package httpserver

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"os"
	"strings"
	"sync"
	"time"

	"networktool/internal/auth"
	"networktool/internal/config"
	"networktool/internal/deviceinfo"
	"networktool/internal/logger"
	"networktool/internal/model"
	applyexecsvc "networktool/internal/network/applyexec"
	configreadersvc "networktool/internal/network/configreader"
	interfacesvc "networktool/internal/network/interfaces"
	netplansvc "networktool/internal/network/netplan"
	validatorsvc "networktool/internal/network/validator"
	"networktool/internal/systemaction"
	"networktool/internal/tasks"
)

type Server struct {
	cfg           config.Config
	log           *logger.Logger
	deviceSvc     *deviceinfo.Service
	interfaceSvc  *interfacesvc.Service
	configSvc     *configreadersvc.Service
	validatorSvc  *validatorsvc.Service
	netplanSvc    *netplansvc.Service
	applySvc      *applyexecsvc.Service
	taskSvc       *tasks.Service
	systemSvc     *systemaction.Service
	confirmMu     sync.Mutex
	applyControls map[string]applyControl
}

type applyControl struct {
	confirm chan struct{}
	cancel  chan struct{}
}

const applyConfirmationTimeout = 20 * time.Second

func New(cfg config.Config, log *logger.Logger, deviceSvc *deviceinfo.Service, interfaceSvc *interfacesvc.Service, configSvc *configreadersvc.Service, validatorSvc *validatorsvc.Service, netplanSvc *netplansvc.Service, applySvc *applyexecsvc.Service, taskSvc *tasks.Service, systemSvc *systemaction.Service) *Server {
	return &Server{cfg: cfg, log: log, deviceSvc: deviceSvc, interfaceSvc: interfaceSvc, configSvc: configSvc, validatorSvc: validatorSvc, netplanSvc: netplanSvc, applySvc: applySvc, taskSvc: taskSvc, systemSvc: systemSvc, applyControls: make(map[string]applyControl)}
}

func (s *Server) Run(ctx context.Context) error {
	mux := http.NewServeMux()
	mux.Handle("/api/health", auth.Middleware(s.cfg, http.HandlerFunc(s.handleHealth)))
	mux.Handle("/api/device/info", auth.Middleware(s.cfg, http.HandlerFunc(s.handleDeviceInfo)))
	mux.Handle("/api/network/interfaces", auth.Middleware(s.cfg, http.HandlerFunc(s.handleInterfaces)))
	mux.Handle("/api/network/configs", auth.Middleware(s.cfg, http.HandlerFunc(s.handleConfigs)))
	mux.Handle("/api/network/validate", auth.Middleware(s.cfg, http.HandlerFunc(s.handleValidate)))
	mux.Handle("/api/network/validate-all", auth.Middleware(s.cfg, http.HandlerFunc(s.handleValidateAll)))
	mux.Handle("/api/network/apply", auth.Middleware(s.cfg, http.HandlerFunc(s.handleApply)))
	mux.Handle("/api/network/apply-all", auth.Middleware(s.cfg, http.HandlerFunc(s.handleApplyAll)))
	mux.Handle("/api/network/apply/confirm", auth.Middleware(s.cfg, http.HandlerFunc(s.handleApplyConfirm)))
	mux.Handle("/api/network/apply/cancel", auth.Middleware(s.cfg, http.HandlerFunc(s.handleApplyCancel)))
	mux.Handle("/api/network/rollback", auth.Middleware(s.cfg, http.HandlerFunc(s.handleRollback)))
	mux.Handle("/api/system/reboot", auth.Middleware(s.cfg, http.HandlerFunc(s.handleReboot)))
	mux.Handle("/api/system/shutdown", auth.Middleware(s.cfg, http.HandlerFunc(s.handleShutdown)))
	mux.Handle("/api/tasks/", auth.Middleware(s.cfg, http.HandlerFunc(s.handleTaskGet)))
	handler := s.withAccessLog(mux)

