class RuboCop::Cop::Style::RandomWithOffset

rand(1…7)
rand(1..6)
# good
rand(0..5) + 1
Kernel.rand(6) + 1
Random.rand(6) + 1
rand(6).pred
rand(6).succ
1 - rand(6)
rand(6) - 1
1 + rand(6)
rand(6) + 1
# bad
@example
as it clearly states the intentions.
Integer#succ and Integer#pred methods. Prefer using ranges instead,
added/subtracted with integer literals, as well as those with
This cop checks for the use of randomly generated numbers,

def autocorrect(corrector, node) 

def autocorrect(corrector, node)
  if integer_op_rand?(node)
    corrector.replace(node, corrected_integer_op_rand(node))
  elsif rand_op_integer?(node)
    corrector.replace(node, corrected_rand_op_integer(node))
  elsif rand_modified?(node)
    corrector.replace(node, corrected_rand_modified(node))
  end
end

def boundaries_from_random_node(random_node) 

def boundaries_from_random_node(random_node)
  case random_node.type
  when :int
    [0, to_int(random_node) - 1]
  when :irange
    [to_int(random_node.begin), to_int(random_node.end)]
  when :erange
    [to_int(random_node.begin), to_int(random_node.end) - 1]
  end
end

def corrected_integer_op_rand(node) 

def corrected_integer_op_rand(node)
  random_call(node) do |prefix_node, random_node|
    prefix = prefix_from_prefix_node(prefix_node)
    left_int, right_int = boundaries_from_random_node(random_node)
    offset = to_int(node.receiver)
    if node.method?(:+)
      "#{prefix}(#{offset + left_int}..#{offset + right_int})"
    else
      "#{prefix}(#{offset - right_int}..#{offset - left_int})"
    end
  end
end

def corrected_rand_modified(node) 

def corrected_rand_modified(node)
  random_call(node) do |prefix_node, random_node|
    prefix = prefix_from_prefix_node(prefix_node)
    left_int, right_int = boundaries_from_random_node(random_node)
    if %i[succ next].include?(node.method_name)
      "#{prefix}(#{left_int + 1}..#{right_int + 1})"
    elsif node.method?(:pred)
      "#{prefix}(#{left_int - 1}..#{right_int - 1})"
    end
  end
end

def corrected_rand_op_integer(node) 

def corrected_rand_op_integer(node)
  random_call(node) do |prefix_node, random_node|
    prefix = prefix_from_prefix_node(prefix_node)
    left_int, right_int = boundaries_from_random_node(random_node)
    offset = to_int(node.first_argument)
    if node.method?(:+)
      "#{prefix}(#{left_int + offset}..#{right_int + offset})"
    else
      "#{prefix}(#{left_int - offset}..#{right_int - offset})"
    end
  end
end

def on_send(node) 

def on_send(node)
  return unless node.receiver
  return unless integer_op_rand?(node) || rand_op_integer?(node) || rand_modified?(node)
  add_offense(node) { |corrector| autocorrect(corrector, node) }
end

def prefix_from_prefix_node(node) 

def prefix_from_prefix_node(node)
  [node&.source, 'rand'].compact.join('.')
end