/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.dtstack.flink.sql.classloader;

import com.dtstack.flink.sql.util.PluginUtil;
import com.dtstack.flink.sql.util.ReflectionUtils;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.FileInputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import java.sql.DriverManager;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * company: www.dtstack.com
 * author: toutian
 * create: 2019/10/14
 */
public class ClassLoaderManager {

    private static final Logger LOG = LoggerFactory.getLogger(ClassLoaderManager.class);
    private static final Map<String, DtClassLoader> pluginClassLoader = new ConcurrentHashMap<>();
    private static final Object LOCK = new Object();

    public static void forName(String clazz, ClassLoader classLoader) {
        synchronized (LOCK) {
            try {
                Class.forName(clazz, true, classLoader);
                DriverManager.setLoginTimeout(10);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    public synchronized static void forName(String clazz) {
        try {
            Class<?> driverClass = Class.forName(clazz);
            driverClass.newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static <R> R newInstance(String pluginJarPath, ClassLoaderSupplier<R> supplier) throws Exception {
        ClassLoader classLoader = retrieveClassLoad(pluginJarPath);
        return ClassLoaderSupplierCallBack.callbackAndReset(supplier, classLoader);
    }

    public static <R> R newInstance(List<URL> jarUrls, ClassLoaderSupplier<R> supplier) throws Exception {
        ClassLoader classLoader = retrieveClassLoad(jarUrls);
        return ClassLoaderSupplierCallBack.callbackAndReset(supplier, classLoader);
    }

    private static DtClassLoader retrieveClassLoad(String pluginJarPath) {
        return pluginClassLoader.computeIfAbsent(pluginJarPath, k -> {
            try {
                URL[] urls = PluginUtil.getPluginJarUrls(pluginJarPath);
                ClassLoader parentClassLoader = Thread.currentThread().getContextClassLoader();
                DtClassLoader classLoader = new DtClassLoader(urls, parentClassLoader);
                LOG.info("pluginJarPath:{} create ClassLoad successful...", pluginJarPath);
                return classLoader;
            } catch (Throwable e) {
                LOG.error("retrieve ClassLoad happens error", e);
                throw new RuntimeException("retrieve ClassLoad happens error");
            }
        });
    }

    public static DtClassLoader retrieveClassLoad(List<URL> jarUrls) {
        jarUrls.sort(Comparator.comparing(URL::toString));

        List<String> jarMd5s = new ArrayList<>(jarUrls.size());
        for (URL jarUrl : jarUrls) {
            try (FileInputStream inputStream = new FileInputStream(jarUrl.getPath())){
                String jarMd5 = DigestUtils.md5Hex(inputStream);
                jarMd5s.add(jarMd5);
            } catch (Exception e) {
                throw new RuntimeException("Exceptions appears when read file:" + e);
            }
        }
        String jarUrlkey = StringUtils.join(jarMd5s, "_");
        return pluginClassLoader.computeIfAbsent(jarUrlkey, k -> {
            try {
                URL[] urls = jarUrls.toArray(new URL[jarUrls.size()]);
                ClassLoader parentClassLoader = Thread.currentThread().getContextClassLoader();
                DtClassLoader classLoader = new DtClassLoader(urls, parentClassLoader);
                LOG.info("jarUrl:{} create ClassLoad successful...", jarUrlkey);
                return classLoader;
            } catch (Throwable e) {
                LOG.error("retrieve ClassLoad happens error:{}", e);
                throw new RuntimeException("retrieve ClassLoad happens error");
            }
        });
    }

    public static List<URL> getClassPath() {
        List<URL> classPaths = new ArrayList<>();
        for (Map.Entry<String, DtClassLoader> entry : pluginClassLoader.entrySet()) {
            classPaths.addAll(Arrays.asList(entry.getValue().getURLs()));
        }
        return classPaths;
    }


    public static URLClassLoader loadExtraJar(List<URL> jarUrlList, URLClassLoader classLoader)
            throws IllegalAccessException, InvocationTargetException {
        for (URL url : jarUrlList) {
            if (url.toString().endsWith(".jar")) {
                urlClassLoaderAddUrl(classLoader, url);
            }
        }
        return classLoader;
    }

    private static void urlClassLoaderAddUrl(URLClassLoader classLoader, URL url) throws InvocationTargetException, IllegalAccessException {
        Method method = ReflectionUtils.getDeclaredMethod(classLoader, "addURL", URL.class);

        if (method == null) {
            throw new RuntimeException("can't not find declared method addURL, curr classLoader is " + classLoader.getClass());
        }
        method.setAccessible(true);
        method.invoke(classLoader, url);
    }
}
