import type { Request, Response, NextFunction } from 'express';
import type { Pool } from 'pg';
import { prisma, tenantDb } from '../config/database.js';

declare global {
  namespace Express {
    interface Request {
      tenantPool?: Pool;
      viewingTenantId?: string;
    }
  }
}

export async function tenantMiddleware(req: Request, res: Response, next: NextFunction) {
  try {
    if (!req.user) {
      return res.status(401).json({ message: 'No autenticado' });
    }

    let tenantId = req.user.tenantId;
    let databaseName = req.user.databaseName;

    // Admin impersonation via X-View-Tenant header
    const viewTenantHeader = req.headers['x-view-tenant'] as string;
    if (viewTenantHeader && req.user.role === 'admin') {
      const viewedTenant = await prisma.tenant.findFirst({
        where: {
          OR: [
            { id: viewTenantHeader },
            { rfc: viewTenantHeader },
          ],
        },
        select: { id: true, databaseName: true, active: true },
      });

      if (!viewedTenant) {
        return res.status(404).json({ message: 'Tenant no encontrado' });
      }

      if (!viewedTenant.active) {
        return res.status(403).json({ message: 'Tenant inactivo' });
      }

      tenantId = viewedTenant.id;
      databaseName = viewedTenant.databaseName;
      req.viewingTenantId = viewedTenant.id;
    }

    req.tenantPool = tenantDb.getPool(tenantId, databaseName);
    next();
  } catch (error) {
    console.error('[TenantMiddleware] Error:', error);
    return res.status(500).json({ message: 'Error al resolver tenant' });
  }
}