/*
 * Copyright 2012-2020 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
 *
 *      https://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.boot.autoconfigure.flyway;

import java.sql.DatabaseMetaData;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.function.Supplier;
import java.util.stream.Collectors;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;

import org.flywaydb.core.Flyway;
import org.flywaydb.core.api.MigrationVersion;
import org.flywaydb.core.api.callback.Callback;
import org.flywaydb.core.api.configuration.FluentConfiguration;
import org.flywaydb.core.api.migration.JavaMigration;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.AnyNestedCondition;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.data.jpa.EntityManagerFactoryDependsOnPostProcessor;
import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.FlywayDataSourceCondition;
import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.FlywayEntityManagerFactoryDependsOnPostProcessor;
import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.FlywayJdbcOperationsDependsOnPostProcessor;
import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.FlywayNamedParameterJdbcOperationsDependencyConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
import org.springframework.boot.autoconfigure.jdbc.JdbcOperationsDependsOnPostProcessor;
import org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.NamedParameterJdbcOperationsDependsOnPostProcessor;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.boot.context.properties.ConfigurationPropertiesBinding;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.context.properties.PropertyMapper;
import org.springframework.boot.jdbc.DatabaseDriver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.io.ResourceLoader;
import org.springframework.jdbc.core.JdbcOperations;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.jdbc.support.MetaDataAccessException;
import org.springframework.orm.jpa.AbstractEntityManagerFactoryBean;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for Flyway database migrations.
 *
 * @author Dave Syer
 * @author Phillip Webb
 * @author Vedran Pavic
 * @author Stephane Nicoll
 * @author Jacques-Etienne Beaudet
 * @author Eddú Meléndez
 * @author Dominic Gunn
 * @author Dan Zheng
 * @author András Deák
 * @author Semyon Danilov
 * @since 1.1.0
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(Flyway.class)
@Conditional(FlywayDataSourceCondition.class)
@ConditionalOnProperty(prefix = "spring.flyway", name = "enabled", matchIfMissing = true)
@AutoConfigureAfter({ DataSourceAutoConfiguration.class, JdbcTemplateAutoConfiguration.class,
		HibernateJpaAutoConfiguration.class })
@Import({ FlywayEntityManagerFactoryDependsOnPostProcessor.class, FlywayJdbcOperationsDependsOnPostProcessor.class,
		FlywayNamedParameterJdbcOperationsDependencyConfiguration.class })
public class FlywayAutoConfiguration {

	@Bean
	@ConfigurationPropertiesBinding
	public StringOrNumberToMigrationVersionConverter stringOrNumberMigrationVersionConverter() {
		return new StringOrNumberToMigrationVersionConverter();
	}

	@Bean
	public FlywaySchemaManagementProvider flywayDefaultDdlModeProvider(ObjectProvider<Flyway> flyways) {
		return new FlywaySchemaManagementProvider(flyways);
	}

	@Configuration(proxyBeanMethods = false)
	@ConditionalOnMissingBean(Flyway.class)
	@EnableConfigurationProperties({ DataSourceProperties.class, FlywayProperties.class })
	@Import({ FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor.class,
			FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor.class,
			FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor.class })
	public static class FlywayConfiguration {

		@Bean
		public Flyway flyway(FlywayProperties properties, DataSourceProperties dataSourceProperties,
				ResourceLoader resourceLoader, ObjectProvider<DataSource> dataSource,
				@FlywayDataSource ObjectProvider<DataSource> flywayDataSource,
				ObjectProvider<FlywayConfigurationCustomizer> fluentConfigurationCustomizers,
				ObjectProvider<JavaMigration> javaMigrations, ObjectProvider<Callback> callbacks) {
			FluentConfiguration configuration = new FluentConfiguration(resourceLoader.getClassLoader());
			DataSource dataSourceToMigrate = configureDataSource(configuration, properties, dataSourceProperties,
					flywayDataSource.getIfAvailable(), dataSource.getIfUnique());
			checkLocationExists(dataSourceToMigrate, properties, resourceLoader);
			configureProperties(configuration, properties);
			List<Callback> orderedCallbacks = callbacks.orderedStream().collect(Collectors.toList());
			configureCallbacks(configuration, orderedCallbacks);
			fluentConfigurationCustomizers.orderedStream().forEach((customizer) -> customizer.customize(configuration));
			configureFlywayCallbacks(configuration, orderedCallbacks);
			List<JavaMigration> migrations = javaMigrations.stream().collect(Collectors.toList());
			configureJavaMigrations(configuration, migrations);
			return configuration.load();
		}

