import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from '@nestjs/common';
import { Request } from 'express';
import { AdminService } from './admin.service';

@Injectable()
export class AdminAuthGuard implements CanActivate {
  constructor(private readonly adminService: AdminService) {}

  canActivate(context: ExecutionContext): boolean {
    const req = context.switchToHttp().getRequest<Request>();
    const headerKey = this.getHeaderValue(req, 'x-dashboard-key');
    const queryKey = this.getQueryValue(req, 'key');
    const bearerKey = this.getBearerToken(req);
    const chave = headerKey || queryKey || bearerKey;

    if (!this.adminService.validarChaveDashboard(chave)) {
      throw new UnauthorizedException('Dashboard key invalida');
    }

    return true;
  }

  private getHeaderValue(req: Request, nome: string): string | undefined {
    const valor = req.headers[nome];
    if (Array.isArray(valor)) {
      return valor[0];
    }
    return typeof valor === 'string' ? valor : undefined;
  }

  private getQueryValue(req: Request, nome: string): string | undefined {
    const valor = req.query?.[nome];
    if (Array.isArray(valor)) {
      return typeof valor[0] === 'string' ? valor[0] : undefined;
    }
    return typeof valor === 'string' ? valor : undefined;
  }

  private getBearerToken(req: Request): string | undefined {
    const authHeader = this.getHeaderValue(req, 'authorization');
    if (!authHeader) return undefined;
    if (!authHeader.toLowerCase().startsWith('bearer ')) return undefined;
    return authHeader.slice(7).trim();
  }
}