# frozen_string_literal: true

module RuboCop
  module Cop
    module Performance
      # Identifies unnecessary use of a regex where `String#include?` would suffice.
      #
      # @safety
      #   This cop's offenses are not safe to autocorrect if a receiver is nil or a Symbol.
      #
      # @example
      #   # bad
      #   str.match?(/ab/)
      #   /ab/.match?(str)
      #   str =~ /ab/
      #   /ab/ =~ str
      #   str.match(/ab/)
      #   /ab/.match(str)
      #
      #   # good
      #   str.include?('ab')
      class StringInclude < Base
        extend AutoCorrector

        MSG = 'Use `%<negation>sString#include?` instead of a regex match with literal-only pattern.'
        RESTRICT_ON_SEND = %i[match =~ !~ match?].freeze

        def_node_matcher :redundant_regex?, <<~PATTERN
          {(send $!nil? {:match :=~ :!~ :match?} (regexp (str $#literal?) (regopt)))
           (send (regexp (str $#literal?) (regopt)) {:match :match?} $_)
           (match-with-lvasgn (regexp (str $#literal?) (regopt)) $_)}
        PATTERN

        def on_send(node)
          return unless (receiver, regex_str = redundant_regex?(node))

          negation = node.send_type? && node.method?(:!~)
          message = format(MSG, negation: ('!' if negation))

          add_offense(node, message: message) do |corrector|
            receiver, regex_str = regex_str, receiver if receiver.is_a?(String)
            regex_str = interpret_string_escapes(regex_str)

            new_source = "#{'!' if negation}#{receiver.source}.include?(#{to_string_literal(regex_str)})"

            corrector.replace(node.source_range, new_source)
          end
        end
        alias on_match_with_lvasgn on_send

        private

        def literal?(regex_str)
          regex_str.match?(/\A#{Util::LITERAL_REGEX}+\z/o)
        end
      end
    end
  end
end