/*
Copyright (c) 2008 Health Market Science, Inc.

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 com.healthmarketscience.jackcess.impl.query;

import java.util.List;

import static com.healthmarketscience.jackcess.impl.query.QueryFormat.*;
import com.healthmarketscience.jackcess.query.BaseSelectQuery;


/**
 * Base class for queries which represent some form of SELECT statement.
 * 
 * @author James Ahlborn
 */
public abstract class BaseSelectQueryImpl extends QueryImpl 
  implements BaseSelectQuery
{

  protected BaseSelectQueryImpl(String name, List<Row> rows, int objectId, 
                                int objectFlag, Type type) {
    super(name, rows, objectId, objectFlag, type);
  }

  protected void toSQLSelectString(StringBuilder builder,
                                   boolean useSelectPrefix) 
  {
    if(useSelectPrefix) {
      builder.append("SELECT ");
      String selectType = getSelectType();
      if(!DEFAULT_TYPE.equals(selectType)) {
        builder.append(selectType).append(' ');
      }
    }

    builder.append(getSelectColumns());
    toSelectInto(builder);

    List<String> fromTables = getFromTables();
    if(!fromTables.isEmpty()) {
      builder.append(NEWLINE).append("FROM ").append(fromTables);
      toRemoteDb(builder, getFromRemoteDbPath(), getFromRemoteDbType());
    }

    String whereExpr = getWhereExpression();
    if(whereExpr != null) {
      builder.append(NEWLINE).append("WHERE ").append(whereExpr);
    }

    List<String> groupings = getGroupings();
    if(!groupings.isEmpty()) {
      builder.append(NEWLINE).append("GROUP BY ").append(groupings);
    }

    String havingExpr = getHavingExpression();
    if(havingExpr != null) {
      builder.append(NEWLINE).append("HAVING ").append(havingExpr);
    }

    List<String> orderings = getOrderings();
    if(!orderings.isEmpty()) {
      builder.append(NEWLINE).append("ORDER BY ").append(orderings);
    }
  }

  public String getSelectType()
  {
    if(hasFlag(DISTINCT_SELECT_TYPE)) {
      return "DISTINCT";
    }

    if(hasFlag(DISTINCT_ROW_SELECT_TYPE)) {
      return "DISTINCTROW";
    }

    if(hasFlag(TOP_SELECT_TYPE)) {
      StringBuilder builder = new StringBuilder();
      builder.append("TOP ").append(getFlagRow().name1);
      if(hasFlag(PERCENT_SELECT_TYPE)) {
        builder.append(" PERCENT");
      }
      return builder.toString();
    }

    return DEFAULT_TYPE;
  }

  public List<String> getSelectColumns() 
  {
    List<String> result = (new RowFormatter(getColumnRows()) {
        @Override protected void format(StringBuilder builder, Row row) {
          // note column expression are always quoted appropriately
          builder.append(row.expression);
          toAlias(builder, row.name1);
        }
      }).format();
    if(hasFlag(SELECT_STAR_SELECT_TYPE)) {
      result.add("*");
    }
    return result;
  }

  protected void toSelectInto(StringBuilder builder)
  {
    // base does nothing
  }

  @Override
  public List<String> getFromTables() 
  {
    return super.getFromTables();
  }

  @Override
  public String getFromRemoteDbPath() 
  {
    return super.getFromRemoteDbPath();
  }

  @Override
  public String getFromRemoteDbType() 
  {
    return super.getFromRemoteDbType();
  }

  @Override
  public String getWhereExpression()
  {
    return super.getWhereExpression();
  }

  public List<String> getGroupings() 
  {
    return (new RowFormatter(getGroupByRows()) {
        @Override protected void format(StringBuilder builder, Row row) {
          builder.append(row.expression);
        }
      }).format();
  }

  public String getHavingExpression()
  {
    return getHavingRow().expression;
  }

  @Override
  public List<String> getOrderings() 
  {
    return super.getOrderings();
  }
  
}