package main

import (
	"sync"
	"time"
)

// FocusTimer suppresses notifications for a configurable duration.
// Thread-safe via mutex.
type FocusTimer struct {
	mu      sync.Mutex
	expires time.Time
}

// Set activates focus mode for duration d.
func (f *FocusTimer) Set(d time.Duration) {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.expires = time.Now().Add(d)
}

// IsActive returns true if focus mode has not expired.
func (f *FocusTimer) IsActive() bool {
	f.mu.Lock()
	defer f.mu.Unlock()
	return time.Now().Before(f.expires)
}

// Remaining returns how much focus time is left. Returns 0 if expired.
func (f *FocusTimer) Remaining() time.Duration {
	f.mu.Lock()
	defer f.mu.Unlock()
	rem := time.Until(f.expires)
	if rem < 0 {
		return 0
	}
	return rem
}