Break out interesting? into its own method

app/models/crop.rb

@@ -13,6 +13,7 @@ class Crop < ActiveRecord::Base
 
   default_scope order("lower(system_name) asc")
   scope :recent, reorder("created_at desc")
+  scope :randomized, reorder('random()') # ok on sqlite and psql, but not on mysql
 
   validates :en_wikipedia_url,
     :format => {
@@ -89,19 +90,14 @@ class Crop < ActiveRecord::Base
   # Crop.interesting
   # returns a list of interesting crops, for use on the homepage etc
   def Crop.interesting
-    return Rails.cache.fetch("interesting_crops", :expires_in => 1.day) do
-      howmany = 12 # max number to find
-      interesting_crops = Array.new
-      # it's inefficient to shuffle this up-front, but if we cache
-      # the crops on the homepage it won't be run too often, and there's
-      # not *that* many crops.
-      Crop.all.each do |c|
-        break if interesting_crops.length == howmany
-        next unless c.interesting?
-        interesting_crops.push(c)
-      end
-      interesting_crops
+  howmany = 12 # max number to find
+  interesting_crops = Array.new
+    Crop.randomized.each do |c|
+      break if interesting_crops.length == howmany
+      next unless c.interesting?
+      interesting_crops.push(c)
     end
+    return interesting_crops
   end
 
 end

app/models/planting.rb

@@ -6,7 +6,8 @@ class Planting < ActiveRecord::Base
     :quantity, :sunniness, :planted_from
 
   belongs_to :garden
-  belongs_to :crop
+  belongs_to :crop, :counter_cache => true
+  has_one :owner, :through => :garden
 
   has_and_belongs_to_many :photos
   before_destroy {|planting| planting.photos.clear}
@@ -19,7 +20,6 @@ class Planting < ActiveRecord::Base
     :plantings_count,
     :to => :crop,
     :prefix => true
-  delegate :owner, :to => :garden
 
   default_scope order("created_at desc")
 
@@ -77,17 +77,17 @@ class Planting < ActiveRecord::Base
   def Planting.interesting
     howmany = 12 # max amount to collect
 
-    return Rails.cache.fetch("interesting_plantings", :expires_in => 3.hours) do
-      interesting_plantings = Array.new
-      seen_owners = Hash.new(false) # keep track of which owners we've seen already
-      Planting.all.each do |p|
-        break if interesting_plantings.count == howmany # got enough yet?
-        next unless p.interesting?    # skip those that don't have photos
-        next if seen_owners[p.owner]  # skip if we already have one from this owner
-        seen_owners[p.owner] = true   # we've seen this owner
-        interesting_plantings.push(p)
-      end
-      interesting_plantings
+    interesting_plantings = Array.new
+    seen_owners = Hash.new(false) # keep track of which owners we've seen already
+
+    Planting.all.each do |p|
+      break if interesting_plantings.count == howmany # got enough yet?
+      next unless p.interesting?    # skip those that don't have photos
+      next if seen_owners[p.owner]  # skip if we already have one from this owner
+      seen_owners[p.owner] = true   # we've seen this owner
+      interesting_plantings.push(p)
     end
+
+    return interesting_plantings
   end
 end

app/models/seed.rb

@@ -33,7 +33,7 @@ class Seed < ActiveRecord::Base
   def interesting?
     # assuming we're passed something that's already known to be tradable
     # eg. from Seed.tradable scope
-    return false if s.owner.location.blank? # don't want unspecified locations
+    return false if owner.location.blank? # don't want unspecified locations
     return true
   end
 

app/views/home/_crops.html.haml

@@ -1,13 +1,15 @@
 .row-fluid
   .span6
-    %h2 Some of our crops
-    - @crops.each do |c|
-      .span3{:style => 'margin:0px; padding: 3px'}
-        = render :partial => 'crops/image_with_popover', :locals => { :crop => c }
+    - cache "interesting_crops", :expires_in => 1.day do
+      %h2 Some of our crops
+      - @crops.each do |c|
+        .span3{:style => 'margin:0px; padding: 3px'}
+          = render :partial => 'crops/image_with_popover', :locals => { :crop => c }
 
   .span6
-    %h2 Recently planted
-    = render :partial => 'plantings/list', :locals => { :plantings => @plantings }
+    - cache "interesting_plantings" do
+      %h2 Recently planted
+      = render :partial => 'plantings/list', :locals => { :plantings => @plantings }
 
 .row-fluid
   .span12

db/migrate/20130819004549_add_planting_count_to_crop.rb

@@ -0,0 +1,5 @@
+class AddPlantingCountToCrop < ActiveRecord::Migration
+  def change
+    add_column :crops, :plantings_count, :integer
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20130723110702) do
+ActiveRecord::Schema.define(:version => 20130819004549) do
 
   create_table "account_types", :force => true do |t|
     t.string   "name",              :null => false
@@ -57,6 +57,7 @@ ActiveRecord::Schema.define(:version => 20130723110702) do
     t.datetime "updated_at",       :null => false
     t.string   "slug"
     t.integer  "parent_id"
+    t.integer  "plantings_count"
   end
 
   add_index "crops", ["slug"], :name => "index_crops_on_slug", :unique => true