class RuboCop::Cop::Lint::Void

def all_keys_entirely_literal?(node)
  node.each_key.all? { |key| entirely_literal?(key) }
end

def all_values_entirely_literal?(node)
  node.each_value.all? { |value| entirely_literal?(value) }
end

def autocorrect_nonmutating_send(corrector, node, suggestion)
  send_node = if node.send_type?
                node
              else
                node.send_node
              end
  corrector.replace(send_node.loc.selector, suggestion)
end

def autocorrect_void_expression(corrector, node)
  return if node.parent.if_type?
  corrector.remove(range_with_surrounding_space(range: node.source_range, side: :left))
end

def autocorrect_void_op(corrector, node)
  if node.arguments.empty?
    corrector.replace(node, node.receiver.source)
  else
    corrector.remove(node.loc.dot) if node.loc.dot
    corrector.replace(
      range_with_surrounding_space(range: node.loc.selector, side: :both,
                                   newlines: false),
      "\n"
    )
  end
end

def check_begin(node)
  expressions = *node
  expressions.pop unless in_void_context?(node)
  expressions.each do |expr|
    check_void_op(expr) do
      block_node = node.each_ancestor(:any_block).first
      block_node&.method?(:each)
    end
    check_expression(expr)
  end
end

def check_ensure(node)
  return unless (body = node.branch)
  # NOTE: the `begin` node case is already handled via `on_begin`
  return if body.begin_type?
  check_expression(body)
end

def check_expression(expr)
  expr = expr.body if expr.if_type?
  return unless expr
  check_literal(expr)
  check_var(expr)
  check_self(expr)
  check_void_expression(expr)
  return unless cop_config['CheckForMethodsWithNoSideEffects']
  check_nonmutating(expr)
end

def check_literal(node)
  return if !entirely_literal?(node) || node.xstr_type? || node.range_type?
  add_offense(node, message: format(LIT_MSG, lit: node.source)) do |corrector|
    autocorrect_void_expression(corrector, node)
  end
end

def check_nonmutating(node)
  return unless node.type?(:send, :any_block)
  method_name = node.method_name
  return unless NONMUTATING_METHODS.include?(method_name)
  suggestion = if METHODS_REPLACEABLE_BY_EACH.include?(method_name)
                 'each'
               else
                 "#{method_name}!"
               end
  add_offense(node,
              message: format(NONMUTATING_MSG, method: method_name,
                                               suggest: suggestion)) do |corrector|
    autocorrect_nonmutating_send(corrector, node, suggestion)
  end
end

def check_self(node)
  return unless node.self_type?
  add_offense(node, message: SELF_MSG) do |corrector|
    autocorrect_void_expression(corrector, node)
  end
end

def check_var(node)
  return unless node.variable? || node.const_type?
  if node.const_type?
    template = node.special_keyword? ? VAR_MSG : CONST_MSG
    offense_range = node
    message = format(template, var: node.source)
  else
    offense_range = node.loc.name
    message = format(VAR_MSG, var: node.loc.name.source)
  end
  add_offense(offense_range, message: message) do |corrector|
    autocorrect_void_expression(corrector, node)
  end
end

def check_void_expression(node)
  return unless node.defined_type? || node.lambda_or_proc?
  add_offense(node, message: format(EXPRESSION_MSG, expression: node.source)) do |corrector|
    autocorrect_void_expression(corrector, node)
  end
end

def check_void_op(node, &block)
  node = node.children.first while node.begin_type?
  return unless node.call_type? && OPERATORS.include?(node.method_name)
  if !UNARY_OPERATORS.include?(node.method_name) && node.loc.dot && node.arguments.none?
    return
  end
  return if block && yield(node)
  add_offense(node.loc.selector,
              message: format(OP_MSG, op: node.method_name)) do |corrector|
    autocorrect_void_op(corrector, node)
  end
end

def entirely_literal?(node)
  case node.type
  when :array
    all_values_entirely_literal?(node)
  when :hash
    all_keys_entirely_literal?(node) && all_values_entirely_literal?(node)
  when :send, :csend
    node.method?(:freeze) && node.receiver && entirely_literal?(node.receiver)
  else
    node.literal?
  end
end

def in_void_context?(node)
  parent = node.parent
  return false unless parent && parent.children.last == node
  parent.respond_to?(:void_context?) && parent.void_context?
end

def on_begin(node)
  check_begin(node)
end

def on_block(node)
  return unless node.body && !node.body.begin_type?
  return unless in_void_context?(node.body)
  check_void_op(node.body) { node.method?(:each) }
  check_expression(node.body)
end

def on_ensure(node)
  check_ensure(node)
end