_form.html.erb

<!-- Classdate form -->

<% if (params[:classdate] and params[:classdate][:course_id]) or @classdate.id %>
<%= nested_form_for(@classdate) do |f| %>
    <% if @classdate.errors.any? %>
      <div id="error_explanation">
        <h2><%= pluralize(@classdate.errors.count, "error") %> prohibited this classdate from being saved:</h2>

        <ul>
        <% @classdate.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
        </ul>
      </div>
    <% end %>
    <%= collection_select(:classdate, :course_id, Course.all, :id, :name, {:include_blank => "Select a Course"},
          { :class => "selectpicker"}
        ) %>
    <div class="field">
      <%= f.label :startdatetime %><br>
      <%= f.text_field :startdatetime, {class:"datetime-picker classdate"} %>
    </div>
    <div class="field">
      <%= f.label :enddatetime %><br>
      <%= f.text_field :enddatetime, {class:"datetime-picker classdate"} %>
    </div>
    <div class="field">
      <%= f.label :priceoverride %><br>
      <%= f.number_field :priceoverride %>
      <span>If this is not set, it will default to the course price.</span>
    </div>


    <!-- ADDITIONAL REQUIREMENTS -->
    <h2>Special Requirements</h2>
    <em>These are in addition to the regular requirements of the class.</em>
    <div class="additional-worker-requirements">
    <h4>Worker requirements</h4>
    <%= f.fields_for :additional_worker_requirements, :wrapper => false do |ff| %>
      <%= ff.collection_select(:role, User::ROLES, :to_s, :humanize, {:include_blank => "Select a User Role"},
            { :class => "selectpicker"}
          ) %><br>
      <%= ff.label :number_required %>
      <%= ff.text_field :number_required %><br>
      <%= ff.link_to_remove "Remove this Requirement" %><br>
    <% end %>
    <p><%= f.link_to_add "Add an additional requirement", :additional_worker_requirements %></p>
  </div>
  <div class="additional-asset-requirements">
    <h4>Asset requirements</h4>
    <%= f.fields_for :additional_asset_requirements, :wrapper => false  do |ff| %>
      <%= ff.label :asset_type %>
      <%= ff.collection_select(:asset_type, @assettypes, :to_s, :humanize, {:include_blank => "Select an Asset Type"},
            { :class => "selectpicker"}
      ) %><br>
      <%= ff.label :number_required %>
      <%= ff.text_field :number_required %><br>
      <%= ff.link_to_remove "Remove this Requirement" %><br>
    <% end %>
    <p><%= f.link_to_add "Add a requirement", :additional_asset_requirements %></p>
  </div>

<h2>Missing assets</h2>
<div class="missing-assets">
  <% @classdate.missing_assets.each_with_index do |ma,i| %>
    <% type = ""
        ma[1].each do |k,v|
          if v.split("_").count > 1
            v = v.split("_")[0] + " (#{v.split("_")[1]})"
          end
          type+= "#{v}".humanize
        end
    %>
    <h3>
      <%= "#{ma[2]} #{type} <small>#{ma[0].to_s.humanize.singularize.pluralize ma[2]}</small>".html_safe %>
    </h3>
    <!-- Here is where I'd like to build and output associated resource fields, as defined by the missing asset object I'm currently looping through -->
    
    <%= f.fields_for :assignments do |ff| %>
      <div class="field assignable_id">
        <%= label "assignable_id", "Select an asset to assign:" %>
          <%= collection_select(nil, nil, PhysicalAsset.all.where(:available => true), :id, :asset_type_and_id, {:include_blank => "Select a Physical Asset"},
                { :class => "selectpicker", :"data-assignable-type" => "PhysicalAsset"}
              ) %> or
          <%= collection_select(nil, nil, User.staff, :id, :fullname, {:include_blank => "Select a User"},
                { :class => "selectpicker", :"data-assignable-type" => "User" }
              ) %>
              <%= ff.hidden_field :assignable_type, {:class => "assignable-type"} %>
              <%= ff.hidden_field :assignable_id, {:class => "assignable-id"} %>
        </div>

        <div class="field">
          <%= ff.label :startdatetime %><br>
          <%= @classdate.startdatetime %>
          <%= ff.hidden_field :startdatetime, :value => @classdate.startdatetime %>
        </div>
        <div class="field">
          <%= ff.label :enddatetime %><br>
          <%= @classdate.enddatetime %>
          <%= ff.hidden_field :enddatetime, :value => @classdate.enddatetime %>
        </div>
        <div class="field">
          <%= ff.hidden_field :classdate_id, :value => @classdate.id %>
        </div>
        <div class="field">
          <%= ff.label :notes %><br>
          <%= ff.text_area :notes %>
        </div>
        <div class="field">
          <%= ff.label :approved %><br>
          <%= ff.check_box :approved %>
        </div>
        <%= ff.link_to_remove "Remove this Assignment" %><br>
    <% end %>
  <% end %>
</div>


  <div class="actions">
    <%= f.submit %>
  </div>

  <% end %>
<% else %>
<form action="./new" method="GET">
<h2>Select a course to create this class date.</h2>
<div class="field">
    <%= label "Course", :course %>
    <%= collection_select(:classdate, :course_id, Course.all, :id, :name, {:include_blank => "Please Select a Course"},
          { :class => "selectpicker"}
        ) %>
  </div>
  <div class="submit"><input type="submit" value="Next &raquo;"></div>
</form>
<% end %>

classdate.rb

class Classdate < ActiveRecord::Base
	validates_presence_of :course_id, :message => "You must have an associated course to create a class date."
	
