import { requireAuth } from "@/lib/jwt";
import { sql } from "@/lib/db";
import { SERVICES } from "@/constants/services";
import { boundingBox, haversine } from "@/lib/utils";
import { DRIVER_STALE_SECONDS } from "@/constants/dispatch";

// GET — how many drivers of each service are within reach of a point.
//
// The rider map filters by the selected service, so an empty map is ambiguous:
// it means "nobody at all" and "nobody driving a moto, though three cars are a
// street away" identically. That's the state riders were getting stuck in —
// staring at an empty map with no way to know that switching service would
// fill it. This answers the question the map can't.
//
// Query: ?lat=33.89&lng=35.50&radius=20000
//
// Returns every known service, zeros included, so the client can render the
// full picker without inventing missing keys.
const DEFAULT_RADIUS_M = 20000;
const MAX_RADIUS_M = 20000;

export async function GET(req: Request) {
  const auth = requireAuth(req);
  if ("error" in auth) return auth.error;

  try {
    const url = new URL(req.url);
    const lat = Number(url.searchParams.get("lat"));
    const lng = Number(url.searchParams.get("lng"));

    if (Number.isNaN(lat) || Number.isNaN(lng)) {
      return Response.json(
        { error: "lat and lng query params are required numbers." },
        { status: 400 },
      );
    }

    const requested = Number(url.searchParams.get("radius"));
    const radius =
      Number.isFinite(requested) && requested > 0
        ? Math.min(requested, MAX_RADIUS_M)
        : DEFAULT_RADIUS_M;

    const box = boundingBox(lat, lng, radius);

    // Same visibility rules as /driver/nearby — vetted, online, fresh, real
    // account, positioned. A driver riders can't be matched to must not be
    // counted here either, or the hint sends them to an empty service.
    const rows = await sql<{
      service: string;
      latitude: number;
      longitude: number;
    }>`
      SELECT service, latitude, longitude
      FROM drivers
      WHERE online = TRUE
        AND approval_status = 'approved'
        AND user_id IS NOT NULL
        AND last_seen > CURRENT_TIMESTAMP - make_interval(secs => ${DRIVER_STALE_SECONDS})
        AND latitude IS NOT NULL
        AND longitude IS NOT NULL
        AND latitude BETWEEN ${box.minLat} AND ${box.maxLat}
        AND longitude BETWEEN ${box.minLng} AND ${box.maxLng}
    `;

    const counts: Record<string, number> = {};
    for (const service of SERVICES) counts[service.id] = 0;

    for (const row of rows) {
      if (haversine(lat, lng, row.latitude, row.longitude) > radius) continue;
      if (counts[row.service] === undefined) continue;
      counts[row.service] += 1;
    }

    return Response.json({ data: { radius, counts } });
  } catch (error) {
    console.error("[DRIVER_AVAILABILITY]: ", error);
    return Response.json({ error: "Internal Server Error" }, { status: 500 });
  }
}