filemenu

#!/bin/bash

#Author:	Jacob Tkeio (jacobtkeio@gmail.com)
#Date:		8/3/2023

#Utility to create a menu out of a list of files.
#Meant primarily for use with 'find' to create
#useful alias commands.


usage="Usage: $0 [OPTION]...

Creates a menu from files passed through standard input.
By default, the menu is sorted by time since last edit.

Choosing a file from the menu will open a subshell in 
	its directory. Exiting the subshell will return
	the user to the original shell.
To exit the menu prompt, type 'e'.

OPTION is one of
	-r, --resume	Do not prompt; cd to last-active file.
	-z, --reverse	Display least-recently edited files first.
	-p, --persist	Redisplay menu after subshell exit.
	-h, --help      Print this help message.

If --resume and --persist are both set, cd to every file
	successively, continuing to the next on subshell exit.
To stop cascading early, press Ctrl-D then Ctrl-C quickly."


while (( $# > 0 )); do 
	case $1 in
		(-h | --help)       echo "$usage"; exit 0 ;;
		(-r | --resume)     resume=amongus ;;
		(-p | --persist)	persist=imposter ;;
		(-z | --reverse)	reverse=sus ;;
		(-*)                echo "Invalid option $1"; exit 1 ;;
		(*)                 echo "Unknown argument $1" ;;
	esac
	shift
done


n=0
while true; do
	case $n in
		(0)	filemenutmp=~/tmp/filemenu.tmp ;;
		(1)	filemenutmp=/tmp/"${USER}"_filemenu.tmp ;;
		(2)	filemenutmp=~/filemenu.tmp ;;
		(*)	echo "Unable to create tmp file at ~/tmp, /tmp, or ~"; exit 1 ;;
	esac

	n=$((n+1))

	touch "${filemenutmp}" 2>/dev/null || continue
	>"${filemenutmp}" && break 
done

trap "[ -e "${filemenutmp}" ] && rm "${filemenutmp}"; echo; exit 0" SIGTERM SIGINT


declare -a sessions
while IFS= read line; do
	[ -e "$line" ] && sessions+=("$line")
done

if ((${#sessions} == 0)); then
	echo "No files to list."
	exit 0
fi


echo "${sessions[@]}" |
xargs ls -t1d ${reverse:+"-r"} |
while IFS= read line; do
	echo "$line" >>${filemenutmp}
done

[ "$resume" ] || #don't output menu on resume
nl -n'ln' -w1 -s'. ' "${filemenutmp}"


#start reading stdin from tty instead of piped input!
exec </dev/tty	

menusize=$(wc -l "${filemenutmp}" | cut -d' ' -f1)
responsedigit=1

while true; do
	if [ ! "$resume" ]; then
		read -p"#> " response

		[[ "$response" =~ ^e.*$ ]] && break

		responsedigit=$(echo "$response" | tr -c -d "[:digit:]")
	fi

	(( responsedigit <= 0 )) || 
	(( responsedigit > menusize )) &&
	if [ $resume ]; then
		echo "No more files."
		break
	else
		continue
	fi


	#grab line $responsedigit from filemenutmp
	finalfile="$(sed "${responsedigit}q;d" "${filemenutmp}")" 

	if [ ! -e "${finalfile}" ]; then
		echo "bad retreival from "${filemenutmp}""
		echo "or "${finalfile}" does not exist."
		exit 1
	fi


	base=$(basename "${finalfile}")
	basedir="${finalfile%/"${base}"}"

	cd "${basedir}"
	"${SHELL}" #solidify cd for user


	if [ "$persist" ]; then
		if [ "$resume" ]; then
			responsedigit=$(( $responsedigit + 1 ))
			sleep 0.1
		else
			nl -n'ln' -w1 -s'. ' "${filemenutmp}"
		fi
	else
		break
	fi
done

rm "${filemenutmp}"