breadcrumb_for.rb

module ApplicationHelper

  #
  # @usage
  #
  # breadcrumb_for @post
  # breadcrumb_for @post, 'comments'
  # breadcrumb_for @post, @comment
  # breadcrumb_for :namespace, @post, @comment
  #

  def breadcrumb_for *args
    options = args.extract_options!
    options[:skip] = options.is_a?(Array) ? options[:skip] : [options[:skip]]
    aux = args.dup
    has_prefix = aux.first.is_a?(Symbol)
    prefix = aux.delete(aux.first) if has_prefix
    breadcrumb = []
    current = aux.last
    args.each do |e|
      unless args.empty? or options[:skip].include?(aux.last)
        scope = aux.last
        if scope.is_a?(ActiveRecord::Base)
          label = scope.to_label
          breadcrumb << { :label => scope.to_label, :url => resource_url_for(aux)}
          breadcrumb << { :label => collection_label_for(scope), :url => collection_url_for(aux) }
        elsif scope.is_a?(String)
          # collection url in current controller
          breadcrumb << {:label => collection_label_for(scope), :url => collection_url_for_current_controller(aux) }
        end
      end
      aux.pop
    end
    apply_prefix_for breadcrumb, prefix if has_prefix
    breadcrumb << {:label => 'Início', :url => namespace_or_root_path_for(prefix)} if has_prefix
    current = breadcrumb.delete_at(0)
    breadcrumb.reverse!.map! { |e| content_tag(:li, link_to(e[:label], eval(e[:url]))) }
    if edit_or_new(current)
      breadcrumb << content_tag(:li, link_to(current[:label], eval(current[:url])))
      breadcrumb << content_tag(:li, edit_or_new(current)[:label])
    else
      breadcrumb << content_tag(:li, current[:label])
    end
    content_tag(:ul, breadcrumb, :id => 'breadcrumb')
  end

  # Tries to guess the url for a single resource based on a given array
  # of resources. The last resource will be the current scope
  # It returns something like "post_comment_path(@post, @comment)"
  def resource_url_for *args
    args = args.first if args.first.is_a?(Array)
    aux = args.dup
    entities = aux.select {|e| e.is_a?(ActiveRecord::Base) }.map {|e| "@#{e.class.to_s.downcase}" }
    entities = entities.inspect.delete('"[]')
    aux.map! { |e| e.class.to_s.downcase }
    aux = aux.join('_')
    "#{aux}_path(#{entities})"
  end


  # Tries to guess the url for a collection of resources based on a given array
  # of resources. The last resource will be the current scope
  # It returns something like "post_comments_path(@post)"
  def collection_url_for *args
    args = args.first if args.first.is_a?(Array)
    aux = args.dup
    if aux.size == 1
      "#{methodize(aux.first).pluralize}_path"
    else
      scope = aux.delete(aux.last)
      entities = aux.select {|e| e.is_a?(ActiveRecord::Base) }.map {|e| "@#{e.class.to_s.downcase}" }
      entities = entities.inspect.delete('"[]')
      aux.map! { |e| e.class.to_s.downcase }
      aux = aux.join('_')
      "#{aux}_#{methodize(scope).pluralize}_path(#{entities})"
    end
  end

  # Tries to guess the colletion path for the current controller, when the 
  # current action is a collection action (like index). You must supply a
  # string with the collection name. Ex: breadcrumb_for('posts').
  # The example above will force the method bellow to be called returning 
  # something like this: "posts_path". If you call: 
  # breadcrumb_for(@post, 'comments') the method bellow will be called 
  # returning something like "post_comments_path(@post)"
  def collection_url_for_current_controller *args
    args = args.first if args.first.is_a?(Array)
    aux = args.dup
    if aux.size == 1
      "#{aux.first}_path"
    else
      scope = aux.delete(aux.last)
      entities = aux.select {|e| e.is_a?(ActiveRecord::Base) }.map {|e| "@#{e.class.to_s.downcase}" }
      entities = entities.inspect.delete('"[]')
      aux.map! { |e| e.class.to_s.downcase }
      aux = aux.join('_')
      "#{aux}_#{scope}_path(#{entities})"
    end
  end

  # This method tries to return the "namespace_root_path" method if it is setted
  # in config/routes.rb. If the root of the namespace is not setted it will return
  # the "root_url"
  def namespace_or_root_path_for namespace
    methods.include?("#{namespace}_root_path") ? "#{namespace}_root_path" : "root_path"
  end

  # Aplies the namespace to all urls in a given array. The array suplied must
  # be an array of hashes with a :url key
  def apply_prefix_for bdc, prefix
    bdc.each {|e| e[:url] = "#{prefix}_#{e[:url]}" }
  end

  # A helper to turn an object into a part of a method name
  def methodize(entity)
    entity.class.to_s.downcase
  end

  # Label display in a collection link breadcrumb
  def collection_label_for resource
    if resource.is_a?(ActiveRecord::Base) 
      resource.class.human_name(:count => 2).capitalize
    elsif resource.is_a?(String)
      resource.singularize.camelize.constantize.human_name(:count => 2).capitalize
    else
      resource.to_s.capitalize.pluralize
    end
  end

  def edit_or_new(current)
    new_page = "new_#{current[:url]}".gsub(/\(.*\)/, '')
    edit_page = "edit_#{current[:url]}".gsub(/\(.*\)/, '')
    if methods.include?(new_page)
      return { :label => 'Cadastrar', :url => new_page } if current_page?(eval("new_#{current[:url]}"))
    end
    if methods.include?(edit_page)
      return { :label => 'Editar', :url => new_page} if current_page?(eval("edit_#{current[:url]}"))
    end
    nil
  end

end