package dhcpsvc

import (
	"fmt"
	"slices"
	"time"
)

// netInterface is a common part of any network interface within the DHCP
// server.
//
// TODO(e.burkov):  Add other methods as [DHCPServer] evolves.
type netInterface struct {
	// name is the name of the network interface.
	name string

	// leases is a set of leases sorted by hardware address.
	leases []*Lease

	// leaseTTL is the default Time-To-Live value for leases.
	leaseTTL time.Duration
}

// reset clears all the slices in iface for reuse.
func (iface *netInterface) reset() {
	iface.leases = iface.leases[:0]
}

// insertLease inserts the given lease into iface.  It returns an error if the
// lease can't be inserted.
func (iface *netInterface) insertLease(l *Lease) (err error) {
	i, found := slices.BinarySearchFunc(iface.leases, l, compareLeaseMAC)
	if found {
		return fmt.Errorf("lease for mac %s already exists", l.HWAddr)
	}

	iface.leases = slices.Insert(iface.leases, i, l)

	return nil
}