		private DataSource configureDataSource(FluentConfiguration configuration, FlywayProperties properties,
				DataSourceProperties dataSourceProperties, DataSource flywayDataSource, DataSource dataSource) {
			if (properties.isCreateDataSource()) {
				String url = getProperty(properties::getUrl, dataSourceProperties::determineUrl);
				String user = getProperty(properties::getUser, dataSourceProperties::determineUsername);
				String password = getProperty(properties::getPassword, dataSourceProperties::determinePassword);
				configuration.dataSource(url, user, password);
				if (!CollectionUtils.isEmpty(properties.getInitSqls())) {
					String initSql = StringUtils.collectionToDelimitedString(properties.getInitSqls(), "\n");
					configuration.initSql(initSql);
				}
			}
			else if (flywayDataSource != null) {
				configuration.dataSource(flywayDataSource);
			}
			else {
				configuration.dataSource(dataSource);
			}
			return configuration.getDataSource();
		}

		private void checkLocationExists(DataSource dataSource, FlywayProperties properties,
				ResourceLoader resourceLoader) {
			if (properties.isCheckLocation()) {
				List<String> locations = new LocationResolver(dataSource).resolveLocations(properties.getLocations());
				if (!hasAtLeastOneLocation(resourceLoader, locations)) {
					throw new FlywayMigrationScriptMissingException(locations);
				}
			}
		}

		private void configureProperties(FluentConfiguration configuration, FlywayProperties properties) {
			PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
			String[] locations = new LocationResolver(configuration.getDataSource())
					.resolveLocations(properties.getLocations()).toArray(new String[0]);
			map.from(locations).to(configuration::locations);
			map.from(properties.getEncoding()).to(configuration::encoding);
			map.from(properties.getConnectRetries()).to(configuration::connectRetries);
			// No method reference for compatibility with Flyway 5.x
			map.from(properties.getDefaultSchema()).to((schema) -> configuration.defaultSchema(schema));
			map.from(properties.getSchemas()).as(StringUtils::toStringArray).to(configuration::schemas);
			configureCreateSchemas(configuration, properties.isCreateSchemas());
			map.from(properties.getTable()).to(configuration::table);
			// No method reference for compatibility with Flyway 5.x
			map.from(properties.getTablespace()).whenNonNull().to((tablespace) -> configuration.tablespace(tablespace));
			map.from(properties.getBaselineDescription()).to(configuration::baselineDescription);
			map.from(properties.getBaselineVersion()).to(configuration::baselineVersion);
			map.from(properties.getInstalledBy()).to(configuration::installedBy);
			map.from(properties.getPlaceholders()).to(configuration::placeholders);
			map.from(properties.getPlaceholderPrefix()).to(configuration::placeholderPrefix);
			map.from(properties.getPlaceholderSuffix()).to(configuration::placeholderSuffix);
			map.from(properties.isPlaceholderReplacement()).to(configuration::placeholderReplacement);
			map.from(properties.getSqlMigrationPrefix()).to(configuration::sqlMigrationPrefix);
			map.from(properties.getSqlMigrationSuffixes()).as(StringUtils::toStringArray)
					.to(configuration::sqlMigrationSuffixes);
			map.from(properties.getSqlMigrationSeparator()).to(configuration::sqlMigrationSeparator);
			map.from(properties.getRepeatableSqlMigrationPrefix()).to(configuration::repeatableSqlMigrationPrefix);
			map.from(properties.getTarget()).to(configuration::target);
			map.from(properties.isBaselineOnMigrate()).to(configuration::baselineOnMigrate);
			map.from(properties.isCleanDisabled()).to(configuration::cleanDisabled);
			map.from(properties.isCleanOnValidationError()).to(configuration::cleanOnValidationError);
			map.from(properties.isGroup()).to(configuration::group);
			map.from(properties.isIgnoreMissingMigrations()).to(configuration::ignoreMissingMigrations);
			map.from(properties.isIgnoreIgnoredMigrations()).to(configuration::ignoreIgnoredMigrations);
			map.from(properties.isIgnorePendingMigrations()).to(configuration::ignorePendingMigrations);
			map.from(properties.isIgnoreFutureMigrations()).to(configuration::ignoreFutureMigrations);
			map.from(properties.isMixed()).to(configuration::mixed);
			map.from(properties.isOutOfOrder()).to(configuration::outOfOrder);
			map.from(properties.isSkipDefaultCallbacks()).to(configuration::skipDefaultCallbacks);
			map.from(properties.isSkipDefaultResolvers()).to(configuration::skipDefaultResolvers);
			configureValidateMigrationNaming(configuration, properties.isValidateMigrationNaming());
			map.from(properties.isValidateOnMigrate()).to(configuration::validateOnMigrate);
			// Pro properties
			map.from(properties.getBatch()).whenNonNull().to(configuration::batch);
			map.from(properties.getDryRunOutput()).whenNonNull().to(configuration::dryRunOutput);
			map.from(properties.getErrorOverrides()).whenNonNull().to(configuration::errorOverrides);
			map.from(properties.getLicenseKey()).whenNonNull().to(configuration::licenseKey);
			map.from(properties.getOracleSqlplus()).whenNonNull().to(configuration::oracleSqlplus);
			// No method reference for compatibility with Flyway 5.x
			map.from(properties.getOracleSqlplusWarn()).whenNonNull()
					.to((oracleSqlplusWarn) -> configuration.oracleSqlplusWarn(oracleSqlplusWarn));
			map.from(properties.getStream()).whenNonNull().to(configuration::stream);
			map.from(properties.getUndoSqlMigrationPrefix()).whenNonNull().to(configuration::undoSqlMigrationPrefix);
		}

