/*
 * 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.ratis.util;

import org.apache.ratis.util.function.CheckedRunnable;
import org.apache.ratis.util.function.CheckedSupplier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.Callable;
import java.util.function.Supplier;

/**
 * Logging (as in log4j) related utility methods.
 */
public interface LogUtils {
  Logger LOG = LoggerFactory.getLogger(LogUtils.class);

  static <THROWABLE extends Throwable> void runAndLog(
      Logger log, CheckedRunnable<THROWABLE> op, Supplier<String> opName)
      throws THROWABLE {
    try {
      op.run();
    } catch (Throwable t) {
      if (log.isTraceEnabled()) {
        log.trace("Failed to " + opName.get(), t);
      } else if (log.isWarnEnabled()){
        log.warn("Failed to " + opName.get() + ": " + t);
      }
      throw t;
    }

    if (log.isTraceEnabled()) {
      log.trace("Successfully ran " + opName.get());
    }
  }

  static <OUTPUT, THROWABLE extends Throwable> OUTPUT supplyAndLog(
      Logger log, CheckedSupplier<OUTPUT, THROWABLE> supplier, Supplier<String> name)
      throws THROWABLE {
    final OUTPUT output;
    try {
      output = supplier.get();
    } catch (Exception e) {
      if (log.isTraceEnabled()) {
        log.trace("Failed to " + name.get(), e);
      } else if (log.isWarnEnabled()){
        log.warn("Failed to " + name.get() + ": " + e);
      }
      throw e;
    }

    if (log.isTraceEnabled()) {
      log.trace("Successfully supplied " + name.get() + ": " + output);
    }
    return output;
  }

  static Runnable newRunnable(Logger log, Runnable runnable, Supplier<String> name) {
    return new Runnable() {
      @Override
      public void run() {
        runAndLog(log, runnable::run, name);
      }

      @Override
      public String toString() {
        return name.get();
      }
    };
  }

  static <T> Callable<T> newCallable(Logger log, Callable<T> callable, Supplier<String> name) {
    return new Callable<T>() {
      @Override
      public T call() throws Exception {
        return supplyAndLog(log, callable::call, name);
      }

      @Override
      public String toString() {
        return name.get();
      }
    };
  }

  static <OUTPUT, THROWABLE extends Throwable> CheckedSupplier<OUTPUT, THROWABLE> newCheckedSupplier(
      Logger log, CheckedSupplier<OUTPUT, THROWABLE> supplier, Supplier<String> name) {
    return new CheckedSupplier<OUTPUT, THROWABLE>() {
      @Override
      public OUTPUT get() throws THROWABLE {
        return supplyAndLog(log, supplier, name);
      }

      @Override
      public String toString() {
        return name.get();
      }
    };
  }

  static void warn(Logger log, Supplier<String> message, Throwable t, Class<?>... exceptionClasses) {
    if (log.isWarnEnabled()) {
      if (ReflectionUtils.isInstance(t, exceptionClasses)) {
        // do not print stack trace for known exceptions.
        final StringBuilder b = new StringBuilder()
            .append(message.get())
            .append(": ").append(t);
        for(Throwable cause = t.getCause(); cause != null; cause = cause.getCause()) {
          b.append("\n  Caused by: ").append(cause);
        }
        log.warn(b.toString());
      } else {
        log.warn(message.get(), t);
      }
    }
  }

  static void infoOrTrace(Logger log, String message, Throwable t) {
    infoOrTrace(log, () -> message, t);
  }

  static void infoOrTrace(Logger log, Supplier<String> message, Throwable t) {
    if (log.isTraceEnabled()) {
      log.trace(message.get(), t);
    } else if (log.isInfoEnabled()) {
      log.info("{}: {}", message.get(), String.valueOf(t));
    }
  }
}
