Support pasting a 19 digit PAN in CardNumberEditText

stripe/src/main/java/com/stripe/android/cards/CardNumber.kt

@@ -93,7 +93,7 @@ internal sealed class CardNumber {
         internal fun getSpacePositions(panLength: Int) = SPACE_POSITIONS[panLength]
             ?: DEFAULT_SPACE_POSITIONS
 
-        private const val MIN_PAN_LENGTH = 14
+        internal const val MIN_PAN_LENGTH = 14
         internal const val MAX_PAN_LENGTH = 19
         internal const val DEFAULT_PAN_LENGTH = 16
         private val DEFAULT_SPACE_POSITIONS = setOf(4, 9, 14)

stripe/src/main/java/com/stripe/android/view/CardInputWidget.kt

@@ -892,7 +892,7 @@ class CardInputWidget @JvmOverloads constructor(
         panLength: Int
     ): String {
         val formattedNumber = CardNumber.Unvalidated(
-            List(panLength) { "0" }.joinToString(separator = "")
+            "0".repeat(panLength)
         ).getFormatted(panLength)
 
         return formattedNumber.take(
@@ -1109,7 +1109,7 @@ class CardInputWidget @JvmOverloads constructor(
                 14 -> 2
                 else -> 4
             }.let { peekSize ->
-                List(peekSize) { "0" }.joinToString(separator = "")
+                "0".repeat(peekSize)
             }
         }
 

stripe/src/main/java/com/stripe/android/view/CardNumberEditText.kt

@@ -174,8 +174,8 @@ class CardNumberEditText internal constructor(
     }
 
     @JvmSynthetic
-    internal fun updateLengthFilter() {
-        filters = arrayOf<InputFilter>(InputFilter.LengthFilter(formattedPanLength))
+    internal fun updateLengthFilter(maxLength: Int = formattedPanLength) {
+        filters = arrayOf<InputFilter>(InputFilter.LengthFilter(maxLength))
     }
 
     /**
@@ -186,13 +186,15 @@ class CardNumberEditText internal constructor(
      * @param editActionStart the position in the string at which the edit action starts
      * @param editActionAddition the number of new characters going into the string (zero for
      * delete)
+     * @param panLength the maximum normalized length of the PAN
      * @return an index within the string at which to put the cursor
      */
     @JvmSynthetic
     internal fun updateSelectionIndex(
         newLength: Int,
         editActionStart: Int,
-        editActionAddition: Int
+        editActionAddition: Int,
+        panLength: Int = this.panLength
     ): Int {
         var gapsJumped = 0
         val gapSet = CardNumber.getSpacePositions(panLength)
@@ -233,8 +235,11 @@ class CardNumberEditText internal constructor(
 
                 private var beforeCardNumber = unvalidatedCardNumber
 
+                private var isPastedPan = false
+
                 override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
                     if (!ignoreChanges) {
+                        isPastedPan = false
                         beforeCardNumber = unvalidatedCardNumber
 
                         latestChangeStart = start
@@ -250,13 +255,26 @@ class CardNumberEditText internal constructor(
                     val cardNumber = CardNumber.Unvalidated(s?.toString().orEmpty())
                     updateAccountRange(cardNumber)
 
-                    val formattedNumber = cardNumber.getFormatted(panLength)
-                    this.newCursorPosition = updateSelectionIndex(
-                        formattedNumber.length,
-                        latestChangeStart,
-                        latestInsertionSize
-                    )
-                    this.formattedNumber = formattedNumber
+                    isPastedPan = isPastedPan(start, cardNumber)
+
+                    if (isPastedPan) {
+                        updateLengthFilter(cardNumber.getFormatted(cardNumber.length).length)
+                    }
+
+                    if (isPastedPan) {
+                        cardNumber.length
+                    } else {
+                        panLength
+                    }.let { maxPanLength ->
+                        val formattedNumber = cardNumber.getFormatted(maxPanLength)
+                        newCursorPosition = updateSelectionIndex(
+                            formattedNumber.length,
+                            latestChangeStart,
+                            latestInsertionSize,
+                            maxPanLength
+                        )
+                        this.formattedNumber = formattedNumber
+                    }
                 }
 
                 override fun afterTextChanged(s: Editable?) {
@@ -311,6 +329,10 @@ class CardNumberEditText internal constructor(
                     unvalidatedCardNumber.isMaxLength ||
                         (isValid && accountRange != null)
                     )
+
+                private fun isPastedPan(start: Int, cardNumber: CardNumber.Unvalidated): Boolean {
+                    return start == 0 && cardNumber.normalized.length >= CardNumber.MIN_PAN_LENGTH
+                }
             }
         )
     }

stripe/src/test/java/com/stripe/android/view/CardNumberEditTextTest.kt

@@ -274,6 +274,26 @@ internal class CardNumberEditTextTest {
             .isEqualTo(1)
     }
 
+    @Test
+    fun `when 19 digit PAN is pasted, full PAN is accepted and formatted`() {
+        val cardNumberEditText = CardNumberEditText(
+            context,
+            workDispatcher = testDispatcher,
+            cardAccountRangeRepository = NullCardAccountRangeRepository(),
+            staticCardAccountRanges = object : StaticCardAccountRanges {
+                override fun match(
+                    cardNumber: CardNumber.Unvalidated
+                ): AccountRange? = null
+            }
+        )
+
+        cardNumberEditText.setText("6216828050000000000")
+        idleLooper()
+
+        assertThat(cardNumberEditText.fieldText)
+            .isEqualTo("6216 8280 5000 0000 000")
+    }
+
     @Test
     fun `updating text with null account range should format text correctly but not set card brand`() {
         val cardNumberEditText = CardNumberEditText(