import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;

import java.io.IOException;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @Author: gaobangpeng
 * @Date: 2018/11/1 14:23
 * @Version 1.0
 */

public class DynamicGetAndSetLog {
    private static final Logger LOGGER = LogManager.getLogger(DynamicGetAndSetLog.class);

    /**
     * 獲取某個類或包的日誌級別
     *
     * @param loggerName 類或包名
     * @return String
     */
    public static String getLoggerLevel(String loggerName) {
        if (loggerName == null || "".equals(loggerName)) {
            return "目標類或包不能為空";
        }
        Logger logger = LogManager.getLogger(loggerName);
        if (logger != null) {
            return logger.getLevel().toString();
        }
        return "當前log等級獲取失敗";
    }

    /**
     * 修改某個類或包的日誌級別
     *
     * @param loggerName 類或包名
     * @param level      log級別
     * @return String
     */
    public static String setLogLevel(String loggerName, String level) {
        try {
            Level newLevel = Level.valueOf(level);
            LoggerContext logContext = (LoggerContext) LogManager.getContext(false);
            Configuration configuration = logContext.getConfiguration();
            LoggerConfig loggerConfig = configuration.getLoggerConfig(loggerName);
            // getLoggerConfig("a.b.c") could return logger for "a.b" if there is no logger for "a.b.c"
            if (loggerConfig.getName().equalsIgnoreCase(loggerName)) {
                loggerConfig.setLevel(newLevel);
            } else {
                // create a new config.
                loggerConfig = new LoggerConfig(loggerName, newLevel, false);
                configuration.addLogger(loggerName, loggerConfig);


                LoggerConfig parentConfig = loggerConfig.getParent();
                do {
                    for (Map.Entry<String, Appender> entry : parentConfig.getAppenders().entrySet()) {
                        loggerConfig.addAppender(entry.getValue(), null, null);
                    }
                    parentConfig = parentConfig.getParent();
                } while (null != parentConfig && parentConfig.isAdditive());
            }
            logContext.updateLoggers();
        } catch (Exception e) {
            LOGGER.info(e);
            return "設定log級別失敗";
        }
        return "設定log級別為" + level;
    }

    /**
     * 通過包名獲取包下所有class類，以及每個類對應的Log級別
     *
     * @param packageName 包名
     * @return Map <類名，log級別>
     */
    public static Map<String, String> getAllClassesAndLogLevelInCurrentPackage(String packageName) {
        List<String> res = null;
        try {
            res = PackageUtil.getClassName(packageName);
        } catch (IOException e) {
            LOGGER.error("獲取包下所有類失敗" + e);
        }
        Map<String, String> result = new HashMap<>();
        String regex = "\\";
        for (String classFile : res) {
            try {
                classFile = classFile.replace(regex, ".");
                classFile = classFile.substring(classFile.indexOf(packageName));
            } catch (Exception e) {
                LOGGER.error("包名替換，出現異常，" + e);
            }
            try {
                Class buildingController = Class.forName(classFile);
                Field[] fields = buildingController.getDeclaredFields();
                for (int s = 0; s < fields.length; s++) {
                    if (fields[s].getName().equals("LOGGER")) {
                        String logLevel = getLoggerLevel(classFile);
                        result.put(classFile, logLevel);
                        break;
                    }
                }
            } catch (ClassNotFoundException e) {
                LOGGER.error("沒有發現該類" + classFile);
            }
        }
        return result;
    }
}