/*
 * 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.iotdb.db.conf;

import org.apache.iotdb.db.engine.fileSystem.SystemFileFactory;
import org.apache.iotdb.db.exception.ConfigurationException;
import org.apache.iotdb.tsfile.common.conf.TSFileConfig;
import org.apache.iotdb.tsfile.common.conf.TSFileDescriptor;
import org.apache.iotdb.tsfile.fileSystem.FSFactoryProducer;
import org.apache.iotdb.tsfile.fileSystem.fsFactory.FSFactory;

import org.apache.commons.io.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.file.Files;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;

public class IoTDBConfigCheck {

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

  private static final IoTDBConfig config = IoTDBDescriptor.getInstance().getConfig();

  private FSFactory fsFactory = FSFactoryProducer.getFSFactory();

  // this file is located in data/system/schema/system.properties
  // If user delete folder "data", system.properties can reset.
  private static final String PROPERTIES_FILE_NAME = "system.properties";
  private static final String SCHEMA_DIR = config.getSchemaDir();
  private static final String WAL_DIR = config.getWalDir();

  private File propertiesFile;
  private File tmpPropertiesFile;

  private Properties properties = new Properties();

  private Map<String, String> systemProperties = new HashMap<>();

  private static final String SYSTEM_PROPERTIES_STRING = "System properties:";

  private static final String TIMESTAMP_PRECISION_STRING = "timestamp_precision";
  private static String timestampPrecision = config.getTimestampPrecision();

  private static final String PARTITION_INTERVAL_STRING = "partition_interval";
  private static long partitionInterval = config.getPartitionInterval();

  private static final String TSFILE_FILE_SYSTEM_STRING = "tsfile_storage_fs";
  private static String tsfileFileSystem = config.getTsFileStorageFs().toString();

  private static final String ENABLE_PARTITION_STRING = "enable_partition";
  private static boolean enablePartition = config.isEnablePartition();

  private static final String TAG_ATTRIBUTE_SIZE_STRING = "tag_attribute_total_size";
  private static String tagAttributeTotalSize = String.valueOf(config.getTagAttributeTotalSize());

  private static final String TAG_ATTRIBUTE_FLUSH_INTERVAL = "tag_attribute_flush_interval";
  private static String tagAttributeFlushInterval =
      String.valueOf(config.getTagAttributeFlushInterval());

  private static final String MAX_DEGREE_OF_INDEX_STRING = "max_degree_of_index_node";
  private static String maxDegreeOfIndexNode =
      String.valueOf(TSFileDescriptor.getInstance().getConfig().getMaxDegreeOfIndexNode());

  private static final String VIRTUAL_STORAGE_GROUP_NUM = "virtual_storage_group_num";
  private static String virtualStorageGroupNum = String.valueOf(config.getVirtualStorageGroupNum());

  private static final String TIME_ENCODER_KEY = "time_encoder";
  private static String timeEncoderValue =
      String.valueOf(TSFileDescriptor.getInstance().getConfig().getTimeEncoder());

  private static final String IOTDB_VERSION_STRING = "iotdb_version";

  public static IoTDBConfigCheck getInstance() {
    return IoTDBConfigCheckHolder.INSTANCE;
  }

  private static class IoTDBConfigCheckHolder {

    private static final IoTDBConfigCheck INSTANCE = new IoTDBConfigCheck();
  }

  private IoTDBConfigCheck() {
    logger.info("Starting IoTDB " + IoTDBConstant.VERSION);

    // check whether SCHEMA_DIR exists, create if not exists
    File dir = SystemFileFactory.INSTANCE.getFile(SCHEMA_DIR);
    if (!dir.exists()) {
      if (!dir.mkdirs()) {
        logger.error("can not create schema dir: {}", SCHEMA_DIR);
        System.exit(-1);
      } else {
        logger.info(" {} dir has been created.", SCHEMA_DIR);
      }
    }

    // check time stamp precision
    if (!("ms".equals(timestampPrecision)
        || "us".equals(timestampPrecision)
        || "ns".equals(timestampPrecision))) {
      logger.error(
          "Wrong {}, please set as: ms, us or ns ! Current is: {}",
          TIMESTAMP_PRECISION_STRING,
          timestampPrecision);
      System.exit(-1);
    }

    if (!enablePartition) {
      partitionInterval = Long.MAX_VALUE;
    }

    // check partition interval
    if (partitionInterval <= 0) {
      logger.error("Partition interval must larger than 0!");
      System.exit(-1);
    }

