/*
 * Copyright 2012-present 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.flyway.autoconfigure;

import java.sql.DatabaseMetaData;
import java.time.Duration;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Supplier;

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.flywaydb.core.extensibility.ConfigurationExtension;
import org.flywaydb.database.oracle.OracleConfigurationExtension;
import org.flywaydb.database.postgresql.PostgreSQLConfigurationExtension;
import org.flywaydb.database.sqlserver.SQLServerConfigurationExtension;
import org.jspecify.annotations.Nullable;

import org.springframework.aot.hint.RuntimeHints;
import org.springframework.aot.hint.RuntimeHintsRegistrar;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfiguration;
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.ConditionalOnBooleanProperty;
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.context.properties.ConfigurationPropertiesBinding;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.context.properties.PropertyMapper;
import org.springframework.boot.flyway.autoconfigure.FlywayAutoConfiguration.FlywayAutoConfigurationRuntimeHints;
import org.springframework.boot.flyway.autoconfigure.FlywayAutoConfiguration.FlywayDataSourceCondition;
import org.springframework.boot.flyway.autoconfigure.FlywayProperties.Oracle;
import org.springframework.boot.flyway.autoconfigure.FlywayProperties.Postgresql;
import org.springframework.boot.flyway.autoconfigure.FlywayProperties.Sqlserver;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.boot.jdbc.DatabaseDriver;
import org.springframework.boot.jdbc.autoconfigure.DataSourceAutoConfiguration;
import org.springframework.boot.jdbc.autoconfigure.JdbcConnectionDetails;
import org.springframework.boot.sql.init.dependency.DatabaseInitializationDependencyConfigurer;
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.context.annotation.ImportRuntimeHints;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.convert.TypeDescriptor;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.io.ResourceLoader;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.jdbc.support.MetaDataAccessException;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.function.SingletonSupplier;

/**
 * {@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
 * @author Chris Bono
 * @author Moritz Halbritter
 * @author Andy Wilkinson
 * @since 4.0.0
 */
@AutoConfiguration(after = DataSourceAutoConfiguration.class)
@ConditionalOnClass(Flyway.class)
@Conditional(FlywayDataSourceCondition.class)
@ConditionalOnBooleanProperty(name = "spring.flyway.enabled", matchIfMissing = true)
@Import(DatabaseInitializationDependencyConfigurer.class)
@ImportRuntimeHints(FlywayAutoConfigurationRuntimeHints.class)
public final class FlywayAutoConfiguration {

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

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

	@Configuration(proxyBeanMethods = false)
	@ConditionalOnClass(JdbcUtils.class)
	@ConditionalOnMissingBean(Flyway.class)
	@EnableConfigurationProperties(FlywayProperties.class)
	static class FlywayConfiguration {

		private final FlywayProperties properties;

		FlywayConfiguration(FlywayProperties properties) {
			this.properties = properties;
		}

		@Bean
		ResourceProviderCustomizer resourceProviderCustomizer() {
			return new ResourceProviderCustomizer();
		}

		@Bean
		@ConditionalOnMissingBean(FlywayConnectionDetails.class)
		PropertiesFlywayConnectionDetails flywayConnectionDetails() {
			return new PropertiesFlywayConnectionDetails(this.properties);
		}

		@Bean
		Flyway flyway(FlywayConnectionDetails connectionDetails, ResourceLoader resourceLoader,
				ObjectProvider<DataSource> dataSource, @FlywayDataSource ObjectProvider<DataSource> flywayDataSource,
				ObjectProvider<FlywayConfigurationCustomizer> fluentConfigurationCustomizers,
				ObjectProvider<JavaMigration> javaMigrations, ObjectProvider<Callback> callbacks,
				ResourceProviderCustomizer resourceProviderCustomizer) {
			FluentConfiguration configuration = new FluentConfiguration(resourceLoader.getClassLoader());
			configureDataSource(configuration, flywayDataSource.getIfAvailable(), dataSource.getIfUnique(),
					connectionDetails);
			configureProperties(configuration, this.properties);
			configureCallbacks(configuration, callbacks.orderedStream().toList());
			configureJavaMigrations(configuration, javaMigrations.orderedStream().toList());
			fluentConfigurationCustomizers.orderedStream().forEach((customizer) -> customizer.customize(configuration));
			resourceProviderCustomizer.customize(configuration);
			return configuration.load();
		}