	server := &http.Server{
		Addr:              fmt.Sprintf("%s:%d", s.cfg.HTTPHost, s.cfg.HTTPPort),
		Handler:           handler,
		ReadHeaderTimeout: 5 * time.Second,
	}

	go func() {
		<-ctx.Done()
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		_ = server.Shutdown(shutdownCtx)
	}()

	s.log.Info("http server listening", "addr", server.Addr)
	err := server.ListenAndServe()
	if err == http.ErrServerClosed {
		return nil
	}
	return err
}

func (s *Server) handleApplyConfirm(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	var input model.ConfirmApplyRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	if input.TaskID == "" {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"缺少 task_id。"}}})
		return
	}

	if !s.confirmApply(input.TaskID) {
		writeJSON(w, http.StatusNotFound, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "已确认保留配置", Data: map[string]any{"task_id": input.TaskID, "confirmed": true}})
}

func (s *Server) handleApplyCancel(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	var input model.ConfirmApplyRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	if input.TaskID == "" {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"缺少 task_id。"}}})
		return
	}

	if !s.cancelApply(input.TaskID) {
		writeJSON(w, http.StatusNotFound, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "已取消保留配置，正在回滚", Data: map[string]any{"task_id": input.TaskID, "cancelled": true}})
}

func (s *Server) withAccessLog(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		started := time.Now()
		rw := &statusRecorder{ResponseWriter: w, statusCode: http.StatusOK}
		next.ServeHTTP(rw, r)
		s.log.Info(
			"http request completed",
			"method", r.Method,
			"path", r.URL.Path,
			"query", r.URL.RawQuery,
			"remote", r.RemoteAddr,
			"status", rw.statusCode,
			"duration_ms", time.Since(started).Milliseconds(),
		)
	})
}

type statusRecorder struct {
	http.ResponseWriter
	statusCode int
}

func (r *statusRecorder) WriteHeader(statusCode int) {
	r.statusCode = statusCode
	r.ResponseWriter.WriteHeader(statusCode)
}

func (s *Server) handleHealth(w http.ResponseWriter, _ *http.Request) {
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "成功", Data: map[string]any{"status": "运行中", "server_version": s.cfg.ServerVersion}})
}

func (s *Server) handleDeviceInfo(w http.ResponseWriter, _ *http.Request) {
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "成功", Data: s.deviceSvc.Get()})
}

func (s *Server) handleInterfaces(w http.ResponseWriter, _ *http.Request) {
	data, err := s.interfaceSvc.List()
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string]string{"error": err.Error()}})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "成功", Data: data})
}

func (s *Server) handleConfigs(w http.ResponseWriter, _ *http.Request) {
	interfaces, err := s.interfaceSvc.List()
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string]string{"error": err.Error()}})
		return
	}

	result := model.InterfaceConfigsResponse{
		Configs: []model.InterfaceConfig{},
		Errors:  []model.InterfaceConfigError{},
	}
	for _, item := range interfaces.Interfaces {
		data, err := s.configSvc.Read(item.SystemName)
		if err != nil {
			result.Errors = append(result.Errors, model.InterfaceConfigError{Interface: item.SystemName, Message: err.Error()})
			continue
		}
		result.Configs = append(result.Configs, data)
	}

	message := "成功"
	if len(result.Errors) > 0 {
		message = "部分接口配置读取失败"
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: message, Data: result})
}

func (s *Server) handleValidate(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	body, err := io.ReadAll(r.Body)
	if err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体读取失败。"}}})
		return
	}
	var input model.InterfaceConfig
	if err := json.Unmarshal(body, &input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	if input.Interface != "" && !s.interfaceExists(input.Interface) {
		result := model.ValidateResponse{Valid: false, Errors: []string{"目标接口不存在。"}, Warnings: []string{}}
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: result})
		return
	}
	result := s.validatorSvc.Validate(input)
	s.addManagementAddressWarning(&result, input)
	if !result.Valid {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: result})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "校验通过", Data: result})
}

