module Pagy::Frontend

def nav_aria_label(pagy, aria_label: nil)
  aria_label ||= pagy_t('pagy.aria_label.nav', count: pagy.pages)
  %(aria-label="#{aria_label}")
end

def next_a(pagy, a, text: pagy_t('pagy.next'), aria_label: pagy_t('pagy.aria_label.next'))
  if (p_next = pagy.next)
    a.(p_next, text, aria_label:)
  else
    %(<a role="link" aria-disabled="true" aria-label="#{aria_label}">#{text}</a>)
  end
end

def pagy_anchor(pagy, anchor_string: nil, **vars)
  anchor_string &&= %( #{anchor_string})
  left, right = %(<a#{anchor_string} href="#{pagy_url_for(pagy, PAGE_TOKEN, **vars)}").split(PAGE_TOKEN, 2)
  # lambda used by all the helpers
  lambda do |page, text = pagy.label_for(page), classes: nil, aria_label: nil|
    classes    = %( class="#{classes}") if classes
    aria_label = %( aria-label="#{aria_label}") if aria_label
    %(#{left}#{page}#{right}#{classes}#{aria_label}>#{text}</a>)
  end
end

def pagy_info(pagy, id: nil, item_name: nil)
  id      = %( id="#{id}") if id
  p_count = pagy.count
  key     = if p_count.zero?
              'pagy.info.no_items'
            elsif pagy.pages == 1
              'pagy.info.single_page'
            else
              'pagy.info.multiple_pages'
            end
  %(<span#{id} class="pagy info">#{
      pagy_t key, item_name: item_name || pagy_t('pagy.item_name', count: p_count),
                  count: p_count, from: pagy.from, to: pagy.to
    }</span>)
end

def pagy_nav(pagy, id: nil, aria_label: nil, **vars)
  id = %( id="#{id}") if id
  a  = pagy_anchor(pagy, **vars)
  html = %(<nav#{id} class="pagy nav" #{nav_aria_label(pagy, aria_label:)}>#{
             prev_a(pagy, a)})
  pagy.series(**vars).each do |item| # series example: [1, :gap, 7, 8, "9", 10, 11, :gap, 36]
    html << case item
            when Integer
              a.(item)
            when String
              %(<a role="link" aria-disabled="true" aria-current="page" class="current">#{pagy.label_for(item)}</a>)
            when :gap
              %(<a role="link" aria-disabled="true" class="gap">#{pagy_t('pagy.gap')}</a>)
            else
              raise InternalError, "expected item types in series to be Integer, String or :gap; got #{item.inspect}"
            end
  end
  html << %(#{next_a(pagy, a)}</nav>)
end

def pagy_t(key, **opts)
  Pagy::I18n.translate(@pagy_locale ||= nil, key, **opts)
end

def prev_a(pagy, a, text: pagy_t('pagy.prev'), aria_label: pagy_t('pagy.aria_label.prev'))
  if (p_prev = pagy.prev)
    a.(p_prev, text, aria_label:)
  else
    %(<a role="link" aria-disabled="true" aria-label="#{aria_label}">#{text}</a>)
  end
end