package server

import (
	"strings"
	"sync"

	nbpeer "github.com/netbirdio/netbird/management/server/peer"
)

const (
	loginFilterSize = 100_000 // Size of the login filter map, making it large enough for a future
)

type loginFilter struct {
	mu     sync.RWMutex
	logged map[string]string
}

func newLoginFilter() *loginFilter {
	return &loginFilter{
		logged: make(map[string]string, loginFilterSize),
	}
}

func (l *loginFilter) addLogin(wgPubKey, metaHash string) {
	l.mu.Lock()
	defer l.mu.Unlock()
	l.logged[wgPubKey] = metaHash
}

func (l *loginFilter) allowLogin(wgPubKey, metaHash string) bool {
	l.mu.RLock()
	defer l.mu.RUnlock()
	if loggedMetaHash, ok := l.logged[wgPubKey]; ok {
		return loggedMetaHash == metaHash
	}
	return true
}

func (l *loginFilter) removeLogin(wgPubKey string) {
	l.mu.Lock()
	defer l.mu.Unlock()
	delete(l.logged, wgPubKey)
}

func metaHash(meta nbpeer.PeerSystemMeta) string {
	estimatedSize := len(meta.WtVersion) + len(meta.OSVersion) + len(meta.KernelVersion) + len(meta.Hostname)

	var b strings.Builder
	b.Grow(estimatedSize)

	b.WriteString(meta.WtVersion)
	b.WriteString(meta.OSVersion)
	b.WriteString(meta.KernelVersion)
	b.WriteString(meta.Hostname)

	return b.String()
}