feat: Added the ability to create Instagram channel (#11182)

This PR is part of https://github.com/chatwoot/chatwoot/pull/11054 to
make the review cycle easier.

spec/controllers/instagram/callbacks_controller_spec.rb

@@ -0,0 +1,113 @@
+require 'rails_helper'
+
+RSpec.describe Instagram::CallbacksController do
+  let(:account) { create(:account) }
+  let(:valid_params) { { code: 'valid_code', state: "#{account.id}|valid_token" } }
+  let(:error_params) { { error: 'access_denied', error_description: 'User denied access', state: "#{account.id}|valid_token" } }
+  let(:oauth_client) { instance_double(OAuth2::Client) }
+  let(:auth_code_object) { instance_double(OAuth2::Strategy::AuthCode) }
+  let(:access_token) { instance_double(OAuth2::AccessToken, token: 'test_token') }
+  let(:long_lived_token_response) { { 'access_token' => 'long_lived_test_token', 'expires_in' => 5_184_000 } }
+  let(:user_details) { { 'username' => 'test_user', 'user_id' => '12345' } }
+  let(:exception_tracker) { instance_double(ChatwootExceptionTracker) }
+
+  before do
+    allow(controller).to receive(:verify_instagram_token).and_return(account.id)
+    allow(controller).to receive(:instagram_client).and_return(oauth_client)
+    allow(controller).to receive(:base_url).and_return('https://app.chatwoot.com')
+    allow(controller).to receive(:account).and_return(account)
+    allow(oauth_client).to receive(:auth_code).and_return(auth_code_object)
+    allow(controller).to receive(:exchange_for_long_lived_token).and_return(long_lived_token_response)
+    allow(controller).to receive(:fetch_instagram_user_details).and_return(user_details)
+    allow(ChatwootExceptionTracker).to receive(:new).and_return(exception_tracker)
+    allow(exception_tracker).to receive(:capture_exception)
+
+    # Stub the exact request format that's being made
+    stub_request(:post, 'https://graph.instagram.com/v22.0/12345/subscribed_apps?access_token=long_lived_test_token&subscribed_fields%5B%5D=messages&subscribed_fields%5B%5D=message_reactions&subscribed_fields%5B%5D=messaging_seen')
+      .with(
+        headers: {
+          'Accept' => '*/*',
+          'Accept-Encoding' => 'gzip;q=1.0,deflate;q=0.6,identity;q=0.3',
+          'User-Agent' => 'Ruby'
+        }
+      )
+      .to_return(status: 200, body: '', headers: {})
+  end
+
+  describe '#show' do
+    context 'when authorization is successful' do
+      before do
+        allow(auth_code_object).to receive(:get_token).and_return(access_token)
+      end
+
+      it 'creates instagram channel and inbox' do
+        expect do
+          get :show, params: valid_params
+        end.to change(Channel::Instagram, :count).by(1).and change(Inbox, :count).by(1)
+
+        expect(Channel::Instagram.last.access_token).to eq('long_lived_test_token')
+        expect(Channel::Instagram.last.instagram_id).to eq('12345')
+        expect(Inbox.last.name).to eq('test_user')
+
+        expect(response).to redirect_to(app_instagram_inbox_agents_url(account_id: account.id, inbox_id: Inbox.last.id))
+      end
+    end
+
+    context 'when user denies authorization' do
+      it 'redirects to error page with authorization error details' do
+        get :show, params: error_params
+
+        expect(response).to redirect_to(
+          app_new_instagram_inbox_url(
+            account_id: account.id,
+            error_type: 'access_denied',
+            code: 400,
+            error_message: 'User denied access'
+          )
+        )
+      end
+    end
+
+    context 'when an OAuth error occurs' do
+      before do
+        oauth_error = OAuth2::Error.new(
+          OpenStruct.new(
+            body: { error_type: 'OAuthException', code: 400, error_message: 'Invalid OAuth code' }.to_json,
+            status: 400
+          )
+        )
+        allow(auth_code_object).to receive(:get_token).and_raise(oauth_error)
+      end
+
+      it 'handles OAuth errors and redirects to error page' do
+        get :show, params: valid_params
+
+        expected_url = app_new_instagram_inbox_url(
+          account_id: account.id,
+          error_type: 'OAuthException',
+          code: 400,
+          error_message: 'Invalid OAuth code'
+        )
+        expect(response).to redirect_to(expected_url)
+      end
+    end
+
+    context 'when a standard error occurs' do
+      before do
+        allow(auth_code_object).to receive(:get_token).and_raise(StandardError.new('Unknown error'))
+      end
+
+      it 'handles standard errors and redirects to error page' do
+        get :show, params: valid_params
+
+        expected_url = app_new_instagram_inbox_url(
+          account_id: account.id,
+          error_type: 'StandardError',
+          code: 500,
+          error_message: 'Unknown error'
+        )
+        expect(response).to redirect_to(expected_url)
+      end
+    end
+  end
+end