import { CanActivate, ExecutionContext, Injectable, UnauthorizedException } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Reflector } from '@nestjs/core';
import type { FastifyRequest } from 'fastify';
import { AuthSessionsService } from '../../modules/auth/auth-sessions.service';
import type { AuthenticatedUser } from './authenticated-user';
import { IS_PUBLIC_KEY } from './public.decorator';

type AuthenticatedRequest = FastifyRequest & { user?: AuthenticatedUser };

@Injectable()
export class SessionAuthGuard implements CanActivate {
  constructor(
    private readonly reflector: Reflector,
    private readonly sessions: AuthSessionsService,
    private readonly config: ConfigService,
  ) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const isPublic = this.reflector.getAllAndOverride<boolean>(IS_PUBLIC_KEY, [
      context.getHandler(),
      context.getClass(),
    ]);
    if (isPublic) return true;

    const request = context.switchToHttp().getRequest<AuthenticatedRequest>();
    const cookieName = this.config.get<string>('SESSION_COOKIE_NAME', 'ck_session');
    const token = request.cookies?.[cookieName];

    if (!token) {
      throw new UnauthorizedException('Authentication required.');
    }

    const user = await this.sessions.resolve(token);
    if (!user) {
      throw new UnauthorizedException('Session is invalid or expired.');
    }

    request.user = user;
    return true;
  }
}