func (s *Server) handleValidateAll(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	var input model.InterfaceConfigsRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	result := s.validateConfigs(input.Configs)
	if !result.Valid {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: result})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "校验通过", Data: result})
}

func (s *Server) handleApply(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	if !hasRootPrivileges() {
		writeJSON(w, http.StatusForbidden, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"Server 未以 root 身份运行，无法写入 netplan 或执行 netplan apply。"}}})
		return
	}
	var input model.InterfaceConfig
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	if !s.interfaceExists(input.Interface) {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: model.ValidateResponse{Valid: false, Errors: []string{"目标接口不存在。"}}})
		return
	}
	result := s.validatorSvc.Validate(input)
	if !result.Valid {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: result})
		return
	}
	management := s.currentManagementInterface()
	if management == "" {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"未能识别管理接口。"}}})
		return
	}
	task := s.taskSvc.Create()
	go s.runApplyTask(task.TaskID, input, management)
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "配置任务已提交", Data: map[string]any{"interface": input.Interface, "task_id": task.TaskID}})
}

func (s *Server) handleApplyAll(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	if !hasRootPrivileges() {
		writeJSON(w, http.StatusForbidden, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"Server 未以 root 身份运行，无法写入 netplan 或执行 netplan apply。"}}})
		return
	}
	var input model.InterfaceConfigsRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	result := s.validateConfigs(input.Configs)
	if !result.Valid {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 3001, Message: "配置校验失败", Data: result})
		return
	}
	management := s.currentManagementInterface()
	if management == "" {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"未能识别管理接口。"}}})
		return
	}
	task := s.taskSvc.Create()
	go s.runApplyAllTask(task.TaskID, input.Configs, management)
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "配置任务已提交", Data: map[string]any{"task_id": task.TaskID}})
}

func (s *Server) handleRollback(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	if !hasRootPrivileges() {
		writeJSON(w, http.StatusForbidden, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"Server 未以 root 身份运行，无法恢复 netplan 或执行 netplan apply。"}}})
		return
	}
	var input model.RollbackRequest
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"请求体格式不正确。"}}})
		return
	}
	filePath, err := s.netplanSvc.FindSingleFile()
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string]string{"error": err.Error()}})
		return
	}
	backupPath := filePath + ".networktool.bak"
	if err := s.netplanSvc.Restore(filePath, backupPath); err != nil {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 3004, Message: "回滚失败", Data: map[string]string{"error": err.Error()}})
		return
	}
	if err := s.applySvc.Apply(); err != nil {
		writeJSON(w, http.StatusInternalServerError, model.APIResponse{Code: 3004, Message: "回滚失败", Data: map[string]string{"error": err.Error()}})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "回滚成功", Data: map[string]any{"interface": input.Interface, "rolled_back": true}})
}

func (s *Server) handleTaskGet(w http.ResponseWriter, r *http.Request) {
	taskID := strings.TrimPrefix(r.URL.Path, "/api/tasks/")
	if taskID == "" {
		writeJSON(w, http.StatusBadRequest, model.APIResponse{Code: 2001, Message: "参数错误", Data: map[string][]string{"errors": []string{"缺少 task_id。"}}})
		return
	}
	item, ok := s.taskSvc.Get(taskID)
	if !ok {
		writeJSON(w, http.StatusNotFound, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: "成功", Data: item})
}

func (s *Server) handleReboot(w http.ResponseWriter, r *http.Request) {
	s.handleSystemAction(w, r, "reboot")
}

func (s *Server) handleShutdown(w http.ResponseWriter, r *http.Request) {
	s.handleSystemAction(w, r, "shutdown")
}

