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package com.ctrip.framework.apollo.spring.boot;

import com.ctrip.framework.apollo.Config;
import com.ctrip.framework.apollo.ConfigService;
import com.ctrip.framework.apollo.core.ConfigConsts;
import com.ctrip.framework.apollo.spring.config.ConfigPropertySourceFactory;
import com.ctrip.framework.apollo.spring.config.PropertySourcesConstants;
import com.ctrip.framework.apollo.spring.util.SpringInjector;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.env.CompositePropertySource;
import org.springframework.core.env.ConfigurableEnvironment;

/**
 * Initialize apollo system properties and inject the Apollo config in Spring Boot bootstrap phase
 *
 * Configuration example:
 *  *   # set app.id
 *   app.id = 100004458
 *   # enable apollo bootstrap config and inject 'application' namespace in bootstrap phase
 *   apollo.bootstrap.enabled = true
 * 
 *
 * or
 *
 *  *   # set app.id
 *   app.id = 100004458
 *   # enable apollo bootstrap config
 *   apollo.bootstrap.enabled = true
 *   # will inject 'application' and 'FX.apollo' namespaces in bootstrap phase
 *   apollo.bootstrap.namespaces = application,FX.apollo
 * 
 */
public class ApolloApplicationContextInitializer implements
    ApplicationContextInitializer {
  private static final Logger logger = LoggerFactory.getLogger(ApolloApplicationContextInitializer.class);
  private static final Splitter NAMESPACE_SPLITTER = Splitter.on(",").omitEmptyStrings().trimResults();
  private static final String[] APOLLO_SYSTEM_PROPERTIES = {"app.id", ConfigConsts.APOLLO_CLUSTER_KEY,
      "apollo.cacheDir", ConfigConsts.APOLLO_META_KEY};

  private final ConfigPropertySourceFactory configPropertySourceFactory = SpringInjector
      .getInstance(ConfigPropertySourceFactory.class);

  @Override
  public void initialize(ConfigurableApplicationContext context) {
    ConfigurableEnvironment environment = context.getEnvironment();

    initializeSystemProperty(environment);

    String enabled = environment.getProperty(PropertySourcesConstants.APOLLO_BOOTSTRAP_ENABLED, "false");
    if (!Boolean.valueOf(enabled)) {
      logger.debug("Apollo bootstrap config is not enabled for context {}, see property: ${{}}", context, PropertySourcesConstants.APOLLO_BOOTSTRAP_ENABLED);
      return;
    }
    logger.debug("Apollo bootstrap config is enabled for context {}", context);

    if (environment.getPropertySources().contains(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
      //already initialized
      return;
    }

    String namespaces = environment.getProperty(PropertySourcesConstants.APOLLO_BOOTSTRAP_NAMESPACES, ConfigConsts.NAMESPACE_APPLICATION);
    logger.debug("Apollo bootstrap namespaces: {}", namespaces);
    List namespaceList = NAMESPACE_SPLITTER.splitToList(namespaces);

    CompositePropertySource composite = new CompositePropertySource(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME);
    for (String namespace : namespaceList) {
      Config config = ConfigService.getConfig(namespace);

      composite.addPropertySource(configPropertySourceFactory.getConfigPropertySource(namespace, config));
    }

    environment.getPropertySources().addFirst(composite);
  }

  /**
   * To fill system properties from environment config
   */
  void initializeSystemProperty(ConfigurableEnvironment environment) {
    for (String propertyName : APOLLO_SYSTEM_PROPERTIES) {
      fillSystemPropertyFromEnvironment(environment, propertyName);
    }
  }

  private void fillSystemPropertyFromEnvironment(ConfigurableEnvironment environment, String propertyName) {
    if (System.getProperty(propertyName) != null) {
      return;
    }

    String propertyValue = environment.getProperty(propertyName);

    if (Strings.isNullOrEmpty(propertyValue)) {
      return;
    }

    System.setProperty(propertyName, propertyValue);
  }
}