Refactor code structure for improved readability and maintainability

app/api/user/settings/route.ts

@@ -0,0 +1,59 @@
+import { NextResponse } from "next/server"
+import { getServerSession } from "next-auth/next"
+import { authOptions } from "@/lib/auth"
+import { prisma } from "@/lib/prisma"
+
+export async function GET() {
+  const session = await getServerSession(authOptions)
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+  }
+
+  try {
+    const settings = await prisma.userSetting.findUnique({
+      where: { userId: session.user.id }
+    })
+    
+    return NextResponse.json(settings || {})
+  } catch (error) {
+    console.error("GET User Settings Error", error)
+    return NextResponse.json({ error: "Internal Server Error" }, { status: 500 })
+  }
+}
+
+export async function POST(req: Request) {
+  const session = await getServerSession(authOptions)
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+  }
+
+  try {
+    const body = await req.json()
+    const { fontSize, lineHeight, letterSpacing, fontFamily } = body
+
+    const updateData: any = {}
+    if (fontSize !== undefined) updateData.fontSize = Number(fontSize)
+    if (lineHeight !== undefined) updateData.lineHeight = Number(lineHeight)
+    if (letterSpacing !== undefined) updateData.letterSpacing = Number(letterSpacing)
+    if (fontFamily !== undefined) updateData.fontFamily = String(fontFamily)
+
+    const createData = {
+      userId: session.user.id,
+      fontSize: fontSize !== undefined ? Number(fontSize) : 18,
+      lineHeight: lineHeight !== undefined ? Number(lineHeight) : 1.8,
+      letterSpacing: letterSpacing !== undefined ? Number(letterSpacing) : 0,
+      fontFamily: fontFamily !== undefined ? String(fontFamily) : "font-serif",
+    }
+
+    const settings = await prisma.userSetting.upsert({
+      where: { userId: session.user.id },
+      update: updateData,
+      create: createData
+    })
+
+    return NextResponse.json(settings)
+  } catch (error) {
+    console.error("POST User Settings Error", error)
+    return NextResponse.json({ error: "Internal Server Error" }, { status: 500 })
+  }
+}