	belongs_to :course
	# delegate :asset_requirements, :to => :course
	# delegate :worker_requirements, :to => :course
	has_many :asset_requirements, :through => :course
	has_many :worker_requirements, :through => :course

	has_many :additional_asset_requirements
	has_many :additional_worker_requirements

	accepts_nested_attributes_for :additional_worker_requirements, :allow_destroy => true
	accepts_nested_attributes_for :additional_asset_requirements, :allow_destroy => true

	has_and_belongs_to_many :people
	has_many :assignments

	accepts_nested_attributes_for :assignments, :allow_destroy => true, reject_if: proc { |attributes| attributes[:assignable_id].blank? }

	def asset_requirements
		# self.asset_requirement_overrides.nil? ? course.asset_requirements : self.asset_requirement_overrides
		course.asset_requirements + self.additional_asset_requirements
	end
	def worker_requirements
		# self.worker_requirement_overrides.nil? ? course.worker_requirements : self.worker_requirement_overrides
		course.worker_requirements + self.additional_worker_requirements
	end

	def auto_assign_assets
		# if current_user.role? :admin
			missing_assets.each do |req|
				klass = req[0].to_s.singularize.camelize.constantize
				notavailable = Assignment.where("((assignments.startdatetime > ? AND assignments.startdatetime < ?) OR (assignments.enddatetime > ? AND assignments.enddatetime < ?)) AND assignments.assignable_type = ?", startdatetime, enddatetime, startdatetime, enddatetime, klass).pluck(:assignable_id)
				if notavailable.empty?
					@available_assets = klass.order("RANDOM()")
				else
					@available_assets = klass.order("RANDOM()").where('id NOT IN (?)', notavailable).where(req[1]).limit(req[2])
				end
				
			end
		# end
	end

	def missing_assets
		assetcounts = { :users => {}, :physical_assets => {} }
		as = assignments
		missing = []
		as.where(:assignable_type => "User").each do |assignment|
			assetcounts[:users][assignment.assignable.role] = assetcounts[:users][assignment.assignable.role].to_i + 1
		end
		as.where(:assignable_type => "PhysicalAsset").each do |pa|
			assetcounts[:physical_assets][pa.assignable.asset_type] = assetcounts[:physical_assets][pa.assignable.asset_type].to_i + 1
		end
		puts assetcounts.inspect
		worker_requirements.each do |req|
			assigned = assetcounts[:users][req.role].to_i
			needed = req.number_required
			assigned < needed and missing << [:users, {:role => req.role}, needed - assigned]
		end
		asset_requirements.each do |req|
			assigned = assetcounts[:physical_assets][req.asset_type].to_i
			needed = req.number_required
			assigned < needed and missing << [:physical_assets, {:asset_type => req.asset_type}, needed - assigned]
		end
		return missing
	end

	def assets_ready?
		missing_assets.empty?
	end
end

course.rb

class Course < ActiveRecord::Base
	has_many :classdates
	has_many :people, :through => :classdates
	has_and_belongs_to_many :instructors, :class_name => "User", :join_table => "instructors_teachable_courses"
	has_many :asset_requirements
	has_many :worker_requirements
	accepts_nested_attributes_for :asset_requirements, :allow_destroy => true
	accepts_nested_attributes_for :worker_requirements, :allow_destroy => true

	has_many :prerequisites
	has_many :prerequisite_courses, :through => :prerequisites
end

course_form.html.erb

<%= nested_form_for(@course) do |f| %>
  <% if @course.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@course.errors.count, "error") %> prohibited this course from being saved:</h2>

      <ul>
      <% @course.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>
  <div class="field">
    <%= f.label :description %><br>
    <%= f.text_area :description %>
  </div>
  <div class="field">
    <%= f.label :price %><br>
    <%= f.number_field :price %>
  </div>
  <div class="field">
    <%= f.label :class_size %><br>
    <%= f.number_field :class_size %>
  </div>
  <div class="field">
    <h3>Prerequisites</h3>
    <%= hidden_field_tag "course[prerequisite_course_ids][]", nil %>
    <% Course.all.where("id NOT IN (?)", @course.id || 0).each do |course| %>
      <div>
        <%= check_box_tag "course[prerequisite_course_ids][]", course.id, @course.prerequisite_courses.include?(course) %>
        <%= link_to course.name, course %>
      </div>
    <% end %>
  </div>
  <div class="field">
    <%= f.label :agemin %><br>
    <%= f.number_field :agemin %>
  </div>
  <div class="field">
    <%= f.label :agemax %><br>
    <%= f.number_field :agemax, :value => 99 %>
  </div>
  <div class="worker-requirements">
    <h4>Worker requirements</h4>
    <%= f.fields_for :worker_requirements, :wrapper => false do |ff| %>
      <%= ff.collection_select(:role, User::ROLES, :to_s, :humanize, {:include_blank => "Select a User Role"},
            { :class => "selectpicker"}
          ) %><br>
      <%= ff.label :number_required %>
      <%= ff.text_field :number_required %><br>
      <%= ff.link_to_remove "Remove this Requirement" %><br>
    <% end %>
    <p><%= f.link_to_add "Add a requirement", :worker_requirements %></p>
  </div>
  <div class="asset-requirements">
    <h4>Asset requirements</h4>
    <%= f.fields_for :asset_requirements, :wrapper => false  do |ff| %>
      <%= ff.label :asset_type %>
      <%= ff.collection_select(:asset_type, @assettypes, :to_s, :humanize, {:include_blank => "Select an Asset Type"},
            { :class => "selectpicker"}
      ) %><br>
      <%= ff.label :number_required %>
      <%= ff.text_field :number_required %><br>
      <%= ff.link_to_remove "Remove this Requirement" %><br>
    <% end %>
    <p><%= f.link_to_add "Add a requirement", :asset_requirements %></p>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>