Unix Bash - Copy files from a source folder recursively to destination/*file_extension*(ex. “txt”) folder - bash

Question

This is my code, something in the rec_copy() function isn't working properly, probably this line:
cp $1/$f $HOME/$2/$dest
The extension named folders are created in the destination folder but the files are not copied there. Can you help me?
#!/bin/bash
if [ $# -ne 2 ]
then
echo "Usage: $0 <source> <destination>"
exit
fi
if [ ! -d $1 ]
then
echo "Source folder does not exist"
exit
fi
if [ -d $2 ]
then
rm -r $2
mkdir $2
else
mkdir $2
fi
extension=`ls -l $1 | grep -v "^d" | awk '{ print $10; }' | sed 's/^.*\.//g'`
for f in $extension
do
if [ ! -d $1/$f ]
then
mkdir $2/$f
fi
done
rec_copy(){
folder=`ls $1`
for f in $folder
do
dest=`echo "$f" | sed 's/.*\.//g'`
if [ -f $1/$f ]
then
cp $1/$f $HOME/$2/$dest
elif [ -d $1/$f ]
then
rec_copy $1/$f
fi
done
}
rec_copy $1

Answer 1

Here is the answer in case someone ever needs it:
#!/bin/bash
if [ $# -ne 2 ]
then
echo "Usage: $0 <izvor> <destinacija>"
exit
fi
if [ ! -d "$1" ]
then
echo "Izvorniot folder ne postoi"
exit
fi
if [ -d "$2" ]
then
rm -r "$2"
mkdir "$2"
else
mkdir "$2"
fi
extension=`ls -l "$1" | grep -v "^d" | awk '{ print $10; }' | sed 's/^.*\.//g' | sort -u`
for f in $extension
do
if [ ! -d "$1/$f" ]
then
mkdir "$2/$f"
fi
done
rec_copy(){
folder=`ls "$1"`
for f in $folder
do
dest=`echo "$f" | sed 's/.*\.//g'`
to=`cp "$1/$f" "$2/$dest"`
if [ -f "$1/$f" ]
then
echo "$to"
elif [ -d "$1/$f" ]
then
rec_copy "$1/$f" "$2"
fi
done
}
rec_copy "./$1" "./$2"