		private void configureCreateSchemas(FluentConfiguration configuration, boolean createSchemas) {
			try {
				configuration.createSchemas(createSchemas);
			}
			catch (NoSuchMethodError ex) {
				// Flyway < 6.5
			}
		}

		private void configureValidateMigrationNaming(FluentConfiguration configuration,
				boolean validateMigrationNaming) {
			try {
				configuration.validateMigrationNaming(validateMigrationNaming);
			}
			catch (NoSuchMethodError ex) {
				// Flyway < 6.2
			}
		}

		private void configureCallbacks(FluentConfiguration configuration, List<Callback> callbacks) {
			if (!callbacks.isEmpty()) {
				configuration.callbacks(callbacks.toArray(new Callback[0]));
			}
		}

		private void configureFlywayCallbacks(FluentConfiguration flyway, List<Callback> callbacks) {
			if (!callbacks.isEmpty()) {
				flyway.callbacks(callbacks.toArray(new Callback[0]));
			}
		}

		private void configureJavaMigrations(FluentConfiguration flyway, List<JavaMigration> migrations) {
			if (!migrations.isEmpty()) {
				try {
					flyway.javaMigrations(migrations.toArray(new JavaMigration[0]));
				}
				catch (NoSuchMethodError ex) {
					// Flyway 5.x
				}
			}
		}

		private String getProperty(Supplier<String> property, Supplier<String> defaultValue) {
			String value = property.get();
			return (value != null) ? value : defaultValue.get();
		}

		private boolean hasAtLeastOneLocation(ResourceLoader resourceLoader, Collection<String> locations) {
			for (String location : locations) {
				if (resourceLoader.getResource(normalizePrefix(location)).exists()) {
					return true;
				}
			}
			return false;
		}

		private String normalizePrefix(String location) {
			return location.replace("filesystem:", "file:");
		}

		@Bean
		@ConditionalOnMissingBean
		public FlywayMigrationInitializer flywayInitializer(Flyway flyway,
				ObjectProvider<FlywayMigrationStrategy> migrationStrategy) {
			return new FlywayMigrationInitializer(flyway, migrationStrategy.getIfAvailable());
		}

	}

	/**
	 * Post processor to ensure that {@link EntityManagerFactory} beans depend on any
	 * {@link FlywayMigrationInitializer} beans.
	 */
	@ConditionalOnClass(LocalContainerEntityManagerFactoryBean.class)
	@ConditionalOnBean(AbstractEntityManagerFactoryBean.class)
	static class FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor
			extends EntityManagerFactoryDependsOnPostProcessor {

		FlywayMigrationInitializerEntityManagerFactoryDependsOnPostProcessor() {
			super(FlywayMigrationInitializer.class);
		}

	}

	/**
	 * Post processor to ensure that {@link JdbcOperations} beans depend on any
	 * {@link FlywayMigrationInitializer} beans.
	 */
	@ConditionalOnClass(JdbcOperations.class)
	@ConditionalOnBean(JdbcOperations.class)
	static class FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor
			extends JdbcOperationsDependsOnPostProcessor {

		FlywayMigrationInitializerJdbcOperationsDependsOnPostProcessor() {
			super(FlywayMigrationInitializer.class);
		}

	}

	/**
	 * Post processor to ensure that {@link NamedParameterJdbcOperations} beans depend on
	 * any {@link FlywayMigrationInitializer} beans.
	 */
	@ConditionalOnClass(NamedParameterJdbcOperations.class)
	@ConditionalOnBean(NamedParameterJdbcOperations.class)
	static class FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor
			extends NamedParameterJdbcOperationsDependsOnPostProcessor {

