module Pagy::BootstrapExtra

def pagy_bootstrap_nav(pagy, pagy_id: nil, link_extra: '')
  p_id = %( id="#{pagy_id}") if pagy_id
  link = pagy_link_proc(pagy, link_extra: %(class="page-link" #{link_extra}))
  html = +%(<nav#{p_id} class="pagy-bootstrap-nav" aria-label="pager"><ul class="pagination">)
  html << pagy_bootstrap_prev_html(pagy, link)
  pagy.series.each do |item| # series example: [1, :gap, 7, 8, "9", 10, 11, :gap, 36]
    html << case item
            when Integer
              %(<li class="page-item">#{link.call item}</li>)
            when String
              %(<li class="page-item active">#{link.call item}</li>)
            when :gap
              %(<li class="page-item gap disabled"><a href="#" class="page-link">#{pagy_t 'pagy.nav.gap'}</a></li>)
            else raise InternalError, "expected item types in series to be Integer, String or :gap; got #{item.inspect}"
            end
  end
  html << pagy_bootstrap_next_html(pagy, link)
  html << %(</ul></nav>)
end