'use strict';

const path = require('path');
const fs = require('fs').promises;
const { normalizeWinGameDir } = require('./win-game-dir');

/** Sources no longer shipped; drop from merged files so old launcher.json does not keep fetching them. */
const DEPRECATED_FILE_SOURCES = new Set(['patch-Z.MPQ', 'Wow-patched.exe']);

function mergeFilesList(defaults, user) {
  const dep = (e) => DEPRECATED_FILE_SOURCES.has(String(e && e.source ? e.source : '').trim());
  if (Array.isArray(user.files) && user.files.length) {
    const filtered = user.files.map((e) => ({ ...e })).filter((e) => !dep(e));
    if (filtered.length) return filtered;
  }
  const defList = Array.isArray(defaults.files) ? defaults.files : [];
  return defList.map((e) => ({ ...e })).filter((e) => !dep(e));
}

function userFilesContainDeprecated(user) {
  const files = user && user.files;
  if (!Array.isArray(files)) return false;
  return files.some((e) => DEPRECATED_FILE_SOURCES.has(String(e && e.source ? e.source : '').trim()));
}

function mergeConfig(defaults, user) {
  return {
    ...defaults,
    ...user,
    update_feed_url:
      user.update_feed_url != null && user.update_feed_url !== ''
        ? user.update_feed_url
        : defaults.update_feed_url,
    launcher_updates_from_github:
      user.launcher_updates_from_github != null
        ? user.launcher_updates_from_github
        : defaults.launcher_updates_from_github,
    github: { ...defaults.github, ...(user.github || {}) },
    gitea: { ...defaults.gitea, ...(user.gitea || {}) },
    patch_manifest: { ...defaults.patch_manifest, ...(user.patch_manifest || {}) },
    launch: { ...defaults.launch, ...(user.launch || {}) },
    auth: user.auth != null ? { ...defaults.auth, ...user.auth } : defaults.auth,
    realmlist: user.realmlist != null ? { ...defaults.realmlist, ...user.realmlist } : defaults.realmlist,
    files: mergeFilesList(defaults, user),
  };
}

/** Hardcoded Gitea host/repo (see lib/baked-gitea-channel.js). Non-empty baked values win. */
function applyBakedGitea(cfg) {
  let baked;
  try {
    baked = require('./baked-gitea-channel');
  } catch {
    return cfg;
  }
  if (!baked || typeof baked !== 'object') return cfg;
  cfg.gitea = { ...(cfg.gitea || {}) };
  for (const k of ['base_url', 'owner', 'repo', 'release_tag']) {
    const v = baked[k];
    if (v != null && String(v).trim() !== '') cfg.gitea[k] = String(v).trim();
  }
  return cfg;
}

function getConfigPath(app) {
  if (process.env.FRACTURED_LAUNCHER_CONFIG) return process.env.FRACTURED_LAUNCHER_CONFIG;
  if (app && app.isPackaged) {
    // AppImage (and macOS .app) run from a read-only mount — cannot write beside execPath.
    if (process.platform === 'linux' || process.platform === 'darwin') {
      return path.join(app.getPath('userData'), 'launcher.json');
    }
    return path.join(path.dirname(process.execPath), 'launcher.json');
  }
  return path.join(__dirname, '..', 'launcher.json');
}

async function loadConfig(app) {
  const p = getConfigPath(app);
  const defPath = path.join(__dirname, '..', 'default-launcher.json');
  const defaults = JSON.parse(await fs.readFile(defPath, 'utf8'));
  try {
    const user = JSON.parse(await fs.readFile(p, 'utf8'));
    const config = applyBakedGitea(mergeConfig(defaults, user));
    if (userFilesContainDeprecated(user)) {
      await fs.writeFile(p, JSON.stringify(config, null, 2), 'utf8');
    }
    return { configPath: p, config };
  } catch (e) {
    if (e.code === 'ENOENT') {
      const initial = applyBakedGitea(mergeConfig(defaults, {}));
      await fs.writeFile(p, JSON.stringify(initial, null, 2), 'utf8');
      return { configPath: p, config: JSON.parse(JSON.stringify(initial)) };
    }
    throw e;
  }
}

async function saveGameDir(configPath, gameDir) {
  const defPath = path.join(__dirname, '..', 'default-launcher.json');
  const defaults = JSON.parse(await fs.readFile(defPath, 'utf8'));
  const user = JSON.parse(await fs.readFile(configPath, 'utf8'));
  user.game_dir = gameDir;
  const merged = applyBakedGitea(mergeConfig(defaults, user));
  await fs.writeFile(configPath, JSON.stringify(merged, null, 2), 'utf8');
  return merged;
}

function resolveGameDir(cfg, configPath) {
  const gd = cfg.game_dir;
  if (!gd) return '';
  const abs = path.isAbsolute(gd) ? path.normalize(gd) : path.normalize(path.join(path.dirname(configPath), gd));
  if (process.platform === 'win32') return normalizeWinGameDir(abs);
  return abs;
}

module.exports = { getConfigPath, loadConfig, saveGameDir, resolveGameDir, mergeConfig, applyBakedGitea };