gem 'graphql_rails'

# config/graphql/routes.rb
GraphqlRails::Router.draw do
  # will create createUser, updateUser, destroyUser mutations and user, users queries.
  # expects that UsersController class exist
  resources :users

  # if you want custom queries or mutation
  query 'searchLogs', to: 'logs#search' # redirects request to LogsController
  mutation 'changeUserPassword', to: 'users#change_password'
end

# app/models/user.rb
class User # works with any class including ActiveRecord
  include GraphqlRails::Model

  graphql do |c|
    # most common attributes, like :id, :name, :title has default type, so you don't have to specify it (but you can!)
    c.attribute :id

    c.attribute :email, type: :string
    c.attribute :surname, type: :string
  end
end

# app/controllers/graphql/users_controller.rb
class Graphql::UsersController < GraphqlApplicationController
  # graphql requires to describe which attributes controller action accepts and which returns
  action(:change_user_password)
    .permit(:password!, :id!) # Bang (!) indicates that attribute is required
    .returns('User!')

  def change_user_password
    user = User.find(params[:id])
    user.update!(password: params[:password])

    # returned value needs to have all methods defined in model `graphql do` part
    user # or SomeDecorator.new(user)
  end

  action(:search)
    .permit(search_fields!: SearchFieldsInput) # you can specify your own input fields
    .returns('[User!]!')
  def search
  end
end

GraphqlRails::Router.draw do
  # generates `friend`, `createFriend`, `updateFriend`, `destroyFriend`, `friends` routes
  resources :friends
  resources :shops, only: [:show, :index] # generates `shop` and `shops` routes only
  resources :orders, except: :update # generates all routes except `updateOrder`

  resources :users do
    # generates `findUser` query
    query :find, on: :member

    # generates `searchUsers` query
    query :search, on: :collection
  end

  # you can use namespaced controllers too:
  scope module: 'admin' do
    # `updateTranslations` route will be handled by `Admin::TranslationsController`
    mutation :updateTranslations, to: 'translations#update'

    # all :groups routes will be handled by `Admin::GroupsController`
    resources :groups
  end
end

# spec/spec_helper.rb
require 'graphql_rails/rspec_controller_helpers'

RSpec.configure do |config|
  config.include(GraphqlRails::RSpecControllerHelpers, type: :graphql_controller)
  # ... your other configuration ...
end

class MyGraphqlController
  action(:create_user).permit(:full_name, :email).returns(User)
  action(:index).returns('String')

  def index
    "Called from index: #{params[:message]}"
  end

  def create_user
    User.create!(params)
  end
end

RSpec.describe MyGraphqlController, type: :graphql_controller do
  describe '#index' do
    it 'is successful' do
      query(:index)
      expect(response).to be_successful
    end

    it 'returns correct message' do
      query(:index, params: { message: 'Hello world!' })
      expect(response.result).to eq "Called from index: Hello world!"
    end
  end

  describe '#create_user' do
    context 'when bad email is given' do
      it 'fails' do
        mutation(:create_user, params { email: 'bad' })
        expect(response).to be_failure
      end

      it 'contains errors' do
        mutation(:create_user, params { email: 'bad' })
        expect(response.errors).not_to be_empty
      end
    end
  end
end

# config/initializers/graphql_rails.rb
GraphqlRails::Integrations.enable(:lograge, :sentry)