package com.example.sbcamel;

import java.io.IOException;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;

import javax.sql.DataSource;

import org.apache.camel.component.mybatis.MyBatisComponent;
import org.apache.camel.spring.spi.SpringTransactionPolicy;
import org.apache.ibatis.mapping.Environment;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy;
import org.springframework.transaction.PlatformTransactionManager;

import com.google.common.reflect.ClassPath;
import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;

@Configuration
public class DatabaseConfig {

	private static final Logger logger = LoggerFactory.getLogger(DatabaseConfig.class);

	public static final String CFG_APP_DATABASE_URL = "${app.database.url}";
	public static final String CFG_APP_DATABASE_USERNAME = "${app.database.username:}";
	public static final String CFG_APP_DATABASE_PASSWORD = "${app.database.password:}";
	public static final String CFG_APP_DATABASE_MAPPER_PACKAGE = "${app.database.mapper-package}";
	public static final String CFG_APP_DATABASE_SPRINGBOOT_CLASS_PREFIX = "${app.database.springboot-class-prefix:BOOT-INF.classes.}";

	@Value(CFG_APP_DATABASE_URL)
	private String dbUrl;

	@Value(CFG_APP_DATABASE_USERNAME)
	private String dbUsername;

	@Value(CFG_APP_DATABASE_PASSWORD)
	private String dbPassword;

	@Value(CFG_APP_DATABASE_MAPPER_PACKAGE)
	private String mapperPackage;

	@Value(CFG_APP_DATABASE_SPRINGBOOT_CLASS_PREFIX)
	private String springBootClassPrefix;

	@Bean
	HikariConfig hikariConfig() {
		HikariConfig config = new HikariConfig();
		config.setJdbcUrl(dbUrl);
		config.setUsername(dbUsername);
		config.setPassword(dbPassword);
		config.addDataSourceProperty("cachePrepStmts", "true");
		config.addDataSourceProperty("prepStmtCacheSize", "250");
		config.addDataSourceProperty("prepStmtCacheSqlLimit", "2048");
		return config;
	}

	@Bean
	DataSource dataSource(HikariConfig hikariConfig) {
		return new TransactionAwareDataSourceProxy(new HikariDataSource(hikariConfig));
	}

	@Bean
	PlatformTransactionManager txManager(DataSource dataSource) {
		return new DataSourceTransactionManager(dataSource);
	}

	@Bean
	SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
		Environment environment = new Environment("development", new JdbcTransactionFactory(), dataSource);
		org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration(
				environment);
		Set<Class<?>> mapperClasses = findAllClassesUsingGuava(mapperPackage);
		mapperClasses.forEach(configuration::addMapper);
		return new SqlSessionFactoryBuilder().build(configuration);
	}

	@Bean
	MyBatisComponent mybatis(SqlSessionFactory sqlSessionFactory) {
		MyBatisComponent mybatis = new MyBatisComponent();
		mybatis.setSqlSessionFactory(sqlSessionFactory);
		return mybatis;
	}

	@Bean
	SpringTransactionPolicy propagationRequired(PlatformTransactionManager txManager) {
		SpringTransactionPolicy propagationRequired = new SpringTransactionPolicy();
		propagationRequired.setTransactionManager(txManager);
		propagationRequired.setPropagationBehaviorName("PROPAGATION_REQUIRED");
		return propagationRequired;
	}

	private Set<Class<?>> findAllClassesUsingGuava(String packageName) throws IOException {
		logger.trace("Orm mappers packageName: {}", packageName);
		return ClassPath.from(ClassLoader.getSystemClassLoader()).getAllClasses().stream()
				.peek(clazz -> logger.trace("candidate class: {}, package name: {}", clazz, clazz.getPackageName()))
				.filter(clazz -> clazz.getPackageName().endsWith(packageName))
				.peek(clazz -> logger.info("accepted class: {}, package name: {}", clazz, clazz.getPackageName()))
				.map(clazz -> {
					try {
						if (clazz.getName().startsWith(springBootClassPrefix)) {
							return Class.forName(clazz.getName().replace(springBootClassPrefix, ""));
						}
						return Class.forName(clazz.getName());
					} catch (ClassNotFoundException e) {
						logger.error("cannot convert this class name to class: {}", clazz.getName());
					}
					return null;
				}).filter(Objects::nonNull).collect(Collectors.toSet());
	}
}