package main

import (
	"errors"
	"strings"
	"testing"
	"time"

	"node-lookup/internal/puppet"
)

func mustTime(t *testing.T, s string) time.Time {
	t.Helper()
	ts, err := time.Parse(time.RFC3339Nano, s)
	if err != nil {
		t.Fatal(err)
	}
	return ts
}

func TestFormatWhen_Absolute(t *testing.T) {
	node := &puppet.Node{ReportTimestamp: "2026-07-15T04:05:06.000Z"}
	now := mustTime(t, "2026-07-15T10:00:00Z")
	got := formatWhen(node, nil, false, time.UTC, now)
	if got != "2026-07-15 04:05:06 UTC" {
		t.Fatalf("unexpected absolute time: %q", got)
	}
}

func TestFormatWhen_TimezoneApplied(t *testing.T) {
	loc, err := time.LoadLocation("Asia/Singapore") // UTC+8, no DST
	if err != nil {
		t.Skipf("tzdata unavailable: %v", err)
	}
	node := &puppet.Node{ReportTimestamp: "2026-07-15T04:05:06Z"}
	now := mustTime(t, "2026-07-15T10:00:00Z")
	got := formatWhen(node, nil, false, loc, now)
	if !strings.HasPrefix(got, "2026-07-15 12:05:06") {
		t.Fatalf("expected +08 time, got %q", got)
	}
}

func TestFormatWhen_Relative(t *testing.T) {
	node := &puppet.Node{ReportTimestamp: "2026-07-15T07:00:00Z"}
	now := mustTime(t, "2026-07-15T10:00:00Z")
	if got := formatWhen(node, nil, true, time.UTC, now); got != "3h ago" {
		t.Fatalf("expected '3h ago', got %q", got)
	}
}

func TestFormatWhen_EdgeCases(t *testing.T) {
	now := mustTime(t, "2026-07-15T10:00:00Z")
	if got := formatWhen(nil, errors.New("down"), false, time.UTC, now); !strings.HasPrefix(got, "error:") {
		t.Fatalf("expected error passthrough, got %q", got)
	}
	if got := formatWhen(nil, nil, false, time.UTC, now); got != "unknown node" {
		t.Fatalf("expected unknown node, got %q", got)
	}
	if got := formatWhen(&puppet.Node{ReportTimestamp: ""}, nil, false, time.UTC, now); got != "no report" {
		t.Fatalf("expected no report, got %q", got)
	}
	if got := formatWhen(&puppet.Node{ReportTimestamp: "garbage"}, nil, false, time.UTC, now); got != "garbage" {
		t.Fatalf("expected raw fallback, got %q", got)
	}
}

func TestHumanizeSince(t *testing.T) {
	base := mustTime(t, "2026-07-15T10:00:00Z")
	cases := []struct {
		ts   string
		want string
	}{
		{"2026-07-15T09:59:30Z", "30s ago"},
		{"2026-07-15T09:45:00Z", "15m ago"},
		{"2026-07-15T05:00:00Z", "5h ago"},
		{"2026-07-13T10:00:00Z", "2d ago"},
		{"2026-07-15T10:01:00Z", "1m from now"},
	}
	for _, c := range cases {
		if got := humanizeSince(base, mustTime(t, c.ts)); got != c.want {
			t.Errorf("humanizeSince(%s) = %q, want %q", c.ts, got, c.want)
		}
	}
}