import path from 'node:path';
import { fileURLToPath } from 'node:url';

const REQUIRED = [
  'DOMAIN',
  'ACME_EMAIL',
  'CORE_REPOSITORY_URL',
  'POSTGRES_PASSWORD',
  'REDIS_PASSWORD',
  'GAME_TOKEN_SECRET',
  'GATEWAY_BOOTSTRAP_TOKEN',
  'INITIAL_ADMIN_USERNAME',
  'INITIAL_ADMIN_PASSWORD',
  'KAKAO_REST_KEY',
];

const MIN_LENGTH = new Map([
  ['POSTGRES_PASSWORD', 24],
  ['REDIS_PASSWORD', 24],
  ['GAME_TOKEN_SECRET', 32],
  ['GATEWAY_BOOTSTRAP_TOKEN', 32],
  ['INITIAL_ADMIN_PASSWORD', 16],
]);

const isPlaceholder = (value) =>
  value.startsWith('replace-with-') || value.includes('example.com') || value.includes('your-org');

const decodeBase64 = (value) => {
  try {
    if (!/^[A-Za-z0-9+/]+={0,2}$/.test(value) || value.length % 4 !== 0) return null;
    return Buffer.from(value, 'base64').toString('utf8');
  } catch {
    return null;
  }
};

export const validateEnvironment = (env) => {
  const errors = [];
  for (const key of REQUIRED) {
    const value = env[key]?.trim() ?? '';
    if (!value) errors.push(`${key} is required`);
    else if (isPlaceholder(value)) errors.push(`${key} still contains an example placeholder`);
  }

  for (const [key, length] of MIN_LENGTH) {
    const value = env[key] ?? '';
    if (value && value.length < length) errors.push(`${key} must contain at least ${length} characters`);
  }

  const domain = env.DOMAIN?.trim() ?? '';
  if (domain && !/^(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?\.)*[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?$/i.test(domain)) {
    errors.push('DOMAIN must be a hostname without a scheme, path, or port');
  }

  const caddySiteAddress = env.CADDY_SITE_ADDRESS?.trim() ?? '';
  if (caddySiteAddress) {
    try {
      const parsed = new URL(caddySiteAddress);
      if (!['http:', 'https:'].includes(parsed.protocol) || parsed.hostname !== domain || parsed.pathname !== '/') {
        errors.push('CADDY_SITE_ADDRESS must be http://DOMAIN or https://DOMAIN');
      }
    } catch {
      errors.push('CADDY_SITE_ADDRESS must be http://DOMAIN or https://DOMAIN');
    }
  }

  const email = env.ACME_EMAIL?.trim() ?? '';
  if (email && !/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) errors.push('ACME_EMAIL must be a valid email address');

  const repositoryUrl = env.CORE_REPOSITORY_URL?.trim() ?? '';
  if (repositoryUrl) {
    if (/^https?:\/\//i.test(repositoryUrl)) {
      try {
        const parsed = new URL(repositoryUrl);
        if (parsed.username || parsed.password) errors.push('CORE_REPOSITORY_URL must not embed credentials');
      } catch {
        errors.push('CORE_REPOSITORY_URL is not a valid HTTP(S) URL');
      }
    } else if (!/^(?:ssh:\/\/|git@)[^\s]+/i.test(repositoryUrl)) {
      errors.push('CORE_REPOSITORY_URL must use HTTP(S) or SSH');
    }
  }

  const httpsUser = env.CORE_REPOSITORY_USERNAME?.trim() ?? '';
  const httpsToken = env.CORE_REPOSITORY_TOKEN?.trim() ?? '';
  const sshKey = env.CORE_SSH_PRIVATE_KEY_BASE64?.trim() ?? '';
  const sshHosts = env.CORE_SSH_KNOWN_HOSTS_BASE64?.trim() ?? '';
  if (Boolean(httpsUser) !== Boolean(httpsToken)) {
    errors.push('CORE_REPOSITORY_USERNAME and CORE_REPOSITORY_TOKEN must be set together');
  }
  if (Boolean(sshKey) !== Boolean(sshHosts)) {
    errors.push('CORE_SSH_PRIVATE_KEY_BASE64 and CORE_SSH_KNOWN_HOSTS_BASE64 must be set together');
  }
  if ((httpsUser || httpsToken) && (sshKey || sshHosts)) errors.push('configure only one Core repository authentication mode');
  if ((httpsUser || httpsToken) && !/^https?:\/\//i.test(repositoryUrl)) {
    errors.push('HTTPS repository credentials require an HTTP(S) CORE_REPOSITORY_URL');
  }
  if ((sshKey || sshHosts) && !/^(?:ssh:\/\/|git@)/i.test(repositoryUrl)) {
    errors.push('SSH repository credentials require an SSH CORE_REPOSITORY_URL');
  }
  if (sshKey) {
    const decoded = decodeBase64(sshKey);
    if (!decoded?.includes('BEGIN OPENSSH PRIVATE KEY')) {
      errors.push('CORE_SSH_PRIVATE_KEY_BASE64 must encode an OpenSSH private key');
    }
  }
  if (sshHosts && !decodeBase64(sshHosts)?.trim()) {
    errors.push('CORE_SSH_KNOWN_HOSTS_BASE64 must contain valid base64-encoded known_hosts data');
  }

  return errors;
};

const isMain = process.argv[1] && fileURLToPath(import.meta.url) === path.resolve(process.argv[1]);
if (isMain) {
  const errors = validateEnvironment(process.env);
  if (errors.length) {
    console.error('Environment validation failed:');
    for (const error of errors) console.error(`- ${error}`);
    process.exitCode = 64;
  } else {
    console.log('Environment validation passed without printing secret values.');
  }
}