From 22e3dc8aa8fdbaf0263294663f0c98adbcc0727c Mon Sep 17 00:00:00 2001
From: "Tommy D. Rossi" <beats.by.morse@gmail.com>
Date: Wed, 24 Dec 2025 21:07:46 +0100
Subject: [PATCH] feat: add onHighlightComplete callback to Code and Diff
 renderables

---
 packages/core/src/renderables/Code.ts | 13 +++++++++++++
 packages/core/src/renderables/Diff.ts | 18 ++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/packages/core/src/renderables/Code.ts b/packages/core/src/renderables/Code.ts
index 9abb2026..6e260d35 100644
--- a/packages/core/src/renderables/Code.ts
+++ b/packages/core/src/renderables/Code.ts
@@ -15,6 +15,7 @@ export interface CodeOptions extends TextBufferOptions {
   conceal?: boolean
   drawUnstyledText?: boolean
   streaming?: boolean
+  onHighlightComplete?: () => void
 }
 
 export class CodeRenderable extends TextBufferRenderable {
@@ -31,6 +32,7 @@ export class CodeRenderable extends TextBufferRenderable {
   private _streaming: boolean
   private _hadInitialContent: boolean = false
   private _lastHighlights: SimpleHighlight[] = []
+  private _onHighlightComplete?: () => void
 
   protected _contentDefaultOptions = {
     content: "",
@@ -49,6 +51,7 @@ export class CodeRenderable extends TextBufferRenderable {
     this._conceal = options.conceal ?? this._contentDefaultOptions.conceal
     this._drawUnstyledText = options.drawUnstyledText ?? this._contentDefaultOptions.drawUnstyledText
     this._streaming = options.streaming ?? this._contentDefaultOptions.streaming
+    this._onHighlightComplete = options.onHighlightComplete
 
     // Set initial content immediately so lineCount is correct for measure functions
     // This prevents width glitches in parent components like LineNumberRenderable
@@ -148,6 +151,14 @@ export class CodeRenderable extends TextBufferRenderable {
     }
   }
 
+  get onHighlightComplete(): (() => void) | undefined {
+    return this._onHighlightComplete
+  }
+
+  set onHighlightComplete(value: (() => void) | undefined) {
+    this._onHighlightComplete = value
+  }
+
   private ensureVisibleTextBeforeHighlight(): void {
     const content = this._content
 
@@ -247,6 +258,7 @@ export class CodeRenderable extends TextBufferRenderable {
       this._isHighlighting = false
       this._highlightsDirty = false
       this.requestRender()
+      this._onHighlightComplete?.()
     } catch (error) {
       // Check if this result is stale
       if (snapshotId !== this._highlightSnapshotId) {
@@ -261,6 +273,7 @@ export class CodeRenderable extends TextBufferRenderable {
       this._isHighlighting = false
       this._highlightsDirty = false
       this.requestRender()
+      this._onHighlightComplete?.()
     }
   }
 
diff --git a/packages/core/src/renderables/Diff.ts b/packages/core/src/renderables/Diff.ts
index 6286e809..c28fb986 100644
--- a/packages/core/src/renderables/Diff.ts
+++ b/packages/core/src/renderables/Diff.ts
@@ -47,6 +47,7 @@ export interface DiffRenderableOptions extends RenderableOptions<DiffRenderable>
   removedSignColor?: string | RGBA
   addedLineNumberBg?: string | RGBA
   removedLineNumberBg?: string | RGBA
+  onHighlightComplete?: () => void
 }
 
 export class DiffRenderable extends Renderable {
@@ -106,6 +107,9 @@ export class DiffRenderable extends Renderable {
   private errorTextRenderable: TextRenderable | null = null
   private errorCodeRenderable: CodeRenderable | null = null
 
+  private _onHighlightComplete?: () => void
+  private _pendingHighlights = 0
+
   constructor(ctx: RenderContext, options: DiffRenderableOptions) {
     super(ctx, {
       ...options,
@@ -141,6 +145,7 @@ export class DiffRenderable extends Renderable {
     this._removedSignColor = parseColor(options.removedSignColor ?? "#ef4444")
     this._addedLineNumberBg = parseColor(options.addedLineNumberBg ?? "transparent")
     this._removedLineNumberBg = parseColor(options.removedLineNumberBg ?? "transparent")
+    this._onHighlightComplete = options.onHighlightComplete
 
     // Only parse and build if diff is provided
     if (this._diff) {
@@ -240,6 +245,13 @@ export class DiffRenderable extends Renderable {
     super.destroyRecursively()
   }
 
+  private handleHighlightComplete(): void {
+    this._pendingHighlights--
+    if (this._pendingHighlights === 0 && this._onHighlightComplete) {
+      this._onHighlightComplete()
+    }
+  }
+
   /**
    * Create or update a CodeRenderable with the given content and options.
    * Reuses existing instances to avoid expensive recreation.
@@ -315,6 +327,10 @@ export class DiffRenderable extends Renderable {
   ): CodeRenderable {
     const existingRenderable = side === "left" ? this.leftCodeRenderable : this.rightCodeRenderable
 
+    if (this._filetype) {
+      this._pendingHighlights++
+    }
+
     if (!existingRenderable) {
       // Create new CodeRenderable
       const codeOptions: CodeOptions = {
@@ -326,6 +342,7 @@ export class DiffRenderable extends Renderable {
         syntaxStyle: this._syntaxStyle ?? SyntaxStyle.create(),
         width: "100%",
         height: "100%",
+        onHighlightComplete: () => this.handleHighlightComplete(),
         ...(this._fg !== undefined && { fg: this._fg }),
         ...(drawUnstyledText !== undefined && { drawUnstyledText }),
         ...(this._selectionBg !== undefined && { selectionBg: this._selectionBg }),
@@ -346,6 +363,7 @@ export class DiffRenderable extends Renderable {
       existingRenderable.content = content
       existingRenderable.wrapMode = wrapMode ?? "none"
       existingRenderable.conceal = this._conceal
+      existingRenderable.onHighlightComplete = () => this.handleHighlightComplete()
       if (drawUnstyledText !== undefined) {
         existingRenderable.drawUnstyledText = drawUnstyledText
       }