/*
 * Copyright 2002-2013 the original author or authors.
 *
 * 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 org.springframework.jdbc.core.simple;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.dao.InvalidDataAccessResourceUsageException;
import org.springframework.jdbc.core.BatchPreparedStatementSetter;
import org.springframework.jdbc.core.ConnectionCallback;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.PreparedStatementCreator;
import org.springframework.jdbc.core.SqlTypeValue;
import org.springframework.jdbc.core.StatementCreatorUtils;
import org.springframework.jdbc.core.metadata.TableMetaDataContext;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor;
import org.springframework.util.Assert;

/**
 * Abstract class to provide base functionality for easy inserts
 * based on configuration options and database metadata.
 * This class provides the base SPI for {@link SimpleJdbcInsert}.
 *
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @since 2.5
 */
public abstract class AbstractJdbcInsert {

	/** Logger available to subclasses */
	protected final Log logger = LogFactory.getLog(getClass());

	/** Lower-level class used to execute SQL */
	private final JdbcTemplate jdbcTemplate;

	/** Context used to retrieve and manage database metadata */
	private final TableMetaDataContext tableMetaDataContext = new TableMetaDataContext();

	/** List of columns objects to be used in insert statement */
	private final List<String> declaredColumns = new ArrayList<String>();

	/**
	 * Has this operation been compiled? Compilation means at least checking
	 * that a DataSource or JdbcTemplate has been provided, but subclasses
	 * may also implement their own custom validation.
	 */
	private boolean compiled = false;

	/** The generated string used for insert statement */
	private String insertString;

	/** The SQL type information for the insert columns */
	private int[] insertTypes;

	/** The names of the columns holding the generated key */
	private String[] generatedKeyNames = new String[0];


	/**
	 * Constructor for sublasses to delegate to for setting the DataSource.
	 */
	protected AbstractJdbcInsert(DataSource dataSource) {
		this.jdbcTemplate = new JdbcTemplate(dataSource);
	}

	/**
	 * Constructor for sublasses to delegate to for setting the JdbcTemplate.
	 */
	protected AbstractJdbcInsert(JdbcTemplate jdbcTemplate) {
		Assert.notNull(jdbcTemplate, "JdbcTemplate must not be null");
		this.jdbcTemplate = jdbcTemplate;
		setNativeJdbcExtractor(jdbcTemplate.getNativeJdbcExtractor());
	}


	//-------------------------------------------------------------------------
	// Methods dealing with configuration properties
	//-------------------------------------------------------------------------

	/**
	 * Get the {@link JdbcTemplate} that is configured to be used.
	 */
	public JdbcTemplate getJdbcTemplate() {
		return this.jdbcTemplate;
	}

	/**
	 * Set the name of the table for this insert
	 */
	public void setTableName(String tableName) {
		checkIfConfigurationModificationIsAllowed();
		this.tableMetaDataContext.setTableName(tableName);
	}

	/**
	 * Get the name of the table for this insert
	 */
	public String getTableName() {
		return this.tableMetaDataContext.getTableName();
	}

	/**
	 * Set the name of the schema for this insert
	 */
	public void setSchemaName(String schemaName) {
		checkIfConfigurationModificationIsAllowed();
		this.tableMetaDataContext.setSchemaName(schemaName);
	}

	/**
	 * Get the name of the schema for this insert
	 */
	public String getSchemaName() {
		return this.tableMetaDataContext.getSchemaName();
	}

	/**
	 * Set the name of the catalog for this insert
	 */
	public void setCatalogName(String catalogName) {
		checkIfConfigurationModificationIsAllowed();
		this.tableMetaDataContext.setCatalogName(catalogName);
	}

	/**
	 * Get the name of the catalog for this insert
	 */
	public String getCatalogName() {
		return this.tableMetaDataContext.getCatalogName();
	}

	/**
	 * Set the names of the columns to be used
	 */
	public void setColumnNames(List<String> columnNames) {
		checkIfConfigurationModificationIsAllowed();
		this.declaredColumns.clear();
		this.declaredColumns.addAll(columnNames);
	}

