package serial

import (
	"testing"
	"time"
)

func TestCRConnectionStatusReportsDownAfterConfirmedResponseExpires(t *testing.T) {
	now := time.Date(2026, 9, 14, 1, 0, 0, 0, time.UTC)
	probe := CRProbeState{Enabled: true, EverUp: true, LastResponseAt: &now}
	for _, state := range []string{CRProbeStateNoResponse, CRProbeStateBusy, CRProbeStateSuppressed, CRProbeStateError} {
		probe.State = state
		for _, age := range []time.Duration{0, 4 * time.Second, CRResponseGracePeriod} {
			if got := CRConnectionStatus(probe, now.Add(age)); got != "up" {
				t.Fatalf("transient %s at %s = %s", state, age, got)
			}
		}
		if got := CRConnectionStatus(probe, now.Add(CRResponseGracePeriod+time.Millisecond)); got != "down" {
			t.Fatalf("stale %s = %s; previously confirmed port must become down", state, got)
		}
	}
	probe.EverUp = false
	if CRConnectionStatus(probe, now) != "unknown" {
		t.Fatal("unconfirmed response promoted")
	}
	probe.Up = true
	if CRConnectionStatus(probe, now) != "up" {
		 t.Fatal("confirmed reply ignored")
	}
	probe.Enabled = false
	if CRConnectionStatus(probe, now) != "unknown" {
		t.Fatal("disabled probe promoted")
	}
}

func TestCRConnectionStatusUnknownUpDownUp(t *testing.T) {
	now := time.Now()
	probe := CRProbeState{Enabled: true, State: CRProbeStateNoResponse}
	if got := CRConnectionStatus(probe, now); got != "unknown" {
		t.Fatalf("initial = %s", got)
	}
	probe.Up, probe.EverUp, probe.LastResponseAt = true, true, &now
	if got := CRConnectionStatus(probe, now); got != "up" {
		t.Fatalf("response = %s", got)
	}
	probe.Up = false
	if got := CRConnectionStatus(probe, now.Add(CRResponseGracePeriod+time.Second)); got != "down" {
		t.Fatalf("response lost = %s", got)
	}
	probe.Up = true
	if got := CRConnectionStatus(probe, now.Add(time.Minute)); got != "up" {
		t.Fatalf("response recovered = %s", got)
	}
}