Initial reader-api backend extracted from reader

app/api/truyen/[id]/rate/route.ts

@@ -0,0 +1,41 @@
+import { NextResponse } from "next/server"
+import { prisma } from "@/lib/prisma"
+
+export async function POST(req: Request, { params }: { params: Promise<{ id: string }> }) {
+    try {
+        const { id } = await params
+        const body = await req.json()
+        const { score } = body
+
+        if (typeof score !== 'number' || score < 1 || score > 5) {
+            return NextResponse.json({ error: "Invalid score" }, { status: 400 })
+        }
+
+        // Fetch current rating
+        const novel = await prisma.novel.findUnique({
+            where: { id },
+            select: { rating: true, ratingCount: true }
+        })
+
+        if (!novel) {
+            return NextResponse.json({ error: "Novel not found" }, { status: 404 })
+        }
+
+        // Atomic increment using raw SQL to avoid race conditions
+        const updatedNovel = await prisma.$queryRaw<{ rating: number; ratingCount: number }[]>`
+          UPDATE "Novel"
+          SET "ratingCount" = "ratingCount" + 1,
+              "rating"      = (("rating" * "ratingCount") + ${score}) / ("ratingCount" + 1)
+          WHERE id = ${id}
+          RETURNING rating, "ratingCount"
+        `.then((rows) => rows[0])
+
+        return NextResponse.json({
+            rating: updatedNovel.rating,
+            ratingCount: updatedNovel.ratingCount
+        })
+    } catch (error) {
+        console.error("Rating Error", error)
+        return NextResponse.json({ error: "Internal Server Error" }, { status: 500 })
+    }
+}