	/**
	 * Get the names of the columns used
	 */
	public List<String> getColumnNames() {
		return Collections.unmodifiableList(this.declaredColumns);
	}

	/**
	 * Get the names of any generated keys
	 */
	public String[] getGeneratedKeyNames() {
		return this.generatedKeyNames;
	}

	/**
	 * Set the names of any generated keys
	 */
	public void setGeneratedKeyNames(String[] generatedKeyNames) {
		checkIfConfigurationModificationIsAllowed();
		this.generatedKeyNames = generatedKeyNames;
	}

	/**
	 * Specify the name of a single generated key column
	 */
	public void setGeneratedKeyName(String generatedKeyName) {
		checkIfConfigurationModificationIsAllowed();
		this.generatedKeyNames = new String[] {generatedKeyName};
	}

	/**
	 * Specify whether the parameter metadata for the call should be used.  The default is true.
	 */
	public void setAccessTableColumnMetaData(boolean accessTableColumnMetaData) {
		this.tableMetaDataContext.setAccessTableColumnMetaData(accessTableColumnMetaData);
	}

	/**
	 * Specify whether the default for including synonyms should be changed.  The default is false.
	 */
	public void setOverrideIncludeSynonymsDefault(boolean override) {
		this.tableMetaDataContext.setOverrideIncludeSynonymsDefault(override);
	}

	/**
	 * Set the {@link NativeJdbcExtractor} to use to retrieve the native connection if necessary
	 */
	public void setNativeJdbcExtractor(NativeJdbcExtractor nativeJdbcExtractor) {
		this.tableMetaDataContext.setNativeJdbcExtractor(nativeJdbcExtractor);
	}

	/**
	 * Get the insert string to be used
	 */
	public String getInsertString() {
		return this.insertString;
	}

	/**
	 * Get the array of {@link java.sql.Types} to be used for insert
	 */
	public int[] getInsertTypes() {
		return this.insertTypes;
	}


	//-------------------------------------------------------------------------
	// Methods handling compilation issues
	//-------------------------------------------------------------------------

	/**
	 * Compile this JdbcInsert using provided parameters and meta data plus other settings.
	 * This finalizes the configuration for this object and subsequent attempts to compile are
	 * ignored. This will be implicitly called the first time an un-compiled insert is executed.
	 * @throws InvalidDataAccessApiUsageException if the object hasn't been correctly initialized,
	 * for example if no DataSource has been provided
	 */
	public synchronized final void compile() throws InvalidDataAccessApiUsageException {
		if (!isCompiled()) {
			if (getTableName() == null) {
				throw new InvalidDataAccessApiUsageException("Table name is required");
			}
			try {
				this.jdbcTemplate.afterPropertiesSet();
			}
			catch (IllegalArgumentException ex) {
				throw new InvalidDataAccessApiUsageException(ex.getMessage());
			}
			compileInternal();
			this.compiled = true;
			if (logger.isDebugEnabled()) {
				logger.debug("JdbcInsert for table [" + getTableName() + "] compiled");
			}
		}
	}

	/**
	 * Method to perform the actual compilation. Subclasses can override this template method
	 * to perform  their own compilation. Invoked after this base class's compilation is complete.
	 */
	protected void compileInternal() {
		this.tableMetaDataContext.processMetaData(
				getJdbcTemplate().getDataSource(), getColumnNames(), getGeneratedKeyNames());
		this.insertString = this.tableMetaDataContext.createInsertString(getGeneratedKeyNames());
		this.insertTypes = this.tableMetaDataContext.createInsertTypes();
		if (logger.isDebugEnabled()) {
			logger.debug("Compiled insert object: insert string is [" + getInsertString() + "]");
		}
		onCompileInternal();
	}

	/**
	 * Hook method that subclasses may override to react to compilation.
	 * This implementation does nothing.
	 */
	protected void onCompileInternal() {
	}

	/**
	 * Is this operation "compiled"?
	 * @return whether this operation is compiled, and ready to use.
	 */
	public boolean isCompiled() {
		return this.compiled;
	}

