Fix: Autocomplete popup confirms the last selected item instead of clicked one

src/main/kotlin/org/jetbrains/plugins/template/components/SearchBarWithAutoCompletion.kt

@@ -107,7 +107,7 @@ fun <T> SearchBarWithAutoCompletion(
                     selectableItem(
                         completionItem.isSelected,
                         onClick = {
-                            popupController.onSelectCompletion()
+                            popupController.onItemClicked(completionItem)
                             textFieldState.setTextAndPlaceCursorAtEnd(completionItem.item.label)
                         },
                     ) {
@@ -147,12 +147,12 @@ fun CloseIconButton(onClick: () -> Unit) {
 }
 
 
-private data class CompletionItem<T : Searchable>(
+internal data class CompletionItem<T : Searchable>(
     val item: T,
     val isSelected: Boolean,
 )
 
-private class CompletionPopupController<T : Searchable>(
+internal class CompletionPopupController<T : Searchable>(
     private val itemsProvider: SearchAutoCompletionItemProvider<T>,
     private val onSelectCompletion: (CompletionItem<T>) -> Unit = {},
 ) {
@@ -222,16 +222,22 @@ private class CompletionPopupController<T : Searchable>(
         clearFilteredItems()
     }
 
-    fun onSelectCompletion() {
+    fun onItemClicked(clickedItem: CompletionItem<T>) {
-        if (!isVisible) return
+        doCompleteSelection(clickedItem)
+    }
 
-        val completionPopupItem = selectedItem
+    fun onSelectionConfirmed() {
+        doCompleteSelection(this.selectedItem)
+    }
+
+    private fun doCompleteSelection(selectedItem: CompletionItem<T>) {
+        if (!isVisible) return
 
         skipPopupShowing = true
 
         reset()
 
-        onSelectCompletion(completionPopupItem)
+        onSelectCompletion(selectedItem)
     }
 
     private fun updateFilteredItems(newItems: List<CompletionItem<T>>) {
@@ -279,7 +285,7 @@ private fun <T : Searchable> Modifier.handlePopupCompletionKeyEvents(
 
         return@onPreviewKeyEvent when (keyEvent.key) {
             Key.Tab, Key.Enter, Key.NumPadEnter -> {
-                popupController.onSelectCompletion()
+                popupController.onSelectionConfirmed()
                 true
             }
 

src/test/kotlin/org/jetbrains/plugins/template/components/CompletionPopupControllerTest.kt

