package service

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

// fakeSystemctl installs a fake systemctl on PATH and returns the path to its
// directory.
func fakeSystemctl(t *testing.T, script string) string {
	t.Helper()
	dir := t.TempDir()
	path := filepath.Join(dir, "systemctl")
	if err := os.WriteFile(path, []byte("#!/bin/sh\n"+script), 0o755); err != nil {
		t.Fatal(err)
	}
	t.Setenv("PATH", dir+string(os.PathListSeparator)+os.Getenv("PATH"))
	return path
}

func TestRestartSuccess(t *testing.T) {
	fakeSystemctl(t, "exit 0\n")
	if err := New("galahad2lcd").Restart(context.Background()); err != nil {
		t.Fatalf("Restart error = %v", err)
	}
}

func TestRestartFailure(t *testing.T) {
	fakeSystemctl(t, "echo 'permission denied' >&2; exit 1\n")
	err := New("galahad2lcd").Restart(context.Background())
	if err == nil {
		t.Fatal("Restart returned nil error, want failure")
	}
}

func TestRestartCancellation(t *testing.T) {
	fakeSystemctl(t, "sleep 5\n")
	ctx, cancel := context.WithCancel(context.Background())
	cancel()

	err := New("galahad2lcd").Restart(ctx)
	if err == nil {
		t.Fatal("Restart returned nil error for cancelled context")
	}
}

// Ensure the default constructor wires up the real exec.CommandContext.
func TestNewDefaultRunCmd(t *testing.T) {
	s := New("x")
	if s.runCmd == nil {
		t.Fatal("runCmd not initialised")
	}
	cmd := s.runCmd(context.Background(), "true")
	if cmd == nil {
		t.Fatal("runCmd returned nil command")
	}
}