#!/bin/sh
set -e

# Later, we're going to want to set $IFS to a single newline, so let's prepare one.
NL='
'

fatal() {
	echo "$@" >&2
	exit 1
}

usage() {
	fatal "Usage: $(basename "$0") [-f] [-p prompt] [--] [file-pattern]

Interactively select a file to open

Options:
    -f            always present given arguments, even when there is only one
    -p            use prompt as prompt string
    file-pattern  list of filenames and directories"
}

# print a list of filenames on stdin and distinguish directories
wrap_dirs() {
	while read -r filename
	do
		if [ -d "$filename" ]; then
			printf '%s/\n' "$filename"
		else
			printf '%s\n' "$filename"
		fi
	done
}

VIS_OPEN_LINES="${VIS_OPEN_LINES:-0}"
VIS_MENU_PROMPT=''
ALLOW_AUTO_SELECT='1'

while getopts fhp: opt; do
	case "$opt" in
	f)
		ALLOW_AUTO_SELECT=''
		;;
	p)
		VIS_MENU_PROMPT="$OPTARG"
		;;
	*)
		usage
		;;
	esac
done
shift "$((OPTIND - 1))"

# At this point, all the remaining arguments should be the expansion of
# any globs that were passed on the command line.

if [ "$#" -eq 1 ] && [ "$ALLOW_AUTO_SELECT" = '1' ]; then
	# If there were globs on the command-line, they've expanded to
	# a single item, so we can just process it.

	if [ -d "$1" ]; then
		# Recurse and show the contents of the named directory,
		# We pass -f to force the next iteration to present the
		# full list, even if it's just an empty directory.
		cd "$1"
		IFS="$NL"  # Don't split ls output on tabs or spaces.
		exec "$0" -p "$VIS_MENU_PROMPT" -f "$(ls -1)"
	else
		# We've found a single item, and it's not a directory,
		# so it must be a filename (or file-like thing) to open,
		# unless the parent directory does not exist.
		parentdir="$(dirname -- "$1")"
		if [ -d "$parentdir" ]; then
			cd "$parentdir"
			printf '%s/%s\n' "$(pwd -P)" "$(basename -- "${1%\*}")"
			exit 0
		else
			exit 1
		fi
	fi
fi

# At this point, we have a bunch of options we need to present to the
# user so they can pick one.
CHOICE="$(printf '%s\n' '..' "$@" | wrap_dirs | vis-menu -b -l "$VIS_OPEN_LINES" -p "$VIS_MENU_PROMPT")"

# Did they pick a file or directory? Who knows, let's let the next iteration figure it out.
exec "$0" -p "$VIS_MENU_PROMPT" -- "$CHOICE"