'use strict';

/*
 * cfimport.js – Instanzen aus dem CurseForge-Launcher übernehmen
 * ---------------------------------------------------------------
 * Unterstützt sowohl den Launcher-Wurzelordner als auch direkt den
 * Instances-Ordner. Gelesen werden nach Möglichkeit minecraftinstance.json
 * und die vorhandenen Spieldaten im Profilordner.
 */

const fs = require('fs');
const os = require('os');
const path = require('path');

const META_FILES = ['minecraftinstance.json', 'instance.json'];

function readJson(file, fallback) {
  try {
    return JSON.parse(fs.readFileSync(file, 'utf8').replace(/^\uFEFF/, ''));
  } catch {
    return fallback;
  }
}

function existingMetaFile(dir) {
  return META_FILES.map((name) => path.join(dir, name)).find((file) => fs.existsSync(file)) || null;
}

function metaVersion(meta) {
  return String(
    (meta && (
      meta.gameVersion || meta.minecraftVersion || meta.mcVersion ||
      (meta.installedModpack && meta.installedModpack.gameVersion)
    )) || ''
  ).trim();
}

function resolveInstancesDir(inputPath) {
  if (!inputPath || !fs.existsSync(inputPath)) return null;
  const directNames = new Set(['instances', 'minecraftinstances']);
  if (directNames.has(path.basename(inputPath).toLowerCase())) return inputPath;

  const candidates = [
    path.join(inputPath, 'Instances'),
    path.join(inputPath, 'instances'),
    path.join(inputPath, 'minecraftInstances'),
    path.join(inputPath, 'Minecraft', 'Instances'),
    path.join(inputPath, 'minecraft', 'Instances'),
  ];

  const looksLikeWindowsInstall =
    /curseforge windows/i.test(inputPath) ||
    (fs.existsSync(path.join(inputPath, 'CurseForge.exe')) && fs.existsSync(path.join(inputPath, 'resources')));
  if (looksLikeWindowsInstall) {
    candidates.push(
      path.join(os.homedir(), 'curseforge', 'minecraft', 'Instances'),
      path.join(os.homedir(), 'CurseForge', 'minecraft', 'Instances'),
    );
  }
  return candidates.find((candidate) => fs.existsSync(candidate)) || null;
}

function normalizeLoaderVersion(loader, rawValue, mcVersion) {
  let value = String(rawValue || '').trim();
  if (!value) return '';

  if (loader === 'forge') {
    value = value.replace(/^forge-/i, '');
    if (mcVersion && value.startsWith(mcVersion + '-')) value = value.slice(mcVersion.length + 1);
    return value;
  }
  if (loader === 'neoforge') {
    return value.replace(/^neoforge-/i, '');
  }
  if (loader === 'fabric') {
    value = value.replace(/^fabric(?:-loader)?-/i, '');
    if (mcVersion && value.endsWith('-' + mcVersion)) value = value.slice(0, -1 * (mcVersion.length + 1));
    return value;
  }
  if (loader === 'quilt') {
    value = value.replace(/^quilt(?:-loader)?-/i, '');
    if (mcVersion && value.endsWith('-' + mcVersion)) value = value.slice(0, -1 * (mcVersion.length + 1));
    return value;
  }
  return value;
}

function detectLoader(meta, mcVersion) {
  const raw = meta && (
    meta.baseModLoader || meta.modLoader || meta.modloader || meta.loader || meta.modLoaderId
  );
  const value = typeof raw === 'object'
    ? (raw.name || raw.id || raw.value || raw.version || '')
    : (raw || '');
  const lower = String(value).toLowerCase();
  const objectVersion = raw && typeof raw === 'object'
    ? (raw.version || raw.name || raw.id || '')
    : '';

