package main

import (
	"archive/tar"
	"compress/gzip"
	"context"
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"hnyfkj.com.cn/rtu/linux/baseapp"
	"hnyfkj.com.cn/rtu/linux/utils/jsonrpc2"
)

type PkgInfo struct {
	FileName    string `json:"fileName"`
	FileSize    int64  `json:"fileSize"`
	CheckMD5Val string `json:"fileMD5"`
	UploadTime  string `json:"uploadTime"`
}

type AppInfo struct {
	Name        string   `json:"name"`
	Version     string   `json:"version"`
	Executable  string   `json:"executable"`
	LibPaths    []string `json:"libraryPaths"`
	Description string   `json:"description"`
	ReadmeFile  string   `json:"readmeFile"`
}

type InsInfo struct {
	Installed   bool   `json:"installed"`
	InstallTime string `json:"installTime"`
}

type AppIns struct {
	Pkg PkgInfo `json:"pkg"` // 应用的安装包
	App AppInfo `json:"app"` // 应用详细信息
	Ins InsInfo `json:"ins"` // 应用是否安装
}

var (
	appMutex sync.Mutex
)

const (
	userAppInsDir  = "/home/root/yfkj-user-app"
	userAppService = "/etc/systemd/system/yfkj-user-app.service"

	ErrConflict jsonrpc2.ErrCode = -32099 ///////// 资源访问冲突
)

// 导入用户安装包
func pkgImport(ctx context.Context, req *jsonrpc2.Request) *jsonrpc2.Response {
	appMutex.Lock()
	defer appMutex.Unlock()

	var params map[string]string

	if err := json.Unmarshal(req.Params, &params); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, err.Error())
	}

	file, ok := params["file"]
	if !ok || file == "" {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, "missing or empty 'file' parameter")
	}

	defer os.Remove(file)

	if !strings.HasSuffix(strings.ToLower(filepath.Base(file)), ".tar.gz") {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, "invalid install package format")
	}

	info, err := os.Stat(file)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, err.Error())
	}

	if !info.Mode().IsRegular() {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, "invalid install package file")
	}

	if err := os.MkdirAll(userAppPkgDir, 0755); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if hasImportedPackage(userAppPkgDir) {
		return jsonrpc2.BuildError(req, ErrConflict, "application package already exists")
	}

	appInfo, err := readAppJSON(file)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, err.Error())
	}

	md5Val, err := fileMD5(file)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	savePkgFile := filepath.Join(userAppPkgDir, filepath.Base(file))
	if err := moveFile(file, savePkgFile); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	appIns := AppIns{
		Pkg: PkgInfo{
			FileName:    filepath.Base(file),
			FileSize:    info.Size(),
			CheckMD5Val: md5Val,
			UploadTime:  time.Now().Format("2006-01-02 15:04:05"),
		},
		App: appInfo,
		Ins: InsInfo{
			Installed: false,
		},
	}

	data, err := json.MarshalIndent(appIns, "", "  ")
	if err != nil {
		os.Remove(savePkgFile)
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	appInsFile := filepath.Join(userAppPkgDir, "appins.json")
	if err := writeFileAtomic(appInsFile, data, 0644); err != nil {
		os.Remove(savePkgFile)
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	baseapp.Logger.Infof("导入用户应用安装包成功: %s, 版本: %s, 描述: %s",
		appIns.App.Name, appIns.App.Version, appIns.App.Description)

	return jsonrpc2.BuildResponse(req, "success", nil)
}

// 删除用户安装包
func pkgRemove(ctx context.Context, req *jsonrpc2.Request) *jsonrpc2.Response {
	appMutex.Lock()
	defer appMutex.Unlock()

	appInsFile := filepath.Join(userAppPkgDir, "appins.json")

	var appIns AppIns
	data, err := os.ReadFile(appInsFile)
	if err == nil {
		if err := json.Unmarshal(data, &appIns); err == nil {
			if appIns.Ins.Installed { // 用户应用已安装
				return jsonrpc2.BuildError(req, ErrConflict, "application is installed, please uninstall it first")
			}
		}
	} else if !os.IsNotExist(err) {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := os.RemoveAll(userAppPkgDir); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := os.MkdirAll(userAppPkgDir, 0755); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	baseapp.Logger.Infof("删除用户应用安装包成功: %s, 版本: %s, 描述: %s",
		appIns.App.Name, appIns.App.Version, appIns.App.Description)

	return jsonrpc2.BuildResponse(req, "success", nil)
}

// 安装包应用安装
func appInstall(ctx context.Context, req *jsonrpc2.Request) *jsonrpc2.Response {
	appMutex.Lock()
	defer appMutex.Unlock()

	appInsFile := filepath.Join(userAppPkgDir, "appins.json")

	data, err := os.ReadFile(appInsFile)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, "application package not found")
	}

	var appIns AppIns
	if err := json.Unmarshal(data, &appIns); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if appIns.Ins.Installed {
		return jsonrpc2.BuildError(req, ErrConflict, "application already installed")
	}

