Class: RuboCop::Cop::Style::IdenticalConditionalBranches

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 140

def check_branches(node, branches)
  # return if any branch is empty. An empty branch can be an `if`
  # without an `else` or a branch that contains only comments.
  return if branches.any?(&:nil?)

  tails = branches.map { |branch| tail(branch) }
  check_expressions(node, tails, :after_condition) if duplicated_expressions?(node, tails)

  return if last_child_of_parent?(node) &&
            branches.any? { |branch| single_child_branch?(branch) }

  heads = branches.map { |branch| head(branch) }

  return unless duplicated_expressions?(node, heads)

  condition_variable = assignable_condition_value(node)

  head = heads.first
  if head.respond_to?(:assignment?) && head.assignment?
    # The `send` node is used instead of the `indexasgn` node, so `name` cannot be used.
    # https://github.com/rubocop/rubocop-ast/blob/v1.29.0/lib/rubocop/ast/node/indexasgn_node.rb
    #
    # FIXME: It would be better to update `RuboCop::AST::OpAsgnNode` or its subclasses to
    # handle `self.foo ||= value` as a solution, instead of using `head.node_parts[0].to_s`.
    assigned_value = head.send_type? ? head.receiver.source : head.node_parts[0].to_s

    return if condition_variable == assigned_value
  end

  check_expressions(node, heads, :before_condition)
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 193

def check_expressions(node, expressions, insert_position)
  return if expressions.any?(&:nil?)

  inserted_expression = false

  expressions.each do |expression|
    add_offense(expression) do |corrector|
      next if node.if_type? && node.ternary?

      range = range_by_whole_lines(expression.source_range, include_final_newline: true)
      corrector.remove(range)
      next if inserted_expression

      if insert_position == :after_condition
        corrector.insert_after(node, "\n#{expression.source}")
      else
        corrector.insert_before(node, "#{expression.source}\n")
      end
      inserted_expression = true
    end
  end
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 173

def duplicated_expressions?(node, expressions)
  unique_expressions = expressions.uniq
  return false unless expressions.size >= 1 && unique_expressions.one?

  unique_expression = unique_expressions.first
  return true unless unique_expression&.assignment?

  lhs = unique_expression.child_nodes.first
  node.condition.child_nodes.none? { |n| n.source == lhs.source if n.variable? }
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 233

def expand_elses(branch)
  if branch.nil?
    [nil]
  elsif branch.if_type?
    _condition, elsif_branch, else_branch = *branch
    expand_elses(else_branch).unshift(elsif_branch)
  else
    [branch]
  end
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 248

def head(node)
  node.begin_type? ? node.children.first : node
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 217

def last_child_of_parent?(node)
  return true unless (parent = node.parent)

  parent.child_nodes.last == node
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 227

def message(node)
  format(MSG, source: node.source)
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 123

def on_case(node)
  return unless node.else? && node.else_branch

  branches = node.when_branches.map(&:body).push(node.else_branch)
  check_branches(node, branches)
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 130

def on_case_match(node)
  return unless node.else? && node.else_branch

  branches = node.in_pattern_branches.map(&:body).push(node.else_branch)
  check_branches(node, branches)
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 116

def on_if(node)
  return if node.elsif?

  branches = expand_elses(node.else_branch).unshift(node.if_branch)
  check_branches(node, branches)
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 223

def single_child_branch?(branch_node)
  !branch_node.begin_type? || branch_node.children.size == 1
end

# File 'lib/rubocop/cop/style/identical_conditional_branches.rb', line 244

def tail(node)
  node.begin_type? ? node.children.last : node
end