module SCSSLint
  # Checks for quotes in URLs.
  class Linter::UrlQuotes < Linter
    include LinterRegistry

    def visit_prop(node)
      case node.value
      when Sass::Script::Tree::Literal
        check(node, node.value.value.to_s)
      when Sass::Script::Tree::ListLiteral
        node.value.children.select { |child| child.is_a?(Sass::Script::Tree::Literal) }
                           .each { |child| check(node, child.value.to_s) }
      end

      yield
    end

  private

    def check(node, string)
      return unless string =~ /^\s*url\(\s*[^"']/
      return if string =~ /^\s*url\(\s*data:/ # Ignore data URIs

      add_lint(node, 'URLs should be enclosed in quotes')
    end
  end
end