//go:build linux

package tc

import (
	"fmt"

	"github.com/vishvananda/netlink"
)

type Htb struct {
	attrs        netlink.QdiscAttrs
	defaultClass uint32
	rate2quantum uint32
}

func NewHtb() *Htb {
	return &Htb{}
}

func (q *Htb) WithDefaultClass(class uint32) *Htb {
	q.defaultClass = class
	return q
}

func (q *Htb) WithRate2Quantum(r2q uint32) *Htb {
	q.rate2quantum = r2q
	return q
}

func (q *Htb) WithAttrs(attrs netlink.QdiscAttrs) *Htb {
	q.attrs = attrs
	return q
}

func (q *Htb) Build() netlink.Qdisc {
	htb := netlink.NewHtb(q.attrs)
	htb.Defcls = q.defaultClass
	htb.Rate2Quantum = q.rate2quantum
	return htb
}

func (q *Htb) Add() error {
	qdisc := q.Build()
	return AddQdisc(qdisc)
}

func (q *Htb) Replace() error {
	qdisc := q.Build()
	return ReplaceQdisc(qdisc)
}

func (q *Htb) Delete() error {
	qdisc := q.Build()
	return DeleteQdisc(qdisc)
}

type Ingress struct {
	attrs netlink.QdiscAttrs
}

func NewIngressQdisc() *Ingress {
	return &Ingress{}
}

func (q *Ingress) WithAttrs(attrs netlink.QdiscAttrs) *Ingress {
	q.attrs = attrs
	return q
}

func (q *Ingress) Build() netlink.Qdisc {
	ingress := netlink.Ingress{}
	ingress.QdiscAttrs = q.attrs
	return &ingress
}

func (q *Ingress) Add() error {
	qdisc := q.Build()
	return AddQdisc(qdisc)
}

func (q *Ingress) Replace() error {
	qdisc := q.Build()
	return ReplaceQdisc(qdisc)
}

func (q *Ingress) Delete() error {
	qdisc := q.Build()
	return DeleteQdisc(qdisc)
}

func ReplaceQdisc(qdisc netlink.Qdisc) error {
	if err := netlink.QdiscReplace(qdisc); err != nil {
		return formatTcError("error replacing qdisc with parent", qdisc.Attrs().LinkIndex, qdisc.Attrs().Parent, qdisc.Attrs().Handle, err)
	}
	return nil
}

func AddQdisc(qdisc netlink.Qdisc) error {
	if err := netlink.QdiscAdd(qdisc); err != nil && !errorIsFileExists(err) {
		return formatTcError("error creating qdisc", qdisc.Attrs().LinkIndex, qdisc.Attrs().Parent, qdisc.Attrs().Handle, err)
	}
	return nil
}

func DeleteQdisc(qdisc netlink.Qdisc) error {
	if err := netlink.QdiscDel(qdisc); err != nil && !errorIsNotFound(err) {
		return fmt.Errorf("error deleting qdisc %+v: %w", qdisc, err)
	}
	return nil
}