[terminal] IJPL-182032 Keep the cursor visible on the screen when the port forwarding panel appears

Previously, when the port forwarding panel appeared on top, the editor was scrolled down, so the cursor position was hidden.
Let's react on port forwarding panel size changes and update the scroll position.
Move top panel management from `ReworkedTerminalWidget` to the `ReworkedTerminalView`. Refactor the TerminalPanel to extract the layered pane logic to the separate `TerminalLayeredPane`.

(cherry picked from commit 78992a106db33e5861d362d5aca00942dbf0382c)

IJ-CR-159801

GitOrigin-RevId: 7bb54ad4cdb89c7f8765b06d340ed3b6eec0a5a4

plugins/terminal/frontend/src/com/intellij/terminal/frontend/ReworkedTerminalView.kt

@@ -13,7 +13,6 @@ import com.intellij.openapi.editor.Document
 import com.intellij.openapi.editor.Editor
 import com.intellij.openapi.editor.EditorFactory
 import com.intellij.openapi.editor.ex.EditorEx
-import com.intellij.openapi.editor.ex.util.EditorUtil
 import com.intellij.openapi.editor.impl.DocumentImpl
 import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.editor.impl.SoftWrapModelImpl
@@ -27,6 +26,7 @@ import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
 import com.intellij.terminal.session.TerminalSession
 import com.intellij.ui.components.JBLayeredPane
 import com.intellij.util.asDisposable
+import com.intellij.util.ui.components.BorderLayoutPanel
 import com.jediterm.core.util.TermSize
 import com.jediterm.terminal.TtyConnector
 import kotlinx.coroutines.*
@@ -66,6 +66,7 @@ internal class ReworkedTerminalView(
 
   private val outputEditor: EditorEx
   private val alternateBufferEditor: EditorEx
+  private val scrollingModel: TerminalOutputScrollingModel
 
   private val terminalPanel: TerminalPanel
 
@@ -101,7 +102,7 @@ internal class ReworkedTerminalView(
 
     outputEditor = createOutputEditor(settings, parentDisposable = this)
     val outputModel = TerminalOutputModelImpl(outputEditor.document, maxOutputLength = TerminalUiUtils.getDefaultMaxOutputLength())
-    val scrollingModel = TerminalOutputScrollingModelImpl(outputEditor, outputModel, sessionModel, coroutineScope.childScope("TerminalOutputScrollingModel"))
+    scrollingModel = TerminalOutputScrollingModelImpl(outputEditor, outputModel, sessionModel, coroutineScope.childScope("TerminalOutputScrollingModel"))
     outputEditor.putUserData(TerminalOutputScrollingModel.KEY, scrollingModel)
 
     configureOutputEditor(
@@ -175,6 +176,23 @@ internal class ReworkedTerminalView(
     return component.hasFocus()
   }
 
+  fun setTopComponent(component: JComponent, disposable: Disposable) {
+    val resizeListener = object : ComponentAdapter() {
+      override fun componentResized(e: ComponentEvent) {
+        // Update scroll position on top component size change
+        // to always keep the cursor visible
+        scrollingModel.scrollToCursor(force = false)
+      }
+    }
+    component.addComponentListener(resizeListener)
+    terminalPanel.setTopComponent(component)
+
+    Disposer.register(disposable) {
+      component.removeComponentListener(resizeListener)
+      terminalPanel.remoteTopComponent(component)
+    }
+  }
+
   private fun listenSearchController() {
     terminalSearchController.addListener(object : TerminalSearchControllerListener {
       override fun searchSessionStarted(session: TerminalSearchSession) {
@@ -349,9 +367,13 @@ internal class ReworkedTerminalView(
     terminalPanel.addFocusListener(parentDisposable, listener)
   }
 
-  private inner class TerminalPanel(initialContent: Editor) : JBLayeredPane(), UiDataProvider {
+  private inner class TerminalPanel(initialContent: Editor) : BorderLayoutPanel(), UiDataProvider {
+    private val layeredPane = TerminalLayeredPane(initialContent)
     private var curEditor: Editor = initialContent
 
+    val preferredFocusableComponent: JComponent
+      get() = layeredPane.preferredFocusableComponent
+
     private val delegatingFocusListener = object : FocusListener {
       override fun focusGained(e: FocusEvent) {
         focusListeners.forEach { it.focusGained(e) }
@@ -363,24 +385,8 @@ internal class ReworkedTerminalView(
     }
 
     init {
-      setTerminalContent(initialContent)
-    }
-
-    val preferredFocusableComponent: JComponent
-      get() = curEditor.contentComponent
-
-    fun setTerminalContent(editor: Editor) {
-      val prevEditor = curEditor
-      @Suppress("SENSELESS_COMPARISON") // called from init when curEditor == null
-      if (prevEditor != null) {
-        prevEditor.contentComponent.removeFocusListener(delegatingFocusListener)
-        remove(curEditor.component)
-      }
-      curEditor = editor
-      addToLayer(editor.component, DEFAULT_LAYER)
-      editor.contentComponent.addFocusListener(delegatingFocusListener)
-      revalidate()
-      repaint()
+      addToCenter(layeredPane)
+      updateFocusListeners(initialContent, initialContent)
     }
 
     override fun uiDataSnapshot(sink: DataSink) {
@@ -389,6 +395,61 @@ internal class ReworkedTerminalView(
       sink[TerminalSearchController.KEY] = terminalSearchController
     }
 
