/*
    * Copyright 2012-2021 CodeLibs Project and the Others.
    *
    * Licensed 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.codelibs.fess.job;
  
  import static org.codelibs.core.stream.StreamUtil.stream;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.ServletContext;
  
  import org.apache.commons.lang3.RandomStringUtils;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.codelibs.core.lang.StringUtil;
  import org.codelibs.core.timer.TimeoutTask;
  import org.codelibs.fess.Constants;
  import org.codelibs.fess.exception.JobProcessingException;
  import org.codelibs.fess.helper.ProcessHelper;
  import org.codelibs.fess.mylasta.direction.FessConfig;
  import org.codelibs.fess.util.ComponentUtil;
  import org.codelibs.fess.util.InputStreamThread;
  import org.codelibs.fess.util.JobProcess;
  
  public class PythonJob extends ExecJob {
      static final Logger logger = LogManager.getLogger(PythonJob.class);
  
      protected String filename;
  
      protected List<String> argList = new ArrayList<>();
  
      public PythonJob filename(final String filename) {
          this.filename = filename;
          return this;
      }
  
      public PythonJob arg(final String value) {
          argList.add(value);
          return this;
      }
  
      public PythonJob args(final String... values) {
          stream(values).of(stream -> stream.forEach(argList::add));
          return this;
      }
  
      @Override
      public String execute() {
          final StringBuilder resultBuf = new StringBuilder();
  
          if (sessionId == null) { // create session id
              sessionId = RandomStringUtils.randomAlphabetic(15);
          }
          resultBuf.append("Session Id: ").append(sessionId).append("\n");
          if (jobExecutor != null) {
              jobExecutor.addShutdownListener(() -> ComponentUtil.getProcessHelper().destroyProcess(sessionId));
          }
  
          final TimeoutTask timeoutTask = createTimeoutTask();
          try {
              executePython();
          } catch (final Exception e) {
              logger.warn("Failed to run python command.", e);
              resultBuf.append(e.getMessage()).append("\n");
          } finally {
              if (timeoutTask != null && !timeoutTask.isCanceled()) {
                  timeoutTask.cancel();
              }
          }
  
          return resultBuf.toString();
  
      }
  
      protected void executePython() {
          final List<String> cmdList = new ArrayList<>();
          final ServletContext servletContext = ComponentUtil.getComponent(ServletContext.class);
          final ProcessHelper processHelper = ComponentUtil.getProcessHelper();
          final FessConfig fessConfig = ComponentUtil.getFessConfig();
  
          if (StringUtil.isBlank(filename)) {
              throw new JobProcessingException("Python script is not specified.");
          }
  
          cmdList.add(fessConfig.getPythonCommandPath());
 
         cmdList.add(getPyFilePath());
 
         cmdList.addAll(argList);
 
         try {
 
             final File baseDir = new File(servletContext.getRealPath("/WEB-INF")).getParentFile();
 
             if (logger.isInfoEnabled()) {
                 logger.info("Python: \nDirectory={}\nOptions={}", baseDir, cmdList);
             }
 
             final JobProcess jobProcess = processHelper.startProcess(sessionId, cmdList, pb -> {
                 pb.directory(baseDir);
                 pb.redirectErrorStream(true);
             });
 
             final InputStreamThread it = jobProcess.getInputStreamThread();
             it.start();
 
             final Process currentProcess = jobProcess.getProcess();
             currentProcess.waitFor();
             it.join(5000);
 
             final int exitValue = currentProcess.exitValue();
 
             if (logger.isInfoEnabled()) {
                 logger.info("Python: Exit Code={} - Process Output:\n{}", exitValue, it.getOutput());
             }
             if (exitValue != 0) {
                 final StringBuilder out = new StringBuilder();
                 if (processTimeout) {
                     out.append("Process is terminated due to ").append(timeout).append(" second exceeded.\n");
                 }
                 out.append("Exit Code: ").append(exitValue).append("\nOutput:\n").append(it.getOutput());
                 throw new JobProcessingException(out.toString());
             }
             ComponentUtil.getPopularWordHelper().clearCache();
         } catch (final JobProcessingException e) {
             throw e;
         } catch (final Exception e) {
             throw new JobProcessingException("Python Process terminated.", e);
         } finally {
             processHelper.destroyProcess(sessionId);
 
         }
     }
 
     protected String getPyFilePath() {
         final StringBuilder buf = new StringBuilder(100);
         buf.append("WEB-INF");
         buf.append(File.separator);
         buf.append("env");
         buf.append(File.separator);
         buf.append(getExecuteType());
         buf.append(File.separator);
         buf.append("resources");
         buf.append(File.separator);
         buf.append(filename.replaceAll("\\.\\.+", ""));
         return buf.toString();
     }
 
     @Override
     protected String getExecuteType() {
         return Constants.EXECUTE_TYPE_PYTHON;
     }
 }