package encfs

import (
	"os"
	"syscall"

	"github.com/spf13/afero"
)

type EncFile struct {
	isDir  bool
	closed bool
	file   *os.File
}

func NewEncFile(file *os.File) (*EncFile, error) {
	fileInfo, err := file.Stat()
	if err != nil {
		return nil, err
	}
	isDir := fileInfo.IsDir()
	return &EncFile{
		isDir:  isDir,
		closed: false,
		file:   file,
	}, nil
}

func (f *EncFile) Close() error {
	if f.closed {
		return afero.ErrFileClosed
	}

	f.closed = true
	return f.file.Close()
}

func (f *EncFile) Read(p []byte) (n int, err error) {
	checkIsFileErr := f.checkIsFile()
	if checkIsFileErr != nil {
		return 0, checkIsFileErr
	}

	// TODO decrypt
	return f.file.Read(p)
}

func (f *EncFile) ReadAt(p []byte, off int64) (n int, err error) {
	checkIsFileErr := f.checkIsFile()
	if checkIsFileErr != nil {
		return 0, checkIsFileErr
	}

	// TODO decrypt
	return f.file.ReadAt(p, off)
}

func (f *EncFile) Seek(offset int64, whence int) (int64, error) {
	checkIsFileErr := f.checkIsFile()
	if checkIsFileErr != nil {
		return 0, checkIsFileErr
	}

	// TODO decrypt
	return f.file.Seek(offset, whence)
}

func (f *EncFile) Write(p []byte) (n int, err error) {
	checkIsFileErr := f.checkIsFile()
	if checkIsFileErr != nil {
		return 0, checkIsFileErr
	}

	// TODO encrypt
	return f.file.Write(p)
}

func (f *EncFile) WriteAt(p []byte, off int64) (n int, err error) {
	checkIsFileErr := f.checkIsFile()
	if checkIsFileErr != nil {
		return 0, checkIsFileErr
	}

	// TODO encrypt
	return f.file.WriteAt(p, off)
}

func (f *EncFile) Name() string {
	return f.file.Name()
}

func (f *EncFile) Readdir(count int) ([]os.FileInfo, error) {
	if f.closed {
		return nil, afero.ErrFileClosed
	}

	return f.file.Readdir(count)
}

func (f *EncFile) Readdirnames(n int) ([]string, error) {
	fi, err := f.Readdir(n)
	if err != nil {
		return nil, err
	}

	var names []string
	for _, f := range fi {
		names = append(names, f.Name())
	}

	return names, nil
}

func (f *EncFile) Stat() (os.FileInfo, error) {
	return f.file.Stat()
}

func (f *EncFile) Sync() error {
	return f.file.Sync()
}

func (f *EncFile) Truncate(size int64) error {
	return f.file.Truncate(size)
}

func (f *EncFile) WriteString(s string) (ret int, err error) {
	// TODO encrypt
	return f.file.WriteString(s)
}

func (f *EncFile) checkIsFile() error {
	if f.closed {
		return afero.ErrFileClosed
	}
	if f.isDir {
		return syscall.EISDIR
	}
	return nil
}