// Package lib provides routines for creating and reading data files as defined by the specification.
package lib

import (
	"os"
	"os/exec"
	"path/filepath"
)

// dataDir holds the configured directory to read/write data from/to.
var dataDir string

// SetDataDir sets the global directory to read/write data from/to. It is typically called once at application start.
func SetDataDir(directory string) {
	dataDir = directory
}

// getDataDir gets the global directory to read/write data from/to for a schema entity.
func getDataDir(entity string) (string, error) {
	if dataDir != "" {
		return filepath.Join(dataDir, entity), nil
	}

	home, homeErr := os.UserHomeDir()
	if homeErr != nil {
		return "", homeErr
	}

	return filepath.Join(home, ".protime", entity), nil
}

// newUUID creates a new UUID for an entity instance using the OS command `uuidgen`.
func newUUID() (string, error) {
	out, err := exec.Command("uuidgen").Output()
	if err != nil {
		return "", err
	}
	return string(out[:len(out)-1]), nil
}