require 'u-service'

require_relative 'calc/operation'
require_relative 'calc/normalize_args'
require_relative 'calc/transform_into_numbers'

module Calc
  TransformArgsIntoNumbers = NormalizeArgs >> TransformIntoNumbers

  module With
    Add = TransformArgsIntoNumbers >> Operation::Add
    Divide = TransformArgsIntoNumbers >> Operation::Divide
    Subtract = TransformArgsIntoNumbers >> Operation::Subtract
    Multiply = TransformArgsIntoNumbers >> Operation::Multiply
  end
end

class PerformTask < Micro::Service::Base
  attributes :args, :operation

  def call!
    operation
      .call(args: args)
      .on_success { |value| print_operation(value) }
      .on_failure(:not_a_number) { |message| puts "ERROR: #{message}" }
      .on_failure(:arguments_with_space_chars) do |(a, b)|
        puts "ERROR: Arguments can't have spaces: a: #{a}, b: #{b}"
      end
  end

  private def print_operation(a:, operator:, b:, result:)
    puts "#{a} #{operator} #{b} = #{result}"
  end
end

namespace :calc do
  desc 'adds two numbers'
  task :add, [:a, :b] do |_task, args|
    PerformTask.call(args: args, operation: Calc::With::Add)
  end

  desc 'divides two numbers'
  task :divide, [:a, :b] do |_task, args|
    begin
      PerformTask.call(args: args, operation: Calc::With::Divide)
    rescue ZeroDivisionError => e
      puts "ERROR: #{e.message}"
    end
  end

  desc 'subtracts two numbers'
  task :subtract, [:a, :b] do |_task, args|
    PerformTask.call(args: args, operation: Calc::With::Subtract)
  end

  desc 'multiplies two numbers'
  task :multiply, [:a, :b] do |_task, args|
    PerformTask.call(args: args, operation: Calc::With::Multiply)
  end
end