	success := false

	defer func() {
		if !success {
			baseapp.Logger.Warnf("安装用户应用失败状态回滚: %s", userAppInsDir)

			systemctlIgnoreError("stop", "yfkj-user-app.service")
			systemctlIgnoreError("disable", "yfkj-user-app.service")

			os.RemoveAll(userAppInsDir)
			os.Remove(userAppService)

			systemctlIgnoreError("daemon-reload")
		}
	}()

	systemctlIgnoreError("stop", "yfkj-user-app.service")

	if err := os.MkdirAll(userAppInsDir, 0755); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	appPkgFile := filepath.Join(userAppPkgDir, appIns.Pkg.FileName)

	if err := extractTarGz(appPkgFile, userAppInsDir); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	execFile := filepath.Join(userAppInsDir, appIns.App.Executable)

	info, err := os.Stat(execFile)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, "executable not found")
	}

	if !info.Mode().IsRegular() {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, "invalid executable")
	}

	if err := os.Chmod(execFile, 0755); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := createUserAppService(appIns.App, userAppInsDir); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := systemctl("daemon-reload"); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := systemctl("enable", "yfkj-user-app.service"); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := systemctl("start", "yfkj-user-app.service"); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	appIns.Ins.Installed = true
	appIns.Ins.InstallTime = time.Now().Format("2006-01-02 15:04:05")

	data, err = json.MarshalIndent(appIns, "", "  ")
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := writeFileAtomic(appInsFile, data, 0644); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	success = true

	baseapp.Logger.Infof("安装用户应用成功: %s, 版本: %s, 描述: %s",
		appIns.App.Name, appIns.App.Version, appIns.App.Description)

	return jsonrpc2.BuildResponse(req, "success", nil)
}

// 卸载已安装应用
func appUninstall(ctx context.Context, req *jsonrpc2.Request) *jsonrpc2.Response {
	appMutex.Lock()
	defer appMutex.Unlock()

	appInsFile := filepath.Join(userAppPkgDir, "appins.json")

	data, err := os.ReadFile(appInsFile)
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInvalidParams, "application package not found")
	}

	var appIns AppIns
	if err := json.Unmarshal(data, &appIns); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if !appIns.Ins.Installed {
		return jsonrpc2.BuildError(req, ErrConflict, "application not installed")
	}

	systemctlIgnoreError("stop", "yfkj-user-app.service")

	systemctlIgnoreError("disable", "yfkj-user-app.service")

	if err := os.Remove(userAppService); err != nil && !os.IsNotExist(err) {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := systemctl("daemon-reload"); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := os.RemoveAll(userAppInsDir); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	appIns.Ins.Installed = false
	appIns.Ins.InstallTime = ""

	data, err = json.MarshalIndent(appIns, "", "  ")
	if err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if err := writeFileAtomic(appInsFile, data, 0644); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	baseapp.Logger.Infof("卸载用户应用成功: %s, 版本: %s, 描述: %s",
		appIns.App.Name, appIns.App.Version, appIns.App.Description)

	return jsonrpc2.BuildResponse(req, "success", nil)
}

// 安装包应用信息
func getInstallInfo(ctx context.Context, req *jsonrpc2.Request) *jsonrpc2.Response {
	appInsFile := filepath.Join(userAppPkgDir, "appins.json")

	data, err := os.ReadFile(appInsFile)
	if err != nil {
		if os.IsNotExist(err) {
			return jsonrpc2.BuildResponse(req, nil, nil)
		}
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	var appIns AppIns
	if err := json.Unmarshal(data, &appIns); err != nil {
		return jsonrpc2.BuildError(req, jsonrpc2.ErrInternal, err.Error())
	}

	if appIns.App.ReadmeFile != "" {
		readme, err := os.ReadFile(filepath.Join(userAppInsDir, appIns.App.ReadmeFile))
		if err != nil {
			appIns.App.ReadmeFile = ""
		} else {
			appIns.App.ReadmeFile = string(readme)
		}
	}

	return jsonrpc2.BuildResponse(req, appIns, nil)
}

func readAppJSON(file string) (AppInfo, error) {
	var app AppInfo

	f, err := os.Open(file)
	if err != nil {
		return app, err
	}
	defer f.Close()

	gz, err := gzip.NewReader(f)
	if err != nil {
		return app, err
	}
	defer gz.Close()

	tr := tar.NewReader(gz)

	for {
		header, err := tr.Next()
		if err == io.EOF {
			break
		}

		if err != nil {
			return app, err
		}

		if header.Typeflag != tar.TypeReg {
			continue
		}

		if path.Base(header.Name) != "app.json" {
			continue
		}

		if header.Size > 2<<20 { // 2MB 上限
			return app, fmt.Errorf("app.json 文件过大")
		}

		data, err := io.ReadAll(io.LimitReader(tr, header.Size))
		if err != nil {
			return app, err
		}

		err = json.Unmarshal(data, &app)
		if err != nil {
			return app, err
		}

		if app.Name == "" || app.Version == "" || app.Executable == "" {
			return app, fmt.Errorf("app.json参数不完整")
		}

