feat(splash): load latest chat message

src/lib/chat/splash_latest_message.ts

@@ -0,0 +1,16 @@
+"use client";
+
+import { getChatRepository } from "@/data/repositories/chat_repository";
+import { Result, type Result as ResultT } from "@/utils";
+
+import { getSplashLatestMessagePreview } from "./splash_latest_message_preview";
+
+export async function fetchSplashLatestMessagePreview(): Promise<
+  ResultT<string | null>
+> {
+  const result = await getChatRepository().getHistory(1, 0);
+  if (Result.isErr(result)) return Result.err(result.error);
+
+  const latestMessage = result.data.messages[0] ?? null;
+  return Result.ok(getSplashLatestMessagePreview(latestMessage));
+}

src/lib/chat/splash_latest_message_preview.ts

@@ -0,0 +1,56 @@
+export interface SplashLatestMessageSource {
+  type?: string | null;
+  content?: string | null;
+  audioUrl?: string | null;
+  image?: {
+    type?: string | null;
+    url?: string | null;
+  } | null;
+  lockDetail?: {
+    reason?: string | null;
+  } | null;
+}
+
+const IMAGE_PREVIEW_TEXT = "[图片]";
+const VOICE_PREVIEW_TEXT = "[语音]";
+const FALLBACK_PREVIEW_TEXT = "[消息]";
+
+export function getSplashLatestMessagePreview(
+  message: SplashLatestMessageSource | null | undefined,
+): string | null {
+  if (!message) return null;
+
+  if (isVoiceMessage(message)) return VOICE_PREVIEW_TEXT;
+  if (isImageMessage(message)) return IMAGE_PREVIEW_TEXT;
+
+  const content = message.content?.trim() ?? "";
+  return content.length > 0 ? content : FALLBACK_PREVIEW_TEXT;
+}
+
+function isVoiceMessage(message: SplashLatestMessageSource): boolean {
+  const type = normalizeMessageType(message.type);
+  return (
+    type === "voice" ||
+    type === "audio" ||
+    hasValue(message.audioUrl) ||
+    message.lockDetail?.reason === "voice_message"
+  );
+}
+
+function isImageMessage(message: SplashLatestMessageSource): boolean {
+  const type = normalizeMessageType(message.type);
+  return (
+    type === "image" ||
+    hasValue(message.image?.url) ||
+    hasValue(message.image?.type) ||
+    message.lockDetail?.reason === "image"
+  );
+}
+
+function normalizeMessageType(value: string | null | undefined): string {
+  return value?.trim().toLowerCase() ?? "";
+}
+
+function hasValue(value: string | null | undefined): boolean {
+  return value != null && value.trim().length > 0;
+}