import { Injectable, NestMiddleware, Logger } from "@nestjs/common";
import type { Request, Response, NextFunction } from "express";

@Injectable()
export class TenantMiddleware implements NestMiddleware {
  private readonly logger = new Logger(TenantMiddleware.name);

  use(req: Request, _res: Response, next: NextFunction) {
    const tenantId =
      req.headers["x-tenant-id"] as string | undefined ??
      req.user?.tenantId ??
      this.extractFromSubdomain(req);

    if (tenantId) {
      (req as Request & { tenantId: string }).tenantId = tenantId;
    }

    next();
  }

  private extractFromSubdomain(req: Request): string | undefined {
    const host = req.headers.host;
    if (!host) return undefined;

    const parts = host.split(".");
    if (parts.length >= 3) {
      return parts[0];
    }

    return undefined;
  }
}