package ser

import (
	"errors"
	"github.com/xdrm-brackets/nix-amer/internal/exec"
)

// ErrUnknownManager is raised when the asked manager does not exist
var ErrUnknownManager = errors.New("unknown service manager")

// ErrNotInstalled is raised when the candidate service manager is not installed
// on the host system (use command-line -dry-run to avoid execution errors and just
// check your buildfile syntax)
var ErrNotInstalled = errors.New("no candidate installed")

// Load a specific service-manager by its name
func Load(_manager string, _exec exec.Executor) (ServiceManager, error) {

	// 1. create manager (fail if unknown)
	var manager ServiceManager
	switch _manager {
	case "systemd":
		manager = new(systemd)
	default:
		return nil, ErrUnknownManager
	}

	// 2. fail if not installed
	// if exec.Command("which", manager.Name()).Run() != nil {
	// 	return nil, ErrNotInstalled
	// }

	manager.SetExecutor(_exec)
	return manager, nil

}