Enroll a fingerprint

val session = sdk.createFingerprintReaderSession(reader.id)
val enrollee = "CR-123"
val position = 2   // ISO 19794-4 finger position (0..10)
 
// Capture 1 — store an unverified print.
val enrolled = session.enroll(enrollee, position)
    ?: return   // null → a handled failure was emitted on session.errors
 
// Capture 2 — promote to verified. Retry while it doesn't match.
var verified = session.verifyEnrollment(enrollee, position)
while (verified != null && !verified.positionVerified && !verified.requiresReenroll) {
    // matched=false is normal — prompt "place the same finger again"
    verified = session.verifyEnrollment(enrollee, position)
}
 
if (verified?.requiresReenroll == true) {
    // attempts exhausted; the backend reset this finger — start over at enroll()
}

suspend fun enrollSubject(session: FingerprintReaderSession, enrollee: String, targets: List<Int>) {
    for (position in targets) {
        // Skip fingers already verified (e.g. resuming a paused enrollment).
        val state = session.fetchEnrolled(enrollee)
        if (state != null && position in state.verified) continue
 
        session.enroll(enrollee, position) ?: continue
 
        var v = session.verifyEnrollment(enrollee, position)
        while (v != null && !v.positionVerified && !v.requiresReenroll) {
            v = session.verifyEnrollment(enrollee, position)
        }
        if (v?.requiresReenroll == true) {
            // finger was reset — re-enroll it before moving on
            session.enroll(enrollee, position)
            session.verifyEnrollment(enrollee, position)
        }
 
        // Done when the subject is fully enrolled — let the server decide.
        if (session.fetchEnrolled(enrollee)?.enrollmentStatus == "fully_enrolled") break
    }
}

viewModelScope.launch { session.state.collect { render(it) } }   // Scanning/Captured/…
viewModelScope.launch { session.errors.collect { toast(it.message) } }