feat(onboarding): restrict display name to ASCII letters, digits and spaces

apps/flipcash/features/user-profile/src/main/kotlin/com/flipcash/app/userprofile/internal/name/NameEntryScreen.kt

@@ -117,7 +117,7 @@ private fun NameEntryScreenContent(
                         bottom = CodeTheme.dimens.grid.x3
                     ).imePadding(),
                 text = stringResource(R.string.action_next),
-                enabled = state.hasName && state.isChanged && state.processingState.isIdle,
+                enabled = state.isSubmittable(source) && state.isChanged && state.processingState.isIdle,
                 isLoading = state.processingState.loading,
                 isSuccess = state.processingState.success,
                 onClick = {

apps/flipcash/features/user-profile/src/main/kotlin/com/flipcash/app/userprofile/internal/name/NameEntryViewModel.kt

@@ -61,6 +61,16 @@ class NameEntryViewModel @Inject constructor(
         val hasName: Boolean
             get() = nameFieldState.text.isNotBlank()
 
+        /**
+         * Whether the current text may be submitted. Onboarding applies the stricter
+         * [isValidOnboardingDisplayName] rule; other sources only need a non-blank name.
+         */
+        fun isSubmittable(source: DisplayNameSource): Boolean = when (source) {
+            DisplayNameSource.Onboarding -> isValidOnboardingDisplayName(nameFieldState.text.toString())
+            DisplayNameSource.MyAccount,
+            DisplayNameSource.TipCardSetup -> hasName
+        }
+
         /** Node 9553:113166 — one character's difference is enough to arm the confirm button. */
         val isChanged: Boolean
             get() = nameFieldState.text.toString() != savedName
@@ -111,6 +121,12 @@ class NameEntryViewModel @Inject constructor(
         eventFlow
             .filterIsInstance<Event.ConfirmNameChange>()
             .onEach { event ->
+                // The keyboard Done action reaches here without passing the button's enabled
+                // gate, so an invalid onboarding name is dropped the same way the disabled
+                // button drops it.
+                if (event.source == DisplayNameSource.Onboarding && !stateFlow.value.isSubmittable(event.source)) {
+                    return@onEach
+                }
                 if (stateFlow.value.savedName.isBlank()) {
                     dispatchEvent(Event.CheckName(event.source))
                     return@onEach
@@ -142,8 +158,9 @@ class NameEntryViewModel @Inject constructor(
                 // pushes the stored name into the field, so the field itself
                 // cannot tell us whether one already existed.
                 val hadPreviousName = !userManager.profile?.displayName.isNullOrBlank()
+                val typed = stateFlow.value.nameFieldState.text.toString()
                 val result = profileController.setDisplayName(
-                    stateFlow.value.nameFieldState.text.toString()
+                    submittedName(typed, event.source)
                 )
                 result.onSuccess {
                     val analyticsEvent = if (hadPreviousName) {
@@ -228,6 +245,10 @@ class NameEntryViewModel @Inject constructor(
         }
     }
     internal companion object {
+        /** Onboarding submits the trimmed name (as iOS does); other sources send the field text as typed. */
+        fun submittedName(typed: String, source: DisplayNameSource): String =
+            if (source == DisplayNameSource.Onboarding) trimOnboardingDisplayName(typed) else typed
+
         val updateStateForEvent: (Event) -> (State.() -> State) = { event ->
             when (event) {
                 is Event.ConfirmNameChange -> { state -> state }

apps/flipcash/features/user-profile/src/main/kotlin/com/flipcash/app/userprofile/internal/name/OnboardingDisplayNameRule.kt

@@ -0,0 +1,31 @@
+package com.flipcash.app.userprofile.internal.name
+
+internal const val ONBOARDING_DISPLAY_NAME_MAX_LENGTH = 64
+
+/**
+ * The onboarding display-name rule, shared in definition with iOS: after trimming leading and
+ * trailing whitespace the name is non-empty, at most [ONBOARDING_DISPLAY_NAME_MAX_LENGTH]
+ * characters, and made only of ASCII letters, ASCII digits and the space character (U+0020).
+ * Any other whitespace (tab, newline, NBSP), punctuation, accented letters or emoji is invalid.
+ * Runs of internal spaces are allowed.
+ *
+ * Pure: no Android types, so it can move to shared code.
+ */
+internal fun isValidOnboardingDisplayName(raw: String): Boolean {
+    val name = trimOnboardingDisplayName(raw)
+    return name.isNotEmpty() &&
+        name.length <= ONBOARDING_DISPLAY_NAME_MAX_LENGTH &&
+        name.all { it in 'A'..'Z' || it in 'a'..'z' || it in '0'..'9' || it == ' ' }
+}
+
+/** The string onboarding submits: [raw] trimmed with [isOnboardingTrimmable] on both ends. */
+internal fun trimOnboardingDisplayName(raw: String): String = raw.trim(::isOnboardingTrimmable)
+
+// Mirrors iOS CharacterSet.whitespacesAndNewlines: U+0009-U+000D, U+0085, and categories Zs/Zl/Zp.
+// Not Char.isWhitespace(), which also strips U+001C-U+001F and misses U+0085.
+private fun isOnboardingTrimmable(c: Char): Boolean =
+    c.code in 0x09..0x0D || c.code == 0x85 ||
+        when (Character.getType(c).toByte()) {
+            Character.SPACE_SEPARATOR, Character.LINE_SEPARATOR, Character.PARAGRAPH_SEPARATOR -> true
+            else -> false
+        }

