refactor(devti): improve diff request handling for AI suggestions

- Use EmptyContent for the 'before' content in SimpleDiffRequest
- Remove redundant getOrCreateDirectory call
- Update diff request title and labels for better clarity

Author: phodal

core/src/main/kotlin/cc/unitmesh/devti/sketch/SketchToolWindow.kt

@@ -382,15 +382,15 @@ open class SketchToolWindow(
                 else -> null
             } ?: return@map null
 
-            panel.border = JBEmptyBorder(4)
+            panel.border = JBEmptyBorder(0, 4, 0, 4)
             panel
         }.filterNotNull()
 
         if (panels.isEmpty()) return null
 
         val blockedPanel = JPanel(VerticalLayout(JBUI.scale(0))).apply {
             this.isOpaque = true
-            this.border = JBEmptyBorder(4)
+            this.border = JBEmptyBorder(0, 4, 0, 4)
             panels.forEach { this.add(it) }
         }
 

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/code/CodeHighlightSketch.kt

@@ -44,7 +44,7 @@ open class CodeHighlightSketch(
     val fileName: String? = null,
     val withLeftRightBorder: Boolean = true,
     val showToolbar: Boolean = true
-) : JBPanel<CodeHighlightSketch>(VerticalLayout(4)), DataProvider, LangSketch, Disposable {
+) : JBPanel<CodeHighlightSketch>(VerticalLayout(2)), DataProvider, LangSketch, Disposable {
     private val devinLineThreshold = 10
     private val minDevinLineThreshold = 1
     private var isDevIns = false
@@ -74,9 +74,9 @@ open class CodeHighlightSketch(
         val editor = EditorUtil.createCodeViewerEditor(project, text, ideaLanguage, fileName, this)
 
         border = if (withLeftRightBorder) {
-            JBEmptyBorder(8, 8, 8, 8)
+            JBEmptyBorder(4, 4, 4, 4)
         } else {
-            JBEmptyBorder(8, 0, 0, 0)
+            JBEmptyBorder(4, 0, 0, 0)
         }
 
         editor.component.isOpaque = true

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/patch/DiffLangSketch.kt

@@ -36,7 +36,7 @@ import javax.swing.JComponent
 import javax.swing.JPanel
 
 class DiffLangSketch(private val myProject: Project, private var patchContent: String) : ExtensionLangSketch {
-    private val mainPanel: JPanel = JPanel(VerticalLayout(5))
+    private val mainPanel: JPanel = JPanel(VerticalLayout(2))
     private val myHeaderPanel: JPanel = JPanel(BorderLayout())
     private val shelfExecutor = ApplyPatchDefaultExecutor(myProject)
     private val myReader: PatchReader? = PatchReader(patchContent).also {
@@ -61,7 +61,7 @@ class DiffLangSketch(private val myProject: Project, private var patchContent: S
             mainPanel.add(myHeaderPanel)
         }
 
-        mainPanel.border = JBUI.Borders.compound(JBUI.Borders.empty(0, 10))
+        mainPanel.border = JBUI.Borders.compound(JBUI.Borders.empty(0, 4))
 
         ApplicationManager.getApplication().invokeLater {
             if (filePatches.isEmpty()) {
@@ -92,17 +92,13 @@ class DiffLangSketch(private val myProject: Project, private var patchContent: S
                 return@invokeLater
             }
 
-//            try {
             filePatches.forEach { patch ->
                 val diffPanel = createDiffPanel(patch)
                 if (diffPanel != null) {
                     mainPanel.add(diffPanel.getComponent())
                     mainPanel.revalidate()
                 }
             }
-//            } catch (e: Exception) {
-//                AutoDevNotifications.error(myProject, "Failed to create diff panel: ${e.message}")
-//            }
         }
     }
 

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/patch/SingleFileDiffSketch.kt

@@ -101,7 +101,7 @@ class SingleFileDiffSketch(
 
         val filepathLabel = JBLabel(fileName).apply {
             icon = currentFile.fileType.icon
-            border = BorderFactory.createEmptyBorder(2, 10, 2, 10)
+            border = BorderFactory.createEmptyBorder(2, 4, 2, 4)
 
             val originalColor = foreground
             val hoverColor = AutoDevColors.FILE_HOVER_COLOR // Extracted from inline JBColor definition
@@ -116,14 +116,14 @@ class SingleFileDiffSketch(
                     cursor = java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.HAND_CURSOR)
                     border = BorderFactory.createCompoundBorder(
                         BorderFactory.createMatteBorder(0, 0, 1, 0, hoverColor),
-                        BorderFactory.createEmptyBorder(2, 10, 1, 10)
+                        BorderFactory.createEmptyBorder(2, 4, 1, 4)
                     )
                 }
 
                 override fun mouseExited(e: MouseEvent?) {
                     foreground = originalColor
                     cursor = java.awt.Cursor.getDefaultCursor()
-                    border = BorderFactory.createEmptyBorder(2, 10, 2, 10)
+                    border = BorderFactory.createEmptyBorder(2, 4, 2, 4)
                 }
             })
         }
@@ -163,7 +163,7 @@ class SingleFileDiffSketch(
         patchActionPanel = JPanel(BorderLayout()).apply {
             add(filePanel, BorderLayout.WEST)
             add(actionPanel, BorderLayout.EAST)
-            border = BorderFactory.createEmptyBorder(5, 5, 5, 5)
+            border = BorderFactory.createEmptyBorder(4, 4, 4, 4)
         }
 
         val fileContainer = JPanel(BorderLayout(10, 10)).also {

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/plan/PlanLangSketch.kt

@@ -21,7 +21,7 @@ class PlanLangSketch(
     private var content: String,
     private var agentTaskItems: MutableList<AgentTaskEntry>,
     private val isInToolwindow: Boolean = false
-) : JBPanel<PlanLangSketch>(BorderLayout(JBUI.scale(8), 0)), ExtensionLangSketch {
+) : JBPanel<PlanLangSketch>(BorderLayout(JBUI.scale(0), 0)), ExtensionLangSketch {
     private val contentPanel = JPanel(VerticalLayout(JBUI.scale(0)))
     val scrollPane: JBScrollPane
     private val toolbarFactory = PlanToolbarFactory(project)
@@ -30,7 +30,7 @@ class PlanLangSketch(
     init {
         if (!isInToolwindow) {
             add(toolbarFactory.createToolbar(this), BorderLayout.NORTH)
-            border = JBUI.Borders.empty(8)
+            border = JBUI.Borders.empty(4)
         }
 
         renderPlan()