/*
 * Copyright (c) 2011-2015 EPFL DATA Laboratory
 * Copyright (c) 2014-2015 The Squall Collaboration (see NOTICE)
 *
 * All rights reserved.
 *
 * 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 ch.epfl.data.squall.api.sql.optimizers.name;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import ch.epfl.data.squall.api.sql.optimizers.Optimizer;
import ch.epfl.data.squall.api.sql.util.ParserUtil;
import ch.epfl.data.squall.api.sql.visitors.jsql.SQLVisitor;
import ch.epfl.data.squall.components.Component;
import ch.epfl.data.squall.query_plans.QueryBuilder;
import ch.epfl.data.squall.utilities.SystemParameters;

/*
 * For lefty plans with explicitly specified parallelism
 */
public class NameManualParOptimizer implements Optimizer {
    private final Map _map;
    private final SQLVisitor _pq;

    private final List<String> _compNames = new ArrayList<String>(); // all the
    // sources in
    // the
    // appropriate
    // order
    private final Map<String, Integer> _compNamePar = new HashMap<String, Integer>(); // all

    // components(including
    // joins)
    // with
    // its
    // parallelism

    public NameManualParOptimizer(Map map) {
	_map = map;
	_pq = ParserUtil.parseQuery(map);

	try {
	    parse();
	} catch (final ArrayIndexOutOfBoundsException a) {
	    throw new RuntimeException(
		    "Invalid DIP_PLAN setting in config file!");
	}
    }

    @Override
    public QueryBuilder generate() {
	final NameCompGenFactory factory = new NameCompGenFactory(_map,
		_pq.getTan());
	final NameCompGen ncg = factory.create();

	Component first = ncg.generateDataSource(_compNames.get(0));
	for (int i = 1; i < _compNames.size(); i++) {
	    final Component second = ncg.generateDataSource(_compNames.get(i));
	    first = ncg.generateEquiJoin(first, second);
	}

	ParserUtil.parallelismToMap(_compNamePar, _map);

	return ncg.getQueryBuilder();
    }

    // HELPER methods
    private void parse() {
	final String plan = SystemParameters.getString(_map, "DIP_PLAN");
	final String[] components = plan.split(",");

	final String firstComponent = components[0];
	final String[] firstParts = firstComponent.split(":");
	String firstCompName = firstParts[0];
	final int firstParallelism = Integer.valueOf(firstParts[1]);

	putSource(firstCompName, firstParallelism);

	for (int i = 1; i < components.length; i++) {
	    final String secondComponent = components[i];
	    final String[] secondParts = secondComponent.split(":");
	    final String secondCompName = secondParts[0];
	    final int secondPar = Integer.valueOf(secondParts[1]);
	    final int secondJoinPar = Integer.valueOf(secondParts[2]);
	    putSource(secondCompName, secondPar);
	    final String joinCompName = firstCompName + "_" + secondCompName;
	    putJoin(joinCompName, secondJoinPar);
	    firstCompName = joinCompName;
	}
    }

    private void putJoin(String compName, int par) {
	_compNamePar.put(compName, par);
    }

    private void putSource(String compName, int par) {
	_compNames.add(compName);
	_compNamePar.put(compName, par);
    }

}