#!/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

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

options='
horizontal
center
input
instant
dynamic
long
prompt
numbered
prefix'

cleanup() { rm -f "$tmp"; }
logn() { >&2 printf '%s\n' "$@"; }

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

help() {
	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
	  -d              Adjust size and style dynamically
	  -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
	  -s              Invert instant select on single match
	  -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")
		# $1: items count
		get_height()
		{
			font_size="$(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)
			))"

		}
		# $1: items length
		get_width()
		{
			font_size="$(get_prop "font-size")"
			padding_left="$(get_prop "padding-left")"
			padding_right="$(get_prop "padding-right")"
			printf "%s" "$(($1*(font_size-2) + 2 + padding_left + padding_right))"
		} ;;
	"dmenu") ;;
	*) ;;
esac


main()
{
	# shellcheck disable=SC2317
	case "$MENUCMD" in
		"tofi")
			center() { add_option "--anchor=center --width=20%"; }

			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"
			}

			dynamic() {
				pre_cmd()
				{
					max_height="$(get_height 8)"
					max_width="$(get_width 48)"

					tee "$tmp"

					items_count="$(wc -l < "$tmp")"
					items_length="$(wc -L < "$tmp")"

					if [ "$long" -ne 1 ] 
					then
						height="$(get_height "$items_count")"
						[ "$height" -gt "$max_height" ] && height="$max_height"
						add_option "--height=$height"
					fi

					width="$(get_width "$items_length")"
					[ "$width" -gt "$max_width" ] && width="$max_width"

					
					if [ "$prompt" -eq 1 ]
					then
						prompt_width="$(printf "%s" "$prompt_arg" | wc -c)"
						width="$((width + $(get_width "$prompt_width")))"
					fi

					add_option "--width=$width"
				}
			}

			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}'; }
			}

			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; }
			}

			dynamic() { 
				pre_cmd()
				{
					tee "$tmp"
					items_count="$(wc -l < "$tmp")"
					number="$items_count"

					for i in $(seq $((number/2)))
					do [ "$((number%i))" -eq 0 ] && factors="$i $factors"
					done

					min_diff=9999999999
					for factor in $factors
					do
						quotient="$((number/factor))"
						diff=$((quotient - factor))
						if [ "$diff" -ge 0 ] && [ "$diff" -lt "$min_diff" ]
						then
							columns="$factor"
							rows="$quotient"
							min_diff="$diff"
						fi
					done

					add_option "-g $columns"
					add_option "-l $rows"
				}
			}

			instant() { add_option "-n"; }

			prefix() { add_option '-x'; }

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

			numbered() { add_option "-px"; }

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

		*)
			center() { :; }

			horizontal() { :; }

			dynamic() { :; }
			
			long() { :; }

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

			prefix() { :; }

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

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

			menucmd() { fzf "$@"; }
			;;
	esac

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

	while getopts ":cdhilop:nrsx" 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
			d) dynamic=1 ;;
			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) shift
				run | $0 "$@"
				exit ;;
			# invert instant select on single match
			s) instant=1 ;;
			# invert prefix matching
			x) prefix=1 ;;

			:)
				logn "Option '-$OPTARG' requires an argument"
				help
				exit 1 ;;
			?)
				logn "Invalid option: -$OPTARG"
				help
				exit 1 ;;
		esac
	done


	# conflicts
	[ "$input" -eq 1 ] && [ "$dynamic" -eq 1 ] && logn "conflicting options." && help && exit 1

	# quit if stdin is empty
	[ -t 0 ] && [ "$input" -eq 0 ] && logn "Stdin is empty." && help && exit 1

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

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

	which "${MENUCMD:-fzf}" > /dev/null || exit 1

	

	if command -v pre_cmd > /dev/null
	then
		pre_cmd > "$tmp"
		>&2 printf "menuopts: %s\n" "$menuopts"
		# shellcheck disable=SC2086
		pre_filter < "$tmp" | menucmd $menuopts | post_filter
	else
		>&2 printf "menuopts: %s\n" "$menuopts"
		# shellcheck disable=SC2086
		pre_filter | menucmd $menuopts | post_filter
	fi
}

main "$@"