/*
 * 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.autoconfigure.h2;

import java.sql.Connection;
import java.util.List;
import java.util.Objects;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.h2.server.web.JakartaWebServlet;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.h2.H2ConsoleProperties.Settings;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.core.log.LogMessage;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for H2's web console.
 *
 * @author Andy Wilkinson
 * @author Marten Deinum
 * @author Stephane Nicoll
 * @author Phillip Webb
 * @since 1.3.0
 */
@AutoConfiguration(after = DataSourceAutoConfiguration.class)
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass(JakartaWebServlet.class)
@ConditionalOnProperty(prefix = "spring.h2.console", name = "enabled", havingValue = "true")
@EnableConfigurationProperties(H2ConsoleProperties.class)
public class H2ConsoleAutoConfiguration {

	private static final Log logger = LogFactory.getLog(H2ConsoleAutoConfiguration.class);

	private final H2ConsoleProperties properties;

	H2ConsoleAutoConfiguration(H2ConsoleProperties properties) {
		this.properties = properties;
	}

	@Bean
	public ServletRegistrationBean<JakartaWebServlet> h2Console() {
		String path = this.properties.getPath();
		String urlMapping = path + (path.endsWith("/") ? "*" : "/*");
		ServletRegistrationBean<JakartaWebServlet> registration = new ServletRegistrationBean<>(new JakartaWebServlet(),
				urlMapping);
		configureH2ConsoleSettings(registration, this.properties.getSettings());
		return registration;
	}

	@Bean
	H2ConsoleLogger h2ConsoleLogger(ObjectProvider<DataSource> dataSources) {
		return new H2ConsoleLogger(dataSources, this.properties.getPath());
	}

	private void configureH2ConsoleSettings(ServletRegistrationBean<JakartaWebServlet> registration,
			Settings settings) {
		if (settings.isTrace()) {
			registration.addInitParameter("trace", "");
		}
		if (settings.isWebAllowOthers()) {
			registration.addInitParameter("webAllowOthers", "");
		}
		if (settings.getWebAdminPassword() != null) {
			registration.addInitParameter("webAdminPassword", settings.getWebAdminPassword());
		}
	}

	static class H2ConsoleLogger {

		H2ConsoleLogger(ObjectProvider<DataSource> dataSources, String path) {
			if (logger.isInfoEnabled()) {
				ClassLoader classLoader = getClass().getClassLoader();
				withThreadContextClassLoader(classLoader, () -> log(getConnectionUrls(dataSources), path));
			}
		}

		private void withThreadContextClassLoader(ClassLoader classLoader, Runnable action) {
			ClassLoader previous = Thread.currentThread().getContextClassLoader();
			try {
				Thread.currentThread().setContextClassLoader(classLoader);
				action.run();
			}
			finally {
				Thread.currentThread().setContextClassLoader(previous);
			}
		}

		private List<String> getConnectionUrls(ObjectProvider<DataSource> dataSources) {
			return dataSources.orderedStream(ObjectProvider.UNFILTERED)
				.map(this::getConnectionUrl)
				.filter(Objects::nonNull)
				.toList();
		}

		private String getConnectionUrl(DataSource dataSource) {
			try (Connection connection = dataSource.getConnection()) {
				return "'" + connection.getMetaData().getURL() + "'";
			}
			catch (Exception ex) {
				return null;
			}
		}

		private void log(List<String> urls, String path) {
			if (!urls.isEmpty()) {
				logger.info(LogMessage.format("H2 console available at '%s'. %s available at %s", path,
						(urls.size() > 1) ? "Databases" : "Database", String.join(", ", urls)));
			}
		}

	}

}
