package multiplex

import (
	"sync/atomic"

	"github.com/juju/ratelimit"
)

// Valve needs to be universal, across all sessions that belong to a user
// gabe please don't sue
type Valve struct {
	// traffic directions from the server's perspective are refered
	// exclusively as rx and tx.
	// rx is from client to server, tx is from server to client
	// DO NOT use terms up or down as this is used in usermanager
	// for bandwidth limiting
	rxtb atomic.Value // *ratelimit.Bucket
	txtb atomic.Value // *ratelimit.Bucket

	rxCredit *int64
	txCredit *int64
}

func MakeValve(rxRate, txRate int64, rxCredit, txCredit *int64) *Valve {
	v := &Valve{
		rxCredit: rxCredit,
		txCredit: txCredit,
	}
	v.SetRxRate(rxRate)
	v.SetTxRate(txRate)
	return v
}

func (v *Valve) SetRxRate(rate int64) { v.rxtb.Store(ratelimit.NewBucketWithRate(float64(rate), rate)) }
func (v *Valve) SetTxRate(rate int64) { v.txtb.Store(ratelimit.NewBucketWithRate(float64(rate), rate)) }
func (v *Valve) rxWait(n int)         { v.rxtb.Load().(*ratelimit.Bucket).Wait(int64(n)) }
func (v *Valve) txWait(n int)         { v.txtb.Load().(*ratelimit.Bucket).Wait(int64(n)) }
func (v *Valve) SetRxCredit(n int64)  { atomic.StoreInt64(v.rxCredit, n) }
func (v *Valve) SetTxCredit(n int64)  { atomic.StoreInt64(v.txCredit, n) }
func (v *Valve) GetRxCredit() int64   { return atomic.LoadInt64(v.rxCredit) }
func (v *Valve) GetTxCredit() int64   { return atomic.LoadInt64(v.txCredit) }

// n can be negative
func (v *Valve) AddRxCredit(n int64) int64 { return atomic.AddInt64(v.rxCredit, n) }

// n can be negative
func (v *Valve) AddTxCredit(n int64) int64 { return atomic.AddInt64(v.txCredit, n) }