HTC - Halal Travel Club

Objective
Allow customers to quickly create an account or sign in using their Google account.
Functional Requirements
Google Sign-In Button
Display a Continue with Google button on:
Registration page
Login page
Existing Customer
If the selected Google account already exists,
The customer shall be signed in automatically.
New Customer
If the selected Google account does not exist,
The system shall automatically create a new customer account.
Customer Cancels Google Sign-In
If the customer closes or cancels the Google sign-in window,
No error message shall be displayed.
The customer remains on the current page.
Google Account Cannot Be Verified
Display:
We couldn't verify your Google account. Please try again.
Temporary Google Service Issue
Display:
Google Sign-In is currently unavailable. Please try again later or sign in using your email address.
Internet Connection Lost
Display:
Unable to connect. Please check your internet connection and try again.
Successful Google Sign-In
The customer shall:
Be signed in.
Be redirected to the Dashboard.
See their Google profile photo if available.
Acceptance Criteria
Existing customers sign in successfully.
New customers have accounts created automatically.
Google cancellation does not show unnecessary errors.
Friendly messages are displayed for all failure scenarios.