#!/usr/bin/env bash

# https://github.com/onespaceman/menu-calc
# https://github.com/BarbUk/menu-qalc
# https://github.com/ClemaX/menu-qalc-wayland
#
# Calculator for use with rofi
# Copying to the clipboard requires wl-copy

usage() {
  echo "$(tput bold)menu-calc$(tput sgr0)"
  echo "A calculator for Rofi"
  echo
  echo "$(tput bold)Usage:$(tput sgr0)"
  echo "    = 4+2"
  echo "    = (4+2)/(4+3)"
  echo "    = 4^2"
  echo "    = sqrt(4)"
  echo "    = c(2)"
  echo
  echo "$(tput bold)Passing arguments to Rofi:$(tput sgr0)"
  echo "Any parameters after ' -- ' will be passed to Rofi."
  echo
  echo "    = -- <Rofi args>"
  echo
  echo "The answer can be copied to the clipboard and used for further calculations inside (or outside) Rofi."
  echo
  echo "If launched outside of Rofi the expression may need quotation marks."
  exit
}

process_query() { # query
  local query="$1"

  qalc +u8 -color=never -terse <<<"$query" |
    awk '!/^>/ && !/^$/ {gsub(/^[ \t]+|[ \t]+$/, "", $0); print}'
}

# Process CLI parameters
for var in "$@"; do
  case $var in
  -h | --help) usage ;;
  --) break ;;
  esac
done

# Path to menu application
if [[ -n $(command -v rofi) ]]; then
  menu="$(command -v rofi)"
  menu="$menu -dmenu -lines 3"
else
  >&2 echo "Rofi not found"
  exit
fi

# Determine args to pass to rofi
while [[ $# -gt 0 && $1 != "--" ]]; do
  shift
done
[[ $1 == "--" ]] && shift

while true; do
  action=$(echo -e "Copy\nClear\nClose" | ${menu} "$@" -p "= $answer")

  case "$action" in
  "Clear") answer= ;;
  "Copy") wl-copy -- "$answer" ;;
  "Close" | "") exit ;;
  *) answer=$(process_query "$answer $action") ;;
  esac
done