finance-app/src/app/api/budgets/route.ts

import { NextRequest, NextResponse } from "next/server";
import { getCurrentUser } from "@/lib/auth";
import { queryRaw } from "@/lib/db";

export async function GET(req: NextRequest) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 403 });

  const { searchParams } = new URL(req.url);
  const month = searchParams.get("month");

  let monthDate: string;
  if (month) {
    monthDate = month.length === 7 ? `${month}-01` : month;
  } else {
    const now = new Date();
    monthDate = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, "0")}-01`;
  }

  const rows = await queryRaw<{ id: number; category: string; month: string; amount_limit: number }>(
    `SELECT id, category, month::text, amount_limit::numeric FROM budgets WHERE owner_id = $1 AND month = $2::date`,
    [user.id, monthDate]
  );
  return NextResponse.json(rows);
}

export async function POST(req: NextRequest) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 403 });

  const { category, month, amount_limit } = await req.json();
  if (!category || !month || amount_limit === undefined) {
    return NextResponse.json({ error: "category, month, and amount_limit required" }, { status: 400 });
  }

  const monthDate = month.length === 7 ? `${month}-01` : month;

  const rows = await queryRaw<{ id: number; category: string; month: string; amount_limit: number }>(
    `INSERT INTO budgets (owner_id, category, month, amount_limit)
     VALUES ($1, $2, $3::date, $4)
     ON CONFLICT (owner_id, category, month) DO UPDATE SET amount_limit = $4, updated_at = NOW()
     RETURNING id, category, month::text, amount_limit::numeric`,
    [user.id, category, monthDate, amount_limit]
  );
  return NextResponse.json(rows[0], { status: 201 });
}