// +build linux

package libconf

import "path/filepath"
import "os"
import "bytes"

func userJoin(rest string) string {
	userp := os.Getenv("HOME")
	return filepath.Join(userp, rest)
}

func UserConfigDir() string {
	return userJoin(".config/")
}

func UserLocalDir() string {
	return userJoin(".local/share/")
}

func UserCacheDir() string {
	return userJoin(".cache/")
}

func FromUserDirJoin(rest string) string {
	return userJoin(rest)
}

const (
	userConfDirs  string = "$HOME/.config/:/etc/xdg/"
	userCacheDirs string = "$HOME/.cache/"
	userDataDirs  string = "$HOME/local/share/:/usr/local/share/:/usr/share/"
)

func UserConfDirs() string {
	if paths := os.Getenv("XDG_CONFIG_DIRS"); paths != "" {
		return paths
	}
	return os.ExpandEnv(userConfDirs)
}

func UserCacheDirs() string {
	if paths := os.Getenv("XDG_CACHE_DIRS"); paths != "" {
		return paths
	}
	return os.ExpandEnv(userCacheDirs)
}

func UserDataDirs() string {
	if paths := os.Getenv("XDG_DATA_DIRS"); paths != "" {
		return paths
	}
	return os.ExpandEnv(userDataDirs)
}

func isStatOk(path string) bool {
	stat, err := os.Stat(path)
	return stat != nil && err == nil
}

func byteSearch(paths string, file string) string {
	buf := bytes.Split([]byte(paths), []byte(":"))
	for _, n := range buf {
		conf := filepath.Join(string(n), file)
		if isStatOk(conf) {
			return conf
		}
	}
	return ""
}

func ConfFileSearch(path string) string {
	result := byteSearch(UserConfDirs(), path)
	return result
}

func CacheFileSearch(path string) string {
	result := byteSearch(UserCacheDirs(), path)
	return result
}

func DataFileSearch(path string) string {
	result := byteSearch(UserDataDirs(), path)
	return result
}

const (
	table = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
)

func RandomFileName(name string) string {
	keys := []rune(table)
	rand.Shuffle(len(keys), func(i, j int) { keys[i], keys[j] = keys[j], keys[i] })
	var buf string
	var x int
	for _, r := range name {
		if r == 'X' {
			buf += string(keys[x])
			x++
		} else {
			buf += string(r)
		}
	}
	return buf
}

func DoesExist(path string) bool {
	return isStatOk(path)
}

func OpenFile(path string, opts int, mode os.FileMode) *os.File {
	file, err := os.OpenFile(path, opts, mode)
	if err != nil {
		return nil
	}
	return file
}