#! /bin/bash

py="$(cat <<EOF
from sys import stdin, stderr
lines = [i.strip() for i in stdin.readlines()]

def frame_duplicate_status(line):
   return "keep" if "keep" in line else "drop", "Parsed_mpdecimate_0" in line
def silence_status(line):
   if not "[silencedetect @ " in line:
      return None
   return line.split()[3:5]
def parse_duration(line):
   if not line.startswith("Duration: "):
      return None
   ts = line.split()[1].strip(",")
   hours, minutes, seconds = [float(i) for i in ts.split(":")]
   return seconds + 60.0 * minutes + 60.0 * 60.0 * hours

state_transition_lines_video = []
state_transition_lines_audio = [0.0]
state_total_duration = 0.0
for i in range(len(lines)):
   status, relevant = frame_duplicate_status(lines[i])
   if relevant:
      if not state_transition_lines_video:
         state_transition_lines_video.append(lines[i])
      else:
         prev_status, _ = frame_duplicate_status(state_transition_lines_video[-1])
         if status != prev_status:
            state_transition_lines_video.append(lines[i-1])
            state_transition_lines_video.append(lines[i])
   status = silence_status(lines[i])
   if status:
      state_transition_lines_audio.append(float(status[1]))
   status = parse_duration(lines[i])
   if not status is None:
      duration = status
state_transition_lines_audio.append(duration)
state_transition_lines_video = [(frame_duplicate_status(i)[0], i.split("pts_time:")[1].split()[0]) for i in state_transition_lines_video]

# just the keeps
state_transition_lines_video = [i for i in state_transition_lines_video[2:] if i[0] == "keep"]

# translate to float spans
spans_to_keep_video = []
spans_to_keep_audio = []
for i in range(0, len(state_transition_lines_video), 2):
   start = float(state_transition_lines_video[i][1])
   if len(state_transition_lines_video) > i+1:
      stop = float(state_transition_lines_video[i+1][1])
      if stop - start > 1:
         spans_to_keep_video.append((start, stop))
   else:
      spans_to_keep_video.append((start, duration))
spans_to_keep_audio = [
   (state_transition_lines_audio[i], state_transition_lines_audio[i+1])
   for i in range(0, len(state_transition_lines_audio), 2)
]

# drop zero len spans
spans_to_keep_video = [i for i in spans_to_keep_video if i[1]-i[0] > 0.1]
spans_to_keep_audio = [i for i in spans_to_keep_audio if i[1]-i[0] > 0.1]

# extend around
for arr in [spans_to_keep_video, spans_to_keep_audio]:
   for i in range(len(arr)):
      arr[i] = (
         max(0.0, arr[i][0] - 1.0),
         min(duration, arr[i][1] + 1.0),
      )

# combine near
for arr in [spans_to_keep_video, spans_to_keep_audio]:
   for i in range(len(arr)-1, 0, -1):
      first_start, first_stop = arr[i-1]
      secnd_start, secnd_stop = arr[i]
      if secnd_start - first_stop < 5:
         arr = arr[:i-1] + [(first_start, secnd_stop)] + arr[i+1:]

# union audio, video spans
spans_to_keep = spans_to_keep_video + spans_to_keep_audio
spans_to_keep = sorted(spans_to_keep)
for i in range(len(spans_to_keep)-1, 0, -1):
   first_start, first_stop = spans_to_keep[i-1]
   secnd_start, secnd_stop = spans_to_keep[i]
   if secnd_start - first_stop < 5:
      spans_to_keep = spans_to_keep[:i-1] + [(first_start, secnd_stop)] + spans_to_keep[i+1:]

print("\n".join([
   f'AUDIO: {i[0]:.2f},{i[1]-i[0]:.2f}' for i in spans_to_keep_audio
]), file=stderr)
print("\n".join([
   f'VIDEO: {i[0]:.2f},{i[1]-i[0]:.2f}' for i in spans_to_keep_video
]), file=stderr)

# output
print("\n".join([
   f'{i[0]:.2f},{i[1]-i[0]:.2f}' for i in spans_to_keep
]))
EOF
)"

d=$(mktemp -d)
echo d=$d >&2
for span in $(
   (
      ffmpeg -i $f -vf mpdecimate -af silencedetect=n=-50dB:d=1 -loglevel debug -f null -
      #ffmpeg -i "$f" -af silencedetect=n=-50dB:d=1 -loglevel debug -f null -
   ) 2>&1 \
   | grep -E 'silencedetect|Parsed_mpdecimate_0|Duration: *[0-9]' \
   | grep -E 'silencedetect| (keep|drop) |Duration: *[0-9]' \
   | python3 -c "$py"
); do
   n=$((n+1))
   ffmpeg -y -ss ${span%,*} -i "$f" -t ${span#*,} "$d/$(printf "%05d" $(ls "$d" | wc -l)).${f##*.}"
done
ls $d
echo rm -rf "$d"