/*
 * 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.rocketmq.broker.config.v1;

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONWriter;
import org.apache.commons.lang3.StringUtils;
import org.apache.rocketmq.broker.BrokerController;
import org.apache.rocketmq.broker.BrokerPathConfigHelper;
import org.apache.rocketmq.broker.topic.TopicConfigManager;
import org.apache.rocketmq.common.TopicConfig;
import org.apache.rocketmq.common.UtilAll;
import org.apache.rocketmq.common.utils.DataConverter;
import org.apache.rocketmq.remoting.protocol.DataVersion;
import org.rocksdb.CompressionType;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

public class RocksDBTopicConfigManager extends TopicConfigManager {
    private static final String VERSION_COLUMN_FAMILY = "topicVersion";
    private static final String TOPIC_COLUMN_FAMILY = "topic";

    protected transient RocksDBConfigManager rocksDBConfigManager;
    private final boolean useSingleRocksDBForAllConfigs;
    private final String storePathRootDir;

    public RocksDBTopicConfigManager(BrokerController brokerController, boolean useSingleRocksDB,
        String storePathRootDir) {
        super(brokerController, false);

        this.useSingleRocksDBForAllConfigs = useSingleRocksDB;
        this.storePathRootDir = StringUtils.isBlank(storePathRootDir) ?
            brokerController.getMessageStoreConfig().getStorePathRootDir() : storePathRootDir;

        long flushInterval = brokerController.getMessageStoreConfig().getMemTableFlushIntervalMs();
        CompressionType compressionType =
            CompressionType.getCompressionType(brokerController.getMessageStoreConfig().getRocksdbCompressionType());
        String rocksDBPath = rocksdbConfigFilePath(storePathRootDir, useSingleRocksDB);

        this.rocksDBConfigManager = useSingleRocksDB ? new RocksDBConfigManager(rocksDBPath, flushInterval,
            compressionType, TOPIC_COLUMN_FAMILY, VERSION_COLUMN_FAMILY) : new RocksDBConfigManager(rocksDBPath,
            flushInterval, compressionType);
    }

    public RocksDBTopicConfigManager(BrokerController brokerController, boolean useSingleRocksDBForAllConfigs) {
        this(brokerController, useSingleRocksDBForAllConfigs, null);
    }

    public RocksDBTopicConfigManager(BrokerController brokerController) {
        this(brokerController, brokerController.getBrokerConfig().isUseSingleRocksDBForAllConfigs(), null);
    }

    @Override
    public boolean load() {
        if (!rocksDBConfigManager.init()) {
            return false;
        }
        if (!loadDataVersion() || !loadTopicConfig()) {
            return false;
        }
        if (useSingleRocksDBForAllConfigs) {
            migrateFromSeparateRocksDBs();
        }
        this.init();
        return true;
    }

    public boolean loadTopicConfig() {
        return this.rocksDBConfigManager.loadData(this::decodeTopicConfig) && merge();
    }

    public boolean loadDataVersion() {
        return this.rocksDBConfigManager.loadDataVersion();
    }

    private boolean merge() {
        if (!UtilAll.isPathExists(this.configFilePath()) && !UtilAll.isPathExists(this.configFilePath() + ".bak")) {
            log.info("topic json file does not exist, so skip merge");
            return true;
        }

        if (!super.loadDataVersion()) {
            log.error("load json topic dataVersion error, startup will exit");
            return false;
        }

        final DataVersion dataVersion = super.getDataVersion();
        final DataVersion kvDataVersion = this.getDataVersion();
        if (dataVersion.getCounter().get() > kvDataVersion.getCounter().get()) {
            if (!super.load()) {
                log.error("load topic config from json file error, startup will exit");
                return false;
            }
            final ConcurrentMap<String, TopicConfig> topicConfigTable = this.getTopicConfigTable();
            for (Map.Entry<String, TopicConfig> entry : topicConfigTable.entrySet()) {
                putTopicConfig(entry.getValue());
                log.info("import topic config to rocksdb, topic={}", entry.getValue());
            }
            this.getDataVersion().assignNewOne(dataVersion);
            updateDataVersion();
        } else {
            log.info("dataVersion is not greater than kvDataVersion, no need to merge topic metaData, dataVersion={}, kvDataVersion={}", dataVersion, kvDataVersion);
        }
        log.info("finish read topic config from json file and merge to rocksdb");
        this.persist();
        return true;
    }


    @Override
    public boolean stop() {
        return this.rocksDBConfigManager.stop();
    }

    protected void decodeTopicConfig(byte[] key, byte[] body) {
        String topicName = new String(key, DataConverter.CHARSET_UTF8);
        TopicConfig topicConfig = JSON.parseObject(body, TopicConfig.class);

        this.topicConfigTable.put(topicName, topicConfig);
        log.info("load exist local topic, {}", topicConfig.toString());
    }

    @Override
    public TopicConfig putTopicConfig(TopicConfig topicConfig) {
        String topicName = topicConfig.getTopicName();
        TopicConfig oldTopicConfig = this.topicConfigTable.put(topicName, topicConfig);
        try {
            byte[] keyBytes = topicName.getBytes(DataConverter.CHARSET_UTF8);
            byte[] valueBytes = JSON.toJSONBytes(topicConfig, JSONWriter.Feature.BrowserCompatible);
            this.rocksDBConfigManager.put(keyBytes, valueBytes);
        } catch (Exception e) {
            log.error("kv put topic Failed, {}", topicConfig.toString(), e);
        }
        return oldTopicConfig;
    }

