package encryptedstring

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"sync"
)

const (
	// defaultIdentifier is the prefix for an encrypted representation of an actual string value
	defaultIdentifier = "$!|"
)

var (
	encryptionProviderMutex sync.Mutex
	encryptionProvider      IDataCryptor
)

// Init initialises the global IDataCryptor instance, if it has not
// been set (or used and hence been initalised with a default).
func Init(idc IDataCryptor) (err error) {
	encryptionProviderMutex.Lock()
	defer encryptionProviderMutex.Unlock()
	if encryptionProvider != nil {
		return errors.New("encryptionProvider already defined")
	}
	encryptionProvider = idc
	return
}

func getEncryptionProvider() IDataCryptor {
	encryptionProviderMutex.Lock()
	defer encryptionProviderMutex.Unlock()
	if encryptionProvider == nil {
		encryptionProvider = NewDefaultDataCryptor()
	}
	return encryptionProvider
}

func getWorkingDirectory() (workingDirectory string) {
	workingDirectory = "."
	fullexecpath, err := os.Executable()
	if err == nil {
		workingDirectory, _ = filepath.Split(fullexecpath)
		workingDirectory = getOSIndependentPath(workingDirectory)
	}
	return
}

// getOSIndependentPath transforms Windows-native paths into Linux-compatible ones.
func getOSIndependentPath(path string) string {
	if len(path) == 0 {
		return ""
	}
	return strings.ReplaceAll(strings.ReplaceAll(path, "\\", "/"), "//", "/")
}

// getLocalPath returns the path to the local startup directory
func getLocalPath() string {
	local := getWorkingDirectory()
	if !strings.HasSuffix(local, "/") {
		local += "/"
	}
	return getOSIndependentPath(local)
}

func unquoteBytes(s []byte) (t []byte, ok bool) {
	if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
		return
	}
	return s[1 : len(s)-1], true
}