+    fun setTerminalContent(editor: Editor) {
+      layeredPane.setTerminalContent(editor)
+      updateFocusListeners(curEditor, editor)
+      curEditor = editor
+    }
+
+    fun installSearchComponent(component: SearchReplaceComponent) {
+      layeredPane.installSearchComponent(component)
+    }
+
+    fun removeSearchComponent(component: SearchReplaceComponent) {
+      layeredPane.removeSearchComponent(component)
+    }
+
+    fun setTopComponent(component: JComponent) {
+      addToTop(component)
+      revalidate()
+      repaint()
+    }
+
+    fun remoteTopComponent(component: JComponent) {
+      remove(component)
+      revalidate()
+      repaint()
+    }
+
+    private fun updateFocusListeners(prevEditor: Editor, newEditor: Editor) {
+      prevEditor.contentComponent.removeFocusListener(delegatingFocusListener)
+      newEditor.contentComponent.addFocusListener(delegatingFocusListener)
+    }
+  }
+
+  private class TerminalLayeredPane(initialContent: Editor) : JBLayeredPane() {
+    private var curEditor: Editor = initialContent
+
+    val preferredFocusableComponent: JComponent
+      get() = curEditor.contentComponent
+
+    init {
+      setTerminalContent(initialContent)
+    }
+
+    fun setTerminalContent(editor: Editor) {
+      val prevEditor = curEditor
+      @Suppress("SENSELESS_COMPARISON") // called from init when curEditor == null
+      if (prevEditor != null) {
+        remove(curEditor.component)
+      }
+      curEditor = editor
+      addToLayer(editor.component, DEFAULT_LAYER)
+
+      revalidate()
+      repaint()
+    }
+
     fun installSearchComponent(component: SearchReplaceComponent) {
       addToLayer(component, POPUP_LAYER)
       revalidate()

plugins/terminal/frontend/src/com/intellij/terminal/frontend/ReworkedTerminalWidget.kt

@@ -8,12 +8,10 @@ import com.intellij.terminal.TerminalTitle
 import com.intellij.terminal.session.TerminalSession
 import com.intellij.terminal.ui.TerminalWidget
 import com.intellij.terminal.ui.TtyConnectorAccessor
-import com.intellij.util.ui.components.BorderLayoutPanel
 import com.jediterm.core.util.TermSize
 import com.jediterm.terminal.TtyConnector
 import org.jetbrains.annotations.Nls
 import org.jetbrains.plugins.terminal.JBTerminalSystemSettingsProvider
-import org.jetbrains.plugins.terminal.block.TerminalContentView
 import java.util.concurrent.CompletableFuture
 import javax.swing.JComponent
 
@@ -23,9 +21,7 @@ internal class ReworkedTerminalWidget(
   parentDisposable: Disposable,
 ) : TerminalWidget {
   private val sessionFuture = CompletableFuture<TerminalSession>()
-  private val view: TerminalContentView = ReworkedTerminalView(project, settings, sessionFuture)
-
-  private val panel: BorderLayoutPanel = BorderLayoutPanel()
+  private val view = ReworkedTerminalView(project, settings, sessionFuture)
 
   override val terminalTitle: TerminalTitle = TerminalTitle()
 
@@ -40,8 +36,6 @@ internal class ReworkedTerminalWidget(
   init {
     Disposer.register(parentDisposable, this)
     Disposer.register(this, view)
-
-    panel.addToCenter(view.component)
   }
 
   override fun connectToSession(session: TerminalSession) {
@@ -53,7 +47,7 @@ internal class ReworkedTerminalWidget(
   }
 
   override fun getComponent(): JComponent {
-    return panel
+    return view.component
   }
 
   override fun getPreferredFocusableComponent(): JComponent {
@@ -81,10 +75,7 @@ internal class ReworkedTerminalWidget(
   }
 
   override fun addNotification(notificationComponent: JComponent, disposable: Disposable) {
-    panel.addToTop(notificationComponent)
-    Disposer.register(disposable) {
-      panel.remove(notificationComponent)
-    }
+    view.setTopComponent(notificationComponent, disposable)
   }
 
   override fun writePlainMessage(message: @Nls String) {