import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { prisma } from "@/lib/db";
import { getCurrentUserId } from "@/lib/session";

const personSchema = z.object({
  role: z.enum(["PERSON_A", "PERSON_B"]),
  name: z.string().max(60).nullish(),
  age: z.number().int().min(0).max(120),
  retirementAge: z.number().int().min(30).max(100),
});

// Ein Plan traegt sein eigenes Grundprofil (Haushaltsform, Personen, Inflation).
export const planProfileSchema = z.object({
  householdType: z.enum(["SINGLE", "COUPLE"]),
  inflationRateDefault: z.number().min(-20).max(50),
  persons: z.array(personSchema).min(1).max(2),
});

const createPlanSchema = z
  .object({ name: z.string().min(1).max(120) })
  .and(planProfileSchema);

export function validatePersonsForType(data: z.infer<typeof planProfileSchema>): string | null {
  if (data.householdType === "SINGLE" && data.persons.length !== 1) {
    return "Einzelperson-Plan benoetigt genau eine Person.";
  }
  if (data.householdType === "COUPLE" && data.persons.length !== 2) {
    return "Paar-Plan benoetigt genau zwei Personen (Person A und Person B).";
  }
  return null;
}

export async function GET() {
  const userId = await getCurrentUserId();
  if (!userId) {
    return NextResponse.json({ error: "Nicht authentifiziert." }, { status: 401 });
  }
  const plans = await prisma.plan.findMany({
    where: { userId },
    orderBy: { createdAt: "asc" },
    select: {
      id: true,
      name: true,
      parentPlanId: true,
      branchFromPhaseId: true,
      createdAt: true,
      phases: {
        select: { id: true, name: true, sequenceNumber: true },
        orderBy: { sequenceNumber: "asc" },
      },
    },
  });
  return NextResponse.json({ plans });
}

export async function POST(request: NextRequest) {
  const userId = await getCurrentUserId();
  if (!userId) {
    return NextResponse.json({ error: "Nicht authentifiziert." }, { status: 401 });
  }

  const body = await request.json();
  const parsed = createPlanSchema.safeParse(body);
  if (!parsed.success) {
    return NextResponse.json({ error: parsed.error.flatten() }, { status: 400 });
  }
  const error = validatePersonsForType(parsed.data);
  if (error) return NextResponse.json({ error }, { status: 400 });

  const plan = await prisma.plan.create({
    data: {
      userId,
      name: parsed.data.name,
      householdType: parsed.data.householdType,
      inflationRateDefault: parsed.data.inflationRateDefault,
      persons: { create: parsed.data.persons },
    },
  });

  return NextResponse.json({ plan: { id: plan.id } }, { status: 201 });
}