    @Override
    protected TopicConfig removeTopicConfig(String topicName) {
        TopicConfig topicConfig = this.topicConfigTable.remove(topicName);
        try {
            this.rocksDBConfigManager.delete(topicName.getBytes(DataConverter.CHARSET_UTF8));
        } catch (Exception e) {
            log.error("kv remove topic Failed, {}", topicConfig.toString());
        }
        return topicConfig;
    }

    @Override
    public synchronized void persist() {
        if (brokerController.getMessageStoreConfig().isRealTimePersistRocksDBConfig()) {
            this.rocksDBConfigManager.flushWAL();
        }
    }

    public synchronized void exportToJson() {
        log.info("RocksDBTopicConfigManager export topic config to json file");
        super.persist();
    }

    public String rocksdbConfigFilePath(String storePathRootDir, boolean useSingleRocksDBForAllConfigs) {
        if (StringUtils.isBlank(storePathRootDir)) {
            storePathRootDir = brokerController.getMessageStoreConfig().getStorePathRootDir();
        }
        Path rootPath = Paths.get(storePathRootDir);
        if (useSingleRocksDBForAllConfigs) {
            return rootPath.resolve("config").resolve("metadata").toString();
        }
        return rootPath.resolve("config").resolve("topics").toString();
    }

    @Override
    public String configFilePath() {
        return BrokerPathConfigHelper.getTopicConfigPath(this.storePathRootDir);
    }

    @Override
    public DataVersion getDataVersion() {
        return rocksDBConfigManager.getKvDataVersion();
    }

    @Override
    public void updateDataVersion() {
        try {
            rocksDBConfigManager.updateKvDataVersion();
        } catch (Exception e) {
            log.error("update topic config dataVersion error", e);
            throw new RuntimeException(e);
        }
    }

    @Override
    public void setDataVersion(DataVersion dataVersion) {
        try {
            rocksDBConfigManager.setKvDataVersion(dataVersion);
        } catch (Exception e) {
            log.error("set topic config dataVersion error", e);
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Migrate data from separate RocksDB instances to the unified RocksDB when useSingleRocksDBForAllConfigs is
     * enabled.
     * This method will only be called when switching from separate RocksDB mode to unified mode.
     * It opens the separate RocksDB in read-only mode, compares versions, and imports data if needed.
     */
    private void migrateFromSeparateRocksDBs() {
        String separateRocksDBPath = rocksdbConfigFilePath(this.storePathRootDir, false);

        // Check if separate RocksDB exists
        if (!UtilAll.isPathExists(separateRocksDBPath)) {
            log.info("Separate RocksDB for topics does not exist at {}, no migration needed", separateRocksDBPath);
            return;
        }

        log.info("Starting migration from separate RocksDB at {} to unified RocksDB", separateRocksDBPath);

        // Open separate RocksDB in read-only mode
        RocksDBConfigManager separateRocksDBConfigManager = null;
        try {
            long memTableFlushIntervalMs = brokerController.getMessageStoreConfig().getMemTableFlushIntervalMs();
            org.rocksdb.CompressionType compressionType =
                org.rocksdb.CompressionType.getCompressionType(brokerController.getMessageStoreConfig().getRocksdbCompressionType());

            separateRocksDBConfigManager = new RocksDBConfigManager(separateRocksDBPath, memTableFlushIntervalMs,
                compressionType);

            // Initialize in read-only mode
            if (!separateRocksDBConfigManager.init(true)) {
                log.error("Failed to initialize separate RocksDB in read-only mode");
                return;
            }

            // Load data version from separate RocksDB
            if (!separateRocksDBConfigManager.loadDataVersion()) {
                log.error("Failed to load data version from separate RocksDB");
                return;
            }

            DataVersion separateDataVersion = separateRocksDBConfigManager.getKvDataVersion();
            DataVersion unifiedDataVersion = this.getDataVersion();

            log.info("Comparing data versions - Separate: {}, Unified: {}", separateDataVersion, unifiedDataVersion);

            // Compare versions and import if separate version is newer
            if (separateDataVersion.getCounter().get() > unifiedDataVersion.getCounter().get()) {
                log.info("Separate RocksDB has newer data, importing...");

                // Load topic configs from separate RocksDB
                if (separateRocksDBConfigManager.loadData(this::importTopicConfig)) {
                    log.info("Successfully imported topic configs from separate RocksDB");

                    this.getDataVersion().assignNewOne(separateDataVersion);
                    this.getDataVersion().nextVersion(); // Make it one version higher
                    updateDataVersion();
                    log.info("Updated unified data version to {}", this.getDataVersion());
                } else {
                    log.error("Failed to import topic configs from separate RocksDB");
                }
            } else {
                log.info("Unified RocksDB is already up-to-date, no migration needed");
            }
        } catch (Exception e) {
            log.error("Error during migration from separate RocksDB", e);
        } finally {
            if (separateRocksDBConfigManager != null) {
                try {
                    separateRocksDBConfigManager.stop();
                } catch (Exception e) {
                    log.warn("Error stopping separate RocksDB config manager", e);
                }
            }
        }
    }

    /**
     * Import a topic config from the separate RocksDB during migration
     *
     * @param key  The topic name bytes
     * @param body The topic config data bytes
     */
    private void importTopicConfig(byte[] key, byte[] body) {
        try {
            decodeTopicConfig(key, body);
            this.rocksDBConfigManager.put(key, body);
        } catch (Exception e) {
            log.error("Error importing topic config", e);
        }
    }
}
