// Worker thread for the alignment server's heavy, synchronous jobs (MIDI preview render, automatic alignment), so the
// server's event loop keeps answering other requests (page, fit, audio) while they run. Started by ./jobs-pool.ts.
/// <reference lib="webworker" />
import { renderMidi } from "./render.ts";
import { autoAlign } from "./auto.ts";
import { makeWarp, type Anchor } from "./warp.ts";
import type { Audio, Role } from "../core/types.ts";
import type { RefTrack, Smf } from "./smf.ts";

export type Job =
  /** Mono, not normalised, audio time [startSec, startSec + durationSec) -> Float32Array. */
  | { type: "render"; sf2Path: string; tracks: RefTrack[]; anchors: Anchor[]; sampleRate: number; startSec: number; durationSec: number }
  | { type: "auto"; sf2Path: string; audio: Audio; smf: Smf; roles: Record<string, Role | null>; manual: Anchor[] };

const sf2s = new Map<string, Promise<Uint8Array>>();
const sf2 = (p: string) => { let x = sf2s.get(p); if (!x) sf2s.set(p, (x = Bun.file(p).arrayBuffer().then((b) => new Uint8Array(b)))); return x; };

async function run(job: Job): Promise<unknown> {
  if (job.type === "render") {
    const a = renderMidi(job.tracks, makeWarp(job.anchors), await sf2(job.sf2Path), {
      sampleRate: job.sampleRate, mono: true, startSec: job.startSec, durationSec: job.durationSec, normalize: false,
    });
    return a.channels[0]!; // transferred back
  }
  return autoAlign(job.audio, job.smf, job.roles, job.manual, await sf2(job.sf2Path));
}

self.onmessage = async (e: MessageEvent<{ id: number; job: Job }>) => {
  const { id, job } = e.data;
  try {
    const result = await run(job);
    self.postMessage({ id, result }, ArrayBuffer.isView(result) ? [result.buffer as ArrayBuffer] : []);
  } catch (err) {
    self.postMessage({ id, error: (err as Error).message ?? String(err) });
  }
};