package systemtime

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

type settingsNTPFake struct {
	fakeNTPApplier
	fail error
}

func (a *settingsNTPFake) ConfigureNTP(context.Context, bool, []string) error { return a.fail }

func TestConfigureTimeDoesNotRewriteClockAndRollsBackOnFailure(t *testing.T) {
	applier := &fakeApplier{}
	ntp := &settingsNTPFake{}
	controller := NewTransactionalController(applier, ntp)
	settings := Settings{Timezone: "Asia/Seoul", NTPEnabled: true, Servers: []string{"time.example"}}
	if err := controller.Configure(context.Background(), settings); err != nil {
		t.Fatal(err)
	}
	if !applier.appliedTime.IsZero() || applier.timezone != "Asia/Seoul" {
		t.Fatal("unexpected clock mutation")
	}
	ntp.fail = errors.New("daemon failed")
	if err := controller.Configure(context.Background(), settings); err == nil || !applier.rollbackCalled {
		t.Fatal("failure not rolled back")
	}
}

type settingsRunner struct {
	running bool
	calls   []string
}

func (r *settingsRunner) Run(_ context.Context, _ string, args ...string) error {
	r.calls = append(r.calls, strings.Join(args, " "))
	r.running = args[0] == "start"
	return nil
}

func TestConfigureNTPWorksOfflineAndDisabledIsIdempotent(t *testing.T) {
	root := t.TempDir()
	a, err := NewOSNTPApplier(filepath.Join(root, "ntp.conf"), filepath.Join(root, "S49ntp"), filepath.Join(root, "ntpd"))
	if err != nil {
		t.Fatal(err)
	}
	runner := &settingsRunner{}
	a.runner = runner
	a.running = func() (bool, error) { return runner.running, nil }
	if err := a.ConfigureNTP(context.Background(), true, []string{"internal.example"}); err != nil {
		t.Fatal(err)
	}
	content, _ := os.ReadFile(a.configPath)
	if !strings.Contains(string(content), "server internal.example iburst") || !runner.running {
		t.Fatal("configuration not applied")
	}
	if len(runner.calls) != 1 || runner.calls[0] != "start" {
		t.Fatal("unexpected one-shot sync", runner.calls)
	}
	if err := a.ConfigureNTP(context.Background(), false, nil); err != nil {
		t.Fatal(err)
	}
	if err := a.ConfigureNTP(context.Background(), false, nil); err != nil {
		t.Fatal(err)
	}
	if runner.running || len(runner.calls) != 2 {
		t.Fatal("disable not idempotent")
	}
}