/**
 * Copyright (C) 2009-2013 FoundationDB, LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.foundationdb.server.service.dxl;

import com.foundationdb.server.api.DDLFunctions;
import com.foundationdb.server.api.DMLFunctions;
import com.foundationdb.server.error.ServiceNotStartedException;
import com.foundationdb.server.error.ServiceAlreadyStartedException;
import com.foundationdb.server.service.Service;
import com.foundationdb.server.service.config.ConfigurationService;
import com.foundationdb.server.service.listener.ListenerService;
import com.foundationdb.server.service.session.SessionService;
import com.foundationdb.server.service.transaction.TransactionService;
import com.foundationdb.server.store.SchemaManager;
import com.foundationdb.server.store.Store;
import com.foundationdb.server.store.statistics.IndexStatisticsService;
import com.google.inject.Inject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Arrays;
import java.util.List;

public class DXLServiceImpl implements DXLService, Service {
    private final static Logger LOG = LoggerFactory.getLogger(DXLServiceImpl.class);

    private final Object MONITOR = new Object();

    private volatile DDLFunctions ddlFunctions;
    private volatile DMLFunctions dmlFunctions;

    private final SchemaManager schemaManager;
    private final Store store;
    private final SessionService sessionService;
    private final IndexStatisticsService indexStatisticsService;
    private final TransactionService txnService;
    private final ListenerService listenerService;
    private final ConfigurationService configService;

    @Override
    public void start() {
        List<DXLFunctionsHook> hooks = getHooks();
        DDLFunctions localDdlFunctions = new HookableDDLFunctions(createDDLFunctions(), hooks, sessionService);
        DMLFunctions localDmlFunctions = new HookableDMLFunctions(createDMLFunctions(), hooks);
        synchronized (MONITOR) {
            if (ddlFunctions != null) {
                throw new ServiceAlreadyStartedException("DXLService");
            }
            ddlFunctions = localDdlFunctions;
            dmlFunctions = localDmlFunctions;
        }
    }

    DMLFunctions createDMLFunctions() {
        return new BasicDMLFunctions(schemaManager, store, listenerService);
    }

    DDLFunctions createDDLFunctions() {
        return new BasicDDLFunctions(schemaManager, store, indexStatisticsService,
                                     txnService, listenerService, configService);
    }

    @Override
    public void stop() {
        synchronized (MONITOR) {
            if (ddlFunctions == null) {
                throw new ServiceNotStartedException("DDL Functions stop");
            }
            ddlFunctions = null;
            dmlFunctions = null;
        }
    }

    @Override
    public DDLFunctions ddlFunctions() {
        final DDLFunctions ret = ddlFunctions;
        if (ret == null) {
            throw new ServiceNotStartedException("DDL Functions");
        }
        return ret;
    }

    @Override
    public DMLFunctions dmlFunctions() {
        final DMLFunctions ret = dmlFunctions;
        if (ret == null) {
            throw new ServiceNotStartedException("DML Functions");
        }
        return ret;
    }

    protected List<DXLFunctionsHook> getHooks() {
        return Arrays.<DXLFunctionsHook>asList(new DXLTransactionHook(txnService));
    }

    @Override
    public void crash() {
    }

    @Inject
    public DXLServiceImpl(SchemaManager schemaManager,
                          Store store,
                          SessionService sessionService,
                          IndexStatisticsService indexStatisticsService,
                          TransactionService txnService,
                          ListenerService listenerService,
                          ConfigurationService configService) {
        this.schemaManager = schemaManager;
        this.store = store;
        this.sessionService = sessionService;
        this.indexStatisticsService = indexStatisticsService;
        this.txnService = txnService;
        this.listenerService = listenerService;
        this.configService = configService;
    }
}