'use strict';

const path = require('path');
const fs = require('fs').promises;
const { downloadGitHubRepoFile, downloadReleaseAsset } = require('./github');

function pad2(n) {
  return String(n).padStart(2, '0');
}
function backupSuffix() {
  const d = new Date();
  return `${d.getFullYear()}${pad2(d.getMonth() + 1)}${pad2(d.getDate())}-${pad2(d.getHours())}${pad2(d.getMinutes())}${pad2(d.getSeconds())}`;
}

function wowExePath(cfg) {
  const exe = (cfg.launch && cfg.launch.exe) || 'Wow.exe';
  const parts = exe.replace(/\\/g, '/').split('/').filter(Boolean);
  return path.join(cfg.game_dir, ...parts);
}

function wowInstallValid(cfg) {
  if (!cfg.game_dir) return false;
  return require('fs').existsSync(wowExePath(cfg));
}

async function installFile(cfg, entry) {
  const parts = String(entry.dest).replace(/\\/g, '/').split('/').filter(Boolean);
  const destAbs = path.join(cfg.game_dir, ...parts);
  if (entry.backup) {
    try {
      const st = await fs.stat(destAbs);
      if (st.isFile()) {
        const bak = `${destAbs}.bak-${backupSuffix()}`;
        await fs.rename(destAbs, bak);
      }
    } catch (e) {
      if (e.code !== 'ENOENT') throw e;
    }
  } else {
    try {
      await fs.unlink(destAbs);
    } catch (e) {
      if (e.code !== 'ENOENT') throw e;
    }
  }
  const tmp = destAbs + '.new';
  if (entry.from_release) {
    await downloadReleaseAsset(cfg, entry.source, tmp);
  } else {
    await downloadGitHubRepoFile(cfg, entry.source, tmp);
  }
  await fs.rename(tmp, destAbs);
}

async function applyRealmlist(cfg) {
  if (!cfg.realmlist || !cfg.realmlist.enabled) return;
  let line = String(cfg.realmlist.line || '').trim();
  if (!line) throw new Error('realmlist.line empty');
  if (!line.toLowerCase().startsWith('set realmlist ')) {
    line = `set realmlist ${line}`;
  }
  const content = line + '\n';
  let paths = cfg.realmlist.paths;
  if (!paths || !paths.length) paths = ['Data/enUS/realmlist.wtf'];
  for (const rel of paths) {
    const r = String(rel).trim().replace(/\\/g, '/');
    if (!r) continue;
    const segs = r.split('/').filter(Boolean);
    const abs = path.join(cfg.game_dir, ...segs);
    await fs.mkdir(path.dirname(abs), { recursive: true });
    await fs.writeFile(abs, content, 'utf8');
  }
}

async function applyPatches(cfg, onStatus) {
  for (const f of cfg.files || []) {
    if (onStatus) onStatus(`Updating ${f.dest} …`);
    try {
      await installFile(cfg, f);
    } catch (e) {
      throw new Error(`sync ${f.dest}: ${e.message || e}`);
    }
  }
  if (cfg.realmlist && cfg.realmlist.enabled) {
    if (onStatus) onStatus('Applying realmlist …');
    await applyRealmlist(cfg);
  }
  if (onStatus) onStatus('All patches applied.');
}

async function doAuth(cfg, username, password) {
  if (!cfg.auth || !cfg.auth.enabled) return;
  const u = String(username || '').trim();
  const p = String(password || '');
  if (!u || !p) throw new Error('username and password required');
  const body = {
    [cfg.auth.username_field || 'username']: u,
    [cfg.auth.password_field || 'password']: p,
  };
  const res = await fetch(cfg.auth.url, {
    method: cfg.auth.method || 'POST',
    headers: { 'Content-Type': 'application/json', Accept: 'application/json' },
    body: JSON.stringify(body),
  });
  const t = await res.text();
  if (res.status < 200 || res.status >= 300) {
    throw new Error(`login failed ${res.status}: ${t.slice(0, 400)}`);
  }
}

module.exports = {
  applyPatches,
  applyRealmlist,
  wowExePath,
  wowInstallValid,
  doAuth,
};