import { betterAuth } from 'better-auth';
import { drizzleAdapter } from 'better-auth/adapters/drizzle';
import { nextCookies } from 'better-auth/next-js';
import { admin, magicLink, organization } from 'better-auth/plugins';
import { db } from '@/lib/server/db';
import { authSchema } from '@/lib/server/db/schema';

type BetterAuthInstance = ReturnType<typeof betterAuth>;

let authInstance: BetterAuthInstance | null = null;

function parseCsvList(value: string | undefined) {
  return (value ?? '')
    .split(',')
    .map((entry) => entry.trim())
    .filter((entry) => entry.length > 0);
}

function buildAuth() {
  const adminUserIds = parseCsvList(process.env.BETTER_AUTH_ADMIN_USER_IDS);
  const trustedOrigins = parseCsvList(process.env.BETTER_AUTH_TRUSTED_ORIGINS);
  const baseURL = process.env.BETTER_AUTH_BASE_URL?.trim()
    || process.env.BETTER_AUTH_URL?.trim()
    || undefined;
  const secret = process.env.BETTER_AUTH_SECRET?.trim() || undefined;

  return betterAuth({
    database: drizzleAdapter(db, {
      provider: 'pg',
      schema: authSchema
    }),
    baseURL,
    secret,
    emailAndPassword: {
      enabled: true
    },
    trustedOrigins: trustedOrigins.length > 0 ? trustedOrigins : undefined,
    plugins: [
      admin(adminUserIds.length > 0 ? { adminUserIds } : undefined),
      magicLink({
        sendMagicLink: async ({ email, url }) => {
          console.info(`[better-auth] Magic link requested for ${email}: ${url}`);
        }
      }),
      organization(),
      nextCookies()
    ]
  });
}

export function getAuth() {
  if (!authInstance) {
    authInstance = buildAuth();
  }

  return authInstance;
}

export async function ensureAuthSchema() {
  return getAuth();
}