package com.avaje.ebeaninternal.server.query;

import javax.persistence.PersistenceException;

import com.avaje.ebean.config.dbplatform.DatabasePlatform;
import com.avaje.ebean.config.dbplatform.SqlLimitResponse;
import com.avaje.ebean.config.dbplatform.SqlLimiter;
import com.avaje.ebeaninternal.api.SpiQuery;
import com.avaje.ebeaninternal.server.core.OrmQueryRequest;
import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
import com.avaje.ebeaninternal.server.deploy.DRawSqlSelect;
import com.avaje.ebeaninternal.server.deploy.DeployNamedQuery;
import com.avaje.ebeaninternal.server.deploy.DeployParser;
import com.avaje.ebeaninternal.server.persist.Binder;
import com.avaje.ebeaninternal.server.querydefn.OrmQueryLimitRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Factory for SqlSelectClause based on raw sql.
 * <p>
 * Its job is to execute the sql, read the meta data to determine the columns to
 * bean property mapping.
 * </p>
 */
public class RawSqlSelectClauseBuilder {

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

  private final Binder binder;

  private final SqlLimiter dbQueryLimiter;
  private final DatabasePlatform dbPlatform;

  public RawSqlSelectClauseBuilder(DatabasePlatform dbPlatform, Binder binder) {

    this.binder = binder;
    this.dbQueryLimiter = dbPlatform.getSqlLimiter();
    this.dbPlatform = dbPlatform;
  }

  /**
   * Build based on the includes and using the BeanJoinTree.
   */
  public <T> CQuery<T> build(OrmQueryRequest<T> request) throws PersistenceException {

    SpiQuery<T> query = request.getQuery();
    BeanDescriptor<T> desc = request.getBeanDescriptor();

    DeployNamedQuery namedQuery = desc.getNamedQuery(query.getName());
    DRawSqlSelect sqlSelect = namedQuery.getSqlSelect();

    // create a parser for this specific SqlSelect... has to be really
    // as each SqlSelect could have different table alias etc
    DeployParser parser = sqlSelect.createDeployPropertyParser();

    CQueryPredicates predicates = new CQueryPredicates(binder, request);
    // prepare and convert logical property names to dbColumns etc
    predicates.prepareRawSql(parser);

    SqlTreeAlias alias = new SqlTreeAlias(sqlSelect.getTableAlias());
    predicates.parseTableAlias(alias);

    String sql = null;
    try {

      boolean includeRowNumColumn = false;
      String orderBy = sqlSelect.getOrderBy(predicates);

      // build the actual sql String
      sql = sqlSelect.buildSql(orderBy, predicates, request);
      if (query.hasMaxRowsOrFirstRow() && dbQueryLimiter != null) {
        // wrap with a limit offset or ROW_NUMBER() etc
        SqlLimitResponse limitSql = dbQueryLimiter.limit(new OrmQueryLimitRequest(sql, orderBy, query, dbPlatform));
        includeRowNumColumn = limitSql.isIncludesRowNumberColumn();

        sql = limitSql.getSql();
      } else {
        // add back select keyword
        // ... was removed to support dbQueryLimiter
        sql = "select " + sql;
      }

      SqlTree sqlTree = sqlSelect.getSqlTree();

      CQueryPlan queryPlan = new CQueryPlan(request, sql, sqlTree, true, includeRowNumColumn, "");
      return new CQuery<T>(request, predicates, queryPlan);

    } catch (Exception e) {

      String msg = "Error with " + desc.getFullName() + " query:\r" + sql;
      logger.error(msg);
      throw new PersistenceException(e);
    }
  }

}