Add reaction deck

app/controllers/api/v1/reaction_deck_controller.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+class Api::V1::ReactionDeckController < Api::BaseController
+  before_action -> { doorkeeper_authorize! :read, :'read:lists' }, only: [:index]
+  before_action -> { doorkeeper_authorize! :write, :'write:lists' }, only: [:create]
+
+  before_action :require_user!
+  before_action :set_deck, only: [:index, :create]
+
+  rescue_from ArgumentError do |e|
+    render json: { error: e.to_s }, status: 422
+  end
+
+  def index
+    render json: @deck
+  end
+
+  def create
+    (deck_params['emojis'] || []).each do |data|
+      raise ArgumentError if data['id'].to_i >= 16 || data['id'].to_i.negative?
+
+      exists = @deck.find { |dd| dd['id'] == data['id'] }
+      if exists
+        exists['emoji'] = data['emoji'].delete(':')
+      else
+        @deck << { id: data['id'], emoji: data['emoji'].delete(':') }
+      end
+    end
+    @deck = @deck.sort_by { |a| a['id'].to_i }
+    current_user.settings['reaction_deck'] = @deck.to_json
+    current_user.save!
+
+    render json: @deck
+  end
+
+  private
+
+  def set_deck
+    @deck = current_user.setting_reaction_deck ? JSON.parse(current_user.setting_reaction_deck) : []
+  end
+
+  def deck_params
+    params
+  end
+end