import { stat, readFile, readdir, copyFile } from "node:fs/promises";
import { join, extname, resolve } from "node:path";
import { parseDwi } from "./parseDwi";
import { parseSm } from "./parseSm";

type RawSimfile = Omit<Simfile, "mix" | "title"> & {
  title: string;
  titletranslit: string | null;
  banner: string | null;
  bannerEncoded: string | null;
  displayBpm: string | undefined;
};
type Parser = (simfileSource: string, titleDir: string) => Promise<RawSimfile>;

const parsers: Record<string, Parser> = {
  ".sm": parseSm,
  ".dwi": parseDwi,
};

async function getSongFile(songDir: string): Promise<string> {
  const files = await readdir(songDir);

  // TODO: support more than .sm
  const extensions = Object.keys(parsers);

  const songFile = files.find((f) => extensions.some((ext) => f.endsWith(ext)));

  if (!songFile) {
    throw new Error(`No song file found in ${songDir}`);
  }

  return songFile;
}

function toSafeName(name: string): string {
  let name2 = name;
  name2 = name2.replace(".png", "");
  name2 = name2.replace(/\s/g, "-").replace(/[^\w]/g, "_");

  return `${name}.png`;
}

function getBpms(sm: RawSimfile): number[] {
  const chart = Object.values(sm.charts)[0];

  return chart.bpm.map((b) => b.bpm);
}

async function parseSimfile(
  rootDir: string,
  mixDir: string,
  titleDir: string,
): Promise<Omit<Simfile, "mix">> {
  const stepchartSongDirPath = join(rootDir, mixDir, titleDir);
  const songFile = await getSongFile(stepchartSongDirPath);
  const stepchartPath = join(stepchartSongDirPath, songFile);
  const extension = extname(stepchartPath);

  const parser = parsers[extension];

  if (!parser) {
    throw new Error(`No parser registered for extension: ${extension}`);
  }

  const fileContents = await readFile(stepchartPath);
  const rawStepchart = await parser(
    fileContents.toString(),
    stepchartSongDirPath,
  );

  const bannerPath = join(stepchartSongDirPath, rawStepchart.banner);
  try {
    const bannerData = await readFile(bannerPath);
    rawStepchart.bannerEncoded = bannerData.toString("base64");
  } catch (e) {}

  //   if (bannerMeta !== undefined) {
  //     const publicName = toSafeName(`${mixDir}-${rawStepchart.banner}`);
  //     const srcPath = resolve(stepchartSongDirPath, rawStepchart.banner);
  //     const destPath = resolve("public/bannerImages", publicName);
  //     await copyFile(srcPath, destPath);
  //     await copyFile(
  //       join(stepchartSongDirPath, rawStepchart.banner),
  //       join("components/bannerImages", publicName),
  //     );
  //     rawStepchart.banner = publicName;
  //   } else {
  //     rawStepchart.banner = null;
  //   }

  const bpms = getBpms(rawStepchart);
  const minBpm = Math.round(Math.min(...bpms));
  const maxBpm = Math.round(Math.max(...bpms));

  const displayBpm =
    minBpm === maxBpm ? minBpm.toString() : `${minBpm}-${maxBpm}`;

  return {
    ...rawStepchart,
    title: {
      titleName: rawStepchart.title,
      translitTitleName: rawStepchart.titletranslit ?? null,
      titleDir,
      banner: rawStepchart.banner,
    },
    minBpm,
    maxBpm,
    displayBpm,
    stopCount: Object.values(rawStepchart.charts)[0].stops.length,
  };
}

export { parseSimfile };
export type { RawSimfile };