/**
 *  Copyright (C) 2011 Cloud.com, Inc.  All rights reserved.
 */

package com.cloud.secstorage;

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

import javax.ejb.Local;
import javax.naming.ConfigurationException;

import org.apache.log4j.Logger;

import com.cloud.agent.api.Command;
import com.cloud.configuration.Config;
import com.cloud.host.HostVO;
import com.cloud.host.Status;
import com.cloud.host.dao.HostDao;
import com.cloud.resource.ResourceManager;
import com.cloud.storage.secondary.SecondaryStorageManagerImpl;
import com.cloud.storage.secondary.SecondaryStorageVmManager;
import com.cloud.utils.DateUtil;
import com.cloud.utils.NumbersUtil;
import com.cloud.utils.Pair;
import com.cloud.utils.component.Inject;
import com.cloud.utils.db.JoinBuilder.JoinType;
import com.cloud.utils.db.SearchBuilder;
import com.cloud.utils.db.SearchCriteria;
import com.cloud.utils.db.SearchCriteria.Op;
import com.cloud.vm.SecondaryStorageVm;
import com.cloud.vm.SecondaryStorageVmVO;
import com.cloud.vm.SystemVmLoadScanner.AfterScanAction;
import com.cloud.vm.VirtualMachine.State;
import com.cloud.vm.dao.SecondaryStorageVmDao;

@Local(value = { SecondaryStorageVmManager.class })
public class PremiumSecondaryStorageManagerImpl extends SecondaryStorageManagerImpl {
    private static final Logger s_logger = Logger.getLogger(PremiumSecondaryStorageManagerImpl.class);

    private int _capacityPerSSVM = SecondaryStorageVmManager.DEFAULT_SS_VM_CAPACITY;
    private int _standbyCapacity = SecondaryStorageVmManager.DEFAULT_STANDBY_CAPACITY;
    private int _maxExecutionTimeMs = 1800000;
    
    @Inject SecondaryStorageVmDao _secStorageVmDao;
    @Inject CommandExecLogDao _cmdExecLogDao;
    @Inject HostDao _hostDao;
    @Inject ResourceManager _resourceMgr;
    protected SearchBuilder<CommandExecLogVO> ActiveCommandSearch;
    protected SearchBuilder<HostVO> HostSearch;
    
    @Override
    public boolean configure(String name, Map<String, Object> params) throws ConfigurationException {
    	super.configure(name, params);
    	
    	_capacityPerSSVM = NumbersUtil.parseInt(_configDao.getValue(Config.SecStorageSessionMax.key()), DEFAULT_SS_VM_CAPACITY);
        _standbyCapacity = NumbersUtil.parseInt(_configDao.getValue(Config.SecStorageCapacityStandby.key()), DEFAULT_STANDBY_CAPACITY);
    	
        int nMaxExecutionMinutes = NumbersUtil.parseInt(_configDao.getValue(Config.SecStorageCmdExecutionTimeMax.key()), 30);
        _maxExecutionTimeMs = nMaxExecutionMinutes*60*1000;

		HostSearch = _hostDao.createSearchBuilder();
		HostSearch.and("dc", HostSearch.entity().getDataCenterId(), Op.EQ);
		HostSearch.and("status", HostSearch.entity().getStatus(), Op.EQ);
		
		ActiveCommandSearch = _cmdExecLogDao.createSearchBuilder();
		ActiveCommandSearch.and("created", ActiveCommandSearch.entity().getCreated(), Op.GTEQ);
		ActiveCommandSearch.join("hostSearch", HostSearch, ActiveCommandSearch.entity().getInstanceId(), HostSearch.entity().getId(), JoinType.INNER);

		HostSearch.done();
		ActiveCommandSearch.done();
    	return true;
    }
    
    @Override
	public Pair<AfterScanAction, Object> scanPool(Long pool) {
		long dataCenterId = pool.longValue();
		Date cutTime = new Date(DateUtil.currentGMTTime().getTime() - _maxExecutionTimeMs);

