package monitor

import (
	"testing"
	"time"
)

func TestSpeedTracker_FirstUpdateBaseline(t *testing.T) {
	s := NewSpeedTracker()
	s.Update(1000, 500)

	down, up := s.Rates()
	if down != 0 || up != 0 {
		t.Errorf("first update should be baseline (0,0), got (%f,%f)", down, up)
	}
}

func TestSpeedTracker_RateCalculation(t *testing.T) {
	s := NewSpeedTracker()

	// Seed baseline
	s.mu.Lock()
	s.lastIn = 0
	s.lastOut = 0
	s.lastTime = time.Now().Add(-1 * time.Second)
	s.mu.Unlock()

	s.Update(1000, 500)

	down, up := s.Rates()
	// Allow some tolerance for timing
	if down < 900 || down > 1100 {
		t.Errorf("expected ~1000 B/s down, got %f", down)
	}
	if up < 400 || up > 600 {
		t.Errorf("expected ~500 B/s up, got %f", up)
	}
}

func TestSpeedTracker_NegativeDeltaClamped(t *testing.T) {
	s := NewSpeedTracker()

	// Seed with high values
	s.mu.Lock()
	s.lastIn = 5000
	s.lastOut = 3000
	s.lastTime = time.Now().Add(-1 * time.Second)
	s.mu.Unlock()

	// Update with lower values (counter reset)
	s.Update(100, 50)

	down, up := s.Rates()
	if down < 0 {
		t.Errorf("negative download rate not clamped: %f", down)
	}
	if up < 0 {
		t.Errorf("negative upload rate not clamped: %f", up)
	}
}