moving cards up and down

app/controllers/merged/cards_controller.rb

@@ -16,6 +16,16 @@ module Merged
       redirect_to section_cards_url(@card.section.id)
     end
 
+    def move
+      if( params[:dir] == "up")
+        @card.move_up
+      else
+        @card.move_down
+      end
+      @card.save
+      redirect_to section_cards_url(@card.section.id)
+    end
+
     def update
       @card.content.each do |key , value|
         next if key == "id"

app/models/merged/card.rb

@@ -35,6 +35,13 @@ module Merged
       @content[key] = value
     end
 
+    def move_up
+      @section.move_card_up(self)
+    end
+    def move_down
+      @section.move_card_down(self)
+    end
+
     def save
       section.save
     end
@@ -45,5 +52,9 @@ module Merged
       raise "Section not found #{id}" unless card
       return card
     end
+
+    def set_index(index)
+      @index = index
+    end
   end
 end

app/models/merged/section.rb

@@ -35,6 +35,40 @@ module Merged
       ! cards.empty?
     end
 
+    def move_up
+      @page.move_section_up(self)
+    end
+    def move_down
+      @section.move_section_down(self)
+    end
+
+    def move_card_up(card)
+      return if cards.length == 1
+      return if card.index == 0
+      swap( card , cards[card.index - 1])
+    end
+
+    def move_card_down(card)
+      return if cards.length == 1
+      return if card.index == cards.last.index
+      swap( card , cards[card.index + 1])
+    end
+
+    def swap( this_card , that_card)
+      # swap in the actual objects, index is cached in the objects
+      this_old_index = this_card.index
+      this_card.set_index( that_card.index )
+      that_card.set_index( this_old_index )
+
+      # swap in the cards cache
+      cards[ this_card.index ] = this_card
+      cards[ that_card.index ] = that_card
+      # swap in the yaml
+      card_content = content["cards"]
+      card_content[this_card.index] = this_card.content
+      card_content[that_card.index] = that_card.content
+    end
+
     def update(key , value)
       return if key == "id" #not updating that
       if(! @content[key].nil? )

app/views/merged/cards/index.haml

@@ -15,9 +15,9 @@
       .p-4
         %h3.mt-4.text-lg.font-bold Card #{index + 1}
         %button.mt-4.rounded-lg.bg-yellow-500.p-4
-          =link_to( "Up" , "/index")
+          =link_to( "Up" , card_move_url(card.id , dir: :up) )
         %button.mt-4.rounded-lg.bg-yellow-500.p-4
-          =link_to "Down" , "/index"
+          =link_to( "Down" , card_move_url(card.id , dir: :down) )
         %button.mt-4.rounded-lg.bg-cyan-400.p-4
           =link_to "New" , "/index"
         %button.mt-4.rounded-lg.bg-red-400.p-4

config/routes.rb

@@ -12,6 +12,7 @@ Merged::Engine.routes.draw do
       resources :cards do
         get :select_image
         get :set_image
+        get :move
       end
     end
   end