	/**
	 * Check whether this operation has been compiled already;
	 * lazily compile it if not already compiled.
	 * <p>Automatically called by {@code validateParameters}.
	 */
	protected void checkCompiled() {
		if (!isCompiled()) {
			logger.debug("JdbcInsert not compiled before execution - invoking compile");
			compile();
		}
	}

	/**
	 * Method to check whether we are allowd to make any configuration changes at this time.
	 * If the class has been compiled, then no further changes to the configuration are allowed.
	 */
	protected void checkIfConfigurationModificationIsAllowed() {
		if (isCompiled()) {
			throw new InvalidDataAccessApiUsageException(
					"Configuration can't be altered once the class has been compiled or used");
		}
	}


	//-------------------------------------------------------------------------
	// Methods handling execution
	//-------------------------------------------------------------------------

	/**
	 * Method that provides execution of the insert using the passed in Map of parameters
	 * @param args Map with parameter names and values to be used in insert
	 * @return number of rows affected
	 */
	protected int doExecute(Map<String, Object> args) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(args);
		return executeInsertInternal(values);
	}

	/**
	 * Method that provides execution of the insert using the passed in {@link SqlParameterSource}
	 * @param parameterSource parameter names and values to be used in insert
	 * @return number of rows affected
	 */
	protected int doExecute(SqlParameterSource parameterSource) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(parameterSource);
		return executeInsertInternal(values);
	}

	/**
	 * Method to execute the insert.
	 */
	private int executeInsertInternal(List<Object> values) {
		if (logger.isDebugEnabled()) {
			logger.debug("The following parameters are used for insert " + getInsertString() + " with: " + values);
		}
		return getJdbcTemplate().update(getInsertString(), values.toArray(), getInsertTypes());
	}

	/**
	 * Method that provides execution of the insert using the passed in Map of parameters
	 * and returning a generated key
	 *
	 * @param args Map with parameter names and values to be used in insert
	 * @return the key generated by the insert
	 */
	protected Number doExecuteAndReturnKey(Map<String, Object> args) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(args);
		return executeInsertAndReturnKeyInternal(values);
	}

	/**
	 * Method that provides execution of the insert using the passed in {@link SqlParameterSource}
	 * and returning a generated key
	 *
	 * @param parameterSource parameter names and values to be used in insert
	 * @return the key generated by the insert
	 */
	protected Number doExecuteAndReturnKey(SqlParameterSource parameterSource) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(parameterSource);
		return executeInsertAndReturnKeyInternal(values);
	}

	/**
	 * Method that provides execution of the insert using the passed in Map of parameters
	 * and returning all generated keys
	 *
	 * @param args Map with parameter names and values to be used in insert
	 * @return the KeyHolder containing keys generated by the insert
	 */
	protected KeyHolder doExecuteAndReturnKeyHolder(Map<String, Object> args) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(args);
		return executeInsertAndReturnKeyHolderInternal(values);
	}

	/**
	 * Method that provides execution of the insert using the passed in {@link SqlParameterSource}
	 * and returning all generated keys
	 *
	 * @param parameterSource parameter names and values to be used in insert
	 * @return the KeyHolder containing keys generated by the insert
	 */
	protected KeyHolder doExecuteAndReturnKeyHolder(SqlParameterSource parameterSource) {
		checkCompiled();
		List<Object> values = matchInParameterValuesWithInsertColumns(parameterSource);
		return executeInsertAndReturnKeyHolderInternal(values);
	}

	/**
	 * Method to execute the insert generating single key
	 */
	private Number executeInsertAndReturnKeyInternal(final List<Object> values) {
		KeyHolder kh = executeInsertAndReturnKeyHolderInternal(values);
		if (kh != null && kh.getKey() != null) {
			return kh.getKey();
		}
		else {
			throw new DataIntegrityViolationException(
					"Unable to retrieve the generated key for the insert: " + getInsertString());
		}
	}

