#!/bin/sh

# An attempt to unify usage of multiple launchers.
# MENUCMD must be set to the name of the lancher
#
# look at the last line to understand how it works

### TODO
# instead of dynamic, provide a command to set width and height manually

tmp="$(mktemp -u)"
export menuopts=""
TOFIRC="$HOME/.config/tofi/config"

options='
horizontal
height
center
input
instant
long
prompt
numbered
prefix
width'

cleanup() { rm -f "$tmp"; }

logn() { >&2 printf '%s\n' "$@"; }
die() { logn "$@"; exit 1; }

help() {
	>&2 cat <<-EOF
	Usage: commander OPTIONS...

	An attempt to regroup multiple launchers into one,
	it detects the value of the MENUCMD variable

	try:
	MENUCMD=tofi commander < /etc/passwd

	Options:
	  -h              Display items horizontally
	  -c              Display centered
	  -i              Take an input and return it to stdout
	  -p ARG          Prompt user with the specified argument
	  -l              Display in long list format
	  -n              Output the number of matches
	  -r              Select an executable from PATH
	  -1              Invert instant select on single match
	  -y ARG          Use specified height
	  -w ARG          Use specified width
	  -x              Invert prefix matching
	EOF
}

add_option() { menuopts="$menuopts $*"; }
get_prop() { awk -F '=' "/$1 *=*/ {print \$2}" "$TOFIRC"; }


trap cleanup EXIT

# Helper functions
case "$MENUCMD" in
	tofi)
		### Get a height based on a number of items
		# $1: max items count
		get_height()
		{
			font_size="$(get_prop "font-size")"
			padding_top="$(get_prop "padding-top")"
			padding_bottom="$(get_prop "padding-bottom")"

			printf "%s" "$((
			font_size*2 + padding_top + padding_bottom + 2 +
			($1)*(font_size*2 - 2)
			))"

		}
		### Get a width based on a maximum character length
		# $1: max character length
		get_width()
		{
			font_size="$(get_prop "font-size")"
			padding_left="$(get_prop "padding-left")"
			padding_right="$(get_prop "padding-right")"
			printf "%s" "$(($1*(font_size-2) + 3 + padding_left + padding_right))"
		} ;;
	*) ;;
esac


main()
{
	# shellcheck disable=SC2317
	case "$MENUCMD" in
		tofi)
			center() { add_option "--anchor=center --width=252"; }

			horizontal() {
				add_option "--horizontal=true --height=32"
				add_option "--result-spacing=12"
				add_option "--selection-background=#88c0d0"
				add_option "--selection-background-padding=6,4"
				add_option "--padding-top=0 --padding-bottom=0"
				add_option "--margin-top=4"
			}

			long() { add_option "--width=100% --height=$(get_height 20)"; }

			input() {
				add_option "--height=$(get_height 0) --width=$(get_width 24)"
				pre_filter() { cat /dev/null; }
			}

			prefix() { add_option '--matching-algorithm=normal'; }

			instant() { add_option "--auto-accept-single=false"; }

			prompt() { add_option '--prompt-text' "$prompt_arg"; }

			numbered() { 
				pre_filter() { awk '{print NR, $0}'; }
				post_filter() { awk '{print $1}'; }
			}

			height() { add_option "--height=$(get_height "$height_arg")"; }
			width() { add_option "--width=$(get_width "$width_arg")"; }

			run() { tofi-run $*; }

			menucmd() { tofi "$@"; } ;;

		dmenu)
			horizontal() { add_option "-l 0"; }

			center() { add_option "-c"; }

			long() { add_option "-l 20 -g 1"; }

			input() {
				pre_filter() { cat /dev/null; }
			}

			instant() { add_option "-n"; }

			prefix() { add_option '-x -i'; }

			prompt() { add_option '-p' "$prompt_arg"; }

			numbered() { add_option "-px"; }


			height() { add_option "-l $height_arg"; }
			width() { add_option "-g $width_arg"; }

			run() { dmenu_path | dmenu $*; }

			menucmd() { dmenu $*; } ;;

		fzf)
			center() { :; }
			horizontal() { :; }
			long() { :; }
			height() { :; }
			width() { :; }
			instant() { :; }
			prefix() { :; }

			input() {
				pre_filter() { cat /dev/null; }
				add_option '--print-query'
			}

			prompt() { add_option "--prompt" "$prompt_arg"; }

			numbered() { 
				pre_filter() { awk '{print NR, $0}'; }
				add_option '--with-nth' '2..'
				post_filter() { awk '{print $1}'; }
			}

			run() {
				IFS=:
				set -f
				find -L $PATH -type f -printf "%f\n" 2> /dev/null | sort -u | fzf $*
			}

			menucmd() { fzf -0 -1 "$@"; } ;;

		*) ;;
	esac

	for option in $options
	do eval "$option=0"
	done

	while getopts ":cdhilop:nr1w:xy:v" opt
	do
		# shellcheck disable=SC2034
		case $opt in
			
			# display horizontal
			h) horizontal=1 ;;
			# display centered
			c) center=1 ;;
			# take an input and return it on stdout
			i) input=1 ;;
			# adjust size and style dynamically
			p) prompt=1; prompt_arg="$OPTARG";;
			# long list format
			l) long=1 ;;
			# output number of match
			n) numbered=1 ;;
			# select an executable from PATH
			r) run=1 ;;
			# invert instant select on single match
			1) instant=1 ;;
			w) width=1; width_arg="$OPTARG" ;;
			# invert prefix matching
			x) prefix=1 ;;
			y) height=1; height_arg="$OPTARG" ;;

			:) die "Option '-$OPTARG' requires an argument" ;;
			?) die "Invalid option: -$OPTARG" ;;
		esac
	done

	# quit if stdin is empty
	[ -t 0 ] && [ "${run:-0}" -eq 0 ] && [ "$input" -eq 0 ] && help && exit 1

	# call options
	for option in $options
	do eval "test \"\$$option\" -eq 1" && $option
	done

	if [ "$run" ] 
	then
		run "$menuopts" 
		exit
	fi

	command -v pre_filter > /dev/null || pre_filter() { cat; }
	command -v post_filter > /dev/null || post_filter() { cat; }

	! which "${MENUCMD:-fzf}" > /dev/null && die "MENUCMD '$MENUCMD' was not found."

	if command -v pre_cmd > /dev/null
	then
		pre_cmd > "$tmp"
		logn "menuopts: $menuopts"
		# shellcheck disable=SC2086
		pre_filter < "$tmp" | menucmd $menuopts | post_filter
	else
		logn "menuopts: $menuopts"
		# shellcheck disable=SC2086
		pre_filter | menucmd $menuopts | post_filter
	fi
}

main "$@"