/*
 * Copyright 2002-2015 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.datasource.embedded;

import javax.sql.DataSource;

import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.ResourceLoader;
import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;
import org.springframework.jdbc.datasource.init.ScriptUtils;
import org.springframework.util.Assert;

/**
 * A builder that provides a convenient API for constructing an embedded database.
 *
 * <h3>Usage Example</h3>
 * <pre class="code">
 * EmbeddedDatabase db = new EmbeddedDatabaseBuilder()
 *     .generateUniqueName(true)
 *     .setType(H2)
 *     .setScriptEncoding("UTF-8")
 *     .ignoreFailedDrops(true)
 *     .addScript("schema.sql")
 *     .addScripts("user_data.sql", "country_data.sql")
 *     .build();
 *
 * // perform actions against the db (EmbeddedDatabase extends javax.sql.DataSource)
 *
 * db.shutdown();
 * </pre>
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @author Dave Syer
 * @author Sam Brannen
 * @since 3.0
 * @see org.springframework.jdbc.datasource.init.ScriptUtils
 * @see org.springframework.jdbc.datasource.init.ResourceDatabasePopulator
 * @see org.springframework.jdbc.datasource.init.DatabasePopulatorUtils
 */
public class EmbeddedDatabaseBuilder {

	private final EmbeddedDatabaseFactory databaseFactory;

	private final ResourceDatabasePopulator databasePopulator;

	private final ResourceLoader resourceLoader;


	/**
	 * Create a new embedded database builder with a {@link DefaultResourceLoader}.
	 */
	public EmbeddedDatabaseBuilder() {
		this(new DefaultResourceLoader());
	}

	/**
	 * Create a new embedded database builder with the given {@link ResourceLoader}.
	 * @param resourceLoader the {@code ResourceLoader} to delegate to
	 */
	public EmbeddedDatabaseBuilder(ResourceLoader resourceLoader) {
		this.databaseFactory = new EmbeddedDatabaseFactory();
		this.databasePopulator = new ResourceDatabasePopulator();
		this.databaseFactory.setDatabasePopulator(this.databasePopulator);
		this.resourceLoader = resourceLoader;
	}

	/**
	 * Specify whether a unique ID should be generated and used as the database name.
	 * <p>If the configuration for this builder is reused across multiple
	 * application contexts within a single JVM, this flag should be <em>enabled</em>
	 * (i.e., set to {@code true}) in order to ensure that each application context
	 * gets its own embedded database.
	 * <p>Enabling this flag overrides any explicit name set via {@link #setName}.
	 * @param flag {@code true} if a unique database name should be generated
	 * @return {@code this}, to facilitate method chaining
	 * @see #setName
	 * @since 4.2
	 */
	public EmbeddedDatabaseBuilder generateUniqueName(boolean flag) {
		this.databaseFactory.setGenerateUniqueDatabaseName(flag);
		return this;
	}

	/**
	 * Set the name of the embedded database.
	 * <p>Defaults to {@link EmbeddedDatabaseFactory#DEFAULT_DATABASE_NAME} if
	 * not called.
	 * <p>Will be overridden if the {@code generateUniqueName} flag has been
	 * set to {@code true}.
	 * @param databaseName the name of the embedded database to build
	 * @return {@code this}, to facilitate method chaining
	 * @see #generateUniqueName
	 */
	public EmbeddedDatabaseBuilder setName(String databaseName) {
		this.databaseFactory.setDatabaseName(databaseName);
		return this;
	}

	/**
	 * Set the type of embedded database.
	 * <p>Defaults to HSQL if not called.
	 * @param databaseType the type of embedded database to build
	 * @return {@code this}, to facilitate method chaining
	 */
	public EmbeddedDatabaseBuilder setType(EmbeddedDatabaseType databaseType) {
		this.databaseFactory.setDatabaseType(databaseType);
		return this;
	}

	/**
	 * Set the factory to use to create the {@link DataSource} instance that
	 * connects to the embedded database.
	 * <p>Defaults to {@link SimpleDriverDataSourceFactory} but can be overridden,
	 * for example to introduce connection pooling.
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder setDataSourceFactory(DataSourceFactory dataSourceFactory) {
		Assert.notNull(dataSourceFactory, "DataSourceFactory is required");
		this.databaseFactory.setDataSourceFactory(dataSourceFactory);
		return this;
	}

