/**
    * Copyright 2011 The Kuali Foundation Licensed under the
    * Educational Community 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.osedu.org/licenses/ECL-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 org.kuali.common.impex.schema.service.impl.liquibase;
  
  import java.sql.Connection;
  import java.sql.SQLException;
  import java.util.ArrayList;
  import java.util.List;
  
  import liquibase.database.Database;
  import liquibase.database.DatabaseFactory;
  import liquibase.database.jvm.JdbcConnection;
  import liquibase.exception.DatabaseException;
  import liquibase.snapshot.DatabaseSnapshot;
  import liquibase.snapshot.InvalidExampleException;
  import liquibase.snapshot.SnapshotControl;
  import liquibase.snapshot.SnapshotGeneratorFactory;
  
  import org.kuali.common.impex.model.ForeignKey;
  import org.kuali.common.impex.model.Schema;
  import org.kuali.common.impex.model.Sequence;
  import org.kuali.common.impex.model.Table;
  import org.kuali.common.impex.model.View;
  import org.kuali.common.impex.schema.service.ExtractSchemaContext;
  import org.kuali.common.impex.schema.service.ExtractSchemaService;
  import org.kuali.common.jdbc.JdbcUtils;
  import org.kuali.common.util.FormatUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class LiquibaseSchemaExtractionService implements ExtractSchemaService {
  
  	private static final Logger log = LoggerFactory.getLogger(LiquibaseSchemaExtractionService.class);
  
  	@Override
  	public Schema getSchema(ExtractSchemaContext context) {
  		try {
  			DatabaseSnapshot snapshot = getDatabaseSnapshot(context);
  			LiquibaseSchemaProvider schemaProvider = getSchemaProvider(snapshot, context);
  
  			return schemaProvider.buildSchema();
  		} catch (Exception e) {
  			log.error("Exception occurred when extracting database schema: " + e.getMessage(), e);
  			throw new RuntimeException(e);
  		}
  	}
  
  	protected DatabaseSnapshot getDatabaseSnapshot(ExtractSchemaContext context) throws DatabaseException, InvalidExampleException, SQLException {
  
  		// Preserve the start time
  		long start = System.currentTimeMillis();
  
  		// get an instance of the database factory
  		DatabaseFactory databaseFactory = DatabaseFactory.getInstance();
  
  		Connection connection = null;
  		DatabaseSnapshot snapshot = null;
  		try {
  
  			log.info("Creating Liquibase snapshot for schema {}", context.getSchemaName());
  
  			connection = context.getDataSource().getConnection();
  
  			// build an instance of the liquibase database object
  			Database database = databaseFactory.findCorrectDatabaseImplementation(new JdbcConnection(connection));
  
  			database.setDefaultCatalogName(null);
  			database.setDefaultSchemaName(context.getSchemaName());
  
  			// Use Liquibase to snapshot the database
  			SnapshotGeneratorFactory factory = SnapshotGeneratorFactory.getInstance();
  			snapshot = factory.createSnapshot(database.getDefaultSchema(), database, new SnapshotControl());
  
  			log.info("Liquibase snapshot created - Time: {}", FormatUtils.getTime(System.currentTimeMillis() - start));
  
  		} finally {
  			JdbcUtils.closeQuietly(context.getDataSource(), connection);
  		}
  
  		return snapshot;
  	}
  
  	protected LiquibaseSchemaProvider getSchemaProvider(DatabaseSnapshot snapshot, ExtractSchemaContext context) throws SQLException {
  		log.info("Creating LiquibaseModelProvider");
  
  		// Preserve the start time
 		long start = System.currentTimeMillis();
 
 		LiquibaseSchemaProvider modelProvider = new LiquibaseSchemaProvider(snapshot, context.getSequenceFinder(), context.getDataSource());
 		modelProvider.setSchemaName(context.getSchemaName());
 		modelProvider.setNameFilter(context.getNameFilter());
 
 		log.info("LiquibaseModelProvider created - Time: {}", FormatUtils.getTime(System.currentTimeMillis() - start));
 
 		return modelProvider;
 	}
 
 	@Override
 	public List<Table> extractTables(List<String> tableNames, ExtractSchemaContext context) throws SQLException {
 		Schema schema = getSchema(context);
 
 		List<Table> result = new ArrayList<Table>(tableNames.size());
 		for (Table table : schema.getTables()) {
 			if (tableNames.contains(table.getName())) {
 				result.add(table);
 			}
 		}
 
 		return result;
 	}
 
 	@Override
 	public List<View> extractViews(ExtractSchemaContext context) throws SQLException {
 		Schema schema = getSchema(context);
 
 		return schema.getViews();
 	}
 
 	@Override
 	public List<Sequence> extractSequences(ExtractSchemaContext context) throws SQLException {
 		Schema schema = getSchema(context);
 
 		return schema.getSequences();
 	}
 
 	@Override
 	public List<ForeignKey> extractForeignKeys(List<String> tableNames, ExtractSchemaContext context) throws SQLException {
 		Schema schema = getSchema(context);
 
 		List<ForeignKey> result = new ArrayList<ForeignKey>(tableNames.size());
 		for (ForeignKey foreignKey : schema.getForeignKeys()) {
 			if (tableNames.contains(foreignKey.getLocalTableName())) {
 				result.add(foreignKey);
 			}
 		}
 
 		return result;
 	}
 }