package templates

import (
	"testing"
	"time"
)

func TestHumanAgoFrom(t *testing.T) {
	now := time.Date(2026, 4, 17, 12, 0, 0, 0, time.UTC)
	cases := []struct {
		name string
		ago  time.Duration
		want string
	}{
		{"just now", 5 * time.Second, "online"},
		{"edge-just-under-minute", 59 * time.Second, "online"},
		{"one minute", 60 * time.Second, "1m ago"},
		{"five minutes", 5 * time.Minute, "5m ago"},
		{"fifty-nine minutes", 59 * time.Minute, "59m ago"},
		{"one hour", 1 * time.Hour, "1h ago"},
		{"eight hours", 8 * time.Hour, "8h ago"},
		{"one day", 24 * time.Hour, "1d ago"},
		{"three days", 72 * time.Hour, "3d ago"},
		// Clock skew: "future" heartbeat clamps to "online" rather than
		// printing "-3m ago" or panicking.
		{"future clamps to online", -5 * time.Second, "online"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got := humanAgoFrom(now, now.Add(-tc.ago))
			if got != tc.want {
				t.Fatalf("humanAgoFrom(%v) = %q, want %q", tc.ago, got, tc.want)
			}
		})
	}
}

func TestLastSeenLabelAndClass(t *testing.T) {
	if got := lastSeenLabel(nil); got != "never" {
		t.Fatalf("label nil = %q, want never", got)
	}
	if got := lastSeenClass(nil); got != "offline" {
		t.Fatalf("class nil = %q, want offline", got)
	}
	recent := time.Now().Add(-5 * time.Second)
	if got := lastSeenClass(&recent); got != "online" {
		t.Fatalf("class recent = %q, want online", got)
	}
	stale := time.Now().Add(-10 * time.Minute)
	if got := lastSeenClass(&stale); got != "stale" {
		t.Fatalf("class stale = %q, want stale", got)
	}
}