Class: RuboCop::Cop::Style::EmptyLiteral

# File 'lib/rubocop/cop/style/empty_literal.rb', line 129

def frozen_strings?
  return true if frozen_string_literals_enabled?

  frozen_string_cop_enabled = config.for_cop('Style/FrozenStringLiteral')['Enabled']
  frozen_string_cop_enabled && !frozen_string_literals_disabled?
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 40

def_node_matcher :array_with_block, '(block (send (const {nil? cbase} :Array) :new) args _)'

# File 'lib/rubocop/cop/style/empty_literal.rb', line 111

def correction(node)
  if offense_array_node?(node)
    '[]'
  elsif str_node(node)
    preferred_string_literal
  elsif offense_hash_node?(node)
    if first_argument_unparenthesized?(node)
      # `some_method {}` is not same as `some_method Hash.new`
      # because the braces are interpreted as a block. We will have
      # to rewrite the arguments to wrap them in parenthesis.
      args = node.parent.arguments
      "(#{args[1..].map(&:source).unshift('{}').join(', ')})"
    else
      '{}'
    end
  end
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 82

def first_argument_unparenthesized?(node)
  parent = node.parent
  return false unless parent && %i[send super zsuper].include?(parent.type)

  node.equal?(parent.first_argument) && !parentheses?(node.parent)
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 34

def_node_matcher :hash_node, '(send (const {nil? cbase} :Hash) :new)'

# File 'lib/rubocop/cop/style/empty_literal.rb', line 43

def_node_matcher :hash_with_block, <<~PATTERN
  {
    (block (send (const {nil? cbase} :Hash) :new) args _)
    (numblock (send (const {nil? cbase} :Hash) :new) ...)
  }
PATTERN

# File 'lib/rubocop/cop/style/empty_literal.rb', line 102

def offense_array_node?(node)
  array_node(node) && !array_with_block(node.parent)
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 106

def offense_hash_node?(node)
  # If Hash.new takes a block, it can't be changed to {}.
  hash_node(node) && !hash_with_block(node.parent)
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 60

def offense_message(node)
  if offense_array_node?(node)
    ARR_MSG
  elsif offense_hash_node?(node)
    HASH_MSG
  elsif str_node(node) && !frozen_strings?
    format(STR_MSG, prefer: preferred_string_literal)
  end
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 50

def on_send(node)
  return unless (message = offense_message(node))

  add_offense(node, message: message) do |corrector|
    corrector.replace(replacement_range(node), correction(node))
  end
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 70

def preferred_string_literal
  enforce_double_quotes? ? '""' : "''"
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 89

def replacement_range(node)
  if hash_node(node) && first_argument_unparenthesized?(node)
    # `some_method {}` is not same as `some_method Hash.new`
    # because the braces are interpreted as a block. We will have
    # to rewrite the arguments to wrap them in parenthesis.
    args = node.parent.arguments

    range_between(args[0].source_range.begin_pos - 1, args[-1].source_range.end_pos)
  else
    node.source_range
  end
end

# File 'lib/rubocop/cop/style/empty_literal.rb', line 37

def_node_matcher :str_node, '(send (const {nil? cbase} :String) :new)'

# File 'lib/rubocop/cop/style/empty_literal.rb', line 78

def string_literals_config
  config.for_cop('Style/StringLiterals')
end