New onboarding, trials, Stripe integration (#2185)

* New onboarding, trials, Stripe integration

* Fix tests

* Lint fixes

* Fix subscription endpoints

app/models/provider/stripe.rb

@@ -0,0 +1,68 @@
+class Provider::Stripe
+  def initialize(secret_key:, webhook_secret:)
+    @client = Stripe::StripeClient.new(
+      secret_key,
+      stripe_version: "2025-04-30.basil"
+    )
+    @webhook_secret = webhook_secret
+  end
+
+  def process_event(event_id)
+    event = retrieve_event(event_id)
+
+    case event.type
+    when /^customer\.subscription\./
+      SubscriptionEventProcessor.new(client).process(event)
+    when /^customer\./
+      CustomerEventProcessor.new(client).process(event)
+    else
+      Rails.logger.info "Unhandled event type: #{event.type}"
+    end
+  end
+
+  def process_webhook_later(webhook_body, sig_header)
+    thin_event = client.parse_thin_event(webhook_body, sig_header, webhook_secret)
+
+    if thin_event.type.start_with?("customer.")
+      StripeEventHandlerJob.perform_later(thin_event.id)
+    else
+      Rails.logger.info "Unhandled event type: #{thin_event.type}"
+    end
+  end
+
+  def create_customer(email:, metadata: {})
+    client.v1.customers.create(
+      email: email,
+      metadata: metadata
+    )
+  end
+
+  def get_checkout_session_url(price_id:, customer_id: nil, success_url: nil, cancel_url: nil)
+    client.v1.checkout.sessions.create(
+      customer: customer_id,
+      line_items: [ { price: price_id, quantity: 1 } ],
+      mode: "subscription",
+      allow_promotion_codes: true,
+      success_url: success_url,
+      cancel_url: cancel_url
+    ).url
+  end
+
+  def get_billing_portal_session_url(customer_id:, return_url: nil)
+    client.v1.billing_portal.sessions.create(
+      customer: customer_id,
+      return_url: return_url
+    ).url
+  end
+
+  def retrieve_checkout_session(session_id)
+    client.v1.checkout.sessions.retrieve(session_id)
+  end
+
+  private
+    attr_reader :client, :webhook_secret
+
+    def retrieve_event(event_id)
+      client.v2.core.events.retrieve(event_id)
+    end
+end