	/**
	 * Method to execute the insert generating any number of keys
	 */
	private KeyHolder executeInsertAndReturnKeyHolderInternal(final List<Object> values) {
		if (logger.isDebugEnabled()) {
			logger.debug("The following parameters are used for call " + getInsertString() + " with: " + values);
		}
		final KeyHolder keyHolder = new GeneratedKeyHolder();
		if (this.tableMetaDataContext.isGetGeneratedKeysSupported()) {
			getJdbcTemplate().update(
					new PreparedStatementCreator() {
						public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
							PreparedStatement ps = prepareStatementForGeneratedKeys(con);
							setParameterValues(ps, values, getInsertTypes());
							return ps;
						}
					},
					keyHolder);
		}
		else {
			if (!this.tableMetaDataContext.isGetGeneratedKeysSimulated()) {
				throw new InvalidDataAccessResourceUsageException(
						"The getGeneratedKeys feature is not supported by this database");
			}
			if (getGeneratedKeyNames().length < 1) {
				throw new InvalidDataAccessApiUsageException("Generated Key Name(s) not specificed. " +
						"Using the generated keys features requires specifying the name(s) of the generated column(s)");
			}
			if (getGeneratedKeyNames().length > 1) {
				throw new InvalidDataAccessApiUsageException(
						"Current database only supports retreiving the key for a single column. There are " +
						getGeneratedKeyNames().length  + " columns specified: " + Arrays.asList(getGeneratedKeyNames()));
			}
			// This is a hack to be able to get the generated key from a database that doesn't support
			// get generated keys feature. HSQL is one, PostgreSQL is another. Postgres uses a RETURNING
			// clause while HSQL uses a second query that has to be executed with the same connection.
			final String keyQuery = this.tableMetaDataContext.getSimulationQueryForGetGeneratedKey(
					this.tableMetaDataContext.getTableName(), getGeneratedKeyNames()[0]);
			Assert.notNull(keyQuery, "Query for simulating get generated keys can't be null");
			if (keyQuery.toUpperCase().startsWith("RETURNING")) {
				Long key = getJdbcTemplate().queryForObject(getInsertString() + " " + keyQuery,
						values.toArray(new Object[values.size()]), Long.class);
				Map<String, Object> keys = new HashMap<String, Object>(1);
				keys.put(getGeneratedKeyNames()[0], key);
				keyHolder.getKeyList().add(keys);
			}
			else {
				getJdbcTemplate().execute(new ConnectionCallback<Object>() {
					public Object doInConnection(Connection con) throws SQLException, DataAccessException {
						// Do the insert
						PreparedStatement ps = null;
						try {
							ps = con.prepareStatement(getInsertString());
							setParameterValues(ps, values, getInsertTypes());
							ps.executeUpdate();
						}
						finally {
							JdbcUtils.closeStatement(ps);
						}
						//Get the key
						Statement keyStmt = null;
						ResultSet rs = null;
						Map<String, Object> keys = new HashMap<String, Object>(1);
						try {
							keyStmt = con.createStatement();
							rs = keyStmt.executeQuery(keyQuery);
							if (rs.next()) {
								long key = rs.getLong(1);
								keys.put(getGeneratedKeyNames()[0], key);
								keyHolder.getKeyList().add(keys);
							}
						}
						finally {
							JdbcUtils.closeResultSet(rs);
							JdbcUtils.closeStatement(keyStmt);
						}
						return null;
					}
				});
			}
			return keyHolder;
		}
		return keyHolder;
	}

	/**
	 * Create the PreparedStatement to be used for insert that have generated keys
	 *
	 * @param con the connection used
	 * @return PreparedStatement to use
	 * @throws SQLException
	 */
	private PreparedStatement prepareStatementForGeneratedKeys(Connection con) throws SQLException {
		if (getGeneratedKeyNames().length < 1) {
			throw new InvalidDataAccessApiUsageException("Generated Key Name(s) not specificed. " +
					"Using the generated keys features requires specifying the name(s) of the generated column(s)");
		}
		PreparedStatement ps;
		if (this.tableMetaDataContext.isGeneratedKeysColumnNameArraySupported()) {
			if (logger.isDebugEnabled()) {
				logger.debug("Using generated keys support with array of column names.");
			}
			ps = con.prepareStatement(getInsertString(), getGeneratedKeyNames());
		}
		else {
			if (logger.isDebugEnabled()) {
				logger.debug("Using generated keys support with Statement.RETURN_GENERATED_KEYS.");
			}
			ps = con.prepareStatement(getInsertString(), Statement.RETURN_GENERATED_KEYS);
		}
		return ps;
	}

