const fs = require('fs');
const os = require('os');
const path = require('path');
const { execFile } = require('child_process');
const logger = require('./logger').child('MAKEMKV_KEY');

const MAKEMKV_BETA_KEY_API_URL = 'https://cable.ayra.ch/makemkv/api.php?json';
const MAKEMKV_BETA_KEY_API_USER_AGENT = process.env.MAKEMKV_BETA_KEY_API_USER_AGENT
  || 'Ripster/1.0 (MakeMKV beta key sync)';
const MAKEMKV_BETA_KEY_API_FROM = process.env.MAKEMKV_BETA_KEY_API_FROM
  || 'admin@example.invalid';
const MAKEMKV_BETA_KEY_API_TIMEOUT_MS = Math.max(
  1000,
  Number(process.env.MAKEMKV_BETA_KEY_API_TIMEOUT_MS || 15000)
);

function normalizeRegistrationKey(rawValue) {
  return String(rawValue || '').trim();
}

function getMakeMKVConfigDir(homeDir = os.homedir()) {
  return path.join(String(homeDir || '').trim() || os.homedir(), '.MakeMKV');
}

function getMakeMKVSettingsFilePath(homeDir = os.homedir()) {
  return path.join(getMakeMKVConfigDir(homeDir), 'settings.conf');
}

function escapeKeyForSettingsFile(value) {
  return String(value || '')
    .replace(/\\/g, '\\\\')
    .replace(/"/g, '\\"');
}

function buildUpdatedSettingsContent(currentContent, registrationKey) {
  const existingLines = String(currentContent || '')
    .split(/\r?\n/)
    .filter((line) => !/^\s*app_Key\s*=/.test(line));
  const normalizedKey = normalizeRegistrationKey(registrationKey);

  while (existingLines.length > 0 && existingLines[existingLines.length - 1] === '') {
    existingLines.pop();
  }

  if (normalizedKey) {
    existingLines.push(`app_Key = "${escapeKeyForSettingsFile(normalizedKey)}"`);
  }

  return existingLines.length > 0 ? `${existingLines.join('\n')}\n` : '';
}

async function syncRegistrationKeyToConfig(rawValue, options = {}) {
  const normalizedKey = normalizeRegistrationKey(rawValue);
  const homeDir = String(options?.homeDir || '').trim() || os.homedir();
  const configDir = getMakeMKVConfigDir(homeDir);
  const settingsFilePath = getMakeMKVSettingsFilePath(homeDir);
  const fileExists = fs.existsSync(settingsFilePath);
  const currentContent = fileExists
    ? await fs.promises.readFile(settingsFilePath, 'utf8')
    : '';
  const nextContent = buildUpdatedSettingsContent(currentContent, normalizedKey);

  if (!normalizedKey && !fileExists) {
    return {
      changed: false,
      path: settingsFilePath,
      hasKey: false
    };
  }

  await fs.promises.mkdir(configDir, { recursive: true });

  if (nextContent) {
    await fs.promises.writeFile(settingsFilePath, nextContent, 'utf8');
    await fs.promises.chmod(settingsFilePath, 0o600).catch(() => {});
    logger.info('settings-conf:key-synced', {
      path: settingsFilePath,
      hasKey: true
    });
  } else {
    await fs.promises.writeFile(settingsFilePath, '', 'utf8');
    await fs.promises.chmod(settingsFilePath, 0o600).catch(() => {});
    logger.info('settings-conf:key-cleared', {
      path: settingsFilePath,
      hasKey: false
    });
  }

  return {
    changed: currentContent !== nextContent,
    path: settingsFilePath,
    hasKey: Boolean(normalizedKey)
  };
}

async function fetchCurrentBetaKey() {
  const errors = [];

  try {
    return await fetchCurrentBetaKeyViaCurl();
  } catch (error) {
    errors.push(error?.message || String(error));
    logger.warn('beta-key:curl-failed', {
      error: error?.message || String(error)
    });
  }

  try {
    return await fetchCurrentBetaKeyViaFetch();
  } catch (error) {
    errors.push(error?.message || String(error));
    logger.warn('beta-key:fetch-failed', {
      error: error?.message || String(error)
    });
  }

  const error = new Error(`Betakey konnte nicht geladen werden. Details: ${errors.join(' | ')}`);
  error.statusCode = 502;
  throw error;
}

function parseBetaKeyResponse(rawBody) {
  let payload = null;
  try {
    payload = JSON.parse(String(rawBody || '{}'));
  } catch (_error) {
    const error = new Error('Betakey-Antwort ist kein gültiges JSON.');
    error.statusCode = 502;
    throw error;
  }

  const betaKey = String(payload?.key || '').trim();

  if (!/^[A-Za-z0-9][A-Za-z0-9-]{15,}$/.test(betaKey)) {
    const error = new Error('Betakey-Antwort ist ungültig.');
    error.statusCode = 502;
    throw error;
  }

  return {
    key: betaKey,
    sourceUrl: MAKEMKV_BETA_KEY_API_URL
  };
}

function fetchCurrentBetaKeyViaCurl() {
  return new Promise((resolve, reject) => {
    execFile(
      'curl',
      [
        '-fsSL',
        '--max-time', String(Math.ceil(MAKEMKV_BETA_KEY_API_TIMEOUT_MS / 1000)),
        '-A', MAKEMKV_BETA_KEY_API_USER_AGENT,
        '-H', `From: ${MAKEMKV_BETA_KEY_API_FROM}`,
        '-H', 'Accept: text/plain, text/html;q=0.9, */*;q=0.8',
        '-H', 'Accept-Language: de,en-US;q=0.7,en;q=0.3',
        '-H', 'Cache-Control: no-cache',
        '-H', 'Pragma: no-cache',
        MAKEMKV_BETA_KEY_API_URL
      ],
      {
        timeout: MAKEMKV_BETA_KEY_API_TIMEOUT_MS,
        maxBuffer: 1024 * 1024
      },
      (error, stdout, stderr) => {
        if (error) {
          const resolvedError = new Error(
            `curl fehlgeschlagen (${error.code || 'unknown'}): ${String(stderr || error.message || '').trim() || 'keine Details'}`
          );
          resolvedError.statusCode = 502;
          reject(resolvedError);
          return;
        }

        try {
          resolve(parseBetaKeyResponse(stdout));
        } catch (parseError) {
          reject(parseError);
        }
      }
    );
  });
}

async function fetchCurrentBetaKeyViaFetch() {
  const response = await fetch(MAKEMKV_BETA_KEY_API_URL, {
    headers: {
      'User-Agent': MAKEMKV_BETA_KEY_API_USER_AGENT,
      'From': MAKEMKV_BETA_KEY_API_FROM,
      'Accept': 'text/plain, text/html;q=0.9, */*;q=0.8',
      'Accept-Language': 'de,en-US;q=0.7,en;q=0.3',
      'Cache-Control': 'no-cache',
      'Pragma': 'no-cache'
    },
    signal: AbortSignal.timeout(MAKEMKV_BETA_KEY_API_TIMEOUT_MS)
  });

  if (!response.ok) {
    const error = new Error(`HTTP ${response.status}`);
    error.statusCode = 502;
    throw error;
  }

  const rawBody = await response.text();
  return parseBetaKeyResponse(rawBody);
}

module.exports = {
  MAKEMKV_BETA_KEY_API_URL,
  fetchCurrentBetaKey,
  getMakeMKVConfigDir,
  getMakeMKVSettingsFilePath,
  normalizeRegistrationKey,
  syncRegistrationKeyToConfig
};