SoundSoftware Code Site

module ActionView

  module Helpers

    # Provides methods for linking to ActionController::Pagination objects using a simple generator API.  You can optionally

    # also build your links manually using ActionView::Helpers::AssetHelper#link_to like so:

    #

    # <%= link_to "Previous page", { :page => paginator.current.previous } if paginator.current.previous %>

    # <%= link_to "Next page", { :page => paginator.current.next } if paginator.current.next %>

    module PaginationHelper

      unless const_defined?(:DEFAULT_OPTIONS)

        DEFAULT_OPTIONS = {

          :name => :page,

          :window_size => 2,

          :always_show_anchors => true,

          :link_to_current_page => false,

          :params => {}

        }

      end

      # Creates a basic HTML link bar for the given +paginator+.  Links will be created

      # for the next and/or previous page and for a number of other pages around the current

      # pages position. The +html_options+ hash is passed to +link_to+ when the links are created.

      #

      # ==== Options

      # <tt>:name</tt>::                 the routing name for this paginator

      #                                  (defaults to +page+)

      # <tt>:prefix</tt>::               prefix for pagination links

      #                                  (i.e. Older Pages: 1 2 3 4)

      # <tt>:suffix</tt>::               suffix for pagination links

      #                                  (i.e. 1 2 3 4 <- Older Pages)

      # <tt>:window_size</tt>::          the number of pages to show around 

      #                                  the current page (defaults to <tt>2</tt>)

      # <tt>:always_show_anchors</tt>::  whether or not the first and last

      #                                  pages should always be shown

      #                                  (defaults to +true+)

      # <tt>:link_to_current_page</tt>:: whether or not the current page

      #                                  should be linked to (defaults to

      #                                  +false+)

      # <tt>:params</tt>::               any additional routing parameters

      #                                  for page URLs

      #

      # ==== Examples

      #  # We'll assume we have a paginator setup in @person_pages...

      #

      #  pagination_links(@person_pages)

      #  # => 1 <a href="/?page=2/">2</a> <a href="/?page=3/">3</a>  ... <a href="/?page=10/">10</a>

      #

      #  pagination_links(@person_pages, :link_to_current_page => true)

      #  # => <a href="/?page=1/">1</a> <a href="/?page=2/">2</a> <a href="/?page=3/">3</a>  ... <a href="/?page=10/">10</a>

      #

      #  pagination_links(@person_pages, :always_show_anchors => false)

      #  # => 1 <a href="/?page=2/">2</a> <a href="/?page=3/">3</a> 

      #

      #  pagination_links(@person_pages, :window_size => 1)

      #  # => 1 <a href="/?page=2/">2</a>  ... <a href="/?page=10/">10</a>

      #

      #  pagination_links(@person_pages, :params => { :viewer => "flash" })

      #  # => 1 <a href="/?page=2&amp;viewer=flash/">2</a> <a href="/?page=3&amp;viewer=flash/">3</a>  ... 

      #  #    <a href="/?page=10&amp;viewer=flash/">10</a>

      def pagination_links(paginator, options={}, html_options={})

        name = options[:name] || DEFAULT_OPTIONS[:name]

        params = (options[:params] || DEFAULT_OPTIONS[:params]).clone

        prefix = options[:prefix] || ''

        suffix = options[:suffix] || ''

        pagination_links_each(paginator, options, prefix, suffix) do |n|

          params[name] = n

          link_to(n.to_s, params, html_options)

        end

      end

      # Iterate through the pages of a given +paginator+, invoking a

      # block for each page number that needs to be rendered as a link.

      # 

      # ==== Options

      # <tt>:window_size</tt>::          the number of pages to show around 

      #                                  the current page (defaults to +2+)

      # <tt>:always_show_anchors</tt>::  whether or not the first and last

      #                                  pages should always be shown

      #                                  (defaults to +true+)

      # <tt>:link_to_current_page</tt>:: whether or not the current page

      #                                  should be linked to (defaults to

      #                                  +false+)

      #

      # ==== Example

      #  # Turn paginated links into an Ajax call

      #  pagination_links_each(paginator, page_options) do |link|

      #    options = { :url => {:action => 'list'}, :update => 'results' }

      #    html_options = { :href => url_for(:action => 'list') }

      #

      #    link_to_remote(link.to_s, options, html_options)

      #  end

      def pagination_links_each(paginator, options, prefix = nil, suffix = nil)

        options = DEFAULT_OPTIONS.merge(options)

        link_to_current_page = options[:link_to_current_page]

        always_show_anchors = options[:always_show_anchors]

        current_page = paginator.current_page

        window_pages = current_page.window(options[:window_size]).pages

        return if window_pages.length <= 1 unless link_to_current_page

        first, last = paginator.first, paginator.last

        html = ''

        html << prefix if prefix

        if always_show_anchors and not (wp_first = window_pages[0]).first?

          html << yield(first.number)

          html << ' ... ' if wp_first.number - first.number > 1

          html << ' '

        end

        window_pages.each do |page|

          if current_page == page && !link_to_current_page

            html << page.number.to_s

          else

            html << yield(page.number)

          end

          html << ' '

        end

        if always_show_anchors and not (wp_last = window_pages[-1]).last? 

          html << ' ... ' if last.number - wp_last.number > 1

          html << yield(last.number)

        end

        html << suffix if suffix

        html

      end

    end # PaginationHelper

  end # Helpers

end # ActionView