/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.inspection.ffmpeg;
  
  import org.opencastproject.inspection.ffmpeg.api.AudioStreamMetadata;
  import org.opencastproject.inspection.ffmpeg.api.MediaAnalyzer;
  import org.opencastproject.inspection.ffmpeg.api.MediaAnalyzerException;
  import org.opencastproject.inspection.ffmpeg.api.MediaContainerMetadata;
  import org.opencastproject.inspection.ffmpeg.api.SubtitleStreamMetadata;
  import org.opencastproject.inspection.ffmpeg.api.VideoStreamMetadata;
  import org.opencastproject.util.IoSupport;
  
  import org.json.simple.JSONArray;
  import org.json.simple.JSONObject;
  import org.json.simple.parser.JSONParser;
  import org.json.simple.parser.ParseException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * This MediaAnalyzer implementation uses the ffprobe binary of FFmpeg for media analysis. Also this implementation does
   * not keep control-, text- or other non-audio or video streams and purposefully ignores them during the
   * <code>postProcess()</code> step.
   */
  public class FFmpegAnalyzer implements MediaAnalyzer {
  
    /** Path to the executable */
    protected String binary;
  
    public static final String FFPROBE_BINARY_CONFIG = "org.opencastproject.inspection.ffprobe.path";
    public static final String FFPROBE_BINARY_DEFAULT = "ffprobe";
  
    /** Logging facility */
    private static final Logger logger = LoggerFactory.getLogger(FFmpegAnalyzer.class);
  
    /** Whether the calculation of the frames is accurate or not */
    private boolean accurateFrameCount;
  
    public FFmpegAnalyzer(boolean accurateFrameCount) {
      this.accurateFrameCount = accurateFrameCount;
      // instantiated using MediaAnalyzerFactory via newInstance()
      this.binary = FFPROBE_BINARY_DEFAULT;
    }
  
    /**
     * Returns the binary used to provide media inspection functionality.
     *
     * @return the binary
     */
    protected String getBinary() {
      return binary;
    }
  
    public void setBinary(String binary) {
      this.binary = binary;
    }
  
    @Override
    public MediaContainerMetadata analyze(File media) throws MediaAnalyzerException {
      if (binary == null) {
        throw new IllegalStateException("Binary is not set");
      }
  
      List<String> command = new ArrayList<>();
      command.add(binary);
      command.add("-show_format");
      command.add("-show_streams");
      if (accurateFrameCount)
        command.add("-count_frames");
      command.add("-of");
      command.add("json");
      command.add(media.getAbsolutePath().replaceAll(" ", "\\ "));
  
     /* Execute ffprobe and obtain the result */
     logger.debug("Running {} {}", binary, command);
 
     MediaContainerMetadata metadata = new MediaContainerMetadata();
 
     final StringBuilder sb = new StringBuilder();
     Process encoderProcess = null;
     try {
       encoderProcess = new ProcessBuilder(command)
           .redirectError(ProcessBuilder.Redirect.DISCARD)
           .start();
 
       // tell encoder listeners about output
       try (var in = new BufferedReader(new InputStreamReader(encoderProcess.getInputStream()))) {
         String line;
         while ((line = in.readLine()) != null) {
           logger.debug(line);
           sb.append(line).append(System.getProperty("line.separator"));
         }
       }
       // wait until the task is finished
       int exitCode = encoderProcess.waitFor();
       if (exitCode != 0) {
         throw new MediaAnalyzerException("Frame analyzer " + binary + " exited with code " + exitCode);
       }
     } catch (IOException | InterruptedException e) {
       logger.error("Error executing ffprobe", e);
       throw new MediaAnalyzerException("Error while running " + binary, e);
     } finally {
       IoSupport.closeQuietly(encoderProcess);
     }
 
     JSONParser parser = new JSONParser();
 
     try {
       JSONObject jsonObject = (JSONObject) parser.parse(sb.toString());
       Object obj;
       Double duration;
 
       /* Get format specific stuff */
       JSONObject jsonFormat = (JSONObject) jsonObject.get("format");
 
       /* File Name */
       obj = jsonFormat.get("filename");
       if (obj != null) {
         metadata.setFileName((String) obj);
       }
 
       /* Format */
       obj = jsonFormat.get("format_long_name");
       if (obj != null) {
         metadata.setFormat((String) obj);
       }
 
       /*
        * Mediainfo does not return a duration if there is no stream but FFprobe will return 0. For compatibility
        * reasons, check if there are any streams before reading the duration:
        */
       obj = jsonFormat.get("nb_streams");
       if (obj != null && (Long) obj > 0) {
         obj = jsonFormat.get("duration");
         if (obj != null) {
           duration = Double.parseDouble((String) obj) * 1000;
           metadata.setDuration(duration.longValue());
         }
       }
 
       /* File Size */
       obj = jsonFormat.get("size");
       if (obj != null) {
         metadata.setSize(Long.parseLong((String) obj));
       }
 
       /* Bitrate */
       obj = jsonFormat.get("bit_rate");
       if (obj != null) {
         metadata.setBitRate(Float.parseFloat((String) obj));
       }
 
       /* Loop through streams */
       /*
        * FFprobe will return an empty stream array if there are no streams. Thus we do not need to check.
        */
       JSONArray streams = (JSONArray) jsonObject.get("streams");
       for (JSONObject stream : (Iterable<JSONObject>) streams) {
         /* Check type of string */
         String codecType = (String) stream.get("codec_type");
 
         /* Handle audio streams ----------------------------- */
 
         if ("audio".equals(codecType)) {
           /* Extract audio stream metadata */
           AudioStreamMetadata aMetadata = new AudioStreamMetadata();
 
