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Provides a UI for db-scheduler
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/*
 * Copyright (C) Bekk
 *
 * 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 no.bekk.dbscheduler.ui.util;

import static java.util.Optional.empty;
import static java.util.stream.Collectors.joining;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;

public class QueryBuilder {

  private final String tableName;
  private final String databaseProductName;

  private final List andConditions = new ArrayList<>();

  private Optional orderBy = empty();
  private int limit;

  QueryBuilder(String tableName, String databaseProductName) {
    this.tableName = tableName;
    this.databaseProductName = databaseProductName;
  }

  public static QueryBuilder selectFromTable(String tableName, String databaseProductName) {
    return new QueryBuilder(tableName, databaseProductName);
  }

  public QueryBuilder andCondition(AndCondition andCondition) {
    andConditions.add(andCondition);
    return this;
  }

  public QueryBuilder orderBy(String orderBy) {
    this.orderBy = Optional.of(orderBy);
    return this;
  }

  public String getQuery() {
    StringBuilder s = new StringBuilder();
    s.append("SELECT");

    if (limit > 0 && databaseProductName.equals("Microsoft SQL Server")) {
      s.append(" TOP ").append(limit);
    }

    s.append(" * FROM ").append(tableName);

    if (!andConditions.isEmpty()) {
      s.append(" WHERE ");
      s.append(andConditions.stream().map(AndCondition::getQueryPart).collect(joining(" AND ")));
    }

    orderBy.ifPresent(o -> s.append(" ORDER BY ").append(o));

    if (limit > 0) {
      if (databaseProductName.equals("Oracle")) {
        s.append(" FETCH NEXT ").append(limit).append(" ROWS ONLY");
      } else if (!databaseProductName.equals("Microsoft SQL Server")) {
        s.append(" LIMIT ").append(limit);
      }
    }

    return s.toString();
  }

  public MapSqlParameterSource getParameters() {
    MapSqlParameterSource parameterSource = new MapSqlParameterSource();
    andConditions.forEach(c -> c.setParameters(parameterSource));
    return parameterSource;
  }

  public void limit(int logLimit) {
    this.limit = logLimit;
  }
}