# frozen_string_literal: true

module RubyAlgebra
  # Команда интерпретатора
  class Command
    attr_reader :type

    def type
      raise NotImplementedError
    end
  end

  # Команда присвоения
  class AssignmentCommand < Command
    attr_reader :lhs, :operation, :operand1, :operand2

    def initialize(lhs, operation, operand1, operand2)
      @lhs = lhs
      @operation = operation
      @operand1 = operand1
      @operand2 = operand2
    end

    def to_s
      result = "Assignment command: "
      result += @lhs.is_a?(Array) ? @lhs.join(', ') : @lhs.to_s
      if @operation == :diff
        result += ' := Diff(' + @operand1.to_s + @operand2.map { |v| ", #{v}"}.join + ')'
      elsif @operation == :subs
        result += ' := Subs(' + @operand1.to_s + @operand2.map { |variable, value| ", #{variable}=#{value}"}.join + ')'
      else
        result += ' := ' + @operand1.to_s
        case @operation
        when :add
          result += ' + '
        when :sub
          result += ' - '
        when :mult, :scale
          result += ' * '
        when :div
          result += ' / '
        end
        result += @operand2.to_s if @operation != :assign
      end
      result
    end

    def type
      :assignment
    end
  end

  # Команда вывода на экран
  class DisplayCommand < Command
    attr_reader :item

    def initialize(item)
      @type = :display
      @item = item
    end

    def to_s
      result = "Display command: "
      result += @item.to_s
      result
    end

    def type
      :display
    end
  end
end