import { NextResponse } from "next/server";
import { z } from "zod";
import { LocationKind } from "@prisma/client";
import { db } from "@/lib/db";
import { requireAuth, isAdmin } from "@/lib/auth";
import { recomputeAllPaths, wouldCreateCycle } from "@/lib/locations/db";

const updateSchema = z.object({
  name: z.string().min(1).optional(),
  kind: z.nativeEnum(LocationKind).optional(),
  parentId: z.string().nullable().optional(), // null → move to top level
  notes: z.string().nullable().optional(),
});

export async function PATCH(req: Request, { params }: { params: { id: string } }) {
  try {
    const session = await requireAuth();
    const location = await db.location.findUnique({ where: { id: params.id } });
    if (!location || !location.active)
      return NextResponse.json({ error: "Not found" }, { status: 404 });

    const data = updateSchema.parse(await req.json());

    // Guard against cycles when re-parenting.
    if (data.parentId) {
      if (await wouldCreateCycle(params.id, data.parentId))
        return NextResponse.json(
          { error: "A location can't be moved under itself or its own descendant" },
          { status: 400 },
        );
      const parent = await db.location.findUnique({ where: { id: data.parentId } });
      if (!parent) return NextResponse.json({ error: "Parent location not found" }, { status: 400 });
    }

    const updated = await db.$transaction(async (tx) => {
      const u = await tx.location.update({
        where: { id: params.id },
        data: {
          ...(data.name !== undefined ? { name: data.name.trim() } : {}),
          ...(data.kind !== undefined ? { kind: data.kind } : {}),
          ...(data.parentId !== undefined ? { parentId: data.parentId } : {}),
          ...(data.notes !== undefined ? { notes: data.notes?.trim() || null } : {}),
        },
      });
      await recomputeAllPaths(tx as unknown as typeof db);
      await tx.auditEvent.create({
        data: {
          action: "location.update",
          entityId: params.id,
          actorId: session.user.id,
          payload: { name: u.name },
        },
      });
      return u;
    });

    return NextResponse.json(updated);
  } catch (err) {
    if (err instanceof z.ZodError)
      return NextResponse.json({ error: err.issues[0]?.message ?? "Invalid data" }, { status: 400 });
    if (err instanceof Error && err.message === "Unauthorized")
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    console.error(err);
    return NextResponse.json({ error: "Server error" }, { status: 500 });
  }
}

export async function DELETE(_req: Request, { params }: { params: { id: string } }) {
  try {
    const session = await requireAuth();
    if (!isAdmin(session.user.role))
      return NextResponse.json({ error: "Forbidden" }, { status: 403 });

    const location = await db.location.findUnique({ where: { id: params.id } });
    if (!location || !location.active)
      return NextResponse.json({ error: "Not found" }, { status: 404 });

    // Don't orphan live records — require the location be emptied first.
    const [plantCount, childCount] = await Promise.all([
      db.plant.count({ where: { locationId: params.id, active: true } }),
      db.location.count({ where: { parentId: params.id, active: true } }),
    ]);
    if (plantCount > 0 || childCount > 0)
      return NextResponse.json(
        { error: "Move the plants and sub-locations out of this location first" },
        { status: 400 },
      );

    await db.location.update({ where: { id: params.id }, data: { active: false } });
    await db.auditEvent.create({
      data: {
        action: "location.delete",
        entityId: params.id,
        actorId: session.user.id,
        payload: { name: location.name },
      },
    });

    return NextResponse.json({ ok: true });
  } catch (err) {
    if (err instanceof Error && err.message === "Unauthorized")
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    console.error(err);
    return NextResponse.json({ error: "Server error" }, { status: 500 });
  }
}