package app

import (
	"os"
	"strconv"
	"strings"

	eventsbuspkg "selective-vpn-api/app/eventsbus"
)

type eventBus struct {
	inner *eventsbuspkg.Bus
}

func newEventBus(capacity int) *eventBus {
	return &eventBus{inner: eventsbuspkg.New(capacity)}
}

func (b *eventBus) push(kind string, data interface{}) Event {
	ev := b.inner.Push(kind, data)
	return Event{ID: ev.ID, Kind: ev.Kind, Ts: ev.Ts, Data: ev.Data}
}

func (b *eventBus) since(id int64) []Event {
	raw := b.inner.Since(id)
	if len(raw) == 0 {
		return nil
	}
	out := make([]Event, 0, len(raw))
	for _, ev := range raw {
		out = append(out, Event{ID: ev.ID, Kind: ev.Kind, Ts: ev.Ts, Data: ev.Data})
	}
	return out
}

// EN: Positive integer env reader with safe default fallback.
// RU: Чтение положительного целого из env с безопасным fallback на дефолт.
func envInt(key string, def int) int {
	if v := strings.TrimSpace(os.Getenv(key)); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 {
			return n
		}
	}
	return def
}

var events = newEventBus(envInt("SVPN_EVENTS_CAP", defaultEventsCapacity))