// Copyright 2020 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE and LICENSE.gogs file.

package osutil

import (
	"os"
	"os/user"
)

// IsFile returns true if given path exists as a file (i.e. not a directory).
func IsFile(path string) bool {
	f, e := os.Stat(path)
	if e != nil {
		return false
	}
	return !f.IsDir()
}

// IsDir returns true if given path is a directory, and returns false when it's
// a file or does not exist.
func IsDir(dir string) bool {
	f, e := os.Stat(dir)
	if e != nil {
		return false
	}
	return f.IsDir()
}

// IsExist returns true if a file or directory exists.
func IsExist(path string) bool {
	_, err := os.Stat(path)
	return err == nil || os.IsExist(err)
}

// CurrentUsername returns the username of the current user.
func CurrentUsername() string {
	// To get the real user of the current process, you should use user.Current(),
	// and USER may not be the real user of the process (for example, executing it
	//through sudo will display the original user)
	if currentUser, err := user.Current(); err == nil && currentUser != nil && len(currentUser.Username) > 0 {
		return currentUser.Username
	}

	username := os.Getenv("USER")
	if len(username) > 0 {
		return username
	}

	username = os.Getenv("USERNAME")
	if len(username) > 0 {
		return username
	}
	return username
}