           /* Codec */
           obj = stream.get("codec_long_name");
           if (obj != null) {
             aMetadata.setFormat((String) obj);
           }
 
           /* Duration */
           obj = stream.get("duration");
           if (obj != null) {
             duration = new Double((String) obj) * 1000;
             aMetadata.setDuration(duration.longValue());
           } else {
             /*
              * If no duration for this stream is specified assume the duration of the file for this as well.
              */
             aMetadata.setDuration(metadata.getDuration());
           }
 
           /* Bitrate */
           obj = stream.get("bit_rate");
           if (obj != null) {
             aMetadata.setBitRate(new Float((String) obj));
           }
 
           /* Channels */
           obj = stream.get("channels");
           if (obj != null) {
             aMetadata.setChannels(((Long) obj).intValue());
           }
 
           /* Sample Rate */
           obj = stream.get("sample_rate");
           if (obj != null) {
             aMetadata.setSamplingRate(Integer.parseInt((String) obj));
           }
 
           /* Frame Count */
           obj = stream.get("nb_read_frames");
           if (obj != null) {
             aMetadata.setFrames(Long.parseLong((String) obj));
           } else {
 
             /* alternate JSON element if accurate frame count is not requested from ffmpeg */
             obj = stream.get("nb_frames");
             if (obj != null) {
               aMetadata.setFrames(Long.parseLong((String) obj));
             }
           }
 
           /* Add video stream metadata to overall metadata */
           metadata.getAudioStreamMetadata().add(aMetadata);
 
           /* Handle video streams ----------------------------- */
 
         } else if ("video".equals(codecType)) {
           /* Extract video stream metadata */
           VideoStreamMetadata vMetadata = new VideoStreamMetadata();
 
           /* Codec */
           obj = stream.get("codec_long_name");
           if (obj != null) {
             vMetadata.setFormat((String) obj);
           }
 
           /* Duration */
           obj = stream.get("duration");
           if (obj != null) {
             duration = new Double((String) obj) * 1000;
             vMetadata.setDuration(duration.longValue());
           } else {
             /*
              * If no duration for this stream is specified assume the duration of the file for this as well.
              */
             vMetadata.setDuration(metadata.getDuration());
           }
 
           /* Bitrate */
           obj = stream.get("bit_rate");
           if (obj != null) {
             vMetadata.setBitRate(new Float((String) obj));
           }
 
           /* Width */
           obj = stream.get("width");
           if (obj != null) {
             vMetadata.setFrameWidth(((Long) obj).intValue());
           }
 
           /* Height */
           obj = stream.get("height");
           if (obj != null) {
             vMetadata.setFrameHeight(((Long) obj).intValue());
           }
 
           /* Profile */
           obj = stream.get("profile");
           if (obj != null) {
             vMetadata.setFormatProfile((String) obj);
           }
 
           /* Aspect Ratio */
           obj = stream.get("sample_aspect_ratio");
           if (obj != null) {
             vMetadata.setPixelAspectRatio(parseFloat((String) obj));
           }
 
           /* Frame Rate */
           obj = stream.get("avg_frame_rate");
           if (obj != null) {
             vMetadata.setFrameRate(parseFloat((String) obj));
           }
 
           /* Frame Count */
           obj = stream.get("nb_read_frames");
           if (obj != null) {
             vMetadata.setFrames(Long.parseLong((String) obj));
           } else {
 
             /* alternate JSON element if accurate frame count is not requested from ffmpeg */
             obj = stream.get("nb_frames");
             if (obj != null) {
               vMetadata.setFrames(Long.parseLong((String) obj));
             } else if (vMetadata.getDuration() != null && vMetadata.getFrameRate() != null) {
               long framesEstimation = Double.valueOf(vMetadata.getDuration() / 1000.0 * vMetadata.getFrameRate())
                   .longValue();
               if (framesEstimation >= 1) {
                 vMetadata.setFrames(framesEstimation);
               }
             }
           }
 
           /* Add video stream metadata to overall metadata */
           metadata.getVideoStreamMetadata().add(vMetadata);
 
           /* Handle subtitle streams ----------------------------- */
 
         } else if ("subtitle".equals(codecType)) {
           /* Extract subtitle stream metadata */
           SubtitleStreamMetadata sMetadata = new SubtitleStreamMetadata();
 
           /* Codec */
           obj = stream.get("codec_long_name");
           if (obj != null) {
             sMetadata.setFormat((String) obj);
           }
 
           metadata.getSubtitleStreamMetadata().add(sMetadata);
         }
       }
 
     } catch (ParseException e) {
       logger.error("Error parsing ffprobe output: {}", e.getMessage());
     }
 
     return metadata;
   }
 
   /**
    * Allows configuration {@inheritDoc}
    *
    * @see org.opencastproject.inspection.ffmpeg.api.MediaAnalyzer#setConfig(java.util.Map)
    */
   @Override
   public void setConfig(Map<String, Object> config) {
     if (config != null) {
       if (config.containsKey(FFPROBE_BINARY_CONFIG)) {
         String binary = (String) config.get(FFPROBE_BINARY_CONFIG);
         setBinary(binary);
         logger.debug("FFmpegAnalyzer config binary: " + binary);
       }
     }
   }
 
   private float parseFloat(String val) {
     if (val.contains("/")) {
       String[] v = val.split("/");
       if (Float.parseFloat(v[1]) == 0) {
         return 0;
       } else {
         return Float.parseFloat(v[0]) / Float.parseFloat(v[1]);
       }
     } else if (val.contains(":")) {
       String[] v = val.split(":");
       if (Float.parseFloat(v[1]) == 0) {
         return 0;
       } else {
         return Float.parseFloat(v[0]) / Float.parseFloat(v[1]);
       }
     } else {
       return Float.parseFloat(val);
     }
   }
 
 }