1 files changed, 47 insertions, 0 deletions
diff --git a/packages/desktop/src/utils/prompt.ts b/packages/desktop/src/utils/prompt.ts
new file mode 100644
index 000000000..45c5ce1f3
--- /dev/null
+++ b/packages/desktop/src/utils/prompt.ts
@@ -0,0 +1,47 @@
+import type { Part, TextPart, FilePart } from "@opencode-ai/sdk/v2"
+import type { Prompt, FileAttachmentPart } from "@/context/prompt"
+
+/**
+ * Extract prompt content from message parts for restoring into the prompt input.
+ * This is used by undo to restore the original user prompt.
+ */
+export function extractPromptFromParts(parts: Part[]): Prompt {
+  const result: Prompt = []
+  let position = 0
+
+  for (const part of parts) {
+    if (part.type === "text") {
+      const textPart = part as TextPart
+      if (!textPart.synthetic && textPart.text) {
+        result.push({
+          type: "text",
+          content: textPart.text,
+          start: position,
+          end: position + textPart.text.length,
+        })
+        position += textPart.text.length
+      }
+    } else if (part.type === "file") {
+      const filePart = part as FilePart
+      if (filePart.source?.type === "file") {
+        const path = filePart.source.path
+        const content = "@" + path
+        const attachment: FileAttachmentPart = {
+          type: "file",
+          path,
+          content,
+          start: position,
+          end: position + content.length,
+        }
+        result.push(attachment)
+        position += content.length
+      }
+    }
+  }
+
+  if (result.length === 0) {
+    result.push({ type: "text", content: "", start: 0, end: 0 })
+  }
+
+  return result
+}