// Package executor exec commands
package executor

import (
	"errors"
	"os/exec"
	"os"
	"strings"
)

var ErrBuiltInExit = errors.New("exit command")
var localVars = make(map[string]string)

func PrepareCommand(in string) (*exec.Cmd, error) {
	in = strings.TrimSpace(in)
	if in == "" {
		return nil, nil
	}
	if strings.Contains(in, "=") && !strings.HasPrefix(in, "export ") {
			parts := strings.SplitN(in, "=", 2)
			key := strings.TrimSpace(parts[0])
			value := strings.TrimSpace(parts[1])

			localVars[key] = value
			return nil,nil
		}

	in = os.Expand(in, GetVariable)


	parts := strings.Fields(in)
	head := parts[0]
	args := parts[1:]

	switch head {
	case "exit":
		return nil, ErrBuiltInExit
	case "help":
		return exec.Command("echo", "noko-shell: available commands: any system command, help, exit"), nil
	}

	// Поиск системной утилиты в PATH (авто-проверка на существование)
	fullPath, err := exec.LookPath(head)
	if err != nil {
		return nil, err
	}

	// Возвращаем подготовленный процесс
	return exec.Command(fullPath, args...), nil
}


func GetVariable(key string) string {
	if val, exists := localVars[key]; exists {
		return val
	}
	if val := os.Getenv(key); val != "" {
		return val
	}
	return ""
}