		_cmdExecLogDao.expungeExpiredRecords(cutTime);
		
		boolean suspendAutoLoading = !reserveStandbyCapacity();
		if(!suspendAutoLoading) {
	        // this is a hacking, has nothing to do with console proxy, it is just a flag that primary storage is being under maintenance mode
	        String restart = _configDao.getValue("consoleproxy.restart");
	        if (restart != null && restart.equalsIgnoreCase("false")) {
	            s_logger.debug("Capacity scan disabled purposefully, consoleproxy.restart = false. This happens when the primarystorage is in maintenance mode");
	            suspendAutoLoading = true;
	        }
		}
		
        List<SecondaryStorageVmVO> alreadyRunning = _secStorageVmDao.getSecStorageVmListInStates(SecondaryStorageVm.Role.templateProcessor, dataCenterId, State.Running,
                State.Migrating, State.Starting);
        if (alreadyRunning.size() == 0) {
            s_logger.info("No running secondary storage vms found in datacenter id=" + dataCenterId + ", starting one");
            
            List<SecondaryStorageVmVO> stopped = _secStorageVmDao.getSecStorageVmListInStates(SecondaryStorageVm.Role.templateProcessor, dataCenterId, State.Stopped,
                    State.Stopping);
            if(stopped.size() == 0 || !suspendAutoLoading) {
                List<SecondaryStorageVmVO> stopping = _secStorageVmDao.getSecStorageVmListInStates(SecondaryStorageVm.Role.templateProcessor,  State.Stopping);
                if(stopping.size() > 0) {
                	s_logger.info("Found SSVMs that are currently at stopping state, wait until they are settled");
    	            return new Pair<AfterScanAction, Object>(AfterScanAction.nop, null);
                }
            	
            	expandPool(pool, SecondaryStorageVm.Role.templateProcessor);
            }
        }
        
        if(!suspendAutoLoading) {
        	// this is to avoid surprises that people may accidently see two SSVMs being launched, capacity expanding only happens when we have at least the primary SSVM is up
	        if(alreadyRunning.size() == 0) {
	        	s_logger.info("Primary secondary storage is not even started, wait until next turn");
	            return new Pair<AfterScanAction, Object>(AfterScanAction.nop, null);
	        }

        	alreadyRunning = _secStorageVmDao.getSecStorageVmListInStates(null, dataCenterId, State.Running,
	                State.Migrating, State.Starting);
	
	        List<CommandExecLogVO> activeCmds = listActiveCommands(dataCenterId, cutTime);
	        if(alreadyRunning.size()*_capacityPerSSVM - activeCmds.size() < _standbyCapacity) {
	            s_logger.info("secondary storage command execution standby capactiy low (running VMs: " + alreadyRunning.size() + ", active cmds: " + activeCmds.size() + "), starting a new one");
	        	return new Pair<AfterScanAction, Object>(AfterScanAction.expand, SecondaryStorageVm.Role.commandExecutor);
	        }
        }
        
        return new Pair<AfterScanAction, Object>(AfterScanAction.nop, null);
	}

    @Override
	public Pair<HostVO, SecondaryStorageVmVO> assignSecStorageVm(long zoneId, Command cmd) {
		
		// TODO, need performance optimization
		List<Long> vms = _secStorageVmDao.listRunningSecStorageOrderByLoad(null, zoneId);
		for(Long vmId : vms) {
			SecondaryStorageVmVO secStorageVm = _secStorageVmDao.findById(vmId);
			HostVO host;
			host = _resourceMgr.findHostByName(secStorageVm.getHostName());
			if(host != null && host.getStatus() == Status.Up)
				return new Pair<HostVO, SecondaryStorageVmVO>(host, secStorageVm);
		}
		
		return null;
	}
	
	private List<CommandExecLogVO> listActiveCommands(long dcId, Date cutTime) {
		SearchCriteria<CommandExecLogVO> sc = ActiveCommandSearch.create();
		
		sc.setParameters("created", cutTime);
		sc.setJoinParameters("hostSearch", "dc", dcId);
		sc.setJoinParameters("hostSearch", "status", Status.Up);
		
		return _cmdExecLogDao.search(sc, null);
	}
	
    private boolean reserveStandbyCapacity() {
        String value = _configDao.getValue(Config.SystemVMAutoReserveCapacity.key());
        if(value != null && value.equalsIgnoreCase("true")) {
            return true;
        }
        
        return false;
    }
}