import NextAuth from 'next-auth';
import { PrismaAdapter } from '@auth/prisma-adapter';
import { authConfig } from './auth.config';
import prisma from '@/lib/prisma';
import { buildAuthProviders } from '@/lib/auth-providers';
import { logAuditEvent } from '@/lib/audit-log';

export const { auth, signIn, signOut, handlers } = NextAuth({
  ...authConfig,
  adapter: PrismaAdapter(prisma),
  providers: buildAuthProviders(),
  events: {
    async createUser({ user }) {
      const adminEmail = process.env.ADMIN_EMAIL?.toLowerCase();
      if (!adminEmail || !user.id || user.email?.toLowerCase() !== adminEmail) {
        logAuditEvent({ userId: user.id, action: 'USER_CREATED', metadata: { email: user.email } });
        return;
      }
      await prisma.user.update({
        where: { id: user.id },
        data: { role: 'ADMIN', emailVerified: new Date() },
      });
      logAuditEvent({ userId: user.id, action: 'USER_CREATED', metadata: { email: user.email, role: 'ADMIN' } });
    },
    async signOut(message) {
      const userId =
        'token' in message && message.token?.sub
          ? message.token.sub
          : 'session' in message && message.session?.userId
            ? message.session.userId
            : null;

      if (!userId) return;

      logAuditEvent({ userId, action: 'LOGOUT' });

      await prisma.$transaction([
        prisma.user.update({
          where: { id: userId },
          data: { sessionVersion: { increment: 1 } },
        }),
        prisma.session.deleteMany({ where: { userId } }),
      ]);
    },
  },
  callbacks: {
    ...authConfig.callbacks,
    async signIn({ user, account }) {
      if (account?.provider === 'google' && user.email) {
        const email = user.email.toLowerCase();
        const adminEmail = process.env.ADMIN_EMAIL?.toLowerCase();
        const existing = await prisma.user.findUnique({ where: { email } });
        if (existing && adminEmail && email === adminEmail && existing.role !== 'ADMIN') {
          await prisma.user.update({
            where: { id: existing.id },
            data: { role: 'ADMIN', emailVerified: new Date() },
          });
        }
      }
      logAuditEvent({
        userId: user.id,
        action: 'LOGIN',
        metadata: { provider: account?.provider ?? 'credentials', email: user.email },
      });
      return true;
    },
    async jwt({ token, user, trigger, session }) {
      if (trigger === 'update' && session) {
        if ('aiSessionConsent' in session) token.aiSessionConsent = session.aiSessionConsent === true;
        if ('onboardingCompleted' in session) token.onboardingCompleted = session.onboardingCompleted === true;
        return token;
      }
      if (user?.id) {
        token.id = user.id;
        token.aiSessionConsent = false;
        const dbUser = await prisma.user.findUnique({
          where: { id: user.id },
          select: { role: true, sessionVersion: true, onboardingCompleted: true },
        });
        if (!dbUser) return null;
        token.role = dbUser.role;
        token.sessionVersion = dbUser.sessionVersion;
        token.onboardingCompleted = dbUser.onboardingCompleted;
      } else if (token.sub) {
        const dbUser = await prisma.user.findUnique({
          where: { id: token.sub },
          select: { role: true, sessionVersion: true, onboardingCompleted: true },
        });
        if (!dbUser) return null;
        if (
          typeof token.sessionVersion === 'number' &&
          token.sessionVersion !== dbUser.sessionVersion
        ) {
          return null;
        }
        token.id = token.sub;
        token.role = dbUser.role;
        token.sessionVersion = dbUser.sessionVersion;
        token.onboardingCompleted = dbUser.onboardingCompleted;
      }
      return token;
    },
  },
});