func (s *Server) handleSystemAction(w http.ResponseWriter, r *http.Request, action string) {
	if r.Method != http.MethodPost {
		writeJSON(w, http.StatusMethodNotAllowed, model.APIResponse{Code: 2002, Message: "资源不存在", Data: nil})
		return
	}
	if !hasRootPrivileges() {
		writeJSON(w, http.StatusForbidden, model.APIResponse{Code: 4001, Message: "系统执行失败", Data: map[string][]string{"errors": []string{"Server 未以 root 身份运行，无法执行重启或关机。"}}})
		return
	}

	task := s.taskSvc.Create()
	go s.runSystemTask(task.TaskID, action)
	message := "系统任务已提交"
	if action == "reboot" {
		message = "重启任务已提交"
	} else if action == "shutdown" {
		message = "关机任务已提交"
	}
	writeJSON(w, http.StatusOK, model.APIResponse{Code: 0, Message: message, Data: map[string]any{"action": action, "task_id": task.TaskID}})
}

func (s *Server) runApplyTask(taskID string, input model.InterfaceConfig, managementInterface string) {
	s.taskSvc.Update(taskID, "running", "validating", "正在校验配置。", false)
	result := s.validatorSvc.Validate(input)
	if !result.Valid {
		s.taskSvc.Update(taskID, "failed", "validating", "配置校验失败。", false)
		return
	}

	filePath, err := s.netplanSvc.FindSingleFile()
	if err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}

	s.taskSvc.Update(taskID, "running", "writing_netplan", "正在写入 netplan 配置。", false)
	backupPath, err := s.netplanSvc.Backup(filePath)
	if err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}
	s.log.Info("preparing to write netplan", "task_id", taskID, "file", filePath, "target_interface", input.Interface, "addresses", formatAddresses(input), "routes", formatRoutes(input), "dns", strings.Join(input.DNS, ","))
	if err := s.netplanSvc.Write(filePath, input.Interface, input, managementInterface, s.cfg.MaintenanceCIDR); err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}
	if writtenData, err := os.ReadFile(filePath); err != nil {
		s.log.Error("failed to read netplan after write", "task_id", taskID, "file", filePath, "error", err.Error())
	} else {
		s.log.Info("netplan written", "task_id", taskID, "file", filePath, "content", string(writtenData))
	}

	control := s.registerApplyControl(taskID)
	defer s.unregisterApplyControl(taskID)
	s.taskSvc.Update(taskID, "running", "applying", "正在应用 netplan 配置。", false)
	if err := s.applySvc.Apply(); err != nil {
		s.log.Error("netplan apply failed, restoring netplan file", "task_id", taskID, "file", filePath, "error", err.Error())
		_ = s.netplanSvc.Restore(filePath, backupPath)
		_ = s.applySvc.Apply()
		s.logNetplanFile(taskID, filePath, "netplan restored after apply failure")
		s.taskSvc.Update(taskID, "rolled_back", "rolling_back", fmt.Sprintf("应用 netplan 失败，已自动回滚：%v", err), true)
		return
	}

	s.taskSvc.Update(taskID, "running", "confirming", fmt.Sprintf("配置已应用，请在 %d 秒内确认保留；未确认将自动回滚。", int(applyConfirmationTimeout.Seconds())), false)
	select {
	case <-control.confirm:
		_ = os.Remove(backupPath)
		s.taskSvc.Update(taskID, "success", "completed", "配置已应用并由客户端确认保留。", false)
		return
	case <-control.cancel:
		s.rollbackAppliedConfig(taskID, filePath, backupPath, "用户取消保留配置")
		return
	case <-time.After(applyConfirmationTimeout):
		s.rollbackAppliedConfig(taskID, filePath, backupPath, "客户端未在限定时间内确认保留配置")
		return
	}
}

func (s *Server) runApplyAllTask(taskID string, inputs []model.InterfaceConfig, managementInterface string) {
	s.taskSvc.Update(taskID, "running", "validating", "正在校验配置。", false)
	result := s.validateConfigs(inputs)
	if !result.Valid {
		s.taskSvc.Update(taskID, "failed", "validating", "配置校验失败。", false)
		return
	}

