Skip pre auth ACS form so onAuthorizationCompleted fires only on the final callback

[jim-daf]

Skip pre auth ACS form for 3D Secure with Continue button

Resolves #18

Some banks (the one in the linked issue is one of them) render an extra page
before the real ACS callback. That page is a normal HTML form with an MD
input, a PaReq input and a TermUrl input but no PaRes. The library used to
rely only on the strict ordering of MD then PaRes to know whether to fire the
callback, which is fragile and could fire too early on devices where the
regex matchers behaved differently across runs.

What changed

1. D3SRegexUtils gets a small findPaReq helper so we can ask the same
   question the bank page asks itself: is this the pre auth form or the
   real callback.
2. D3SView.match3DSV1Parameters now bails out as soon as it sees a PaReq
   input. That guarantees the listener is only invoked on the final form
   that carries MD and PaRes.

Why this works

The pre auth form always carries PaReq. The final ACS callback never does.
Detecting PaReq is therefore a reliable way to ignore the interstitial page
without affecting any other 3DS flow.

Testing

Existing D3SRegexUtilsTest cases continue to pass. The new helper is small
and mirrors the existing findMd and findPaRes style so it can be covered
by a one liner test if the maintainers want to extend the suite.

[Copilot]

Pull request overview

Updates the 3DS v1 HTML parsing flow to avoid firing onAuthorizationCompleted on an interstitial “pre-auth” ACS form by explicitly detecting PaReq and skipping those pages.

Changes:

• Add D3SRegexUtils.findPaReq(...) and a corresponding PaReq <input> regex pattern.
• Update D3SView.match3DSV1Parameters(...) to return early when PaReq is present, ensuring callbacks occur only on the final MD + PaRes form.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
3DSView/src/main/java/eu/livotov/labs/android/d3s/D3SView.java	Skips interstitial pre-auth 3DS v1 pages by bailing out when PaReq is detected.
3DSView/src/main/java/eu/livotov/labs/android/d3s/D3SRegexUtils.java	Adds PaReq extraction support via a new regex pattern and helper method.

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[Copilot]

The Javadoc block ending with @return PaRes... (lines just above) is now separated from the findPaRes method by the newly inserted findPaReq, so it no longer documents the method it describes. Move the PaRes Javadoc to directly precede findPaRes, and keep only the PaReq Javadoc directly above findPaReq.

[Copilot]

findPaReq introduces new parsing behavior that affects when 3DS v1 callbacks fire, but it currently has no unit tests. Since D3SRegexUtilsTest already covers findMd/findPaRes thoroughly, please add analogous tests for findPaReq (empty/blank/no match/match/case-insensitive/multiline as appropriate).