fix: normalize phone numbers during whatsapp channel lookup (#13709)

Fixes
https://linear.app/chatwoot/issue/PLA-99/whatsapp-messages-dropped-for-brazilargentina-numbers-due-to-phone
Fixes https://github.com/chatwoot/chatwoot/issues/14492

Meta's WhatsApp Cloud API includes `display_phone_number` in webhook
payloads, but its format can differ from the number stored in Chatwoot's
channel record.
In Brazil, Meta omits the mobile 9 prefix. For example, it sends
55419XXXXXXX (12 digits) instead of 554199XXXXXXX (13 digits). In
Argentina, Meta adds an extra 9 after the country code. For example, it
sends 549XXXXXXXXXX instead of 54XXXXXXXXXX.
The whatsapp event job uses `display_phone_number` for an exact-match
channel lookup. When the formats do not match, the lookup returns nil
and the incoming message is silently dropped, logging:

`Inactive WhatsApp channel: unknown - <phone_number>.`

The fix extends `get_channel_from_wb_payload` to fall back to normalized
phone number matching using the existing PhoneNumberNormalizationService
normalizers (Brazil, Argentina), which were previously only used for
contact-level lookups.

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>

app/controllers/webhooks/whatsapp_controller.rb

@@ -47,18 +47,10 @@ class Webhooks::WhatsappController < ActionController::API
     metadata = params.dig(:entry, 0, :changes, 0, :value, :metadata)
     return if metadata.blank?
 
-    phone_number = normalized_phone_number(metadata[:display_phone_number])
-    phone_number_id = metadata[:phone_number_id]
-    channel = Channel::Whatsapp.find_by(phone_number: phone_number)
-
-    return channel if channel && channel.provider_config['phone_number_id'] == phone_number_id
-  end
-
-  def normalized_phone_number(phone_number)
-    return if phone_number.blank?
-
-    phone_number = phone_number.to_s
-    phone_number.start_with?('+') ? phone_number : "+#{phone_number}"
+    Whatsapp::WebhookChannelFinderService.new(
+      display_phone_number: metadata[:display_phone_number],
+      phone_number_id: metadata[:phone_number_id]
+    ).perform
   end
 
   def inactive_whatsapp_number?

app/jobs/webhooks/whatsapp_events_job.rb

@@ -153,11 +153,11 @@ class Webhooks::WhatsappEventsJob < MutexApplicationJob
   end
 
   def get_channel_from_wb_payload(wb_params)
-    phone_number = "+#{wb_params[:entry].first[:changes].first.dig(:value, :metadata, :display_phone_number)}"
-    phone_number_id = wb_params[:entry].first[:changes].first.dig(:value, :metadata, :phone_number_id)
-    channel = Channel::Whatsapp.find_by(phone_number: phone_number)
-    # validate to ensure the phone number id matches the whatsapp channel
-    return channel if channel && channel.provider_config['phone_number_id'] == phone_number_id
+    metadata = wb_params[:entry].first[:changes].first.dig(:value, :metadata) || {}
+    Whatsapp::WebhookChannelFinderService.new(
+      display_phone_number: metadata[:display_phone_number],
+      phone_number_id: metadata[:phone_number_id]
+    ).perform
   end
 end
 

app/services/whatsapp/webhook_channel_finder_service.rb

@@ -0,0 +1,35 @@
+# Resolves the WhatsApp channel for an inbound WhatsApp Cloud webhook. Meta's
+# display_phone_number can arrive formatted or in a country-specific variant (e.g. Brazil
+# omits the mobile 9, Argentina adds a digit after the country code), so we try the
+# raw digits first and then a normalized fallback, accepting only a candidate whose
+# phone_number_id matches.
+class Whatsapp::WebhookChannelFinderService
+  def initialize(display_phone_number:, phone_number_id:)
+    @display_phone_number = display_phone_number
+    @phone_number_id = phone_number_id
+  end
+
+  def perform
+    return if digits.blank?
+
+    candidates = [
+      Channel::Whatsapp.find_by(phone_number: "+#{digits}"),
+      channel_by_normalized_number
+    ]
+    candidates.compact.find { |channel| channel.provider_config['phone_number_id'] == @phone_number_id }
+  end
+
+  private
+
+  def digits
+    @digits ||= @display_phone_number.to_s.gsub(/[^0-9]/, '')
+  end
+
+  def channel_by_normalized_number
+    normalizer = Whatsapp::PhoneNumberNormalizationService::NORMALIZERS
+                 .lazy.map(&:new).find { |n| n.handles_country?(digits) }
+    return unless normalizer
+
+    Channel::Whatsapp.find_by(phone_number: "+#{normalizer.normalize(digits)}")
+  end
+end