/**
 * NOTE: This copyright does *not* cover user programs that use HQ
 * program services by normal system calls through the application
 * program interfaces provided as part of the Hyperic Plug-in Development
 * Kit or the Hyperic Client Development Kit - this is merely considered
 * normal use of the program, and does *not* fall under the heading of
 *  "derived work".
 *
 *  Copyright (C) [2009-2010], VMware, Inc.
 *  This file is part of HQ.
 *
 *  HQ is free software; you can redistribute it and/or modify
 *  it under the terms version 2 of the GNU General Public License as
 *  published by the Free Software Foundation. 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 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 *
 */

package org.hyperic.hq.events.server.session;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hyperic.hq.bizapp.server.shared.HeartbeatCurrentTime;
import org.hyperic.hq.events.EventConstants;
import org.hyperic.hq.zevents.ZeventEnqueuer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * Default implementation of {@link AlertConditionEvaluatorFactory}
 * @author jhickey
 * 
 */
@Component
public class AlertConditionEvaluatorFactoryImpl implements AlertConditionEvaluatorFactory {

    private final ZeventEnqueuer zeventEnqueuer;
    
    private final Log log = LogFactory.getLog(AlertConditionEvaluatorFactoryImpl.class);

    /**
     * 
     * @param zeventEnqueuer The {@link ZeventEnqueuer} to pass to created
     *        {@link AlertConditionEvaluator}s
     */
    @Autowired
    public AlertConditionEvaluatorFactoryImpl(ZeventEnqueuer zeventEnqueuer)
    {
        this.zeventEnqueuer = zeventEnqueuer;
    }

    public AlertConditionEvaluator create(AlertDefinition alertDefinition) {
        // range doesn't get reset to 0 if switching from counter freq to
        // everytime. Pass in 0 if not counter freq just to be on the safe side
        long range = 0;
        if (alertDefinition.getFrequencyType() == EventConstants.FREQ_COUNTER) {
            range = alertDefinition.getRange() * 1000l;
        }
        AlertConditionEvaluator evaluator;
        if (alertDefinition.isRecoveryDefinition()) {
            Integer alertTriggerId = Integer.valueOf(0);
            Integer recoveringFromAlertDefId = Integer.valueOf(0);
            List<AlertCondition> conditions = new ArrayList<AlertCondition>();
            for (AlertCondition condition: alertDefinition.getConditions()) {
                if (condition.getType() == EventConstants.TYPE_ALERT) {
                    alertTriggerId = condition.getTrigger().getId();
                    recoveringFromAlertDefId = Integer.valueOf(condition.getMeasurementId());
                } else {
                    conditions.add(condition);
                }
            }
            evaluator = new RecoveryConditionEvaluator(alertDefinition.getId(),
                                                       alertTriggerId, recoveringFromAlertDefId,
                                                       conditions,
                                                       createExecutionStrategy(alertDefinition));
        } else if (alertDefinition.getConditions().size() > 1) {
            evaluator = new MultiConditionEvaluator(alertDefinition.getId(),
                                                    alertDefinition.getConditions(),
                                                    range,
                                                    createExecutionStrategy(alertDefinition));
        } else {
            evaluator = new SingleConditionEvaluator(alertDefinition.getId(), createExecutionStrategy(alertDefinition));
        }
      
        return evaluator;
    }

    private ExecutionStrategy createExecutionStrategy(AlertDefinition alertDefinition) {
        ExecutionStrategy executionStrategy;
        if (alertDefinition.getFrequencyType() == EventConstants.FREQ_EVERYTIME ||
            alertDefinition.getFrequencyType() == EventConstants.FREQ_ONCE)
        {
            executionStrategy = new SingleAlertExecutionStrategy(zeventEnqueuer);
        } else if (alertDefinition.getFrequencyType() == EventConstants.FREQ_COUNTER) {
            executionStrategy = new CounterExecutionStrategy(alertDefinition.getCount(),
                                                             alertDefinition.getRange() * 1000l,
                                                             zeventEnqueuer,
                                                             new HeartbeatCurrentTime() {
                                                                public long getTimeMillis() {
                                                                    return System.currentTimeMillis();
                                                                }
                                                            });
        } else {
            log.warn("Encountered an alert with unsupported frequency type: " + alertDefinition.getFrequencyType() +
                     ".  This alert will be treated as frequency type everytime.");
            executionStrategy = new SingleAlertExecutionStrategy(zeventEnqueuer);
        }
        return executionStrategy;
    }
}