	/**
	 * Method that provides execution of a batch insert using the passed in Maps of parameters.
	 * @param batch array of Maps with parameter names and values to be used in batch insert
	 * @return array of number of rows affected
	 */
	@SuppressWarnings("unchecked")
	protected int[] doExecuteBatch(Map<String, Object>[] batch) {
		checkCompiled();
		List<Object>[] batchValues = new ArrayList[batch.length];
		int i = 0;
		for (Map<String, Object> args : batch) {
			List<Object> values = matchInParameterValuesWithInsertColumns(args);
			batchValues[i++] = values;
		}
		return executeBatchInternal(batchValues);
	}

	/**
	 * Method that provides execution of a batch insert using the passed in array of {@link SqlParameterSource}
	 * @param batch array of SqlParameterSource with parameter names and values to be used in insert
	 * @return array of number of rows affected
	 */
	@SuppressWarnings("unchecked")
	protected int[] doExecuteBatch(SqlParameterSource[] batch) {
		checkCompiled();
		List<Object>[] batchValues = new ArrayList[batch.length];
		int i = 0;
		for (SqlParameterSource parameterSource : batch) {
			List<Object> values = matchInParameterValuesWithInsertColumns(parameterSource);
			batchValues[i++] = values;
		}
		return executeBatchInternal(batchValues);
	}

	/**
	 * Method to execute the batch insert.
	 */
	private int[] executeBatchInternal(final List<Object>[] batchValues) {
		if (logger.isDebugEnabled()) {
			logger.debug("Executing statement " + getInsertString() + " with batch of size: " + batchValues.length);
		}
		return getJdbcTemplate().batchUpdate(getInsertString(),
				new BatchPreparedStatementSetter() {
					public void setValues(PreparedStatement ps, int i) throws SQLException {
						List<Object> values = batchValues[i];
						setParameterValues(ps, values, getInsertTypes());
					}
					public int getBatchSize() {
						return batchValues.length;
					}
				});
	}

	/**
	 * Internal implementation for setting parameter values
	 * @param preparedStatement the PreparedStatement
	 * @param values the values to be set
	 */
	private void setParameterValues(PreparedStatement preparedStatement, List<Object> values, int[] columnTypes)
			throws SQLException {

		int colIndex = 0;
		for (Object value : values) {
			colIndex++;
			if (columnTypes == null || colIndex > columnTypes.length) {
				StatementCreatorUtils.setParameterValue(preparedStatement, colIndex, SqlTypeValue.TYPE_UNKNOWN, value);
			}
			else {
				StatementCreatorUtils.setParameterValue(preparedStatement, colIndex, columnTypes[colIndex - 1], value);
			}
		}
	}

	/**
	 * Match the provided in parameter values with regitered parameters and parameters defined
	 * via metadata processing.
	 * @param parameterSource the parameter vakues provided as a {@link SqlParameterSource}
	 * @return Map with parameter names and values
	 */
	protected List<Object> matchInParameterValuesWithInsertColumns(SqlParameterSource parameterSource) {
		return this.tableMetaDataContext.matchInParameterValuesWithInsertColumns(parameterSource);
	}

	/**
	 * Match the provided in parameter values with regitered parameters and parameters defined
	 * via metadata processing.
	 * @param args the parameter values provided in a Map
	 * @return Map with parameter names and values
	 */
	protected List<Object> matchInParameterValuesWithInsertColumns(Map<String, Object> args) {
		return this.tableMetaDataContext.matchInParameterValuesWithInsertColumns(args);
	}

}
