import worker from "node:worker_threads";
import {Transfer, expose} from "@chainsafe/threads/worker";
import {chainConfigFromJson, createBeaconConfig} from "@lodestar/config";
import {LevelDbController} from "@lodestar/db/controller/level";
import {getNodeLogger} from "@lodestar/logger/node";
import {BeaconDb} from "../../../db/index.js";
import {RegistryMetricCreator, collectNodeJSMetrics} from "../../../metrics/index.js";
import {JobFnQueue} from "../../../util/queue/fnQueue.js";
import {QueueMetrics} from "../../../util/queue/options.js";
import {getHistoricalState} from "./getHistoricalState.js";
import {
  HistoricalStateRegenMetrics,
  createHistoricalStateQueueMetrics,
  createHistoricalStateRegenMetrics,
} from "./metrics.js";
import {HistoricalStateWorkerApi, HistoricalStateWorkerData} from "./types.js";

// most of this setup copied from networkCoreWorker.ts

const workerData = worker.workerData as HistoricalStateWorkerData;

const logger = getNodeLogger(workerData.loggerOpts);

logger.info("Historical state worker started");

const config = createBeaconConfig(chainConfigFromJson(workerData.chainConfigJson), workerData.genesisValidatorsRoot);

const db = new BeaconDb(config, await LevelDbController.create({name: workerData.dbLocation}, {logger}));

const abortController = new AbortController();

// Set up metrics, nodejs, state transition, queue
const metricsRegister = workerData.metricsEnabled ? new RegistryMetricCreator() : null;
let historicalStateRegenMetrics: HistoricalStateRegenMetrics | undefined;
let queueMetrics: QueueMetrics | undefined;

if (metricsRegister) {
  const closeMetrics = collectNodeJSMetrics(metricsRegister, "lodestar_historical_state_worker_");
  abortController.signal.addEventListener("abort", closeMetrics, {once: true});

  historicalStateRegenMetrics = createHistoricalStateRegenMetrics(metricsRegister);
  queueMetrics = createHistoricalStateQueueMetrics(metricsRegister);
}

const queue = new JobFnQueue(
  {
    maxConcurrency: workerData.maxConcurrency,
    maxLength: workerData.maxLength,
    signal: abortController.signal,
  },
  queueMetrics
);

const api: HistoricalStateWorkerApi = {
  async close() {
    abortController.abort();
  },
  async scrapeMetrics() {
    return metricsRegister?.metrics() ?? "";
  },
  async getHistoricalState(slot) {
    historicalStateRegenMetrics?.regenRequestCount.inc();

    const stateBytes = await queue.push<Uint8Array>(() =>
      getHistoricalState(slot, config, db, workerData.nativeStateView, historicalStateRegenMetrics)
    );
    const result = Transfer(stateBytes, [stateBytes.buffer]) as unknown as Uint8Array;

    historicalStateRegenMetrics?.regenSuccessCount.inc();
    return result;
  },
};

expose(api);