package nodes

import (
	"crypto/md5"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"time"

	"github.com/TeaOSLab/EdgeCommon/pkg/rpc/pb"
	teaconst "github.com/TeaOSLab/EdgeHttpDNS/internal/const"
	"github.com/TeaOSLab/EdgeHttpDNS/internal/rpc"
	"github.com/TeaOSLab/EdgeHttpDNS/internal/utils"
	"github.com/iwind/TeaGo/Tea"
	stringutil "github.com/iwind/TeaGo/utils/string"
	"github.com/iwind/gosock/pkg/gosock"
)

// UpgradeManager 节点升级管理器
type UpgradeManager struct {
	isInstalling bool
	lastFile     string
	exe          string
}

// NewUpgradeManager 获取新对象
func NewUpgradeManager() *UpgradeManager {
	return &UpgradeManager{}
}

// Loop 启动升级检查循环（每1分钟）
func (this *UpgradeManager) Loop() {
	rpcClient, err := rpc.SharedRPC()
	if err != nil {
		log.Println("[UPGRADE_MANAGER]" + err.Error())
		return
	}

	var ticker = time.NewTicker(1 * time.Minute)
	for range ticker.C {
		resp, err := rpcClient.HTTPDNSNodeRPC.CheckHTTPDNSNodeLatestVersion(rpcClient.Context(), &pb.CheckHTTPDNSNodeLatestVersionRequest{
			Os:             runtime.GOOS,
			Arch:           runtime.GOARCH,
			CurrentVersion: teaconst.Version,
		})
		if err != nil {
			log.Println("[UPGRADE_MANAGER]check version failed: " + err.Error())
			continue
		}
		if resp.HasNewVersion {
			this.Start()
		}
	}
}

// Start 启动升级
func (this *UpgradeManager) Start() {
	// 必须放在文件解压之前读取可执行文件路径，防止解压之后，当前的可执行文件路径发生改变
	exe, err := os.Executable()
	if err != nil {
		log.Println("[UPGRADE_MANAGER]can not find current executable file name")
		return
	}
	this.exe = exe

	// 测试环境下不更新
	if Tea.IsTesting() {
		return
	}

	if this.isInstalling {
		return
	}
	this.isInstalling = true

	// 还原安装状态
	defer func() {
		this.isInstalling = false
	}()

	log.Println("[UPGRADE_MANAGER]upgrading httpdns node ...")
	err = this.install()
	if err != nil {
		log.Println("[UPGRADE_MANAGER]download failed: " + err.Error())
		return
	}

	log.Println("[UPGRADE_MANAGER]upgrade successfully")

	go func() {
		err = this.restart()
		if err != nil {
			log.Println("[UPGRADE_MANAGER]" + err.Error())
		}
	}()
}

func (this *UpgradeManager) install() error {
	// 检查是否有已下载但未安装成功的
	if len(this.lastFile) > 0 {
		_, err := os.Stat(this.lastFile)
		if err == nil {
			err = this.unzip(this.lastFile)
			if err != nil {
				return err
			}
			this.lastFile = ""
			return nil
		}
	}

	// 创建临时文件
	dir := Tea.Root + "/tmp"
	_, err := os.Stat(dir)
	if err != nil {
		if os.IsNotExist(err) {
			err = os.Mkdir(dir, 0777)
			if err != nil {
				return err
			}
		} else {
			return err
		}
	}

	log.Println("[UPGRADE_MANAGER]downloading new node ...")

	path := dir + "/" + teaconst.ProcessName + ".tmp"
	fp, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0777)
	if err != nil {
		return err
	}
	isClosed := false
	defer func() {
		if !isClosed {
			_ = fp.Close()
		}
	}()

	client, err := rpc.SharedRPC()
	if err != nil {
		return err
	}

	var offset int64
	var h = md5.New()
	var sum = ""
	var filename = ""
	for {
		resp, err := client.HTTPDNSNodeRPC.DownloadHTTPDNSNodeInstallationFile(client.Context(), &pb.DownloadHTTPDNSNodeInstallationFileRequest{
			Os:          runtime.GOOS,
			Arch:        runtime.GOARCH,
			ChunkOffset: offset,
		})
		if err != nil {
			return err
		}
		if len(resp.Sum) == 0 {
			return nil
		}
		sum = resp.Sum
		filename = resp.Filename
		if stringutil.VersionCompare(resp.Version, teaconst.Version) <= 0 {
			return nil
		}
		if len(resp.ChunkData) == 0 {
			break
		}

		// 写入文件
		_, err = fp.Write(resp.ChunkData)
		if err != nil {
			return err
		}
		_, err = h.Write(resp.ChunkData)
		if err != nil {
			return err
		}

		offset = resp.Offset
	}

	if len(filename) == 0 {
		return nil
	}

	isClosed = true
	err = fp.Close()
	if err != nil {
		return err
	}

	if fmt.Sprintf("%x", h.Sum(nil)) != sum {
		_ = os.Remove(path)
		return nil
	}

	// 改成zip
	zipPath := dir + "/" + filename
	err = os.Rename(path, zipPath)
	if err != nil {
		return err
	}
	this.lastFile = zipPath

	// 解压
	err = this.unzip(zipPath)
	if err != nil {
		return err
	}

	return nil
}

// 解压
func (this *UpgradeManager) unzip(zipPath string) error {
	var isOk = false
	defer func() {
		if isOk {
			// 只有解压并覆盖成功后才会删除
			_ = os.Remove(zipPath)
		}
	}()

	// 解压
	var target = Tea.Root
	if Tea.IsTesting() {
		// 测试环境下只解压在tmp目录
		target = Tea.Root + "/tmp"
	}

	// 先改先前的可执行文件
	err := os.Rename(target+"/bin/"+teaconst.ProcessName, target+"/bin/."+teaconst.ProcessName+".dist")
	hasBackup := err == nil
	defer func() {
		if !isOk && hasBackup {
			// 失败时还原
			_ = os.Rename(target+"/bin/."+teaconst.ProcessName+".dist", target+"/bin/"+teaconst.ProcessName)
		}
	}()

	unzip := utils.NewUnzip(zipPath, target, teaconst.ProcessName+"/")
	err = unzip.Run()
	if err != nil {
		return err
	}

	isOk = true

	return nil
}

// 重启
func (this *UpgradeManager) restart() error {
	// 关闭当前sock，防止无法重启
	_ = gosock.NewTmpSock(teaconst.ProcessName).Close()

	// 重新启动
	if DaemonIsOn && DaemonPid == os.Getppid() {
		os.Exit(0)
	} else {
		// 启动
		var exe = filepath.Dir(this.exe) + "/" + teaconst.ProcessName

		log.Println("[UPGRADE_MANAGER]restarting ...", exe)
		cmd := exec.Command(exe, "start")
		err := cmd.Start()
		if err != nil {
			return err
		}

		// 退出当前进程
		time.Sleep(1 * time.Second)
		os.Exit(0)
	}
	return nil
}