		private void configureDataSource(FluentConfiguration configuration, @Nullable DataSource flywayDataSource,
				@Nullable DataSource dataSource, FlywayConnectionDetails connectionDetails) {
			DataSource migrationDataSource = getMigrationDataSource(flywayDataSource, dataSource, connectionDetails);
			configuration.dataSource(migrationDataSource);
		}

		private DataSource getMigrationDataSource(@Nullable DataSource flywayDataSource,
				@Nullable DataSource dataSource, FlywayConnectionDetails connectionDetails) {
			if (flywayDataSource != null) {
				return flywayDataSource;
			}
			String url = connectionDetails.getJdbcUrl();
			if (url != null) {
				DataSourceBuilder<?> builder = DataSourceBuilder.create().type(SimpleDriverDataSource.class);
				builder.url(url);
				applyConnectionDetails(connectionDetails, builder);
				return builder.build();
			}
			String user = connectionDetails.getUsername();
			if (user != null && dataSource != null) {
				DataSourceBuilder<?> builder = DataSourceBuilder.derivedFrom(dataSource)
					.type(SimpleDriverDataSource.class);
				applyConnectionDetails(connectionDetails, builder);
				return builder.build();
			}
			Assert.state(dataSource != null, "Flyway migration DataSource missing");
			return dataSource;
		}

		private void applyConnectionDetails(FlywayConnectionDetails connectionDetails, DataSourceBuilder<?> builder) {
			builder.username(connectionDetails.getUsername());
			builder.password(connectionDetails.getPassword());
			String driverClassName = connectionDetails.getDriverClassName();
			if (StringUtils.hasText(driverClassName)) {
				builder.driverClassName(driverClassName);
			}
		}

