fix(app): support text attachments (#17335)

4 files changed, 131 insertions, 38 deletions

diff --git a/packages/ui/src/components/message-file.test.ts b/packages/ui/src/components/message-file.test.ts
new file mode 100644
index 000000000..7bdf00763
--- /dev/null
+++ b/packages/ui/src/components/message-file.test.ts
@@ -0,0 +1,55 @@
+import { describe, expect, test } from "bun:test"
+import type { FilePart } from "@opencode-ai/sdk/v2"
+import { attached, inline, kind } from "./message-file"
+
+function file(part: Partial<FilePart> = {}): FilePart {
+  return {
+    id: "part_1",
+    sessionID: "ses_1",
+    messageID: "msg_1",
+    type: "file",
+    mime: "text/plain",
+    url: "file:///repo/README.txt",
+    filename: "README.txt",
+    ...part,
+  }
+}
+
+describe("message-file", () => {
+  test("treats data URLs as attachments", () => {
+    expect(attached(file({ url: "data:text/plain;base64,SGVsbG8=" }))).toBe(true)
+    expect(attached(file())).toBe(false)
+  })
+
+  test("treats only non-attachment source ranges as inline references", () => {
+    expect(
+      inline(
+        file({
+          source: {
+            type: "file",
+            path: "/repo/README.txt",
+            text: { value: "@README.txt", start: 0, end: 11 },
+          },
+        }),
+      ),
+    ).toBe(true)
+
+    expect(
+      inline(
+        file({
+          url: "data:text/plain;base64,SGVsbG8=",
+          source: {
+            type: "file",
+            path: "/repo/README.txt",
+            text: { value: "@README.txt", start: 0, end: 11 },
+          },
+        }),
+      ),
+    ).toBe(false)
+  })
+
+  test("separates image and file attachment kinds", () => {
+    expect(kind(file({ mime: "image/png" }))).toBe("image")
+    expect(kind(file({ mime: "application/pdf" }))).toBe("file")
+  })
+})
diff --git a/packages/ui/src/components/message-file.ts b/packages/ui/src/components/message-file.ts
new file mode 100644
index 000000000..ecc745690
--- /dev/null
+++ b/packages/ui/src/components/message-file.ts
@@ -0,0 +1,14 @@
+import type { FilePart } from "@opencode-ai/sdk/v2"
+
+export function attached(part: FilePart) {
+  return part.url.startsWith("data:")
+}
+
+export function inline(part: FilePart) {
+  if (attached(part)) return false
+  return part.source?.text?.start !== undefined && part.source?.text?.end !== undefined
+}
+
+export function kind(part: FilePart) {
+  return part.mime.startsWith("image/") ? "image" : "file"
+}
diff --git a/packages/ui/src/components/message-part.css b/packages/ui/src/components/message-part.css
index f01408a38..5a325693b 100644
--- a/packages/ui/src/components/message-part.css
+++ b/packages/ui/src/components/message-part.css
@@ -38,10 +38,12 @@
     flex-direction: column;
     align-items: center;
     justify-content: center;
+    min-width: 0;
     border-radius: 6px;
     overflow: hidden;
     background: var(--surface-weak);
     border: 1px solid var(--border-weak-base);
+    cursor: default;
     transition:
       border-color 0.15s ease,
       opacity 0.3s ease;
@@ -50,14 +52,19 @@
       border-color: var(--border-strong-base);
     }
 
+    &[data-clickable] {
+      cursor: pointer;
+    }
+
     &[data-type="image"] {
       width: 48px;
       height: 48px;
     }
 
     &[data-type="file"] {
-      width: 48px;
+      width: min(220px, 100%);
       height: 48px;
+      padding: 0 10px;
     }
   }
 
