package server

import (
	"encoding/binary"
	"errors"
	"file-manger-server/config"
	"file-manger-server/db"
	"file-manger-server/domain"
	"fmt"
	"io"
	"os"
	"strings"
)

type ReturnCommand interface {
	Return() []byte
}

func HandlerReceiveFile(info *ConnInfo, msg []byte) {
	var commandId = msg[0]

	//事务id解析
	var transactionId = msg[1:33]
	fmt.Println(ToHexBytes(transactionId))
	var tranId = ToHexBytes(transactionId)
	if commandId == 0 {
		InfoTransaction(info, msg, tranId)
	} else if commandId == 1 {

		err := InfoTransactionSplit(info, msg, tranId)
		fmt.Println(err)
	}
	//1. 接收基本元数据（事务id（32），len文件名（4+？），文件大小（8），相对路径（4+？），分片数量（按特定大小进行分片）（4），创建时间（8），修改时间（8），访问时间（8）=> 返回事务id，如果重复则返回错误 76+？
	//2. 接收包含事务id的分片内容
}

// InfoTransaction 获取的事务数据内容
func InfoTransaction(info *ConnInfo, msg []byte, transactionId string) error {

	fileUser, err := db.FileUserDao{}.Get(transactionId)
	if err != nil {
		return errors.New("FileUser transactionId is not found")
	}
	if fileUser.UserId == 0 {
		return errors.New("FileUser userId is not found")
	}

	var fileNameLength = binary.BigEndian.Uint32(msg[33:37])
	var filename = string(msg[37 : 37+fileNameLength])
	var fileSize = int64(binary.BigEndian.Uint64(msg[37+fileNameLength : 45+fileNameLength]))
	var pathLength = binary.BigEndian.Uint32(msg[45+fileNameLength : 49+fileNameLength])
	var path = string(msg[49+fileNameLength : 49+fileNameLength+pathLength])
	path = fmt.Sprint(config.Conf.File.Upload.Path, "/", fileUser.UserId, "/", transactionId, "/", path)

	var splitCount = binary.BigEndian.Uint32(msg[49+fileNameLength+pathLength : 53+fileNameLength+pathLength])

	var createTime = binary.BigEndian.Uint64(msg[53+fileNameLength+pathLength : 61+fileNameLength+pathLength])
	var modifyTime = binary.BigEndian.Uint64(msg[61+fileNameLength+pathLength : 69+fileNameLength+pathLength])
	var accessTime = binary.BigEndian.Uint64(msg[69+fileNameLength+pathLength : 77+fileNameLength+pathLength])

	Type := ""
	if fileSize == -1 {
		Type = "folder"
	} else {
		Type = "file"
	}
	ExtensionName := ""
	index := strings.Index(filename, ".")
	if index != -1 {
		ExtensionName = filename[index+1:]
	}

	file := domain.File{
		Name:          filename,
		Url:           path,
		Size:          fileSize,
		Type:          Type,
		MD5:           "",
		TransactionId: transactionId,
		Extension:     ExtensionName,
		Access:        domain.FileAccess{},
		CreateUser:    0,
		CreateTime:    int64(createTime),
		UpdateTime:    int64(modifyTime),
	}
	//添加元素
	db.FileDao{}.Insert(file)
	//递归创建前面的文件夹
	lastIndex := strings.LastIndex(path, "/")
	if lastIndex != -1 {
		err := os.MkdirAll(path[:lastIndex], 0755)
		if err != nil {
			return err
		}
	}
	if splitCount == 0 {
		if fileSize >= 0 {
			//打开文件
			openFile, err := os.Create(path)
			if err != nil {
				fmt.Println("err:", err)
			}
			defer openFile.Close()
			var content = msg[77+fileNameLength+pathLength:]
			openFile.Write(content)
		} else {
			err := os.Mkdir(path, 0755)
			if err != nil {
				fmt.Println(err)
			}
		}
	} else {
		// 创建一个空文件
		file, err := os.Create(path)
		if err != nil {
			fmt.Println("Error creating file:", err)
			return err
		}
		defer file.Close() // 确保在函数结束时关闭文件
		fmt.Println("file size :", fileSize)
		err = file.Truncate(fileSize)

