Revert "Merge pull request #775 from pozorvlak/speed_up_homepage"

This reverts commit fa50ff47bb, reversing
changes made to 5b19d236d0.

Once fixed, please read https://www.kernel.org/pub/software/scm/git/docs/howto/revert-a-faulty-merge.html carefully to get it back in properly.

app/models/crop.rb

@@ -29,12 +29,6 @@ class Crop < ActiveRecord::Base
   scope :pending_approval, -> { where(:approval_status => "pending") }
   scope :approved, -> { where(:approval_status => "approved") }
   scope :rejected, -> { where(:approval_status => "rejected") }
-  # Crops with enough plantings and photos
-  # ActiveRecord wizardry copied from
-  # http://stackoverflow.com/questions/13226913/how-do-i-select-all-records-with-more-than-n-child-records
-  scope :has_plantings, ->(min_plantings) { select("crops.*").joins(:plantings).group("crops.id").having("count(crops.id) >= ?", min_plantings) }
-  scope :has_photos, ->(min_photos) { select("crops.*").joins(:photos).group("crops.id").having("count(crops.id) >= ?", min_photos) }
-  scope :interesting, -> { has_plantings(3).has_photos(3).randomized.limit(12) }
 
   ## Wikipedia urls are only necessary when approving a crop
   validates :en_wikipedia_url,
@@ -180,6 +174,14 @@ class Crop < ActiveRecord::Base
     return popular_plant_parts
   end
 
+  def interesting?
+    min_plantings = 3 # needs this many plantings to be interesting
+    min_photos    = 3 # needs this many photos to be interesting
+    return false unless photos.size >= min_photos
+    return false unless plantings_count >= min_plantings
+    return true
+  end
+
   def pending?
     approval_status == "pending"
   end
@@ -200,6 +202,19 @@ class Crop < ActiveRecord::Base
     [ "already in database", "not edible", "not enough information", "other" ]
   end
 
+  # Crop.interesting
+  # returns a list of interesting crops, for use on the homepage etc
+  def Crop.interesting
+  howmany = 12 # max number to find
+  interesting_crops = Array.new
+    Crop.randomized.each do |c|
+      break if interesting_crops.size == howmany
+      next unless c.interesting?
+      interesting_crops.push(c)
+    end
+    return interesting_crops
+  end
+
 # Crop.create_from_csv(row)
 # used by db/seeds.rb and rake growstuff:import_crops
 # CSV fields:

app/models/planting.rb

@@ -90,6 +90,10 @@ class Planting < ActiveRecord::Base
     return photos.first
   end
 
+  def interesting?
+    return photos.present?
+  end
+
   def calculate_days_before_maturity(planting, crop)
     p_crop = Planting.where(:crop_id => crop).where.not(:id => planting)
     differences = p_crop.collect do |p|
@@ -109,15 +113,19 @@ class Planting < ActiveRecord::Base
   # we can't do this via a scope (as far as we know) so sadly we have to
   # do it this way.
   def Planting.interesting(howmany=12, require_photo=true)
-    if require_photo then
-      candidates = Planting.joins(:photos).uniq
-    else
-      candidates = Planting
+    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.size == howmany # got enough yet?
+      if require_photo
+        next unless p.photos.present? # skip those without photos, if required
+      end
+      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
-    # Find the most recent acceptable planting for each member
-    most_recent_ids = candidates.select("max(plantings.id)")
-                                .unscope(:order)
-                                .group("plantings.owner_id")
-    return candidates.where(id: most_recent_ids).limit(howmany)
+
+    return interesting_plantings
   end
 end