		if !validRelativePath(app.Executable) {
			return app, fmt.Errorf("invalid executable path")
		}

		for _, p := range app.LibPaths {
			if validRelativePath(p) {
				continue
			}
			return app, fmt.Errorf("invalid library path: %s", p)
		}

		return app, nil
	}

	return app, fmt.Errorf("安装包中未找到 app.json")
}

func fileMD5(file string) (string, error) {
	f, err := os.Open(file)
	if err != nil {
		return "", err
	}
	defer f.Close()

	h := md5.New()
	if _, err := io.Copy(h, f); err != nil {
		return "", err
	}
	return hex.EncodeToString(h.Sum(nil)), nil
}

func moveFile(src, dst string) error {
	if err := os.Rename(src, dst); err == nil {
		return nil
	}

	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}

	_, err = io.Copy(out, in)
	if err != nil {
		out.Close()
		os.Remove(dst)
		return err
	}

	if err := out.Close(); err != nil {
		os.Remove(dst)
		return err
	}

	return os.Remove(src)
}

func validRelativePath(p string) bool {
	if p == "" {
		return false
	}

	if filepath.IsAbs(p) {
		return false
	}

	clean := filepath.Clean(p)

	if clean != p {
		return false
	}

	if clean == ".." ||
		strings.HasPrefix(clean, ".."+string(os.PathSeparator)) {
		return false
	}

	return true
}

func isRegularFile(name string) bool {
	info, err := os.Stat(name)
	if err != nil {
		return false
	}
	return info.Mode().IsRegular()
}

func hasImportedPackage(dir string) bool {
	if isRegularFile(filepath.Join(dir, "appins.json")) {
		return true
	}

	entries, err := os.ReadDir(dir)
	if err != nil {
		return false
	}

	for _, entry := range entries {
		if entry.IsDir() {
			continue
		}

		if strings.HasSuffix(strings.ToLower(entry.Name()), ".tar.gz") {
			return true
		}
	}

	return false
}

func writeFileAtomic(name string, data []byte, perm os.FileMode) error {
	tmp := name + ".tmp"

	defer os.Remove(tmp)

	f, err := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, perm)
	if err != nil {
		return err
	}

	if _, err := f.Write(data); err != nil {
		f.Close()
		return err
	}

	if err := f.Sync(); err != nil {
		f.Close()
		return err
	}

	if err := f.Close(); err != nil {
		return err
	}

	return os.Rename(tmp, name)
}

func extractTarGz(src string, dst string) error {
	f, err := os.Open(src)
	if err != nil {
		return err
	}
	defer f.Close()

	gz, err := gzip.NewReader(f)
	if err != nil {
		return err
	}
	defer gz.Close()

	tr := tar.NewReader(gz)

	root := filepath.Clean(dst) + string(os.PathSeparator)

	for {
		header, err := tr.Next()

		if err == io.EOF {
			break
		}

		if err != nil {
			return err
		}

		name := filepath.Join(dst, header.Name)
		name = filepath.Clean(name)

		if !strings.HasPrefix(name+string(os.PathSeparator), root) {
			return fmt.Errorf("invalid path: %s", header.Name)
		}

		switch header.Typeflag {
		case tar.TypeDir:
			if err := os.MkdirAll(name, 0755); err != nil {
				return err
			}
		case tar.TypeReg:
			if err := os.MkdirAll(filepath.Dir(name), 0755); err != nil {
				return err
			}

			out, err := os.OpenFile(
				name,
				os.O_CREATE|os.O_WRONLY|os.O_TRUNC,
				os.FileMode(header.Mode),
			)

			if err != nil {
				return err
			}

			_, err = io.Copy(out, tr)

			out.Close()

			if err != nil {
				return err
			}
		default:
			return fmt.Errorf("unsupported tar entry: %s", header.Name)
		}
	}

	return nil
}

func createUserAppService(app AppInfo, installDir string) error {
	execFile := filepath.Join(installDir, app.Executable)

	libPaths := ""
	if len(app.LibPaths) > 0 {
		paths := make([]string, 0, len(app.LibPaths))

		for _, p := range app.LibPaths {
			paths = append(paths, filepath.Join(installDir, p))
		}

		libPaths = strings.Join(paths, ":")
	}

	content := fmt.Sprintf(`[Unit]
Description=%s
After=yfkj-networkd.service
Wants=yfkj-networkd.service

[Service]
Environment="PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin"
Environment="LD_LIBRARY_PATH=%s"
WorkingDirectory=%s
ExecStart=%s
Restart=always
RestartSec=5
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target
`,
		"Yunfei User Application",
		libPaths,
		installDir,
		execFile,
	)

	return os.WriteFile(userAppService, []byte(content), 0644)
}

func systemctl(args ...string) error {
	out, err := exec.Command("systemctl", args...).CombinedOutput()
	if err != nil {
		return fmt.Errorf("systemctl %v failed: %v %s", args, err, string(out))
	}
	return nil
}

func systemctlIgnoreError(args ...string) {
	_ = exec.Command("systemctl", args...).Run()
}