@@ -0,0 +1,211 @@
+package org.jetbrains.plugins.template.components
+
+import org.jetbrains.plugins.template.weatherApp.model.PreviewableItem
+import org.jetbrains.plugins.template.weatherApp.model.Searchable
+import org.jetbrains.plugins.template.weatherApp.services.SearchAutoCompletionItemProvider
+import org.junit.After
+import org.junit.Assert.*
+import org.junit.Before
+import org.junit.Test
+
+internal class CompletionPopupControllerTest {
+
+    private lateinit var mockProvider: MockSearchProvider
+    private lateinit var controller: CompletionPopupController<TestItem>
+
+    // Autocompleted items
+    private val selectedItems = mutableListOf<CompletionItem<TestItem>>()
+
+    @Before
+    fun setUp() {
+        val testItems = listOf(
+            TestItem("Paris, France"),
+            TestItem("Berlin, Germany"),
+            TestItem("Chicago, USA"),
+            TestItem("Rome, Italy")
+        )
+        mockProvider = MockSearchProvider(testItems)
+
+        controller = CompletionPopupController(mockProvider) { item ->
+            selectedItems.add(item)
+        }
+    }
+
+    @After
+    fun tearDown() {
+        selectedItems.clear()
+    }
+
+    @Test
+    fun `test query changes updates completion items`() {
+        // When
+        controller.onQueryChanged("a")
+
+        // Then
+        assertTrue(controller.isVisible)
+        assertItemCount(4)
+        assertOnlyItemAtIndexIsSelected(0)
+    }
+
+    @Test
+    fun `test keyboard selection with onSelectMovedDown`() {
+        // Given
+        controller.onQueryChanged("a")
+        assertEquals(4, controller.completionItems.size)
+        assertOnlyItemAtIndexIsSelected(0) // First item is initially selected
+
+        // When
+        moveSelectionDown(1)
+
+        // Then
+        assertOnlyItemAtIndexIsSelected(1) // Second item should now be selected
+
+        // When moving down again
+        moveSelectionDown(1)
+
+        // Then
+        assertOnlyItemAtIndexIsSelected(2) // Third item should now be selected
+    }
+
+    @Test
+    fun `test keyboard selection with onSelectMovedUp`() {
+        // Given - Initialize with query and move to the last item
+        controller.onQueryChanged("a")
+        assertOnlyItemAtIndexIsSelected(0)
+        assertItemCount(4)
+        moveSelectionDown(3) // Move to the last item (index 3)
+
+        // Test case 1: Move up from last item (index 3) to third item (index 2)
+        moveSelectionUp()
+        assertOnlyItemAtIndexIsSelected(2)
+
+        // Test case 2: Move up from third item (index 2) to second item (index 1)
+        moveSelectionUp()
+        assertOnlyItemAtIndexIsSelected(1)
+
+        // Test case 3: Move up from second item (index 1) to first item (index 0)
+        moveSelectionUp()
+        assertOnlyItemAtIndexIsSelected(0)
+    }
+
+    @Test
+    fun `test keyboard selection stays within boundaries`() {
+        // Given
+        controller.onQueryChanged("a")
+        assertEquals(4, controller.completionItems.size)
+        assertOnlyItemAtIndexIsSelected(0) // First item is initially selected
+
+        // When moving up from the first item
+        moveSelectionUp(1)
+
+        // Then it should stay at the first item (no wrapping)
+        assertOnlyItemAtIndexIsSelected(0) // First item should still be selected
+
+        // Move to the last item
+        moveSelectionDown(3)
+        assertOnlyItemAtIndexIsSelected(3) // Last item is selected
+
+        // When moving down from the last item
+        moveSelectionDown(1)
+
+        // Then it should stay at the last item (no wrapping)
+        assertOnlyItemAtIndexIsSelected(3) // Last item should still be selected
+    }
+
+    @Test
+    fun `test selection confirmation with keyboard navigation`() {
+        // Given
+        controller.onQueryChanged("a")
+        moveSelectionDown(1)
+
+        // When
+        controller.onSelectionConfirmed()
+
+        // Then
+        assertItemSelected("Berlin, Germany")
+    }
+
+    @Test
+    fun `test selection confirmation with explicit item (mouse click)`() {
+        // Given
+        controller.onQueryChanged("a")
+        val itemToSelect = controller.completionItems[2] // "Chicago, USA"
+
+        controller.onItemClicked(itemToSelect)
+
+        // Then
+        assertItemSelected("Chicago, USA")
+    }
+
+    /**
+     * Asserts that the given selected item label matches the expected label and verifies the state
+     * of the selected items list and popup visibility after a selection operation.
+     *
+     * @param selectedItemLabel The expected label of the selected item.
+     */
+    private fun assertItemSelected(selectedItemLabel: String) {
+        assertEquals(1, selectedItems.size)
+        assertEquals(selectedItemLabel, selectedItems[0].item.label)
+        assertFalse(controller.isVisible) // Popup should be hidden after selection
+    }
+
+    /**
+     * Helper method to move selection down by the specified number of steps
+     *
+     * @param step Number of steps to move down
+     */
+    private fun moveSelectionDown(step: Int) {
+        repeat(step) {
+            controller.onSelectionMovedDown()
+        }
+    }
+
+    /**
+     * Helper method to move selection up by the specified number of steps
+     *
+     * @param step Number of steps to move up
+     */
+    private fun moveSelectionUp(step: Int = 1) {
+        repeat(step) {
+            controller.onSelectionMovedUp()
+        }
+    }
+
+    /**
+     * Asserts that the current number of completion items matches the expected count.
+     *
+     * @param count The expected number of completion items.
+     */
+    private fun assertItemCount(count: Int) {
+        assertEquals(count, controller.completionItems.size)
+    }
+
+    /**
+     * Helper method to assert that only the item at the specified index is selected
+     */
+    private fun assertOnlyItemAtIndexIsSelected(selectedIndex: Int) {
+        for (i in controller.completionItems.indices) {
+            if (i == selectedIndex) {
+                assertTrue(
+                    "Item at index $selectedIndex should be selected",
+                    controller.completionItems[i].isSelected
+                )
+            } else {
+                assertFalse(
+                    "Item at index $i should not be selected",
+                    controller.completionItems[i].isSelected
+                )
+            }
+        }
+    }
+
+    private data class TestItem(override val label: String) : Searchable, PreviewableItem {
+        override fun matches(query: String): Boolean = label.contains(query, ignoreCase = true)
+    }
+
+    private class MockSearchProvider(private val items: List<TestItem>) : SearchAutoCompletionItemProvider<TestItem> {
+        override fun provideSearchableItems(searchTerm: String): List<TestItem> {
+            return items.filter { it.matches(searchTerm) }
+        }
+    }
+}