	/**
	 * Add default SQL scripts to execute to populate the database.
	 * <p>The default scripts are {@code "schema.sql"} to create the database
	 * schema and {@code "data.sql"} to populate the database with data.
	 * @return {@code this}, to facilitate method chaining
	 */
	public EmbeddedDatabaseBuilder addDefaultScripts() {
		return addScripts("schema.sql", "data.sql");
	}

	/**
	 * Add an SQL script to execute to initialize or populate the database.
	 * @param script the script to execute
	 * @return {@code this}, to facilitate method chaining
	 */
	public EmbeddedDatabaseBuilder addScript(String script) {
		this.databasePopulator.addScript(this.resourceLoader.getResource(script));
		return this;
	}

	/**
	 * Add multiple SQL scripts to execute to initialize or populate the database.
	 * @param scripts the scripts to execute
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder addScripts(String... scripts) {
		for (String script : scripts) {
			addScript(script);
		}
		return this;
	}

	/**
	 * Specify the character encoding used in all SQL scripts, if different from
	 * the platform encoding.
	 * @param scriptEncoding the encoding used in scripts
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder setScriptEncoding(String scriptEncoding) {
		this.databasePopulator.setSqlScriptEncoding(scriptEncoding);
		return this;
	}

	/**
	 * Specify the statement separator used in all SQL scripts, if a custom one.
	 * <p>Defaults to {@code ";"} if not specified and falls back to {@code "\n"}
	 * as a last resort; may be set to {@link ScriptUtils#EOF_STATEMENT_SEPARATOR}
	 * to signal that each script contains a single statement without a separator.
	 * @param separator the statement separator
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder setSeparator(String separator) {
		this.databasePopulator.setSeparator(separator);
		return this;
	}

	/**
	 * Specify the single-line comment prefix used in all SQL scripts.
	 * <p>Defaults to {@code "--"}.
	 * @param commentPrefix the prefix for single-line comments
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder setCommentPrefix(String commentPrefix) {
		this.databasePopulator.setCommentPrefix(commentPrefix);
		return this;
	}

	/**
	 * Specify the start delimiter for block comments in all SQL scripts.
	 * <p>Defaults to {@code "/*"}.
	 * @param blockCommentStartDelimiter the start delimiter for block comments
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 * @see #setBlockCommentEndDelimiter
	 */
	public EmbeddedDatabaseBuilder setBlockCommentStartDelimiter(String blockCommentStartDelimiter) {
		this.databasePopulator.setBlockCommentStartDelimiter(blockCommentStartDelimiter);
		return this;
	}

	/**
	 * Specify the end delimiter for block comments in all SQL scripts.
	 * <p>Defaults to <code>"*&#47;"</code>.
	 * @param blockCommentEndDelimiter the end delimiter for block comments
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 * @see #setBlockCommentStartDelimiter
	 */
	public EmbeddedDatabaseBuilder setBlockCommentEndDelimiter(String blockCommentEndDelimiter) {
		this.databasePopulator.setBlockCommentEndDelimiter(blockCommentEndDelimiter);
		return this;
	}

	/**
	 * Specify that all failures which occur while executing SQL scripts should
	 * be logged but should not cause a failure.
	 * <p>Defaults to {@code false}.
	 * @param flag {@code true} if script execution should continue on error
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder continueOnError(boolean flag) {
		this.databasePopulator.setContinueOnError(flag);
		return this;
	}

	/**
	 * Specify that a failed SQL {@code DROP} statement within an executed
	 * script can be ignored.
	 * <p>This is useful for a database whose SQL dialect does not support an
	 * {@code IF EXISTS} clause in a {@code DROP} statement.
	 * <p>The default is {@code false} so that {@link #build building} will fail
	 * fast if a script starts with a {@code DROP} statement.
	 * @param flag {@code true} if failed drop statements should be ignored
	 * @return {@code this}, to facilitate method chaining
	 * @since 4.0.3
	 */
	public EmbeddedDatabaseBuilder ignoreFailedDrops(boolean flag) {
		this.databasePopulator.setIgnoreFailedDrops(flag);
		return this;
	}

	/**
	 * Build the embedded database.
	 * @return the embedded database
	 */
	public EmbeddedDatabase build() {
		return this.databaseFactory.getDatabase();
	}

}
