Downloading only new subtitles in RaspberyPi - bash

Question

I have problems with writing downloading subtitles on Raspberry Pi with bash script.
The issue is I would like to have 1 script running with cron every hour or so that would download subtitles for new video files in some directory.
There is a program called qnapi that automatically downloads subtitles in the correct format in the directory but it works for 1 folder and always re-downloads subtitle files.
usage is:
qnapi /path/to/folder
So what I've found is
find /media/pi/RaspStorage -iname "*.mkv"
basically gives me a list of all movie files. Now I would like to somehow compare if a *.srt subtitle file with a same base name exists and if no then somehow loop through all found files with qnapi command. Write it in a bash script and cron it.

Answer 1

Perhaps something along the line of this would work (untested, may have typos).
I'm guessing at the syntax of qnapi from a google search.
Basically, symlink videos that don't have subtitles into a temporary folder, download the subtitles there, then move them back to the main folder.
#!/bin/bash
MEDIA=/media/pi/RaspStorage
WORK=/tmp/workingfolder
mkdir -p "$WORK"
pushd "$WORK" || { echo "ERROR: no working directory"; exit 1; }
# assuming subtitle name is video name except with ".srt" extension
find "$MEDIA" -iname "*.mkv" | while read video; do
vidnoext="${video%????}"
viddir="${vidnoext%/*}"
subtitle="${vidnoext}.srt"
if [ ! -f "$subtitle" ]; then
# this assumes bare filenames (without directory) are distinct
ln -s "$video" "${vidnoext}.mkv"
fi
done
qnapi -c .
find . -iname '*.srt' | while IFS= read -r subtitle; do
video="$(realpath "$(subtitle%????}.mkv")"
mv -i "$subtitle" "$(dirname "$video")/"
done
rm *
popd
rmdir "$WORK"

Answer 2

thanks for help :)
I got it working
#!/bin/bash
echo "Updated DLNA folder"
sudo minidlnad -R
for file in $(find /media/pi/RaspStorage -name '*.mkv' -or -name '*.avi'); do
name=${file:: -4}
ext=".srt"
name=$name$ext
if [ -f $name ]; then
echo "Napisy już ściągnięte dla:" "$(basename "$file")"
else
qnapi "$(dirname "$file")"/"$(basename "$file")"
fi
done
Works fine. All subtitles are downloading and if there are some already it's skipping