import { NextRequest, NextResponse } from "next/server";
import { sql } from "@/lib/db";

export const runtime = "nodejs";

export async function GET(
  req: NextRequest,
  { params }: { params: Promise<{ tile: string[] }> },
) {
  const { tile } = await params;
  if (tile.length !== 3) {
    return new NextResponse("Invalid tile path", { status: 400 });
  }
  const z = parseInt(tile[0], 10);
  const x = parseInt(tile[1], 10);
  const y = parseInt(tile[2], 10);

  if ([z, x, y].some(isNaN)) {
    return new NextResponse("Invalid tile coordinates", { status: 400 });
  }

  const city = req.nextUrl.searchParams.get("city") ?? "";
  if (!city) return new NextResponse("Missing city", { status: 400 });

  try {
    const rows = await Promise.resolve(sql<{ mvt: Uint8Array }[]>`
      WITH
        envelope  AS (SELECT ST_TileEnvelope(${z}, ${x}, ${y}) AS env),
        city_info AS (SELECT COALESCE(resolution_m, 200) AS resolution_m FROM cities WHERE slug = ${city})
      SELECT ST_AsMVT(t, 'hidden-gems', 4096, 'geom') AS mvt
      FROM (
        SELECT
          ST_AsMVTGeom(
            ST_Expand(ST_Transform(gp.geom, 3857), ci.resolution_m::float / 2),
            e.env,
            4096, 0, true
          ) AS geom,
          ROUND(gp.hidden_gem_score * 100)::int AS score
        FROM grid_points gp
        CROSS JOIN envelope e
        CROSS JOIN city_info ci
        WHERE gp.city_slug = ${city}
          AND gp.hidden_gem_score IS NOT NULL
          AND ST_Intersects(
            ST_Transform(gp.geom, 3857),
            ST_Expand(e.env, ci.resolution_m::float / 2)
          )
      ) t
      WHERE t.geom IS NOT NULL
    `);

    const buf = rows[0]?.mvt;
    const data = buf ? new Uint8Array(buf) : new Uint8Array(0);

    return new NextResponse(data, {
      headers: {
        "Content-Type": "application/x-protobuf",
        "Cache-Control": "public, max-age=3600",
        "Access-Control-Allow-Origin": "*",
      },
    });
  } catch (err) {
    console.error("[tiles/hidden-gems] Error:", err);
    return new NextResponse("Internal Server Error", { status: 500 });
  }
}