import { NextResponse } from "next/server";

import { loadIncidentsPage } from "@/lib/loaders";
import { jsonError } from "@/lib/poll-response";

export const dynamic = "force-dynamic";

const SORTS = new Set(["status", "opened_at", "resolved_at"]);
const DIRS = new Set(["asc", "desc"]);

// PH-001: poll a single page, not the entire incident history. Sort and
// direction are forwarded so the server orders consistently across pages.
export async function GET(request: Request) {
  const url = new URL(request.url);
  const stateParam = url.searchParams.get("state");
  const state = stateParam === "open" || stateParam === "resolved" ? stateParam : undefined;
  const cursor = url.searchParams.get("cursor") ?? undefined;
  const back = url.searchParams.get("back") === "1";
  const limitRaw = url.searchParams.get("limit");
  const parsed = limitRaw ? Number(limitRaw) : undefined;
  const limit = parsed && Number.isFinite(parsed) ? Math.min(Math.max(parsed, 1), 500) : 100;
  const sortRaw = url.searchParams.get("sort") ?? undefined;
  const sort =
    sortRaw && SORTS.has(sortRaw)
      ? (sortRaw as "status" | "opened_at" | "resolved_at")
      : undefined;
  const dirRaw = url.searchParams.get("direction") ?? undefined;
  const direction = dirRaw && DIRS.has(dirRaw) ? (dirRaw as "asc" | "desc") : undefined;

  try {
    const page = await loadIncidentsPage({ state, cursor, back, limit, sort, direction });
    return NextResponse.json(page);
  } catch (e) {
    return jsonError(e);
  }
}