package ftp

import (
	"io"
	"os"

	"ftp-server/database"

	"github.com/spf13/afero"
)

// loggingFs 带日志功能的文件系统包装器
type loggingFs struct {
	afero.Fs
	db       *database.DB
	username string
}

// loggingFile 带日志功能的文件包装器
type loggingFile struct {
	afero.File
	fs       *loggingFs
	name     string
	flags    int
	written  int64
	read     int64
	logged   bool
}

// newLoggingFs 创建带日志的文件系统
func newLoggingFs(base afero.Fs, db *database.DB, username string) *loggingFs {
	return &loggingFs{
		Fs:       base,
		db:       db,
		username: username,
	}
}

// GetHandle 实现 ftpserverlib.ClientDriverExtentionFileTransfer 接口
// flags: os.O_RDONLY 表示下载, os.O_WRONLY/os.O_CREATE 表示上传
func (fs *loggingFs) GetHandle(name string, flags int, offset int64) (interface {
	io.Reader
	io.Writer
	io.Seeker
	io.Closer
}, error) {
	file, err := fs.Fs.OpenFile(name, flags, 0666)
	if err != nil {
		return nil, err
	}

	// 如果有偏移量（断点续传），先 Seek
	if offset > 0 {
		if _, err := file.Seek(offset, 0); err != nil {
			file.Close()
			return nil, err
		}
	}

	return &loggingFile{
		File:   file,
		fs:     fs,
		name:   name,
		flags:  flags,
		logged: false,
	}, nil
}

func (f *loggingFile) Write(p []byte) (int, error) {
	n, err := f.File.Write(p)
	f.written += int64(n)
	return n, err
}

func (f *loggingFile) Read(p []byte) (int, error) {
	n, err := f.File.Read(p)
	f.read += int64(n)
	return n, err
}

func (f *loggingFile) Close() error {
	err := f.File.Close()

	// 避免重复记录
	if f.logged {
		return err
	}
	f.logged = true

	if f.fs.db == nil {
		return err
	}

	// 判断是上传还是下载
	isWrite := (f.flags & os.O_WRONLY) != 0 || (f.flags & os.O_RDWR) != 0 || (f.flags & os.O_CREATE) != 0

	if isWrite && f.written > 0 {
		f.fs.db.AddLog(&database.FTPLog{
			Username: f.fs.username,
			Action:   "upload",
			FilePath: f.name,
			FileSize: f.written,
			Status:   "success",
		})
	} else if !isWrite && f.read > 0 {
		f.fs.db.AddLog(&database.FTPLog{
			Username: f.fs.username,
			Action:   "download",
			FilePath: f.name,
			FileSize: f.read,
			Status:   "success",
		})
	}

	return err
}