		FlywayMigrationInitializerNamedParameterJdbcOperationsDependsOnPostProcessor() {
			super(FlywayMigrationInitializer.class);
		}

	}

	/**
	 * Post processor to ensure that {@link EntityManagerFactory} beans depend on any
	 * {@link Flyway} beans.
	 */
	@ConditionalOnClass(LocalContainerEntityManagerFactoryBean.class)
	@ConditionalOnBean(AbstractEntityManagerFactoryBean.class)
	static class FlywayEntityManagerFactoryDependsOnPostProcessor extends EntityManagerFactoryDependsOnPostProcessor {

		FlywayEntityManagerFactoryDependsOnPostProcessor() {
			super(Flyway.class);
		}

	}

	/**
	 * Post processor to ensure that {@link JdbcOperations} beans depend on any
	 * {@link Flyway} beans.
	 */
	@ConditionalOnClass(JdbcOperations.class)
	@ConditionalOnBean(JdbcOperations.class)
	static class FlywayJdbcOperationsDependsOnPostProcessor extends JdbcOperationsDependsOnPostProcessor {

		FlywayJdbcOperationsDependsOnPostProcessor() {
			super(Flyway.class);
		}

	}

	/**
	 * Post processor to ensure that {@link NamedParameterJdbcOperations} beans depend on
	 * any {@link Flyway} beans.
	 */
	@ConditionalOnClass(NamedParameterJdbcOperations.class)
	@ConditionalOnBean(NamedParameterJdbcOperations.class)
	protected static class FlywayNamedParameterJdbcOperationsDependencyConfiguration
			extends NamedParameterJdbcOperationsDependsOnPostProcessor {

		public FlywayNamedParameterJdbcOperationsDependencyConfiguration() {
			super(Flyway.class);
		}

	}

	private static class LocationResolver {

		private static final String VENDOR_PLACEHOLDER = "{vendor}";

		private final DataSource dataSource;

		LocationResolver(DataSource dataSource) {
			this.dataSource = dataSource;
		}

		List<String> resolveLocations(List<String> locations) {
			if (usesVendorLocation(locations)) {
				DatabaseDriver databaseDriver = getDatabaseDriver();
				return replaceVendorLocations(locations, databaseDriver);
			}
			return locations;
		}

		private List<String> replaceVendorLocations(List<String> locations, DatabaseDriver databaseDriver) {
			if (databaseDriver == DatabaseDriver.UNKNOWN) {
				return locations;
			}
			String vendor = databaseDriver.getId();
			return locations.stream().map((location) -> location.replace(VENDOR_PLACEHOLDER, vendor))
					.collect(Collectors.toList());
		}

		private DatabaseDriver getDatabaseDriver() {
			try {
				String url = JdbcUtils.extractDatabaseMetaData(this.dataSource, DatabaseMetaData::getURL);
				return DatabaseDriver.fromJdbcUrl(url);
			}
			catch (MetaDataAccessException ex) {
				throw new IllegalStateException(ex);
			}

		}

		private boolean usesVendorLocation(Collection<String> locations) {
			for (String location : locations) {
				if (location.contains(VENDOR_PLACEHOLDER)) {
					return true;
				}
			}
			return false;
		}

	}

	/**
	 * Convert a String or Number to a {@link MigrationVersion}.
	 */
	private static class StringOrNumberToMigrationVersionConverter implements GenericConverter {

		private static final Set<ConvertiblePair> CONVERTIBLE_TYPES;

		static {
			Set<ConvertiblePair> types = new HashSet<>(2);
			types.add(new ConvertiblePair(String.class, MigrationVersion.class));
			types.add(new ConvertiblePair(Number.class, MigrationVersion.class));
			CONVERTIBLE_TYPES = Collections.unmodifiableSet(types);
		}

		@Override
		public Set<ConvertiblePair> getConvertibleTypes() {
			return CONVERTIBLE_TYPES;
		}

		@Override
		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
			String value = ObjectUtils.nullSafeToString(source);
			return MigrationVersion.fromVersion(value);
		}

	}

	static final class FlywayDataSourceCondition extends AnyNestedCondition {

		FlywayDataSourceCondition() {
			super(ConfigurationPhase.REGISTER_BEAN);
		}

		@ConditionalOnBean(DataSource.class)
		private static final class DataSourceBeanCondition {

		}

		@ConditionalOnProperty(prefix = "spring.flyway", name = "url", matchIfMissing = false)
		private static final class FlywayUrlCondition {

		}

	}

}
