// TODO: Make this concurrent instead of serial

import { join, extname } from "node:path";
import { pipeline } from "node:stream/promises";
import { Readable } from "node:stream";
import * as ndjson from "ndjson";
import { readdir, writeFile, stat } from "node:fs/promises";
import { createWriteStream } from "node:fs";
import { parseSm } from "../lib/stepcharts/parseSm";
import { parseSimfile } from "../lib/stepcharts/parseSimfile";

const rootDir = process.env.STEPCHARTS_DIR ?? "/tmp/stepcharts";
const stepchartsDir = join(rootDir, "prodStepcharts");
const outFile = process.env.OUT_FILE ?? "data/stepData.ndjson";

async function* mixToSongs(
  mixDirs: string[],
): AsyncGenerator<[string, string], void, unknown> {
  for (const mix of mixDirs) {
    const mixDir = join(stepchartsDir, mix);
    const files = await readdir(mixDir);
    for (const song of files) {
      yield [mix, song];
    }
  }
}

async function* processSong(gen: AsyncGenerator<[string, string]>) {
  for await (const [mix, song] of gen) {
    const totalPath = join(stepchartsDir, mix, song);
    const meta = await stat(totalPath);
    if (!meta.isDirectory()) continue;

    try {
      const parsed = await parseSimfile(stepchartsDir, mix, song);
      for (const [name, chart] of Object.entries(parsed.charts)) {
        yield {
          difficulty: name,
          artist: parsed.artist,
          title: parsed.title.titleName,
          titleRomanized: parsed.title.translitTitleName,
          bannerFilename: parsed.bannerFilename,
        };
      }
      // yield parsed;
    } catch (e) {
      console.error("failed on", mix, song, ":", e.message);
    }
  }
}

const mixDirs = await readdir(stepchartsDir);
const songIter = mixToSongs(mixDirs);
const outIter = processSong(songIter);

const writer = createWriteStream(outFile);
for await (const songObj of outIter) {
  writer.write(JSON.stringify(songObj));
  writer.write("\n");
}

console.log("Done.");