MyCyma

module SortableListHelper

# To use simply put this in your table header

#

# <th><%=s :first_name%></th>

#

# This will create markup that looks like the following:

#

# <th><a href="?sort=first_name%20ASC">First Name</a></th>

#

# Then in your controller just do:

#

# @users = User.find :all, :order => params[:sort]

#

# If the current field is the field being sorted then it will do the opposite

# direction. So if the user clicked the link for the past request then the

# same code will now generate

#

# <th><a href="?sort=first_name%20DESC">First Name</a></th>

#

# This allows users to reverse the order simply by clicking the link again.

# In addition sortable_header method takes a option hash as the second

# argument with the following valid options:

#

# label::

# If humanize is not guessing your field name correctly you can use this to

# give an explicit label.

# descend::

# Set to true if you want this column to initially be decending. Date

# columns are often used in this way.

# default::

# Set to true if this column is the default sort column. This means that if

# the :sort param has no value this column assumes it is sorting the data.

# You should specify one column with default => true

# asc_img::

# The name of an image to show beside the column if we are sorting in an

# assending order (this should probably be a down arrow).

# desc_img::

# The name of an image to show beside the column if we are sorting in a

# descending order (this should probably be a up arrow).

#

# Since you most likely do not want to specify a asc_img and desc_img on every

# execution of the sortable_header method you can also define the following

# constants so the images are automatically included without explicit

# specification

#

# * SORTABLE_COLUMN_ASC

# * SORTABLE_COLUMN_DESC

#

# NOTE: This method is aliased as #s for easy programming much like

# the #h method which escapes #html_escape

def sortable_header(field, options={})

dir = 'ASC'

dir = 'DESC' if options[:descend]

fld = field.to_s

cur = nil

cur = "#{fld} #{dir}" if options[:default]

cur = @sort || params[:sort] unless (@sort || params[:sort]).blank?

if cur

cur_fld, cur_dir = cur.split(/\s*,\s*/).first.split /\s+/

dir = cur_dir == 'ASC' ? 'DESC' : 'ASC' if cur_fld == fld

end

label = options[:label] || fld.titleize

asc_img = desc_img = ''

if cur_fld == fld

asc_img = SORTABLE_COLUMN_ASC if Object.const_defined? 'SORTABLE_COLUMN_ASC'

desc_img = SORTABLE_COLUMN_DESC if Object.const_defined? 'SORTABLE_COLUMN_DESC'

asc_img = options[:asc_img] || asc_img

desc_img = options[:desc_img] || desc_img

end

img = dir == 'ASC' ? asc_img : desc_img

img = image_tag(img, :alt => '', :border => 0) + ' ' unless img.blank?

args = params.merge :sort => "#{fld} #{dir}"

args.delete_if {|k, v| %w(controller action).include? k}

link_to (img+label), args

end

alias_method :s, :sortable_header

end