refactor: P0-1/2/4 解耦修复 - 拆分过耦合文件 + dashboard 解耦

src/modules/textbooks/data-access.ts

@@ -1,7 +1,7 @@
 import "server-only"
 
 import { cache } from "react"
-import { and, asc, eq, inArray, like, or, sql, isNull, type SQL } from "drizzle-orm"
+import { and, asc, count, eq, inArray, like, or, sql, isNull, type SQL } from "drizzle-orm"
 import { createId } from "@paralleldrive/cuid2"
 
 import { db } from "@/shared/db"
@@ -417,12 +417,28 @@ export async function reorderChapters(chapterId: string, newIndex: number, paren
       if (ch.order !== i || (ch.id === chapterId && ch.parentId !== parentId)) {
         await tx
           .update(chapters)
-          .set({ 
+          .set({
             order: i,
-            parentId: ch.id === chapterId ? parentId : ch.parentId 
+            parentId: ch.id === chapterId ? parentId : ch.parentId
           })
           .where(eq(chapters.id, ch.id))
       }
     }
   })
 }
+
+export type TextbooksDashboardStats = {
+  textbookCount: number
+  chapterCount: number
+}
+
+export const getTextbooksDashboardStats = cache(async (): Promise<TextbooksDashboardStats> => {
+  const [textbookCountRow, chapterCountRow] = await Promise.all([
+    db.select({ value: count() }).from(textbooks),
+    db.select({ value: count() }).from(chapters),
+  ])
+  return {
+    textbookCount: Number(textbookCountRow[0]?.value ?? 0),
+    chapterCount: Number(chapterCountRow[0]?.value ?? 0),
+  }
+})