import fs from 'node:fs';
import path from 'node:path';
import { pipeline } from 'node:stream/promises';
import { Readable } from 'node:stream';
import { AO_BIN_DUMPS_BASE, GAMEDATA_DIR } from '../config.js';

/** Files pulled from ao-data/ao-bin-dumps. Add zone/world files in the travel phase. */
export const GAMEDATA_FILES = [
  { remote: 'items.json', local: 'items.json' },
  { remote: 'formatted/items.json', local: 'items_localized.json' },
] as const;

export function gamedataFilePath(local: string): string {
  return path.join(GAMEDATA_DIR, local);
}

async function downloadFile(remote: string, dest: string): Promise<void> {
  const url = `${AO_BIN_DUMPS_BASE}/${remote}`;
  const res = await fetch(url);
  if (!res.ok || !res.body) {
    throw new Error(`Download failed for ${url}: HTTP ${res.status}`);
  }
  fs.mkdirSync(path.dirname(dest), { recursive: true });
  const tmp = `${dest}.download`;
  await pipeline(Readable.fromWeb(res.body as import('node:stream/web').ReadableStream), fs.createWriteStream(tmp));
  fs.renameSync(tmp, dest);
}

export interface DownloadResult {
  file: string;
  status: 'downloaded' | 'cached';
  bytes: number;
}

/**
 * Ensure all game data files exist locally. With force=true, re-download everything
 * (used by the "refresh game data" action after a game patch).
 */
export async function downloadGameData(force = false): Promise<DownloadResult[]> {
  const results: DownloadResult[] = [];
  for (const f of GAMEDATA_FILES) {
    const dest = gamedataFilePath(f.local);
    if (!force && fs.existsSync(dest)) {
      results.push({ file: f.local, status: 'cached', bytes: fs.statSync(dest).size });
      continue;
    }
    await downloadFile(f.remote, dest);
    results.push({ file: f.local, status: 'downloaded', bytes: fs.statSync(dest).size });
  }
  return results;
}