  if (!lower) return { loader: 'vanilla', loaderVersion: '' };
  if (lower.includes('neoforge')) return { loader: 'neoforge', loaderVersion: normalizeLoaderVersion('neoforge', objectVersion || value, mcVersion) };
  if (lower.includes('fabric')) return { loader: 'fabric', loaderVersion: normalizeLoaderVersion('fabric', objectVersion || value, mcVersion) };
  if (lower.includes('quilt')) return { loader: 'quilt', loaderVersion: normalizeLoaderVersion('quilt', objectVersion || value, mcVersion) };
  if (lower.includes('forge')) return { loader: 'forge', loaderVersion: normalizeLoaderVersion('forge', objectVersion || value, mcVersion) };
  return { loader: 'vanilla', loaderVersion: '' };
}

function detectVersion(meta, loaderVersion) {
  return metaVersion(meta) || (loaderVersion && loaderVersion.includes('-') ? loaderVersion.split('-')[0] : '');
}

function findGameDir(dir) {
  const nested = ['minecraft', '.minecraft']
    .map((name) => path.join(dir, name))
    .find((candidate) => fs.existsSync(candidate));
  if (nested) return nested;

  const markers = ['mods', 'config', 'resourcepacks', 'shaderpacks', 'saves', 'options.txt'];
  return markers.some((name) => fs.existsSync(path.join(dir, name))) ? dir : null;
}

function scan(inputPath) {
  const instancesDir = resolveInstancesDir(inputPath);
  if (!instancesDir) return { ok: false, reason: 'not-found' };

  const list = [];
  for (const entry of fs.readdirSync(instancesDir, { withFileTypes: true })) {
    if (!entry.isDirectory()) continue;
    const dir = path.join(instancesDir, entry.name);
    const metaFile = existingMetaFile(dir);
    const meta = metaFile ? readJson(metaFile, {}) : {};
    const gameDir = findGameDir(dir);
    if (!metaFile && !gameDir) continue;

    const versionHint = metaVersion(meta);
    const loaderInfo = detectLoader(meta, versionHint);
    list.push({
      folder: entry.name,
      dir,
      name: meta.name || meta.displayName || entry.name,
      group: '',
      notes: meta.notes || meta.summary || '',
      version: versionHint || detectVersion(meta, loaderInfo.loaderVersion),
      loader: loaderInfo.loader,
      loaderVersion: loaderInfo.loaderVersion,
      javaPath: String(meta.javaPath || meta.javaExecutable || '').trim(),
      minMemMb: Number(meta.minimumMemory || meta.minMemory || meta.minMemAlloc) || null,
      maxMemMb: Number(meta.maximumMemory || meta.maxMemory || meta.maxMemAlloc || meta.allocatedMemory) || null,
      gameDir: gameDir || dir,
      hasGameData: !!gameDir,
    });
  }
  list.sort((a, b) => a.name.localeCompare(b.name));
  return { ok: true, instancesDir, count: list.length, instances: list };
}

function copyInto(sourceDir, targetDir) {
  fs.mkdirSync(targetDir, { recursive: true });
  for (const name of fs.readdirSync(sourceDir)) {
    if (META_FILES.includes(name)) continue;
    fs.cpSync(path.join(sourceDir, name), path.join(targetDir, name), { recursive: true });
  }
}

function importOne(store, entry, copyData = true) {
  const created = store.createOrReplaceImportedInstance({
    name: entry.name,
    group: entry.group,
    notes: entry.notes,
    minecraft: {
      version: entry.version,
      loader: entry.loader,
      loaderVersion: entry.loaderVersion,
    },
  });

  const patch = {};
  if (entry.javaPath || entry.minMemMb || entry.maxMemMb) {
    patch.java = {
      path: entry.javaPath || '',
      minMemMb: entry.minMemMb || null,
      maxMemMb: entry.maxMemMb || null,
      extraArgs: '',
    };
  }
  if (Object.keys(patch).length) store.updateInstance(created.id, patch);

  let copied = false;
  if (copyData && entry.gameDir && fs.existsSync(entry.gameDir)) {
    copyInto(entry.gameDir, store.gameDir(created.id));
    copied = true;
  }
  return { id: created.id, name: created.name, copied };
}

module.exports = { scan, importOne, resolveInstancesDir };