/*
 * 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
 *
 *   https://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.accumulo.manager.tableOps.tableImport;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.apache.accumulo.core.Constants.IMPORT_MAPPINGS_FILE;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;

import org.apache.accumulo.core.clientImpl.AcceptableThriftTableOperationException;
import org.apache.accumulo.core.clientImpl.thrift.TableOperation;
import org.apache.accumulo.core.clientImpl.thrift.TableOperationExceptionType;
import org.apache.accumulo.core.fate.FateId;
import org.apache.accumulo.core.fate.Repo;
import org.apache.accumulo.core.file.FileOperations;
import org.apache.accumulo.core.file.FilePrefix;
import org.apache.accumulo.manager.Manager;
import org.apache.accumulo.manager.tableOps.ManagerRepo;
import org.apache.accumulo.server.fs.VolumeManager;
import org.apache.accumulo.server.tablets.UniqueNameAllocator;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.Path;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

class MapImportFileNames extends ManagerRepo {
  private static final Logger log = LoggerFactory.getLogger(MapImportFileNames.class);

  private static final long serialVersionUID = 1L;

  private final ImportedTableInfo tableInfo;

  MapImportFileNames(ImportedTableInfo ti) {
    this.tableInfo = ti;
  }

  @Override
  public Repo<Manager> call(FateId fateId, Manager environment) throws Exception {

    for (ImportedTableInfo.DirectoryMapping dm : tableInfo.directories) {
      Path path = new Path(dm.importDir, IMPORT_MAPPINGS_FILE);

      BufferedWriter mappingsWriter = null;

      try {
        VolumeManager fs = environment.getVolumeManager();

        fs.mkdirs(new Path(dm.importDir));

        FileStatus[] files = fs.listStatus(new Path(dm.exportDir));

        UniqueNameAllocator namer = environment.getContext().getUniqueNameAllocator();

        mappingsWriter = new BufferedWriter(new OutputStreamWriter(fs.create(path), UTF_8));

        var names = namer.getNextNames(files.length);
        for (FileStatus fileStatus : files) {
          String fileName = fileStatus.getPath().getName();
          log.info("filename " + fileStatus.getPath());
          String[] sa = fileName.split("\\.");
          String extension = "";
          if (sa.length > 1) {
            extension = sa[sa.length - 1];

            // skip files with unknown extensions
            if (!FileOperations.getValidExtensions().contains(extension)) {
              continue;
            }
          } else {
            // skip files without an extension
            continue;
          }

          String newName = FilePrefix.BULK_IMPORT.createFileName(names.next() + "." + extension);

          mappingsWriter.append(fileName);
          mappingsWriter.append(':');
          mappingsWriter.append(newName);
          mappingsWriter.newLine();
        }

        mappingsWriter.close();
        mappingsWriter = null;
      } catch (IOException ioe) {
        log.warn("{}", ioe.getMessage(), ioe);
        throw new AcceptableThriftTableOperationException(tableInfo.tableId.canonical(),
            tableInfo.tableName, TableOperation.IMPORT, TableOperationExceptionType.OTHER,
            "Error writing mapping file " + path + " " + ioe.getMessage());
      } finally {
        if (mappingsWriter != null) {
          try {
            mappingsWriter.close();
          } catch (IOException ioe) {
            log.warn("Failed to close " + path, ioe);
          }
        }
      }
    }

    return new PopulateMetadataTable(tableInfo);
  }

  @Override
  public void undo(FateId fateId, Manager env) throws Exception {
    // TODO: will this be OK for partially complete operations?
    for (ImportedTableInfo.DirectoryMapping dm : tableInfo.directories) {
      env.getVolumeManager().deleteRecursively(new Path(dm.importDir));
    }
  }
}