apps/flipcash/features/user-profile/src/test/kotlin/com/flipcash/app/userprofile/internal/name/OnboardingDisplayNameRuleTest.kt

@@ -0,0 +1,74 @@
+package com.flipcash.app.userprofile.internal.name
+
+import androidx.compose.foundation.text.input.setTextAndPlaceCursorAtEnd
+import com.flipcash.app.core.DisplayNameSource
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class OnboardingDisplayNameRuleTest {
+
+    @Test
+    fun `accepts ASCII letters digits and spaces`() {
+        assertTrue(isValidOnboardingDisplayName("Taylor Smith 2"))
+        assertTrue(isValidOnboardingDisplayName("Taylor  Smith"))
+    }
+
+    @Test
+    fun `trims surrounding whitespace before validating`() {
+        assertTrue(isValidOnboardingDisplayName("  Taylor "))
+        assertTrue(isValidOnboardingDisplayName("\tTaylor\n"))
+    }
+
+    @Test
+    fun `rejects empty and whitespace only`() {
+        assertFalse(isValidOnboardingDisplayName(""))
+        assertFalse(isValidOnboardingDisplayName("   "))
+    }
+
+    @Test
+    fun `rejects accents punctuation emoji and non-space whitespace`() {
+        assertFalse(isValidOnboardingDisplayName("José"))
+        assertFalse(isValidOnboardingDisplayName("Taylor!"))
+        assertFalse(isValidOnboardingDisplayName("😀"))
+        assertFalse(isValidOnboardingDisplayName("Tay\tlor"))
+        assertFalse(isValidOnboardingDisplayName("Tay\nlor"))
+        assertFalse(isValidOnboardingDisplayName("Tay lor"))
+    }
+
+    @Test
+    fun `length limit is 64 after trimming`() {
+        assertTrue(isValidOnboardingDisplayName("a".repeat(64)))
+        assertTrue(isValidOnboardingDisplayName(" " + "a".repeat(64) + " "))
+        assertFalse(isValidOnboardingDisplayName("a".repeat(65)))
+    }
+
+    @Test
+    fun `only onboarding applies the ASCII rule`() {
+        val state = NameEntryViewModel.State()
+        state.nameFieldState.setTextAndPlaceCursorAtEnd("José")
+
+        assertFalse(state.isSubmittable(DisplayNameSource.Onboarding))
+        assertTrue(state.isSubmittable(DisplayNameSource.MyAccount))
+        assertTrue(state.isSubmittable(DisplayNameSource.TipCardSetup))
+        assertEquals(true, state.hasName)
+    }
+
+    @Test
+    fun `trims the same set as iOS whitespacesAndNewlines`() {
+        assertTrue(isValidOnboardingDisplayName("Taylor\u00A0"))
+        assertTrue(isValidOnboardingDisplayName("\u3000Taylor"))
+        assertTrue(isValidOnboardingDisplayName("Taylor\u0085"))
+        assertFalse(isValidOnboardingDisplayName("Taylor\u001F"))
+        assertFalse(isValidOnboardingDisplayName("Tay\u00A0lor"))
+    }
+
+    @Test
+    fun `onboarding submits the trimmed name and other sources the typed text`() {
+        val typed = "\u3000Taylor Smith\u0085"
+        assertEquals("Taylor Smith", NameEntryViewModel.submittedName(typed, DisplayNameSource.Onboarding))
+        assertEquals(typed, NameEntryViewModel.submittedName(typed, DisplayNameSource.MyAccount))
+        assertEquals(typed, NameEntryViewModel.submittedName(typed, DisplayNameSource.TipCardSetup))
+    }
+}