Refactor #create

This method is humongous and very confusing, and often gives double render errors. This refactor breaks things up into smaller methods to help make it a bit more readable.

app/controllers/api/v1/grid_weapons_controller.rb

@@ -3,44 +3,24 @@
 module Api
   module V1
     class GridWeaponsController < Api::V1::ApiController
+      attr_reader :party, :incoming_weapon
+
+      before_action :find_party, only: :create
+      before_action :find_incoming_weapon, only: :create
+      before_action :check_weapon_compatibility, only: :create
       before_action :set, except: %w[create update_uncap_level destroy]
 
       def create
-        # BUG: I can create grid weapons even when I'm not logged in on an authenticated party
+        if conflict_weapon
-        party = Party.find(weapon_params[:party_id])
+          if conflict_weapon.weapon.id != incoming_weapon.id
-        render_unauthorized_response if current_user && (party.user != current_user)
+            # Render the conflict view as a string and assign it to a variable
-
+            conflict_view = render_conflict_view(conflict_weapon, incoming_weapon, weapon_params[:position])
-        incoming_weapon = Weapon.find(weapon_params[:weapon_id])
+            return render json: conflict_view
-        incoming_weapon.limit
+          else
-
+            # Destroy the original grid weapon
-        # Set up conflict_position in case it is used
+            # TODO: Use conflict_position to alert the client that that position has changed
-        conflict_position = nil
+            conflict_position = conflict_weapon.position
-
+            GridWeapon.destroy(conflict_weapon.id)
-        if [9, 10, 11].include?(weapon_params[:position].to_i) && ![11, 16, 17, 28, 29].include?(incoming_weapon.series)
-          raise Api::V1::IncompatibleWeaponForPositionError.new(weapon: incoming_weapon)
-        end
-
-        # 1. If the weapon has a limit
-        # 2. If the weapon does not match a weapon already in grid
-        # 3. If the incoming weapon has a limit and other weapons of the same series are in grid
-        if incoming_weapon.limit && incoming_weapon.limit.positive?
-          conflict_weapon = party.weapons.find do |weapon|
-            weapon if incoming_weapon.series == weapon.weapon.series ||
-                      ([2, 3].include?(incoming_weapon.series) && [2, 3].include?(weapon.weapon.series))
-          end
-
-          if conflict_weapon
-            if conflict_weapon.weapon.id != incoming_weapon.id
-              return render json: ConflictBlueprint.render(nil, view: :weapons,
-                                                                conflict_weapons: [conflict_weapon],
-                                                                incoming_weapon: incoming_weapon,
-                                                                incoming_position: weapon_params[:position])
-            else
-              # Destroy the original grid weapon
-              # TODO: Use conflict_position to alert the client that that position has changed
-              conflict_position = conflict_weapon.position
-              GridWeapon.destroy(conflict_weapon.id)
-            end
           end
         end
 
@@ -60,15 +40,9 @@ module Api
           party.save!
         end
 
-        # Render the new weapon and any weapons changed
+        # Render the grid weapon view as a string and assign it to a variable
-        return unless weapon.save!
+        grid_weapon_view = render_grid_weapon_view(weapon, conflict_position)
-
+        render json: grid_weapon_view, status: :created if weapon.save!
-        render json: GridWeaponBlueprint.render(weapon, view: :full,
-                                                        root: :grid_weapon,
-                                                        meta: {
-                                                          replaced: conflict_position
-                                                        }),
-               status: :created
       end
 
       def resolve
@@ -121,6 +95,56 @@ module Api
 
       private
 
+      def check_weapon_compatibility
+        return if compatible_with_position?(incoming_weapon, weapon_params[:position])
+
+        raise Api::V1::IncompatibleWeaponForPositionError.new(weapon: incoming_weapon)
+      end
+
+      # Check if the incoming weapon is compatible with the specified position
+      def compatible_with_position?(incoming_weapon, position)
+        false if [9, 10, 11].include?(position.to_i) && ![11, 16, 17, 28, 29].include?(incoming_weapon.series)
+        true
+      end
+
+      def conflict_weapon
+        @conflict_weapon ||= find_conflict_weapon(party, incoming_weapon)
+      end
+
+      # Find a conflict weapon if one exists
+      def find_conflict_weapon(party, incoming_weapon)
+        return unless incoming_weapon.limit
+
+        party.weapons.find do |weapon|
+          weapon if incoming_weapon.series == weapon.weapon.series || [2, 3].include?(weapon.weapon.series)
+        end
+      end
+
+      def find_incoming_weapon
+        @incoming_weapon = Weapon.find(weapon_params[:weapon_id])
+        @incoming_weapon.limit
+      end
+
+      def find_party
+        # BUG: I can create grid weapons even when I'm not logged in on an authenticated party
+        @party = Party.find(weapon_params[:party_id])
+        render_unauthorized_response if current_user && (party.user != current_user)
+      end
+
+      # Render the conflict view as a string
+      def render_conflict_view(conflict_weapon, incoming_weapon, incoming_position)
+        ConflictBlueprint.render(nil, view: :weapons,
+                                      conflict_weapons: [conflict_weapon],
+                                      incoming_weapon: incoming_weapon,
+                                      incoming_position: incoming_position)
+      end
+
+      def render_grid_weapon_view(grid_weapon, conflict_position)
+        GridWeaponBlueprint.render(grid_weapon, view: :full,
+                                                root: :grid_weapon,
+                                                meta: { replaced: conflict_position })
+      end
+
       def set
         @weapon = GridWeapon.where('id = ?', params[:id]).first
       end