/*
   Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

package com.mysql.clusterj.core.query;


import com.mysql.clusterj.ClusterJUserException;
import com.mysql.clusterj.Results;
import com.mysql.clusterj.core.*;
import com.mysql.clusterj.Query;
import com.mysql.clusterj.core.util.I18NHelper;
import com.mysql.clusterj.core.util.Logger;
import com.mysql.clusterj.core.util.LoggerFactoryService;

import java.util.List;
import java.util.Map;

public class QueryImpl<E> implements Query<E> {

    /** My message translator */
    static final I18NHelper local = I18NHelper.getInstance(BetweenPredicateImpl.class);

    /** My logger */
    static final Logger logger = LoggerFactoryService.getFactory().getInstance(BetweenPredicateImpl.class);

    /** My session. */
    protected SessionImpl session;

    /** My DomainObject */
    protected QueryDomainTypeImpl<E> dobj;

    /** My query execution context. */
    protected QueryExecutionContextImpl context = null;

    /** The number to skip */
    protected long skip = 0;

    /** The limit */
    protected long limit = Long.MAX_VALUE;

    /** The order */
    protected Query.Ordering ordering = null;

    /** The ordering fields */
    protected String[] orderingFields = null;

    public QueryImpl(SessionImpl session, QueryDomainTypeImpl<E> dobj) {
        this.session = session;
        context = new QueryExecutionContextImpl(session);
        this.dobj = dobj;
    }

    /**
     * Set limits on results to return. The execution of the query is
     * modified to return only a subset of results. If the filter would
     * normally return 100 instances, skip is set to 50, and
     * limit is set to 40, then the first 50 results that would have 
     * been returned are skipped, the next 40 results are returned and the
     * remaining 10 results are ignored.
     * <p>
     * Skip must be greater than or equal to 0. Limit must be greater than or equal to 0.
     * Limits may not be used with deletePersistentAll.
     * <p>
     * The limits as specified by the user are converted here into an internal form
     * where the limit is the last record to deliver instead of the number of records
     * to deliver. So if the user specifies limits of (10, 20) we convert this 
     * to limits of (10, 30) for the lower layers of the implementation.
     * @param skip the number of results to skip
     * @param limit the number of results to return after skipping;
     * use Long.MAX_VALUE for no limit.
     */
    public void setLimits(long skip, long limit) {
        if (skip < 0 || limit < 0) {
            throw new ClusterJUserException(local.message("ERR_Invalid_Limits", skip, limit));
        }
        this.skip = skip;
        if (Long.MAX_VALUE - skip < limit) {
            limit = Long.MAX_VALUE;
        } else {
            this.limit = limit + skip;
        }
    }

    /** Set ordering for this query. Verify that the ordering fields exist in the domain type.
     * @param ordering the ordering for the query
     * @param orderingFields the list of fields to order by
     */
    public void setOrdering(com.mysql.clusterj.Query.Ordering ordering,
            String... orderingFields) {
        this.ordering = ordering;
        this.orderingFields = orderingFields;
        // verify that all ordering fields actually are fields
        StringBuilder builder = new StringBuilder();
        String separator = "";
        for (String orderingField : orderingFields) {
            try {
                dobj.get(orderingField);
            } catch (ClusterJUserException ex) {
                builder.append(separator);
                builder.append(orderingField);
                separator = ", ";
            }
        }
        String errors = builder.toString();
        if (errors.length() > 0) {
            throw new ClusterJUserException(local.message("ERR_Ordering_Field_Does_Not_Exist", errors));
        }
    }

    public Results<E> execute(Object arg0) {
            throw new UnsupportedOperationException(
                    local.message("ERR_NotImplemented"));
    }

    public Results<E> execute(Object... arg0) {
            throw new UnsupportedOperationException(
                    local.message("ERR_NotImplemented"));
    }

    public Results<E> execute(Map<String, ?> arg0) {
            throw new UnsupportedOperationException(
                    local.message("ERR_NotImplemented"));
    }

    public void setParameter(String parameterName, Object parameterValue) {
        context.bindParameterValue(parameterName, parameterValue);
    }

    public List<E> getResultList() {
        List<E> results = dobj.getResultList(context, skip, limit, ordering, orderingFields);
        // create new context, copying the parameters, for another execution
        context = new QueryExecutionContextImpl(context);
        return results;
    }

    /** Delete the instances that satisfy the query criteria.
     * @return the number of instances deleted
     */
    public int deletePersistentAll() {
        if (skip != 0 || limit != Long.MAX_VALUE) {
            throw new ClusterJUserException(local.message("ERR_Invalid_Limits", skip, limit));
        }
        int result = dobj.deletePersistentAll(context);
        return result;
    }

    /**
     * Explain this query.
     * @return the data about the execution of this query
     */
    public Map<String, Object> explain() {
        Map<String, Object> result = context.getExplain();
        if (result == null) {
            dobj.explain(context);
            return context.getExplain();
        }
        return result;
    }

}
