title Account identifier-based signup

actor User
participant App
participant Azure B2C
participant API

User->App:Click login
App->App: Generate Code Verifier\nand Code Challenge
App->Azure B2C: Authorize Code Request+\n Code Challenge\n to /authorize
Azure B2C->App: 200 OK
App->App: Open Azure B2C signin\nflow in web browser
group Azure B2C signin flow

User->App: User clicks signup
App->App: Open Azure B2C signup\nsub flow in web browser
User->App: User enters email
App->Azure B2C: Trigger email validation step
Azure B2C->User: Sends verification email
User->App: User enter verification code
App->Azure B2C: Send verification code
Azure B2C->Azure B2C: Store email in session
User->App: User enters account identifier(s)
App->Azure B2C: Trigger account validation step
Azure B2C->API: Request account id from\n/accounts/search
Azure B2C<-API: Retrieves account id
Azure B2C->Azure B2C: Store account information in session
User->App: User enters account identifier\nfor verification
App->Azure B2C: Trigger account validation step
Azure B2C->API: Request account id from\n/accounts/search
Azure B2C<-API: Retrieves account id (or error)
Azure B2C->Azure B2C: Verify that account information\nmatch stored account
User->App: User enters password
App->Azure B2C: Send password
Azure B2C->Azure B2C: Store password in session
Azure B2C->Azure B2C: Store profile in AD
end

Azure B2C->App: Authorization Code
App->Azure B2C: Authorization Code +\nCode Verifier\nto /token
Azure B2C->App: ID Token, Access Token\n and Refresh Token