@@ -81,6 +88,30 @@
     }
   }
 
+  [data-slot="user-message-attachment-file"] {
+    width: 100%;
+    min-width: 0;
+    display: flex;
+    align-items: center;
+    gap: 8px;
+
+    [data-component="file-icon"] {
+      width: 20px;
+      height: 20px;
+      flex: none;
+    }
+  }
+
+  [data-slot="user-message-attachment-name"] {
+    min-width: 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    color: var(--text-base);
+    font-size: var(--font-size-small);
+    line-height: var(--line-height-large);
+  }
+
   [data-slot="user-message-body"] {
     width: fit-content;
     max-width: min(82%, 64ch);
diff --git a/packages/ui/src/components/message-part.tsx b/packages/ui/src/components/message-part.tsx
index b580998b6..e8c9dcf95 100644
--- a/packages/ui/src/components/message-part.tsx
+++ b/packages/ui/src/components/message-part.tsx
@@ -54,6 +54,7 @@ import { AnimatedCountList } from "./tool-count-summary"
 import { ToolStatusTitle } from "./tool-status-title"
 import { animate } from "motion"
 import { useLocation } from "@solidjs/router"
+import { attached, inline, kind } from "./message-file"
 
 function ShellSubmessage(props: { text: string; animate?: boolean }) {
   let widthRef: HTMLSpanElement | undefined
@@ -901,19 +902,9 @@ export function UserMessageDisplay(props: { message: UserMessage; parts: PartTyp
 
   const files = createMemo(() => (props.parts?.filter((p) => p.type === "file") as FilePart[]) ?? [])
 
-  const attachments = createMemo(() =>
-    files()?.filter((f) => {
-      const mime = f.mime
-      return mime.startsWith("image/") || mime === "application/pdf"
-    }),
-  )
+  const attachments = createMemo(() => files().filter(attached))
 
-  const inlineFiles = createMemo(() =>
-    files().filter((f) => {
-      const mime = f.mime
-      return !mime.startsWith("image/") && mime !== "application/pdf" && f.source?.text?.start !== undefined
-    }),
-  )
+  const inlineFiles = createMemo(() => files().filter(inline))
 
   const agents = createMemo(() => (props.parts?.filter((p) => p.type === "agent") as AgentPart[]) ?? [])
 
@@ -973,32 +964,34 @@ export function UserMessageDisplay(props: { message: UserMessage; parts: PartTyp
       <Show when={attachments().length > 0}>
         <div data-slot="user-message-attachments">
           <For each={attachments()}>
-            {(file) => (
-              <div
-                data-slot="user-message-attachment"
-                data-type={file.mime.startsWith("image/") ? "image" : "file"}
-                onClick={() => {
-                  if (file.mime.startsWith("image/") && file.url) {
-                    openImagePreview(file.url, file.filename)
-                  }
-                }}
-              >
-                <Show
-                  when={file.mime.startsWith("image/") && file.url}
-                  fallback={
-                    <div data-slot="user-message-attachment-icon">
-                      <Icon name="folder" />
-                    </div>
-                  }
+            {(file) => {
+              const type = kind(file)
+              const name = file.filename ?? i18n.t("ui.message.attachment.alt")
+
+              return (
+                <div
+                  data-slot="user-message-attachment"
+                  data-type={type}
+                  data-clickable={type === "image" ? "true" : undefined}
+                  title={type === "file" ? name : undefined}
+                  onClick={() => {
+                    if (type === "image") openImagePreview(file.url, name)
+                  }}
                 >
-                  <img
-                    data-slot="user-message-attachment-image"
-                    src={file.url}
-                    alt={file.filename ?? i18n.t("ui.message.attachment.alt")}
-                  />
-                </Show>
-              </div>
-            )}
+                  <Show
+                    when={type === "image"}
+                    fallback={
+                      <div data-slot="user-message-attachment-file">
+                        <FileIcon node={{ path: name, type: "file" }} />
+                        <span data-slot="user-message-attachment-name">{name}</span>
+                      </div>
+                    }
+                  >
+                    <img data-slot="user-message-attachment-image" src={file.url} alt={name} />
+                  </Show>
+                </div>
+              )
+            }}
           </For>
         </div>
       </Show>