/*
 * 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 org.apache.dubbo.config.spring.beans.factory.annotation;

import org.apache.dubbo.common.utils.Assert;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.config.AbstractConfig;
import org.apache.dubbo.config.spring.context.annotation.DubboConfigBindingRegistrar;
import org.apache.dubbo.config.spring.context.annotation.EnableDubboConfigBinding;
import org.apache.dubbo.config.spring.context.config.DubboConfigBeanCustomizer;
import org.apache.dubbo.config.spring.context.properties.DefaultDubboConfigBinder;
import org.apache.dubbo.config.spring.context.properties.DubboConfigBinder;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.core.env.Environment;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import static org.springframework.beans.factory.BeanFactoryUtils.beansOfTypeIncludingAncestors;

/**
 * Dubbo Config Binding {@link BeanPostProcessor}
 *
 * @see EnableDubboConfigBinding
 * @see DubboConfigBindingRegistrar
 * @since 2.5.8
 */

public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, ApplicationContextAware, InitializingBean
        , BeanDefinitionRegistryPostProcessor {

    private final Log log = LogFactory.getLog(getClass());

    /**
     * The prefix of Configuration Properties
     */
    private final String prefix;

    /**
     * Binding Bean Name
     */
    private final String beanName;

    private DubboConfigBinder dubboConfigBinder;

    private ApplicationContext applicationContext;

    private BeanDefinitionRegistry beanDefinitionRegistry;

    private boolean ignoreUnknownFields = true;

    private boolean ignoreInvalidFields = true;

    private List<DubboConfigBeanCustomizer> configBeanCustomizers = Collections.emptyList();

    /**
     * @param prefix   the prefix of Configuration Properties
     * @param beanName the binding Bean Name
     */
    public DubboConfigBindingBeanPostProcessor(String prefix, String beanName) {
        Assert.notNull(prefix, "The prefix of Configuration Properties must not be null");
        Assert.notNull(beanName, "The name of bean must not be null");
        this.prefix = prefix;
        this.beanName = beanName;
    }

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {

        // 每个XxConfig对应一个BeanPostProcessor，所以每个DubboConfigBindingBeanPostProcessor只处理对应的beanName

        if (this.beanName.equals(beanName) && bean instanceof AbstractConfig) {

            AbstractConfig dubboConfig = (AbstractConfig) bean;
            // 从properties文件中获取值，并设置到dubboConfig对象中
            bind(prefix, dubboConfig);

            // 设置dubboConfig对象的name属性，设置为beanName
            customize(beanName, dubboConfig);

        }

        return bean;

    }

    private void bind(String prefix, AbstractConfig dubboConfig) {

        dubboConfigBinder.bind(prefix, dubboConfig);

        if (log.isInfoEnabled()) {
            log.info("The properties of bean [name : " + beanName + "] have been binding by prefix of " +
                    "configuration properties : " + prefix);
        }
    }

    private void customize(String beanName, AbstractConfig dubboConfig) {

        for (DubboConfigBeanCustomizer customizer : configBeanCustomizers) {
            customizer.customize(beanName, dubboConfig);
        }

    }

    public boolean isIgnoreUnknownFields() {
        return ignoreUnknownFields;
    }

    public void setIgnoreUnknownFields(boolean ignoreUnknownFields) {
        this.ignoreUnknownFields = ignoreUnknownFields;
    }

    public boolean isIgnoreInvalidFields() {
        return ignoreInvalidFields;
    }

    public void setIgnoreInvalidFields(boolean ignoreInvalidFields) {
        this.ignoreInvalidFields = ignoreInvalidFields;
    }

    public DubboConfigBinder getDubboConfigBinder() {
        return dubboConfigBinder;
    }

    public void setDubboConfigBinder(DubboConfigBinder dubboConfigBinder) {
        this.dubboConfigBinder = dubboConfigBinder;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof AbstractConfig) {
            // 添加别名，id属性的值为别名

            String id = ((AbstractConfig) bean).getId();
            if (beanDefinitionRegistry != null && beanDefinitionRegistry instanceof DefaultListableBeanFactory) {
                DefaultListableBeanFactory factory = (DefaultListableBeanFactory) beanDefinitionRegistry;
                if (!StringUtils.isBlank(id) && !factory.hasAlias(beanName, id)) {
                    beanDefinitionRegistry.registerAlias(beanName, id);
                }
            }
        }
        return bean;
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    @Override
    public void afterPropertiesSet() throws Exception {

        initDubboConfigBinder();        // 创建DefaultDubboConfigBinder

        initConfigBeanCustomizers();

    }

    private void initDubboConfigBinder() {

        if (dubboConfigBinder == null) {
            try {
                // 先从Spring容器中获取DubboConfigBinder，默认获取不到
                dubboConfigBinder = applicationContext.getBean(DubboConfigBinder.class);
            } catch (BeansException ignored) {
                if (log.isDebugEnabled()) {
                    log.debug("DubboConfigBinder Bean can't be found in ApplicationContext.");
                }

                // Use Default implementation
                // 生成一个默认的
                dubboConfigBinder = createDubboConfigBinder(applicationContext.getEnvironment());
            }
        }

        dubboConfigBinder.setIgnoreUnknownFields(ignoreUnknownFields);
        dubboConfigBinder.setIgnoreInvalidFields(ignoreInvalidFields);

    }

    private void initConfigBeanCustomizers() {

        // 得到之前创建了的NamePropertyDefaultValueDubboConfigBeanCustomizer
        Collection<DubboConfigBeanCustomizer> configBeanCustomizers =
                beansOfTypeIncludingAncestors(applicationContext, DubboConfigBeanCustomizer.class).values();

        this.configBeanCustomizers = new ArrayList<>(configBeanCustomizers);

        AnnotationAwareOrderComparator.sort(this.configBeanCustomizers);
    }

    /**
     * Create {@link DubboConfigBinder} instance.
     *
     * @param environment
     * @return {@link DefaultDubboConfigBinder}
     */
    protected DubboConfigBinder createDubboConfigBinder(Environment environment) {
        DefaultDubboConfigBinder defaultDubboConfigBinder = new DefaultDubboConfigBinder();
        defaultDubboConfigBinder.setEnvironment(environment);
        return defaultDubboConfigBinder;
    }

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        if (this.beanDefinitionRegistry == null) {
            this.beanDefinitionRegistry = registry;
        }
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        //do nothing here
    }
}
