package gateway

import "sync"

// logRing keeps the most recent log entries in memory.
type logRing struct {
	mu      sync.Mutex
	entries []LogEntry
	cap     int
}

func newLogRing(capacity int) *logRing {
	return &logRing{cap: capacity}
}

func (r *logRing) add(entry LogEntry) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.entries = append(r.entries, entry)
	if len(r.entries) > r.cap {
		r.entries = r.entries[len(r.entries)-r.cap:]
	}
}

// list returns entries newest first.
func (r *logRing) list() []LogEntry {
	r.mu.Lock()
	defer r.mu.Unlock()
	out := make([]LogEntry, len(r.entries))
	for i, e := range r.entries {
		out[len(r.entries)-1-i] = e
	}
	return out
}