		if err != nil {
			fmt.Println("Error setting file size:", err)
			return err
		}
	}
	// 返回状态信息
	//info.conn.Write()
	fmt.Println(fmt.Sprintf("事务id：%d\n文件名：%s\n文件大小：%d\n相对路径：%s\n分片数量：%d\n创建时间：%d\n修改时间：%d\n访问时间：%d", transactionId, filename, fileSize, path, splitCount, createTime, modifyTime, accessTime))
	return nil
}

// InfoTransactionSplit 获取的事务数据内容
func InfoTransactionSplit(info *ConnInfo, msg []byte, transactionId string) error {
	fileUser, err := db.FileUserDao{}.Get(transactionId)
	if err != nil {
		return errors.New("FileUser transactionId is not found")
	}
	if fileUser.UserId == 0 {
		return errors.New("FileUser userId is not found")
	}

	var splitNum = binary.BigEndian.Uint32(msg[33:37])
	var pathLength = binary.BigEndian.Uint32(msg[37:41])
	var path = string(msg[41 : 41+pathLength])
	path = fmt.Sprint(config.Conf.File.Upload.Path, "/", fileUser.UserId, "/", transactionId, "/", path)
	var content = msg[41+pathLength:]
	err = insertDataAtPosition(path, int64(splitNum*1024), content)
	return err
	// 返回状态信息
	//info.conn.Write()
	//fmt.Println(fmt.Sprintf("事务id：%d\n文件名：%s\n文件大小：%d\n相对路径：%s\n分片数量：%d\n创建时间：%d\n修改时间：%d\n访问时间：%d", transactionId, filename, fileSize, path, splitCount, createTime, modifyTime, accessTime))
}

var sign = 0

func insertDataAtPosition(filePath string, position int64, data []byte) error {
	// 1. 打开文件
	file, err := os.OpenFile(filePath, os.O_RDWR, 0644)
	if err != nil {
		return fmt.Errorf("error opening file: %v", err)
	}
	defer file.Close()

	// 2. 获取文件元数据
	fileInfo, err := file.Stat()
	if err != nil {
		return fmt.Errorf("error getting file info: %v", err)
	}
	fileSize := fileInfo.Size()

	// 3. 校验插入位置
	if position > fileSize {
		return fmt.Errorf("position exceeds file size")
	}

	// 4. 计算需要移动的数据量
	//originalDataLength := fileSize - position
	insertLength := int64(len(data))

	// 5. 分块移动原始数据（从后往前处理）
	//var offset int64 = position

	//for offset > 0 {
	// 定位读取位置
	readPos := position

	// 读取块数据
	buffer := make([]byte, insertLength)
	_, err = file.ReadAt(buffer, readPos)
	if err != nil && err != io.EOF {
		return fmt.Errorf("read block error: %v", err)
	}
	sign += 1
	fmt.Println("buffer len :", len(buffer), "  sign => ", sign)
	// 写入新位置
	_, err = file.WriteAt(buffer, readPos)
	if err != nil {
		return fmt.Errorf("write block error: %v", err)
	}
	fmt.Println("writePos ind :", readPos+int64(len(buffer)))
	//}

	// 6. 写入新数据
	_, err = file.WriteAt(data, position)
	if err != nil {
		return fmt.Errorf("write data error: %v", err)
	}

	// 7. 扩展文件大小（如果需要）
	//newSize := fileSize + insertLength
	//if newSize > fileSize {
	//	if err := file.Truncate(newSize); err != nil {
	//		return fmt.Errorf("truncate error: %v", err)
	//	}
	//}

	return nil
}

func ToHexBytes(bytes []byte) string {
	var hexBytes string
	for b := range bytes {
		hexBytes = fmt.Sprint(hexBytes, fmt.Sprintf("%02X", bytes[b]))
	}
	return strings.TrimSpace(hexBytes)
}