		/**
		 * Configure the given {@code configuration} using the given {@code properties}.
		 * <p>
		 * To maximize forwards- and backwards-compatibility method references are not
		 * used.
		 * @param configuration the configuration
		 * @param properties the properties
		 */
		@SuppressWarnings("removal")
		private void configureProperties(FluentConfiguration configuration, FlywayProperties properties) {
			// NOTE: Using method references in the mapper methods can break
			// back-compatibility (see gh-38164)
			PropertyMapper map = PropertyMapper.get();
			String[] locations = new LocationResolver(configuration.getDataSource())
				.resolveLocations(properties.getLocations())
				.toArray(new String[0]);
			configuration.locations(locations);
			map.from(properties.getCallbackLocations())
				.when((callbackLocations) -> !ObjectUtils.isEmpty(callbackLocations))
				.to((callbackLocations) -> configuration.callbackLocations(
						new LocationResolver(configuration.getDataSource()).resolveLocations(callbackLocations)
							.toArray(new String[0])));
			map.from(properties.isFailOnMissingLocations())
				.to((failOnMissingLocations) -> configuration.failOnMissingLocations(failOnMissingLocations));
			map.from(properties.getEncoding()).to((encoding) -> configuration.encoding(encoding));
			map.from(properties.getConnectRetries())
				.to((connectRetries) -> configuration.connectRetries(connectRetries));
			map.from(properties.getConnectRetriesInterval())
				.as(Duration::getSeconds)
				.as(Long::intValue)
				.to((connectRetriesInterval) -> configuration.connectRetriesInterval(connectRetriesInterval));
			map.from(properties.getLockRetryCount())
				.to((lockRetryCount) -> configuration.lockRetryCount(lockRetryCount));
			map.from(properties.getDefaultSchema()).to((schema) -> configuration.defaultSchema(schema));
			map.from(properties.getSchemas())
				.as(StringUtils::toStringArray)
				.to((schemas) -> configuration.schemas(schemas));
			map.from(properties.isCreateSchemas()).to((createSchemas) -> configuration.createSchemas(createSchemas));
			map.from(properties.getTable()).to((table) -> configuration.table(table));
			map.from(properties.getTablespace()).to((tablespace) -> configuration.tablespace(tablespace));
			map.from(properties.getBaselineDescription())
				.to((baselineDescription) -> configuration.baselineDescription(baselineDescription));
			map.from(properties.getBaselineVersion())
				.to((baselineVersion) -> configuration.baselineVersion(baselineVersion));
			map.from(properties.getInstalledBy()).to((installedBy) -> configuration.installedBy(installedBy));
			map.from(properties.getPlaceholders()).to((placeholders) -> configuration.placeholders(placeholders));
			map.from(properties.getPlaceholderPrefix())
				.to((placeholderPrefix) -> configuration.placeholderPrefix(placeholderPrefix));
			map.from(properties.getPlaceholderSuffix())
				.to((placeholderSuffix) -> configuration.placeholderSuffix(placeholderSuffix));
			map.from(properties.getPlaceholderSeparator())
				.to((placeHolderSeparator) -> configuration.placeholderSeparator(placeHolderSeparator));
			map.from(properties.isPlaceholderReplacement())
				.to((placeholderReplacement) -> configuration.placeholderReplacement(placeholderReplacement));
			map.from(properties.getSqlMigrationPrefix())
				.to((sqlMigrationPrefix) -> configuration.sqlMigrationPrefix(sqlMigrationPrefix));
			map.from(properties.getSqlMigrationSuffixes())
				.as(StringUtils::toStringArray)
				.to((sqlMigrationSuffixes) -> configuration.sqlMigrationSuffixes(sqlMigrationSuffixes));
			map.from(properties.getSqlMigrationSeparator())
				.to((sqlMigrationSeparator) -> configuration.sqlMigrationSeparator(sqlMigrationSeparator));
			map.from(properties.getRepeatableSqlMigrationPrefix())
				.to((repeatableSqlMigrationPrefix) -> configuration
					.repeatableSqlMigrationPrefix(repeatableSqlMigrationPrefix));
			map.from(properties.getTarget()).to((target) -> configuration.target(target));
			map.from(properties.isBaselineOnMigrate())
				.to((baselineOnMigrate) -> configuration.baselineOnMigrate(baselineOnMigrate));
			map.from(properties.isCleanDisabled()).to((cleanDisabled) -> configuration.cleanDisabled(cleanDisabled));
			map.from(properties.isGroup()).to((group) -> configuration.group(group));
			map.from(properties.isMixed()).to((mixed) -> configuration.mixed(mixed));
			map.from(properties.isOutOfOrder()).to((outOfOrder) -> configuration.outOfOrder(outOfOrder));
			map.from(properties.isSkipDefaultCallbacks())
				.to((skipDefaultCallbacks) -> configuration.skipDefaultCallbacks(skipDefaultCallbacks));
			map.from(properties.isSkipDefaultResolvers())
				.to((skipDefaultResolvers) -> configuration.skipDefaultResolvers(skipDefaultResolvers));
			map.from(properties.isValidateMigrationNaming())
				.to((validateMigrationNaming) -> configuration.validateMigrationNaming(validateMigrationNaming));
			map.from(properties.isValidateOnMigrate())
				.to((validateOnMigrate) -> configuration.validateOnMigrate(validateOnMigrate));
			map.from(properties.getInitSqls())
				.whenNot(CollectionUtils::isEmpty)
				.as((initSqls) -> StringUtils.collectionToDelimitedString(initSqls, "\n"))
				.to((initSql) -> configuration.initSql(initSql));
			map.from(properties.getScriptPlaceholderPrefix())
				.to((prefix) -> configuration.scriptPlaceholderPrefix(prefix));
			map.from(properties.getScriptPlaceholderSuffix())
				.to((suffix) -> configuration.scriptPlaceholderSuffix(suffix));
			map.from(properties.getPowershellExecutable())
				.to((powershellExecutable) -> configuration.powershellExecutable(powershellExecutable));
			configureExecuteInTransaction(configuration, properties, map);
			map.from(properties::getLoggers).to((loggers) -> configuration.loggers(loggers));
			map.from(properties::getCommunityDbSupportEnabled)
				.to((communityDbSupportEnabled) -> configuration.communityDBSupportEnabled(communityDbSupportEnabled));
			map.from(properties.getBatch()).to((batch) -> configuration.batch(batch));
			map.from(properties.getDryRunOutput()).to((dryRunOutput) -> configuration.dryRunOutput(dryRunOutput));
			map.from(properties.getErrorOverrides())
				.to((errorOverrides) -> configuration.errorOverrides(errorOverrides));
			map.from(properties.getStream()).to((stream) -> configuration.stream(stream));
			map.from(properties.getJdbcProperties())
				.whenNot(Map::isEmpty)
				.to((jdbcProperties) -> configuration.jdbcProperties(jdbcProperties));
			map.from(properties.getKerberosConfigFile())
				.to((configFile) -> configuration.kerberosConfigFile(configFile));
			map.from(properties.getOutputQueryResults())
				.to((outputQueryResults) -> configuration.outputQueryResults(outputQueryResults));
			map.from(properties.getSkipExecutingMigrations())
				.to((skipExecutingMigrations) -> configuration.skipExecutingMigrations(skipExecutingMigrations));
			map.from(properties.getIgnoreMigrationPatterns())
				.to((ignoreMigrationPatterns) -> configuration
					.ignoreMigrationPatterns(ignoreMigrationPatterns.toArray(new String[0])));
			map.from(properties.getDetectEncoding())
				.to((detectEncoding) -> configuration.detectEncoding(detectEncoding));
		}

