#!/usr/bin/env ruby
# frozen_string_literal: true

require 'rubulator'
require 'readline'

rubulator = Rubulator.new

Readline.completer_word_break_characters = ' '
Readline.completion_append_character = ' '
Readline.completion_proc = proc do |partial|
  completions = rubulator.operators + rubulator.functions + rubulator.constants + rubulator.variable_names
  completions.select { |v| v.start_with?(partial) }.sort
end

puts "Rubulator version #{Rubulator::VERSION} on Ruby version #{RUBY_VERSION}."
puts 'Supported operations:'
puts "  * Operators: #{rubulator.operators.sort.join(', ')}"
puts "  * Functions: #{rubulator.functions.sort.join(', ')}"
puts "  * Constants: #{rubulator.constants.sort.join(', ')}"
puts

while (line = Readline.readline("\u001b[32;1m>>\u001b[0m \u001b[1m", true))
  print "\u001b[0m"
  begin
    result = rubulator.calculate(line)
    if result
      puts format("\u001b[34m$$ <- \u001b[1m%<result>g\u001b[0m", result: result)
      puts
    end
  rescue Rubulator::CalculationError => e
    puts "\u001b[31m!! Error: #{e}\u001b[0m"
    puts
  end
end

print "\u001b[0m\n"