feat(app): redesign attachment cards (#35945)

Co-authored-by: Brendan Allan <git@brendonovich.dev>
Co-authored-by: Brendan Allan <14191578+Brendonovich@users.noreply.github.com>

packages/app/src/pages/session.tsx

@@ -1,4 +1,5 @@
-import type { Project, UserMessage, VcsFileDiff } from "@opencode-ai/sdk/v2"
+import type { FilePart, Project, UserMessage, VcsFileDiff } from "@opencode-ai/sdk/v2"
+import { getFilename } from "@opencode-ai/core/util/path"
 import { useDialog } from "@opencode-ai/ui/context/dialog"
 import { createQuery, skipToken, useMutation, useQueryClient } from "@tanstack/solid-query"
 import {
@@ -1905,7 +1906,30 @@ export default function Page() {
       .map((item) => ({ id: item.id, text: line(item.id) }))
   })
 
-  const actions = { revert }
+  // attachment bytes are embedded as a data URL, so downloading always works;
+  // revealing requires the on-disk path captured by the client that attached the file
+  const openAttachment = (file: FilePart) => {
+    const download = () => {
+      const anchor = document.createElement("a")
+      anchor.href = file.url
+      anchor.download = getFilename(file.filename) || "attachment"
+      anchor.click()
+    }
+    const path = file.filename ?? ""
+    const absolute = path.startsWith("/") || path.startsWith("\\\\") || /^[a-zA-Z]:[\\/]/.test(path)
+    if (platform.revealPath && absolute) {
+      void platform.revealPath(path).then(
+        (revealed) => {
+          if (!revealed) download()
+        },
+        () => download(),
+      )
+      return
+    }
+    download()
+  }
+
+  const actions = { revert, openAttachment }
 
   createEffect(() => {
     const sessionID = params.id

packages/app/src/pages/session/timeline/message-timeline.tsx

@@ -327,6 +327,7 @@ export function MessageTimeline(props: {
     parts: getMsgParts,
     status: sessionStatus,
     showReasoningSummaries: settings.general.showReasoningSummaries,
+    inlineComments: settings.general.newLayoutDesigns,
   })
   const activeMessageID = projection.activeMessageID
   const assistantMessagesByParent = projection.assistantMessagesByParent
@@ -1135,6 +1136,10 @@ export function MessageTimeline(props: {
           const m = messageByID().get(userMessageRow().userMessageID)
           if (m?.role === "user") return m
         })
+        const messageComments = createMemo(() => {
+          if (!settings.general.newLayoutDesigns()) return []
+          return getMsgParts(userMessageRow().userMessageID).flatMap((part) => MessageComment.fromPart(part) ?? [])
+        })
         return (
           <TimelineRowFrame row={userMessageRow}>
             <Show when={message()}>
@@ -1146,6 +1151,7 @@ export function MessageTimeline(props: {
                       parts={getMsgParts(userMessageRow().userMessageID)}
                       actions={props.actions}
                       useV2Actions={settings.general.newLayoutDesigns()}
+                      comments={messageComments()}
                     />
                   </div>
                 </div>

packages/app/src/pages/session/timeline/projection.ts

@@ -14,6 +14,7 @@ export function createTimelineProjection(input: {
   parts: (messageID: string) => Part[]
   status: Accessor<SessionStatus>
   showReasoningSummaries: Accessor<boolean>
+  inlineComments: Accessor<boolean>
 }) {
   const messageByID = createMemo(() => new Map(input.messages().map((message) => [message.id, message] as const)))
   const assistantMessagesByParent = createMemo(() => {
@@ -59,6 +60,7 @@ export function createTimelineProjection(input: {
             input.showReasoningSummaries(),
             input.status().type,
             activeMessageID() === userMessage.id,
+            input.inlineComments(),
           ),
         ),
       ),

packages/app/src/pages/session/timeline/rows.ts

@@ -38,6 +38,8 @@ export namespace Timeline {
     showReasoning: boolean,
     status: SessionStatus["type"],
     isActive: boolean,
+    // v2 renders comments inside the user message attachments row instead of a strip row
+    inlineComments: boolean,
   ) {
     const rows: TimelineRow.TimelineRow[] = []
 
@@ -74,7 +76,7 @@ export namespace Timeline {
         : groupParts(assistantPartRefs).map((group) => ({ type: "part" as const, group }))
     if (previousUserMessage) rows.push(new TimelineRow.TurnGap({ userMessageID: userMessage.id }))
 
-    if (comments.length > 0)
+    if (comments.length > 0 && !inlineComments)
       rows.push(
         new TimelineRow.CommentStrip({
           userMessageID: userMessage.id,
@@ -84,7 +86,7 @@ export namespace Timeline {
     rows.push(
       new TimelineRow.UserMessage({
         userMessageID: userMessage.id,
-        anchor: comments.length === 0,
+        anchor: inlineComments || comments.length === 0,
       }),
     )