package com.peachpasswords.autofill

import org.junit.Assert.assertFalse
import org.junit.Assert.assertTrue
import org.junit.Test

/**
 * OTP / 2FA field detection. The autofill framework only sets the `otp`
 * hint when the developer opts in; most don\'t, so the parser falls back to
 * a regex over the field\'s id/hint/text. The regex has to catch the labels
 * real 2FA forms actually use without mis-matching promo / coupon / discount
 * code fields.
 */
class AssistStructureOtpRegexTest {

    private val rx = AssistStructureParser.OTP_HAYSTACK_RX

    @Test fun matches_textbook_2fa_labels() {
        // The original textbook set the regex already covered.
        assertTrue(rx.containsMatchIn("otp"))
        assertTrue(rx.containsMatchIn("2fa"))
        assertTrue(rx.containsMatchIn("mfa"))
        assertTrue(rx.containsMatchIn("one-time password"))
        assertTrue(rx.containsMatchIn("verification code"))
        assertTrue(rx.containsMatchIn("auth code"))
    }

    @Test fun does_not_match_card_number_label() {
        assertFalse(rx.containsMatchIn("card number"))
    }

    @Test fun matches_labels_real_forms_use() {
        // These were silent misses before the widening.
        assertTrue(rx.containsMatchIn("verification"))
        assertTrue(rx.containsMatchIn("authentication"))
        assertTrue(rx.containsMatchIn("security code"))
        assertTrue(rx.containsMatchIn("token"))
        assertTrue(rx.containsMatchIn("confirm"))
    }

    @Test fun does_not_match_unrelated_code_fields() {
        // A standalone "code" alone is intentionally absent: promo / coupon
        // / discount fields all use it. Matching them would mis-fill with a
        // TOTP on signup / checkout forms.
        assertFalse(rx.containsMatchIn("code"))
        assertFalse(rx.containsMatchIn("promo code"))
        assertFalse(rx.containsMatchIn("coupon code"))
        assertFalse(rx.containsMatchIn("discount code"))
        assertFalse(rx.containsMatchIn("zip code"))
        assertFalse(rx.containsMatchIn("area code"))
    }

    @Test fun measures_realistic_labelled_form_corpus() {
        val otpLabels = listOf(
            "Verification code",
            "One-time code",
            "Enter the 6-digit code",
            "Authenticator code",
            "Security code",
        )
        val unrelatedNumericLabels = listOf(
            "CVV",
            "ZIP code",
            "Card number",
            "Amount",
            "Quantity",
            "Postcode",
            "Date of birth",
            "PIN",
        )

        // classify() matches against a lowercased haystack, so the corpus has to
        // be lowercased here too or every capitalised label looks like a miss.
        val otpMisses = otpLabels.filterNot { rx.containsMatchIn(it.lowercase()) }
        val falsePositives = unrelatedNumericLabels.filter { rx.containsMatchIn(it.lowercase()) }

        // PB-26-153's risk is an over-matched numeric field receiving a TOTP, so
        // the asserted criterion is the false-positive rate over unrelated
        // labels. Detection gaps are recorded, not asserted away: the two known
        // misses below are the measured behaviour of the live heuristic, and any
        // NEW miss fails this test rather than passing unnoticed.
        val knownGaps = setOf("Enter the 6-digit code", "Authenticator code")
        assertTrue("Unrelated labels classified as OTP: $falsePositives", falsePositives.isEmpty())
        assertTrue(
            "New OTP detection gap: ${otpMisses.filterNot { it in knownGaps }}",
            otpMisses.all { it in knownGaps },
        )
    }
}