		private void configureExecuteInTransaction(FluentConfiguration configuration, FlywayProperties properties,
				PropertyMapper map) {
			try {
				map.from(properties.isExecuteInTransaction()).to(configuration::executeInTransaction);
			}
			catch (NoSuchMethodError ex) {
				// Flyway < 10.x/11.x compatibility
			}
		}

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

		private void configureJavaMigrations(FluentConfiguration flyway, List<JavaMigration> migrations) {
			if (!migrations.isEmpty()) {
				flyway.javaMigrations(migrations.toArray(new JavaMigration[0]));
			}
		}

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

		@ConditionalOnClass(name = "org.flywaydb.database.sqlserver.SQLServerConfigurationExtension")
		@Configuration(proxyBeanMethods = false)
		static class SqlServerConfiguration {

			@Bean
			SqlServerFlywayConfigurationCustomizer sqlServerFlywayConfigurationCustomizer(FlywayProperties properties) {
				return new SqlServerFlywayConfigurationCustomizer(properties);
			}

		}

		@Configuration(proxyBeanMethods = false)
		@ConditionalOnClass(name = "org.flywaydb.database.oracle.OracleConfigurationExtension")
		static class OracleConfiguration {

			@Bean
			OracleFlywayConfigurationCustomizer oracleFlywayConfigurationCustomizer(FlywayProperties properties) {
				return new OracleFlywayConfigurationCustomizer(properties);
			}

		}

		@ConditionalOnClass(name = "org.flywaydb.database.postgresql.PostgreSQLConfigurationExtension")
		@Configuration(proxyBeanMethods = false)
		static class PostgresqlConfiguration {

			@Bean
			PostgresqlFlywayConfigurationCustomizer postgresqlFlywayConfigurationCustomizer(
					FlywayProperties properties) {
				return new PostgresqlFlywayConfigurationCustomizer(properties);
			}

		}

	}

	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)).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}.
	 */
	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(@Nullable 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 {

		}

		@ConditionalOnBean(JdbcConnectionDetails.class)
		private static final class JdbcConnectionDetailsCondition {

		}

		@ConditionalOnProperty("spring.flyway.url")
		private static final class FlywayUrlCondition {

		}

	}

	static class FlywayAutoConfigurationRuntimeHints implements RuntimeHintsRegistrar {

		@Override
		public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
			hints.resources().registerPattern("db/migration/**");
		}

	}

	/**
	 * Adapts {@link FlywayProperties} to {@link FlywayConnectionDetails}.
	 */
	static final class PropertiesFlywayConnectionDetails implements FlywayConnectionDetails {

		private final FlywayProperties properties;

