import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { JwtService } from '@nestjs/jwt';
import type { FastifyRequest } from 'fastify';
import { IS_PUBLIC_KEY } from '../decorators/public.decorator';

export interface AuthenticatedUser {
  id: string;
  email: string;
  permissions: string[];
}

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

// Extrai o access token do cookie HttpOnly (fluxo normal do frontend) ou do
// header Authorization (útil para clients/scripts/testes).
function extractToken(request: FastifyRequest): string | null {
  const cookieToken = request.cookies?.['access_token'];
  if (cookieToken) return cookieToken;

  const authHeader = request.headers.authorization;
  if (authHeader?.startsWith('Bearer '))
    return authHeader.slice('Bearer '.length);

  return null;
}

@Injectable()
export class AuthGuard implements CanActivate {
  constructor(
    private readonly jwtService: JwtService,
    private readonly reflector: Reflector,
  ) {}

  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<RequestWithUser>();
    const token = extractToken(request);
    if (!token) throw new UnauthorizedException('Token de acesso ausente');

    try {
      const payload = await this.jwtService.verifyAsync<{
        sub: string;
        email: string;
        permissions: string[];
      }>(token);
      request.user = {
        id: payload.sub,
        email: payload.email,
        permissions: payload.permissions,
      } satisfies AuthenticatedUser;
      return true;
    } catch {
      throw new UnauthorizedException('Token de acesso inválido ou expirado');
    }
  }
}