Fix chip text field focus synchronization

chiptextfield-core/build.gradle

@@ -53,5 +53,10 @@ kotlin {
                 api(libs.jetbrains.compose.foundation)
             }
         }
+        commonTest {
+            dependencies {
+                implementation(kotlin("test"))
+            }
+        }
     }
 }

chiptextfield-core/src/commonMain/kotlin/com/dokar/chiptextfield/BasicChipTextField.kt

@@ -330,10 +330,10 @@ fun <T : Chip> BasicChipTextField(
     }
 
     LaunchedEffect(focusManager, state, textFieldFocusRequester) {
-        snapshotFlow { state.textFieldFocusState }
+        snapshotFlow { state.textFieldFocusRequest }
             .distinctUntilChanged()
-            .collect {
-                when (it) {
+            .collect { request ->
+                when (request.state) {
                     TextFieldFocusState.None -> {}
                     TextFieldFocusState.Focused -> runCatching {
                         textFieldFocusRequester.requestFocus()
@@ -344,6 +344,7 @@ fun <T : Chip> BasicChipTextField(
                         textFieldFocusRequester.freeFocus()
                     }
                 }
+                state.consumeTextFieldFocusRequest(request)
             }
     }
 
@@ -604,10 +605,8 @@ private fun <T : Chip> Input(
         modifier = modifier
             .focusRequester(focusRequester)
             .onFocusChanged {
+                state.updateTextFieldFocus(it.isFocused)
                 onFocusChange(it.isFocused)
-                if (it.isFocused) {
-                    state.focusTextField()
-                }
             }
             .onPreviewKeyEvent {
                 if (it.type == KeyEventType.KeyDown && it.key == Key.Backspace) {

chiptextfield-core/src/commonMain/kotlin/com/dokar/chiptextfield/ChipTextFieldState.kt

@@ -58,9 +58,12 @@ class ChipTextFieldState<T : Chip>(
 
     internal var recordFocusedChip = true
 
-    internal var textFieldFocusState by mutableStateOf(TextFieldFocusState.None)
+    private var nextTextFieldFocusRequestId = 0
 
-    val isTextFieldFocused get() = textFieldFocusState == TextFieldFocusState.Focused
+    internal var textFieldFocusRequest by mutableStateOf(TextFieldFocusRequest())
+
+    private var _isTextFieldFocused by mutableStateOf(false)
+    val isTextFieldFocused get() = _isTextFieldFocused
 
     var chips by mutableStateOf(chips)
 
@@ -110,12 +113,24 @@ class ChipTextFieldState<T : Chip>(
 
     internal fun updateFocusedChip(chip: T?) {
         if (chip != null) {
-            textFieldFocusState = TextFieldFocusState.None
+            textFieldFocusRequest = textFieldFocusRequest.copy(
+                state = TextFieldFocusState.None,
+            )
         }
         this._focusedChip = chip
         this._focusedChipIndex = chips.indexOf(chip)
     }
 
+    internal fun updateTextFieldFocus(isFocused: Boolean) {
+        _isTextFieldFocused = isFocused
+    }
+
+    internal fun consumeTextFieldFocusRequest(request: TextFieldFocusRequest) {
+        if (textFieldFocusRequest == request) {
+            textFieldFocusRequest = request.copy(state = TextFieldFocusState.None)
+        }
+    }
+
     /**
      * Focus a chip by index.
      */
@@ -141,17 +156,29 @@ class ChipTextFieldState<T : Chip>(
      * Focus the text field at the end of chips.
      */
     fun focusTextField() {
-        textFieldFocusState = TextFieldFocusState.Focused
+        updateTextFieldFocusRequest(TextFieldFocusState.Focused)
     }
 
     /**
      * Clear focus from the focused text field at the end chips.
      */
     fun clearTextFieldFocus() {
-        textFieldFocusState = TextFieldFocusState.Unfocused
+        updateTextFieldFocusRequest(TextFieldFocusState.Unfocused)
+    }
+
+    private fun updateTextFieldFocusRequest(state: TextFieldFocusState) {
+        textFieldFocusRequest = TextFieldFocusRequest(
+            id = ++nextTextFieldFocusRequestId,
+            state = state,
+        )
     }
 }
 
+internal data class TextFieldFocusRequest(
+    val id: Int = 0,
+    val state: TextFieldFocusState = TextFieldFocusState.None,
+)
+
 internal enum class TextFieldFocusState {
     None,
     Focused,

chiptextfield-core/src/commonTest/kotlin/com/dokar/chiptextfield/ChipTextFieldStateTest.kt

@@ -0,0 +1,77 @@
+package com.dokar.chiptextfield
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNotEquals
+import kotlin.test.assertTrue
+
+class ChipTextFieldStateTest {
+    @Test
+    fun textFieldFocusReflectsUiFocus() {
+        val state = ChipTextFieldState<Chip>()
+
+        assertFalse(state.isTextFieldFocused)
+
+        state.updateTextFieldFocus(true)
+        assertTrue(state.isTextFieldFocused)
+
+        state.updateTextFieldFocus(false)
+        assertFalse(state.isTextFieldFocused)
+    }
+
+    @Test
+    fun repeatedTextFieldFocusRequestsAreDistinct() {
+        val state = ChipTextFieldState<Chip>()
+
+        state.focusTextField()
+        val firstRequest = state.textFieldFocusRequest
+        assertFalse(state.isTextFieldFocused)
+
+        state.focusTextField()
+        val secondRequest = state.textFieldFocusRequest
+
+        assertEquals(TextFieldFocusState.Focused, firstRequest.state)
+        assertEquals(TextFieldFocusState.Focused, secondRequest.state)
+        assertNotEquals(firstRequest, secondRequest)
+    }
+
+    @Test
+    fun consumedTextFieldFocusRequestBecomesInert() {
+        val state = ChipTextFieldState<Chip>()
+        state.focusTextField()
+        val request = state.textFieldFocusRequest
+
+        state.consumeTextFieldFocusRequest(request)
+
+        assertEquals(TextFieldFocusState.None, state.textFieldFocusRequest.state)
+    }
+
+    @Test
+    fun consumingOldTextFieldFocusRequestDoesNotClearNewRequest() {
+        val state = ChipTextFieldState<Chip>()
+        state.focusTextField()
+        val oldRequest = state.textFieldFocusRequest
+        state.clearTextFieldFocus()
+        val newRequest = state.textFieldFocusRequest
+
+        state.consumeTextFieldFocusRequest(oldRequest)
+
+        assertEquals(newRequest, state.textFieldFocusRequest)
+        assertEquals(TextFieldFocusState.Unfocused, state.textFieldFocusRequest.state)
+    }
+
+    @Test
+    fun focusingChipCancelsPendingTextFieldFocusRequest() {
+        val chip = Chip("Chip")
+        val state = ChipTextFieldState(chips = listOf(chip))
+        state.focusTextField()
+        val pendingRequest = state.textFieldFocusRequest
+
+        state.focusChip(0)
+
+        assertEquals(pendingRequest.id, state.textFieldFocusRequest.id)
+        assertEquals(TextFieldFocusState.None, state.textFieldFocusRequest.state)
+        assertEquals(0, state.focusedChipIndex)
+    }
+}