    systemProperties.put(IOTDB_VERSION_STRING, IoTDBConstant.VERSION);
    systemProperties.put(TIMESTAMP_PRECISION_STRING, timestampPrecision);
    systemProperties.put(PARTITION_INTERVAL_STRING, String.valueOf(partitionInterval));
    systemProperties.put(TSFILE_FILE_SYSTEM_STRING, tsfileFileSystem);
    systemProperties.put(ENABLE_PARTITION_STRING, String.valueOf(enablePartition));
    systemProperties.put(TAG_ATTRIBUTE_SIZE_STRING, tagAttributeTotalSize);
    systemProperties.put(TAG_ATTRIBUTE_FLUSH_INTERVAL, tagAttributeFlushInterval);
    systemProperties.put(MAX_DEGREE_OF_INDEX_STRING, maxDegreeOfIndexNode);
    systemProperties.put(VIRTUAL_STORAGE_GROUP_NUM, virtualStorageGroupNum);
    systemProperties.put(TIME_ENCODER_KEY, timeEncoderValue);
  }

  /**
   * check configuration in system.properties when starting IoTDB
   *
   * <p>When init: create system.properties directly
   *
   * <p>When upgrading the system.properties: (1) create system.properties.tmp (2) delete
   * system.properties (3) rename system.properties.tmp to system.properties
   */
  public void checkConfig() throws ConfigurationException, IOException {
    propertiesFile =
        SystemFileFactory.INSTANCE.getFile(
            IoTDBConfigCheck.SCHEMA_DIR + File.separator + PROPERTIES_FILE_NAME);
    tmpPropertiesFile =
        SystemFileFactory.INSTANCE.getFile(
            IoTDBConfigCheck.SCHEMA_DIR + File.separator + PROPERTIES_FILE_NAME + ".tmp");

    // system init first time, no need to check, write system.properties and return
    if (!propertiesFile.exists() && !tmpPropertiesFile.exists()) {
      // create system.properties
      if (propertiesFile.createNewFile()) {
        logger.info(" {} has been created.", propertiesFile.getAbsolutePath());
      } else {
        logger.error("can not create {}", propertiesFile.getAbsolutePath());
        System.exit(-1);
      }

      // write properties to system.properties
      try (FileOutputStream outputStream = new FileOutputStream(propertiesFile)) {
        systemProperties.forEach((k, v) -> properties.setProperty(k, v));
        properties.store(outputStream, SYSTEM_PROPERTIES_STRING);
      }
      return;
    }

    if (!propertiesFile.exists() && tmpPropertiesFile.exists()) {
      // rename tmp file to system.properties, no need to check
      FileUtils.moveFile(tmpPropertiesFile, propertiesFile);
      logger.info("rename {} to {}", tmpPropertiesFile, propertiesFile);
      return;
    } else if (propertiesFile.exists() && tmpPropertiesFile.exists()) {
      // both files exist, remove tmp file
      FileUtils.forceDelete(tmpPropertiesFile);
      logger.info("remove {}", tmpPropertiesFile);
    }

    // no tmp file, read properties from system.properties
    try (FileInputStream inputStream = new FileInputStream(propertiesFile);
        InputStreamReader inputStreamReader =
            new InputStreamReader(inputStream, TSFileConfig.STRING_CHARSET)) {
      properties.load(inputStreamReader);
    }
    // check whether upgrading from <=v0.9
    if (!properties.containsKey(IOTDB_VERSION_STRING)) {
      logger.error(
          "DO NOT UPGRADE IoTDB from v0.9 or lower version to v0.12!"
              + " Please upgrade to v0.10 first");
      System.exit(-1);
    }
    // check whether upgrading from [v0.10, v.12]
    String versionString = properties.getProperty(IOTDB_VERSION_STRING);
    if (versionString.startsWith("0.10") || versionString.startsWith("0.11")) {
      logger.error("IoTDB version is too old, please upgrade to 0.12 firstly.");
      System.exit(-1);
    } else if (versionString.startsWith("0.12")) {
      checkWALNotExists();
      upgradePropertiesFile();
    }
    checkProperties();
  }

  private void checkWALNotExists() {
    if (SystemFileFactory.INSTANCE.getFile(WAL_DIR).isDirectory()) {
      File[] sgWALs = SystemFileFactory.INSTANCE.getFile(WAL_DIR).listFiles();
      if (sgWALs != null) {
        for (File sgWAL : sgWALs) {
          // make sure wal directory of each sg is empty
          if (sgWAL.isDirectory() && sgWAL.list().length != 0) {
            logger.error(
                "WAL detected, please stop insertion and run 'SET SYSTEM TO READONLY', then run 'flush' on IoTDB {} before upgrading to {}.",
                properties.getProperty(IOTDB_VERSION_STRING),
                IoTDBConstant.VERSION);
            System.exit(-1);
          }
        }
      }
    }
  }

