Плавный прогрессбар 2fa

usecases/src/main/java/com/github/nullptroma/wallenc/usecases/TwoFaTotp.kt

@@ -11,9 +11,21 @@ data class TwoFaCodeState(
     val secondsUntilRefresh: Int,
 )
 
+/** Доля прошедшего TOTP-периода [0f, 1f] для плавного progress bar. */
+fun totpPeriodProgress(nowMillis: Long, periodSeconds: Int): Float {
+    val period = periodSeconds.coerceAtLeast(1)
+    val elapsedSec = (nowMillis / 1000.0) % period
+    return (elapsedSec / period).toFloat().coerceIn(0f, 1f)
+}
+
+fun totpSecondsUntilRefresh(nowMillis: Long, periodSeconds: Int): Int {
+    val period = periodSeconds.coerceAtLeast(1)
+    return (period - ((nowMillis / 1000L) % period)).toInt().coerceAtLeast(0)
+}
+
 fun buildTwoFaCodeState(token: TwoFaTokenRecord, nowMillis: Long): TwoFaCodeState? {
     val period = token.periodSeconds.coerceAtLeast(1)
-    val remaining = (period - ((nowMillis / 1000L) % period)).toInt().coerceAtLeast(0)
+    val remaining = totpSecondsUntilRefresh(nowMillis, period)
     val code = generateTotpCode(
         secret = token.secret,
         nowMillis = nowMillis,

usecases/src/test/java/com/github/nullptroma/wallenc/usecases/TwoFaTotpTest.kt

@@ -33,6 +33,24 @@ class TwoFaTotpTest {
         assertTrue(state.secondsUntilRefresh in 1..30)
     }
 
+    @Test
+    fun totpPeriodProgressIsContinuousWithinPeriod() {
+        val period = 30
+        val periodStartMillis = 1_700_000_100_000L // epoch sec кратна period
+        assertEquals(0f, totpPeriodProgress(periodStartMillis, period), 0.001f)
+        assertEquals(0.5f, totpPeriodProgress(periodStartMillis + 15_000L, period), 0.001f)
+        assertEquals(29f / 30f, totpPeriodProgress(periodStartMillis + 29_000L, period), 0.001f)
+    }
+
+    @Test
+    fun totpSecondsUntilRefreshCountsDownWithinPeriod() {
+        val period = 30
+        val t0 = 1_700_000_100_000L
+        assertEquals(30, totpSecondsUntilRefresh(t0, period))
+        assertEquals(15, totpSecondsUntilRefresh(t0 + 15_000L, period))
+        assertEquals(1, totpSecondsUntilRefresh(t0 + 29_000L, period))
+    }
+
     @Test
     fun buildTwoFaCodeStateReturnsNullForInvalidSecret() {
         val token = TwoFaTokenRecord(