#!/usr/bin/env sh

# Description: An almost fully POSIX compliant batch file renamer
#
# Note: nnn auto-detects and invokes this plugin if available
#
# Capabilities:
#    1. Basic file rename
#    2. Detects order change
#    3. Can move files
#    4. Can remove files
#    5. Switch number pairs to swap filenames
#
# Shell: POSIX compliant
# Author: KlzXS

EDITOR="${EDITOR:-vi}"
TMPDIR="${TMPDIR:-/tmp}"
INCLUDE_HIDDEN="${INCLUDE_HIDDEN:-0}"

selection=${XDG_CONFIG_HOME:-$HOME/.config}/nnn/.selection
exit_status=0

dst_file=$(mktemp "$TMPDIR/.nnnXXXXXX")

if [ -s "$selection" ]; then
	printf "Rename 'c'urrent / 's'election? "
	read -r resp
fi

if [ "$resp" = "s" ]; then
	arr=$(tr '\0' '\n' < "$selection")
else
	if [ "$INCLUDE_HIDDEN" -eq 0 ]; then
		arr=$(find . ! -name . -prune ! -name ".*" -print | sort)
	else
		arr=$(find . ! -name . -prune -print | sort)
	fi
fi

printf "%s" "$arr" | awk '{print NR " " $0}' > "$dst_file"
arr=$(printf "%s" "$arr" | sed "s/'/'\\\\''/g;s/^\(.*\)$/'\1'/" | tr '\n' ' ')

eval "set -- $arr"
$EDITOR "$dst_file"

while read -r num name; do
	if [ -z "$name" ]; then
		if [ -z "$num" ]; then
			continue
		fi

		printf "%s: unable to parse line, aborting\n" "$0"
		exit 1
	fi

	# check if $num is an integer
	if [ ! "$num" -eq "$num" ] 2> /dev/null; then
		printf "%s: unable to parse line, aborting\n" "$0"
		exit 1
	fi

	src=$(eval printf "%s" "\"\${$num}\"")

	if [ -z "$src" ]; then
		printf "%s: unknown item number %s\n" "$0" "$num" > /dev/stderr
		continue
	elif [ "$name" != "$src" ]; then
		if [ -z "$name" ]; then
			continue
		fi

		if [ ! -e "$src" ] && [ ! -L "$src" ]; then
			printf "%s: %s does not exit\n" "$0" "$src" > /dev/stderr

			c=1
			new_args=""
			while [ $c -le $# ]; do
				tmp=$(eval printf "%s" "\"\${$c}\"")
				if [ "$c" -eq "$num" ]; then
					new_args="$new_args ''"
				else
					if [ -z "$tmp" ]; then
						tmp="''"
					else
						tmp=$(printf "%s" "$tmp" | sed "s/'/'\\\\''/g;s/^\(.*\)$/'\1'/")
					fi
					new_args="$new_args $tmp"
				fi
				c=$((c+1))
			done

			eval "set -- $new_args"
			continue
		fi

		# handle swaps
		if [ -e "$name" ] || [ -L "$name" ]; then
			tmp="$name~"
			c=0

			while [ -e "$tmp" ] || [ -L "$tmp" ]; do
				c=$((c+1))
				tmp="$tmp~$c"
			done

			if mv "$name" "$tmp"; then
				printf "'%s' -> '%s'\n" "$name" "$tmp"
			else
				printf "%s: failed to rename %s to %s: %s\n" "$0" "$name" "$tmp" "$!" > /dev/stderr
				exit_status=1
			fi

			c=1
			new_args=""
			while [ $c -le $# ]; do
				item=$(eval printf "%s" "\"\${$c}\"")
				if [ "$item" = "$name" ]; then
					item=$(printf "%s" "$tmp" | sed "s/'/'\\\\''/g;s/^\(.*\)$/'\1'/")
					new_args="$new_args $item"
				else
					if [ -z "$item" ]; then
						item="''"
					else
						item=$(printf "%s" "$item" | sed "s/'/'\\\\''/g;s/^\(.*\)$/'\1'/")
					fi
					new_args="$new_args $item"
				fi
				c=$((c+1))
			done

			eval "set -- $new_args"
		fi

		dir=$(dirname "$name")
		if [ ! -d "$dir" ] && ! mkdir -p "$dir"; then
			printf "%s: failed to create directory tree %s\n" "$0" "$dir" > /dev/stderr
			exit_status=1
		elif ! mv "$src" "$name"; then
			printf "%s: failed to rename %s to %s: %s\n" "$0" "$name" "$tmp" "$!" > /dev/stderr
			exit_status=1
		else
			printf "'%s' -> '%s'\n" "$src" "$name"
			if [ -d "$name" ]; then
				c=1
				new_args=""
				while [ $c -le $# ]; do
					tmp=$(eval printf "\"\${$c}\"")
					if [ -z "$tmp" ]; then
						tmp="''"
					else
						tmp=$(printf "%s" "$tmp" | sed "s|^$src\(\$\|\/\)|$name\1|;s/'/'\\\\''/g;s/^\(.*\)$/'\1'/")
					fi
					new_args="$new_args $tmp"
					c=$((c+1))
				done

				eval "set -- $new_args"
				printf "'%s' => '%s'\n" "$src" "$name"
			fi
		fi
	fi

	c=1
	new_args=""
	while [ $c -le $# ]; do
		tmp=$(eval printf "%s" "\"\${$c}\"")
		if [ "$c" -eq "$num" ]; then
			new_args="$new_args ''"
		else
			if [ -z "$tmp" ]; then
				tmp="''"
			else
				tmp=$(printf "%s" "$tmp" | sed "s/'/'\\\\''/g;s/^\(.*\)$/'\1'/")
			fi
			new_args="$new_args $tmp"
		fi
		c=$((c+1))
	done

	eval "set -- $new_args"
done <"$dst_file"

c=1
new_args=""
while [ $c -le $# ]; do
	tmp=$(eval printf "%s" "\"\${$c}\"")
	if [ -n "$tmp" ]; then
		rm -ri "$tmp"
	fi
	c=$((c+1))
done

rm "$dst_file"
exit $exit_status