("Updating metadata version of path {}", path);
                ObjectNode objectNode;
                try (InputStream is = this.store.getResource(path).getByteSource().openStream()) {
                    objectNode = (ObjectNode) mapper.readTree(is);
                }
                objectNode.put("version", version);
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                mapper.writeValue(baos, objectNode);
                this.store.checkAndPutResource(path, ByteSource.wrap(baos.toByteArray()), -1);
            }
        }
    }

    public static void collectFiles(ResourceStore src, String path, List<String> ret) throws IOException {
        NavigableSet<String> children = src.listResources(path);

        if (children == null) {
            // case of resource (not a folder)

            ret.add(path);
        } else {
            // case of folder

            for (String child : children) {
                collectFiles(src, child, ret);
            }
        }
    }
}
