package app

import (
	"sync"
	"time"
)

const (
	transportHealthFreshTTL           = 45 * time.Second
	transportHealthBackoffMin         = 5 * time.Second
	transportHealthBackoffMax         = 2 * time.Minute
	transportHealthPersistMinAge      = 90 * time.Second
	transportHealthMaxConcurrentProbe = 2
)

type transportHealthRefreshEntry struct {
	swr refreshCoordinator
}

type transportHealthRefresher struct {
	mu      sync.Mutex
	entries map[string]*transportHealthRefreshEntry
	sem     chan struct{}
}

func newTransportHealthRefresher(maxConcurrent int) *transportHealthRefresher {
	n := maxConcurrent
	if n <= 0 {
		n = transportHealthMaxConcurrentProbe
	}
	return &transportHealthRefresher{
		entries: map[string]*transportHealthRefreshEntry{},
		sem:     make(chan struct{}, n),
	}
}

var transportHealthSWR = newTransportHealthRefresher(envInt("SVPN_TRANSPORT_HEALTH_MAX_PARALLEL", transportHealthMaxConcurrentProbe))