xd

#!/bin/sh

set -eu


do_zip() {
	unzip -x "$2"
}

do_rar() {
	unrar x "$2"
}

do_tar() {
	tar x <$2
}

do_tgz() {
	gzip -d <$2 | tar x
}

do_txz() {
	xz -d <$2 | tar x
}

do_tbz() {
	bzip2 -d <$2 | tar x
}

do_tbz2() {
	bzip2 -d <$2 | tar x
}

do_tlzma() {
	lzma -d <$2 | tar x
}


err() {
	echo "$*" >&2
}


handle_dir() {
	n=0
	f=
	for i in * .*; do
		if [ -e "$i" ] && [ x"$i" != x. ] && [ x"$i" != x.. ]; then
			n=$(( $n + 1 ))
			f=$i
		fi
	done

	if [ $n -eq 0 ]; then
		err "$file: no files extracted"
		return 1
	elif [ $n -ne 1 ]; then
		return 0
	elif [ -e "../$f" ]; then
		err "$PWD/../$f: already exists"
		err "$f: will not move the only extracted file"
		return 0
	else
		err "$f: moving to parent"
		mv -i -- "$f" ..
		return 1
	fi
}


oldpwd=$PWD

for file; do
	base=${file%.*}
	handler=${file##*.}
	case $file in
		*.zip|*.tar|*.rar)
			;;
		*.part??.rar)
			base=${file%.part??.rar}
			;;
		*.tar.gz|*.tar.bz2|*.tar.lzma|*.tar.xz)
			base=${file%.tar.*}
			handler=t$handler
			;;
		*.gz|*.bz2|*.lzma|*.xz)
			do_single_$handler
			return $?
			;;
		*)
			err "$file: could not figure out way to decompress"
			continue
	esac

	if [ -e "$base" ]; then
		err "$base: already exists"
		continue
	fi

	mkdir -- "$base" || continue

	case $file in
		/*)
			;;
		*)
			file=$oldpwd/$file
	esac

	cd "$base" || continue
	if do_$handler "$handler" "$file" && handle_dir; then
		cd "$oldpwd"
	else
		cd "$oldpwd"
		rmdir -- "$base"
	fi
done