/*
    * Copyright 2021 TiKV Project Authors.
    *
    * Licensed 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.tikv.common.key;
  
  import com.google.common.base.Joiner;
  import java.util.List;
  import org.tikv.common.codec.Codec.IntegerCodec;
  import org.tikv.common.codec.CodecDataOutput;
  import org.tikv.common.exception.TypeException;
  import org.tikv.common.meta.TiIndexColumn;
  import org.tikv.common.meta.TiTableInfo;
  import org.tikv.common.row.Row;
  import org.tikv.common.types.DataType;
  import org.tikv.common.types.IntegerType;
  
  public class IndexKey extends Key {
    private static final byte[] IDX_PREFIX_SEP = new byte[] {'_', 'i'};
  
    private final long tableId;
    private final long indexId;
    private final Key[] dataKeys;
  
    private IndexKey(long tableId, long indexId, Key[] dataKeys) {
      super(encode(tableId, indexId, dataKeys));
      this.tableId = tableId;
      this.indexId = indexId;
      this.dataKeys = dataKeys;
    }
  
    public static class EncodeIndexDataResult {
      public EncodeIndexDataResult(Key[] keys, boolean appendHandle) {
        this.keys = keys;
        this.appendHandle = appendHandle;
      }
  
      public Key[] keys;
      public boolean appendHandle;
    }
  
    public static IndexKey toIndexKey(long tableId, long indexId, Key... dataKeys) {
      return new IndexKey(tableId, indexId, dataKeys);
    }
  
    public static EncodeIndexDataResult encodeIndexDataValues(
        Row row,
        List<TiIndexColumn> indexColumns,
        long handle,
        boolean appendHandleIfContainsNull,
        TiTableInfo tableInfo) {
      // when appendHandleIfContainsNull is true, append handle column if any of the index column is
      // NULL
      boolean appendHandle = false;
      if (appendHandleIfContainsNull) {
        for (TiIndexColumn col : indexColumns) {
          DataType colTp = tableInfo.getColumn(col.getOffset()).getType();
          if (row.get(col.getOffset(), colTp) == null) {
            appendHandle = true;
            break;
          }
        }
      }
      Key[] keys = new Key[indexColumns.size() + (appendHandle ? 1 : 0)];
      for (int i = 0; i < indexColumns.size(); i++) {
        TiIndexColumn col = indexColumns.get(i);
        DataType colTp = tableInfo.getColumn(col.getOffset()).getType();
        // truncate index's if necessary
        Key key =
            org.tikv.common.key.TypedKey.toTypedKey(
                row.get(col.getOffset(), colTp), colTp, (int) col.getLength());
        keys[i] = key;
      }
      if (appendHandle) {
        Key key = org.tikv.common.key.TypedKey.toTypedKey(handle, IntegerType.BIGINT);
        keys[keys.length - 1] = key;
      }
  
      return new EncodeIndexDataResult(keys, appendHandle);
    }
  
    private static byte[] encode(long tableId, long indexId, Key[] dataKeys) {
      CodecDataOutput cdo = new CodecDataOutput();
      cdo.write(TBL_PREFIX);
      IntegerCodec.writeLong(cdo, tableId);
      cdo.write(IDX_PREFIX_SEP);
     IntegerCodec.writeLong(cdo, indexId);
     for (Key key : dataKeys) {
       if (key == null) {
         throw new TypeException("key cannot be null");
       }
       cdo.write(key.getBytes());
     }
     return cdo.toBytes();
   }
 
   public long getTableId() {
     return tableId;
   }
 
   public long getIndexId() {
     return indexId;
   }
 
   public Key[] getDataKeys() {
     return dataKeys;
   }
 
   @Override
   public String toString() {
     return String.format("[%s]", Joiner.on(",").useForNull("null").join(dataKeys));
   }
 }