Set member status to sustainer upon payment

Introduces a state machine for the payment status as well.

refs #213

app/models/donation.rb

@@ -1,22 +1,41 @@
 class Donation < ApplicationRecord
-  # Relations
+  include AASM
+
   belongs_to :user
 
-  # Validations
   validates_presence_of :user
   validates_presence_of :donation_method,
     inclusion: { in: %w[ custom btcpay lndhub ] }
   validates_presence_of :payment_status, allow_nil: true,
-    inclusion: { in: %w[ processing settled ] }
+    inclusion: { in: %w[ pending processing settled ] }
   validates_presence_of :paid_at, allow_nil: true
   validates_presence_of :amount_sats, allow_nil: true
   validates_presence_of :fiat_amount, allow_nil: true
   validates_presence_of :fiat_currency, allow_nil: true,
     inclusion: { in: %w[ EUR USD ] }
 
-  #Scopes
+  scope :pending,    -> { where(payment_status: "pending") }
   scope :processing, -> { where(payment_status: "processing") }
-  scope :completed, -> { where(payment_status: "settled") }
+  scope :completed,  -> { where(payment_status: "settled") }
+
+  aasm column: :payment_status do
+    state :pending, initial: true
+    state :processing
+    state :settled
+
+    event :start_processing do
+      transitions from: :pending, to: :processing
+    end
+
+    event :complete do
+      transitions from: :processing, to: :settled, after: [:set_paid_at, :set_sustainer_status]
+      transitions from: :pending, to: :settled, after: [:set_paid_at, :set_sustainer_status]
+    end
+  end
+
+  def pending?
+    payment_status == "pending"
+  end
 
   def processing?
     payment_status == "processing"
@@ -25,4 +44,17 @@ class Donation < ApplicationRecord
   def completed?
     payment_status == "settled"
   end
+
+  private
+
+    def set_paid_at
+      update paid_at: DateTime.now if paid_at.nil?
+    end
+
+    def set_sustainer_status
+      user.add_member_status :sustainer
+    rescue => e
+      Sentry.capture_exception(e) if Setting.sentry_enabled?
+      Rails.logger.error("Failed to set memberStatus: #{e.message}")
+    end
 end