feat: Conversation update API for sla_policy_id (#8973)

- Add an endpoint for updating conversation attributes (priority / sla_policy_id )
- Swagger spec
- minor chores around the conversation API/spec

Fixes: https://linear.app/chatwoot/issue/CW-2100/feat-backend-api-to-update-the-sla-of-a-conversation

enterprise/app/controllers/enterprise/api/v1/accounts/conversations_controller.rb

@@ -0,0 +1,5 @@
+module Enterprise::Api::V1::Accounts::ConversationsController
+  def permitted_update_params
+    super.merge(params.permit(:sla_policy_id))
+  end
+end

enterprise/app/models/applied_sla.rb

@@ -23,6 +23,13 @@ class AppliedSla < ApplicationRecord
   belongs_to :conversation
 
   validates :account_id, uniqueness: { scope: %i[sla_policy_id conversation_id] }
+  before_validation :ensure_account_id
 
   enum sla_status: { active: 0, hit: 1, missed: 2 }
+
+  private
+
+  def ensure_account_id
+    self.account_id ||= sla_policy&.account_id
+  end
 end

enterprise/app/models/enterprise/enterprise_conversation_concern.rb

@@ -3,5 +3,35 @@ module Enterprise::EnterpriseConversationConcern
 
   included do
     belongs_to :sla_policy, optional: true
+    has_one :applied_sla, dependent: :destroy
+    before_validation :validate_sla_policy, if: -> { sla_policy_id_changed? }
+    around_save :ensure_applied_sla_is_created, if: -> { sla_policy_id_changed? }
+  end
+
+  private
+
+  def validate_sla_policy
+    # TODO: remove these validations once we figure out how to deal with these cases
+    if sla_policy_id.nil? && changes[:sla_policy_id].first.present?
+      errors.add(:sla_policy, 'cannot remove sla policy from conversation')
+      return
+    end
+
+    if changes[:sla_policy_id].first.present?
+      errors.add(:sla_policy, 'conversation already has a different sla')
+      return
+    end
+
+    errors.add(:sla_policy, 'sla policy account mismatch') if sla_policy&.account_id != account_id
+  end
+
+  # handling inside a transaction to ensure applied sla record is also created
+  def ensure_applied_sla_is_created
+    ActiveRecord::Base.transaction do
+      yield
+      create_applied_sla(sla_policy_id: sla_policy_id) if applied_sla.blank?
+    end
+  rescue ActiveRecord::RecordInvalid
+    raise ActiveRecord::Rollback
   end
 end

enterprise/app/models/sla_policy.rb

@@ -22,6 +22,7 @@ class SlaPolicy < ApplicationRecord
   validates :name, presence: true
 
   has_many :conversations, dependent: :nullify
+  has_many :applied_slas, dependent: :destroy
 
   def push_event_data
     {

enterprise/app/services/enterprise/action_service.rb

@@ -8,16 +8,5 @@ module Enterprise::ActionService
 
     Rails.logger.info "SLA:: Adding SLA #{sla_policy.id} to conversation: #{@conversation.id}"
     @conversation.update!(sla_policy_id: sla_policy.id)
-    create_applied_sla(sla_policy)
-  end
-
-  def create_applied_sla(sla_policy)
-    Rails.logger.info "SLA:: Creating Applied SLA for conversation: #{@conversation.id}"
-    AppliedSla.create!(
-      account_id: @conversation.account_id,
-      sla_policy_id: sla_policy.id,
-      conversation_id: @conversation.id,
-      sla_status: 'active'
-    )
   end
 end