Get mime-type of a file based on extension if exists or by using file command

mime_type.sh

#!/bin/bash

FILE=$(basename $1)
FILENAME="${FILE%.*}"
EXTENSION="${FILE##*.}"

echo "$FILE"
echo "$FILENAME"
echo "$EXTENSION"

if [ "$FILENAME" == "$EXTENSION" ]
   then
     MIMETYPE=`file --brief --mime-type "$1"`
   else
        MIMETYPE=`mimetype --output-format %m  "$1"`
   
fi
echo "$MIMETYPE"