		PropertiesFlywayConnectionDetails(FlywayProperties properties) {
			this.properties = properties;
		}

		@Override
		public @Nullable String getUsername() {
			return this.properties.getUser();
		}

		@Override
		public @Nullable String getPassword() {
			return this.properties.getPassword();
		}

		@Override
		public @Nullable String getJdbcUrl() {
			return this.properties.getUrl();
		}

		@Override
		public @Nullable String getDriverClassName() {
			return this.properties.getDriverClassName();
		}

	}

	@Order(Ordered.HIGHEST_PRECEDENCE)
	static final class OracleFlywayConfigurationCustomizer implements FlywayConfigurationCustomizer {

		private final FlywayProperties properties;

		OracleFlywayConfigurationCustomizer(FlywayProperties properties) {
			this.properties = properties;
		}

		@Override
		public void customize(FluentConfiguration configuration) {
			Extension<OracleConfigurationExtension> extension = new Extension<>(configuration,
					OracleConfigurationExtension.class, "Oracle");
			Oracle properties = this.properties.getOracle();
			PropertyMapper map = PropertyMapper.get();
			map.from(properties::getSqlplus).to(extension.via((ext, sqlplus) -> ext.setSqlplus(sqlplus)));
			map.from(properties::getSqlplusWarn)
				.to(extension.via((ext, sqlplusWarn) -> ext.setSqlplusWarn(sqlplusWarn)));
			map.from(properties::getWalletLocation)
				.to(extension.via((ext, walletLocation) -> ext.setWalletLocation(walletLocation)));
			map.from(properties::getKerberosCacheFile)
				.to(extension.via((ext, kerberosCacheFile) -> ext.setKerberosCacheFile(kerberosCacheFile)));
		}

	}

	@Order(Ordered.HIGHEST_PRECEDENCE)
	static final class PostgresqlFlywayConfigurationCustomizer implements FlywayConfigurationCustomizer {

		private final FlywayProperties properties;

		PostgresqlFlywayConfigurationCustomizer(FlywayProperties properties) {
			this.properties = properties;
		}

		@Override
		public void customize(FluentConfiguration configuration) {
			Extension<PostgreSQLConfigurationExtension> extension = new Extension<>(configuration,
					PostgreSQLConfigurationExtension.class, "PostgreSQL");
			Postgresql properties = this.properties.getPostgresql();
			PropertyMapper map = PropertyMapper.get();
			map.from(properties::getTransactionalLock)
				.to(extension.via((ext, transactionalLock) -> ext.setTransactionalLock(transactionalLock)));
		}

	}

	@Order(Ordered.HIGHEST_PRECEDENCE)
	static final class SqlServerFlywayConfigurationCustomizer implements FlywayConfigurationCustomizer {

		private final FlywayProperties properties;

		SqlServerFlywayConfigurationCustomizer(FlywayProperties properties) {
			this.properties = properties;
		}

		@Override
		public void customize(FluentConfiguration configuration) {
			Extension<SQLServerConfigurationExtension> extension = new Extension<>(configuration,
					SQLServerConfigurationExtension.class, "SQL Server");
			Sqlserver properties = this.properties.getSqlserver();
			PropertyMapper map = PropertyMapper.get();
			map.from(properties::getKerberosLoginFile).to(extension.via(this::setKerberosLoginFile));
		}

		private void setKerberosLoginFile(SQLServerConfigurationExtension configuration, String file) {
			configuration.getKerberos().getLogin().setFile(file);
		}

	}

	/**
	 * Helper class used to map properties to a {@link ConfigurationExtension}.
	 *
	 * @param <E> the extension type
	 */
	static class Extension<E extends ConfigurationExtension> {

		private final Supplier<E> extension;

		Extension(FluentConfiguration configuration, Class<E> type, String name) {
			this.extension = SingletonSupplier.of(() -> {
				E extension = configuration.getPluginRegister().getExact(type);
				Assert.state(extension != null, () -> "Flyway %s extension missing".formatted(name));
				return extension;
			});
		}

		<T> Consumer<T> via(BiConsumer<E, T> action) {
			return (value) -> action.accept(this.extension.get(), value);
		}

	}

}
