import type { Job } from "bullmq";
import { FlowProducer } from "bullmq";
import { createBullMQConnection } from "../redis.js";
import { getSql } from "../db.js";
import { JOB_OPTIONS, VALID_THRESHOLDS } from "@transportationer/shared";
import type { JobProgress } from "@transportationer/shared";

export type RefreshCityData = {
  type: "refresh-city";
  citySlug: string;
  geofabrikUrl: string;
  resolutionM?: number;
  /** Set after flow.add() — the ID of the enqueued compute-scores job. */
  computeScoresJobId?: string;
};

const OSM_DATA_DIR = process.env.OSM_DATA_DIR ?? "/data/osm";

/** True when the given bbox intersects Niedersachsen. */
function isInNiedersachsen(minLng: number, minLat: number, maxLng: number, maxLat: number): boolean {
  return minLng < 11.779 && maxLng > 6.526 && minLat < 54.033 && maxLat > 51.197;
}

export async function handleRefreshCity(
  job: Job<RefreshCityData>,
): Promise<void> {
  const { citySlug, geofabrikUrl, resolutionM = 200 } = job.data;
  const sql = getSql();

  const pbfPath = `${OSM_DATA_DIR}/${citySlug}-latest.osm.pbf`;

  // Read the user-specified bbox from the database (set at city creation time).
  // If present, it will be passed to extract-pois to clip the PBF before import.
  // Also read ALL city bboxes for the GTFS filter: each city gets its own bbox
  // (with a small buffer) so valhalla_ingest_transit only processes relevant stops.
  const [bboxRows, allCityBboxRows] = await Promise.all([
    Promise.resolve(sql<{
      minlng: number; minlat: number; maxlng: number; maxlat: number;
    }[]>`
      SELECT
        ST_XMin(bbox)::float AS minlng,
        ST_YMin(bbox)::float AS minlat,
        ST_XMax(bbox)::float AS maxlng,
        ST_YMax(bbox)::float AS maxlat
      FROM cities WHERE slug = ${citySlug} AND bbox IS NOT NULL
    `),
    Promise.resolve(sql<{
      minlng: number; minlat: number; maxlng: number; maxlat: number;
    }[]>`
      SELECT
        ST_XMin(bbox)::float AS minlng,
        ST_YMin(bbox)::float AS minlat,
        ST_XMax(bbox)::float AS maxlng,
        ST_YMax(bbox)::float AS maxlat
      FROM cities WHERE bbox IS NOT NULL
    `),
  ]);

  const bbox: [number, number, number, number] | undefined =
    bboxRows.length > 0
      ? [bboxRows[0].minlng, bboxRows[0].minlat, bboxRows[0].maxlng, bboxRows[0].maxlat]
      : undefined;

  // ~10 km buffer for GTFS stop coverage near city edges (0.09° ≈ 10 km)
  const GTFS_BUFFER = 0.09;
  const gtfsBboxes: [number, number, number, number][] = allCityBboxRows.map((r) => [
    r.minlng - GTFS_BUFFER,
    r.minlat - GTFS_BUFFER,
    r.maxlng + GTFS_BUFFER,
    r.maxlat + GTFS_BUFFER,
  ]);

  await job.updateProgress({
    stage: "Orchestrating pipeline",
    pct: 0,
    message: `Starting full ingest for ${citySlug}`,
  } satisfies JobProgress);

  // Mark city as processing
  await Promise.resolve(sql`
    UPDATE cities SET status = 'processing' WHERE slug = ${citySlug}
  `);

  // Shared download node factory — produces an idempotent download-pbf node.
  // Two independent nodes with the same geofabrikUrl are safe: the idempotency
  // check in download-pbf.ts skips the download if the file already exists.
  const downloadNode = () => ({
    name: "download-pbf",
    queueName: "pipeline",
    data: { type: "download-pbf" as const, citySlug, geofabrikUrl },
    opts: JOB_OPTIONS["download-pbf"],
  });

  // For NI cities: ingest-boris-ni is dispatched in Phase 1 of compute-scores.
  const niApplicable = !!(bbox && isInNiedersachsen(...bbox));

  // Parallel pipeline DAG (bottom-up — leaves execute first):
  //
  //   download-pbf ──────┬─→ extract-pois ────────────────────┐
  //                      │                                      ├─→ generate-grid → compute-scores
  //   download-pbf ──┐   └─→ build-valhalla ──────────────────┘
  //                  └──→ build-valhalla (waits for both ↑)
  //   download-gtfs-de ──┘
  //
  // compute-scores Phase 1 also dispatches ingest-boris-ni (NI cities only)
  // as a child alongside the routing jobs, so it runs during routing.
  const rootNode = {
    name: "compute-scores",
    queueName: "pipeline",
    data: {
      type: "compute-scores" as const,
      citySlug,
      modes: ["walking", "cycling", "driving", "transit"] as const,
      thresholds: [...VALID_THRESHOLDS],
      ingestBorisNi: niApplicable,
    },
    opts: JOB_OPTIONS["compute-scores"],
    children: [
      {
        name: "generate-grid",
        queueName: "pipeline",
        data: { type: "generate-grid" as const, citySlug, resolutionM },
        opts: JOB_OPTIONS["generate-grid"],
        children: [
          // extract-pois and build-valhalla run in parallel — each gets its
          // own download-pbf child; the idempotency guard ensures only one
          // actually downloads when they race.
          {
            name: "extract-pois",
            queueName: "pipeline",
            data: {
              type: "extract-pois" as const,
              citySlug,
              pbfPath,
              ...(bbox ? { bbox } : {}),
            },
            opts: JOB_OPTIONS["extract-pois"],
            children: [downloadNode()],
          },
          {
            name: "build-valhalla",
            queueName: "valhalla",
            data: {
              type: "build-valhalla" as const,
              citySlug,
              pbfPath,
              ...(bbox ? { bbox } : {}),
            },
            opts: JOB_OPTIONS["build-valhalla"],
            children: [
              downloadNode(),
              // Download GTFS feed before building tiles so valhalla_build_transit
              // runs during this build. The job is idempotent — it skips immediately
              // if the feed is already present, so subsequent refreshes are cheap.
              {
                name: "download-gtfs-de",
                queueName: "valhalla",
                data: {
                  type: "download-gtfs-de" as const,
                  url: "https://download.gtfs.de/germany/nv_free/latest.zip",
                  // Per-city bboxes (with ~10 km buffer) so valhalla_ingest_transit
                  // only processes stops/trips relevant to the known cities.
                  ...(gtfsBboxes.length > 0 ? { bboxes: gtfsBboxes } : {}),
                },
                opts: JOB_OPTIONS["download-gtfs-de"],
              },
            ],
          },
        ],
      },
    ],
  };

  const flow = new FlowProducer({ connection: createBullMQConnection() });
  let computeScoresJobId: string | undefined;
  try {
    const jobNode = await flow.add(rootNode);
    // jobNode.job is the root (compute-scores) job. Store its ID in this
    // refresh-city job's data so the SSE stream can match by exact job ID
    // rather than by citySlug (which would match stale completed jobs).
    computeScoresJobId = jobNode.job.id;
  } finally {
    await flow.close();
  }

  if (computeScoresJobId) {
    await job.updateData({ ...job.data, computeScoresJobId });
  }

  await job.updateProgress({
    stage: "Orchestrating pipeline",
    pct: 100,
    message: `All pipeline jobs enqueued${niApplicable ? " (includes BORIS NI, parallel with routing)" : ""}. Processing will begin shortly.`,
  } satisfies JobProgress);
}