Group duplicates of files into hardlinks, check using SHA256 and matching file size

dedupe

#!/bin/zsh
[ $# -eq 1 ] && {
	echo you must specify more than one file to be deduped
	echo
}
[ $# -lt 2 ] && {
	echo "dedupe [input files]"
	echo "- replace multiple unchanging"
	echo copies of the same files with
	echo hardlinks to save space
	return 1
}
declare -a hashset
hashset=()
declare -a baseset
baseset=()
# i feel like i'm missing something, even before
# i just capped off writing the code for this
NUL=/dev/null
wpathfail() { echo $2; }
fsize() { stat -c "%s" "$1"; }
dsize() { df --output=source,avail --block-size=M --total | tail -1; } # prints kb
wpath=wpathfail
which cygpath 2>$NUL >$NUL && wpath=cygpath || {
	which wslpath 2>$NUL >$NUL && wpath=wslpath || {
		# wtf to do here
		echo No path converter utility found. 1>&2
	}
}
copycount=0
before=$(dsize)
for ff in "$@"; do
	f=$($wpath -u "$ff")
	if [ -e "$f" ] && {
		test=($(sha256sum "${f}")) #weird
		test="${test[1]:1}"
		# INDEXES START FROM 1, ABSOLUTE CRINGE
		check=${hashset[(Ie)$test]:-0}
		[ $check -eq 0 ] && {
			hashset+=($test)
			baseset+=("$f")
			#baseset+=("$(realpath "$f")")
		} || {
			base="${baseset[$check]}"
			[ $(fsize "$f") -eq $(fsize "$base") ] && {
				copycount=$(($copycount + 1))
				ln -f "$base" "$f"
				echo "[${test:0:15}] $(basename "$base") <- $f"
			} || {
				echo "$base and $(basename "$f") have matching hashes but different size!!!!" 1>&2
			}
		}
	} || {
		echo "$f is not a file."
	}
done
after=$(dsize)
echo Free space:
echo Before: $before
echo After : $after
uniqcount=${#hashset[@]}
echo Found $uniqcount unique files, $copycount duplicates
return 0