  /** upgrade 0.12 properties to 0.13 properties */
  private void upgradePropertiesFile() throws IOException {
    // create an empty tmpPropertiesFile
    if (tmpPropertiesFile.createNewFile()) {
      logger.info("Create system.properties.tmp {}.", tmpPropertiesFile);
    } else {
      logger.error("Create system.properties.tmp {} failed.", tmpPropertiesFile);
      System.exit(-1);
    }

    try (FileOutputStream tmpFOS = new FileOutputStream(tmpPropertiesFile.toString())) {
      systemProperties.forEach(
          (k, v) -> {
            if (!properties.containsKey(k)) {
              properties.setProperty(k, v);
            }
          });
      properties.setProperty(IOTDB_VERSION_STRING, IoTDBConstant.VERSION);
      properties.store(tmpFOS, SYSTEM_PROPERTIES_STRING);

      // upgrade finished, delete old system.properties file
      if (propertiesFile.exists()) {
        Files.delete(propertiesFile.toPath());
      }
    }
    // rename system.properties.tmp to system.properties
    FileUtils.moveFile(tmpPropertiesFile, propertiesFile);
  }

  /** repair broken properties */
  private void upgradePropertiesFileFromBrokenFile() throws IOException {
    // create an empty tmpPropertiesFile
    if (tmpPropertiesFile.createNewFile()) {
      logger.info("Create system.properties.tmp {}.", tmpPropertiesFile);
    } else {
      logger.error("Create system.properties.tmp {} failed.", tmpPropertiesFile);
      System.exit(-1);
    }

    try (FileOutputStream tmpFOS = new FileOutputStream(tmpPropertiesFile.toString())) {
      systemProperties.forEach(
          (k, v) -> {
            if (!properties.containsKey(k)) {
              properties.setProperty(k, v);
            }
          });
      properties.setProperty(IOTDB_VERSION_STRING, IoTDBConstant.VERSION);
      properties.store(tmpFOS, SYSTEM_PROPERTIES_STRING);
      // upgrade finished, delete old system.properties file
      if (propertiesFile.exists()) {
        Files.delete(propertiesFile.toPath());
      }
    }
    // rename system.properties.tmp to system.properties
    FileUtils.moveFile(tmpPropertiesFile, propertiesFile);
  }

  /** Check all immutable properties */
  private void checkProperties() throws ConfigurationException, IOException {
    for (Entry<String, String> entry : systemProperties.entrySet()) {
      if (!properties.containsKey(entry.getKey())) {
        upgradePropertiesFileFromBrokenFile();
        logger.info("repair system.properties, lack {}", entry.getKey());
      }
    }

    if (!properties.getProperty(TIMESTAMP_PRECISION_STRING).equals(timestampPrecision)) {
      throwException(TIMESTAMP_PRECISION_STRING, timestampPrecision);
    }

    if (Boolean.parseBoolean(properties.getProperty(ENABLE_PARTITION_STRING)) != enablePartition) {
      throwException(ENABLE_PARTITION_STRING, enablePartition);
    }

    if (Long.parseLong(properties.getProperty(PARTITION_INTERVAL_STRING)) != partitionInterval) {
      throwException(PARTITION_INTERVAL_STRING, partitionInterval);
    }

    if (!(properties.getProperty(TSFILE_FILE_SYSTEM_STRING).equals(tsfileFileSystem))) {
      throwException(TSFILE_FILE_SYSTEM_STRING, tsfileFileSystem);
    }

    if (!(properties.getProperty(TAG_ATTRIBUTE_SIZE_STRING).equals(tagAttributeTotalSize))) {
      throwException(TAG_ATTRIBUTE_SIZE_STRING, tagAttributeTotalSize);
    }

    if (!(properties.getProperty(TAG_ATTRIBUTE_FLUSH_INTERVAL).equals(tagAttributeFlushInterval))) {
      throwException(TAG_ATTRIBUTE_FLUSH_INTERVAL, tagAttributeFlushInterval);
    }

    if (!(properties.getProperty(MAX_DEGREE_OF_INDEX_STRING).equals(maxDegreeOfIndexNode))) {
      throwException(MAX_DEGREE_OF_INDEX_STRING, maxDegreeOfIndexNode);
    }

    if (!(properties.getProperty(VIRTUAL_STORAGE_GROUP_NUM).equals(virtualStorageGroupNum))) {
      throwException(VIRTUAL_STORAGE_GROUP_NUM, virtualStorageGroupNum);
    }

    if (!(properties.getProperty(TIME_ENCODER_KEY).equals(timeEncoderValue))) {
      throwException(TIME_ENCODER_KEY, timeEncoderValue);
    }
  }

  private void throwException(String parameter, Object badValue) throws ConfigurationException {
    throw new ConfigurationException(
        parameter, String.valueOf(badValue), properties.getProperty(parameter));
  }
}
