#!/usr/bin/env bash

# Description: An almost fully POSIX compliant batch file renamer
#
# Note: nnn auto-detects and invokes this plugin if available
#       Whitespace is used as delimiter for read.
#       The plugin doesn't support filenames with leading or trailing whitespace
#       To use NNN_LIST your shell must support readlink(1)
#
# 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: bash
# Author: KlzXS

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

selection=${NNN_SEL:-${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

    if ! [ "$resp" = "c" ] && ! [ "$resp" = "s" ]; then
        exit 1
    fi
fi

if [ "$resp" = "s" ]; then
	arr=$(tr '\0' '\n' < "$selection")
else
	findcmd="find . ! -name ."

	if [ "$RECURSIVE" -eq 0 ]; then
		findcmd="$findcmd -prune"
	fi

	if [ "$INCLUDE_HIDDEN" -eq 0 ]; then
		findcmd="$findcmd ! -name \".*\""
	fi

	if [ -z "$NNN_LIST" ]; then
		findcmd="$findcmd -print"
	else
		findcmd="$findcmd -printf "'"'"$NNN_LIST/%P\n"'"'
	fi

	arr=$(eval "$findcmd" | sort)
fi

lines=$(printf "%s\n" "$arr" | wc -l)
width=${#lines}

printf "%s" "$arr" | awk '{printf("%'"${width}"'d %s\n", NR, $0)}' > "$dst_file"

items=("~")
while IFS='' read -r line; do
	if [ "$NNN_LIST" -eq 1 ]; then
		line=$(readlink "$line" || printf "%s" "$line")
	fi

	items+=("$line");
done < <(printf "%s\n" "$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=${items[$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

			unset "items[$num]"
			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
				if [ "$VERBOSE" -ne 0 ]; then
					printf "'%s' -> '%s'\n" "$name" "$tmp"
				fi
			else
				printf "%s: failed to rename %s to %s: %s\n" "$0" "$name" "$tmp" "$!" > /dev/stderr
				exit_status=1
			fi

			for key in "${!items[@]}"; do
				if [ "${items[$key]}" = "$name" ]; then
					items[$key]="$tmp"
				fi
			done
		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 -i "$src" "$name"; then
			printf "%s: failed to rename %s to %s: %s\n" "$0" "$name" "$tmp" "$!" > /dev/stderr
			exit_status=1
		else
			if [ -d "$name" ]; then
				for key in "${!items[@]}"; do
					items[$key]=$(printf "%s" "${items[$key]}" | sed "s|^$src\(\$\|\/\)|$name\1|")
				done

				if [ "$VERBOSE" -ne 0 ]; then
					printf "'%s' => '%s'\n" "$src" "$name"
				fi
			else
				true
				if [ "$VERBOSE" -ne 0 ]; then
					printf "'%s' -> '%s'\n" "$src" "$name"
				fi
			fi
		fi
	fi

	unset "items[$num]"
done <"$dst_file"

unset "items[0]"
for item in "${items[@]}"; do
	rm -ri "$item"
done

rm "$dst_file"
exit $exit_status