import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { prisma } from "@/lib/db";
import { toPlanInput, getOwnedPlan } from "@/lib/queries";
import { getCurrentUserId } from "@/lib/session";
import { computePlan } from "@/lib/calculations";
import { planProfileSchema, validatePersonsForType } from "@/app/api/plans/route";

export async function GET(
  _request: NextRequest,
  { params }: { params: Promise<{ planId: string }> }
) {
  const userId = await getCurrentUserId();
  if (!userId) return NextResponse.json({ error: "Nicht authentifiziert." }, { status: 401 });
  const { planId } = await params;

  const plan = await getOwnedPlan(planId, userId);
  if (!plan) return NextResponse.json({ error: "Plan nicht gefunden." }, { status: 404 });

  const planInput = toPlanInput(plan);
  const computed = computePlan(planInput);

  return NextResponse.json({ plan: planInput, computed });
}

// Name allein aendern ODER das ganze Plan-Profil (Haushaltsform/Personen/Inflation).
const patchSchema = z.union([
  z.object({ name: z.string().min(1).max(120) }),
  planProfileSchema.extend({ name: z.string().min(1).max(120).optional() }),
]);

export async function PATCH(
  request: NextRequest,
  { params }: { params: Promise<{ planId: string }> }
) {
  const userId = await getCurrentUserId();
  if (!userId) return NextResponse.json({ error: "Nicht authentifiziert." }, { status: 401 });
  const { planId } = await params;

  const plan = await prisma.plan.findFirst({ where: { id: planId, userId } });
  if (!plan) return NextResponse.json({ error: "Plan nicht gefunden." }, { status: 404 });

  const body = await request.json();
  const parsed = patchSchema.safeParse(body);
  if (!parsed.success) return NextResponse.json({ error: "Ungueltige Eingabe." }, { status: 400 });

  const data = parsed.data;
  const hasProfile = "householdType" in data;

  if (hasProfile) {
    const error = validatePersonsForType(data);
    if (error) return NextResponse.json({ error }, { status: 400 });
    const updated = await prisma.$transaction(async (tx) => {
      await tx.person.deleteMany({ where: { planId: plan.id } });
      return tx.plan.update({
        where: { id: plan.id },
        data: {
          name: data.name ?? undefined,
          householdType: data.householdType,
          inflationRateDefault: data.inflationRateDefault,
          persons: { create: data.persons },
        },
      });
    });
    return NextResponse.json({ plan: { id: updated.id, name: updated.name } });
  }

  const updated = await prisma.plan.update({
    where: { id: plan.id },
    data: { name: data.name },
  });
  return NextResponse.json({ plan: { id: updated.id, name: updated.name } });
}

export async function DELETE(
  _request: NextRequest,
  { params }: { params: Promise<{ planId: string }> }
) {
  const userId = await getCurrentUserId();
  if (!userId) return NextResponse.json({ error: "Nicht authentifiziert." }, { status: 401 });
  const { planId } = await params;
  const plan = await prisma.plan.findFirst({ where: { id: planId, userId } });
  if (!plan) return NextResponse.json({ error: "Plan nicht gefunden." }, { status: 404 });
  await prisma.plan.delete({ where: { id: plan.id } });
  return NextResponse.json({ ok: true });
}