first commit

server/internal/security/limiter.go

@@ -0,0 +1,54 @@
+//go:build ignore
+
+package security
+
+import (
+	"sync"
+	"time"
+)
+
+type limiterEntry struct {
+	Count   int
+	ResetAt time.Time
+}
+
+type LoginLimiter struct {
+	mu      sync.Mutex
+	window  time.Duration
+	max     int
+	records map[string]limiterEntry
+}
+
+func NewLoginLimiter(max int, window time.Duration) *LoginLimiter {
+	return &LoginLimiter{window: window, max: max, records: make(map[string]limiterEntry)}
+}
+
+func (l *LoginLimiter) Allow(key string) bool {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	entry, ok := l.records[key]
+	if !ok || time.Now().After(entry.ResetAt) {
+		delete(l.records, key)
+		return true
+	}
+	return entry.Count < l.max
+}
+
+func (l *LoginLimiter) RegisterFailure(key string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	now := time.Now()
+	entry, ok := l.records[key]
+	if !ok || now.After(entry.ResetAt) {
+		l.records[key] = limiterEntry{Count: 1, ResetAt: now.Add(l.window)}
+		return
+	}
+	entry.Count++
+	l.records[key] = entry
+}
+
+func (l *LoginLimiter) Reset(key string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	delete(l.records, key)
+}