	filePath, err := s.netplanSvc.FindSingleFile()
	if err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}

	s.taskSvc.Update(taskID, "running", "writing_netplan", "正在写入 netplan 配置。", false)
	backupPath, err := s.netplanSvc.Backup(filePath)
	if err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}
	if err := s.netplanSvc.WriteMany(filePath, inputs, managementInterface, s.cfg.MaintenanceCIDR); err != nil {
		s.taskSvc.Update(taskID, "failed", "writing_netplan", err.Error(), false)
		return
	}
	if writtenData, err := os.ReadFile(filePath); err != nil {
		s.log.Error("failed to read netplan after write", "task_id", taskID, "file", filePath, "error", err.Error())
	} else {
		s.log.Info("netplan written", "task_id", taskID, "file", filePath, "content", string(writtenData))
	}

	control := s.registerApplyControl(taskID)
	defer s.unregisterApplyControl(taskID)
	s.taskSvc.Update(taskID, "running", "applying", "正在应用 netplan 配置。", false)
	if err := s.applySvc.Apply(); err != nil {
		s.log.Error("netplan apply failed, restoring netplan file", "task_id", taskID, "file", filePath, "error", err.Error())
		_ = s.netplanSvc.Restore(filePath, backupPath)
		_ = s.applySvc.Apply()
		s.logNetplanFile(taskID, filePath, "netplan restored after apply failure")
		s.taskSvc.Update(taskID, "rolled_back", "rolling_back", fmt.Sprintf("应用 netplan 失败，已自动回滚：%v", err), true)
		return
	}

	s.taskSvc.Update(taskID, "running", "confirming", fmt.Sprintf("配置已应用，请在 %d 秒内确认保留；未确认将自动回滚。", int(applyConfirmationTimeout.Seconds())), false)
	select {
	case <-control.confirm:
		_ = os.Remove(backupPath)
		s.taskSvc.Update(taskID, "success", "completed", "配置已应用并由客户端确认保留。", false)
		return
	case <-control.cancel:
		s.rollbackAppliedConfig(taskID, filePath, backupPath, "用户取消保留配置")
		return
	case <-time.After(applyConfirmationTimeout):
		s.rollbackAppliedConfig(taskID, filePath, backupPath, "客户端未在限定时间内确认保留配置")
		return
	}
}

func (s *Server) validateConfigs(inputs []model.InterfaceConfig) model.ValidateResponse {
	result := model.ValidateResponse{Valid: true, Warnings: []string{}, Errors: []string{}}
	if len(inputs) == 0 {
		result.Valid = false
		result.Errors = append(result.Errors, "接口配置不能为空。")
		return result
	}
	seen := make(map[string]struct{})
	defaultRouteInterfaces := make([]string, 0, 1)
	managementInterface := s.currentManagementInterface()
	for _, input := range inputs {
		name := strings.TrimSpace(input.Interface)
		if name == "" {
			result.Valid = false
			result.Errors = append(result.Errors, "目标接口不能为空。")
			continue
		}
		if _, ok := seen[name]; ok {
			result.Valid = false
			result.Errors = append(result.Errors, fmt.Sprintf("接口重复：%s", name))
			continue
		}
		seen[name] = struct{}{}
		if !s.interfaceExists(name) {
			result.Valid = false
			result.Errors = append(result.Errors, fmt.Sprintf("目标接口不存在：%s", name))
			continue
		}
		if hasDefaultRouteConfig(input) {
			defaultRouteInterfaces = append(defaultRouteInterfaces, name)
		}
		item := s.validatorSvc.Validate(input)
		if name == managementInterface {
			addManagementAddressWarning(&item, input)
		}
		if !item.Valid {
			result.Valid = false
		}
		for _, err := range item.Errors {
			result.Errors = append(result.Errors, fmt.Sprintf("%s：%s", name, err))
		}
		for _, warning := range item.Warnings {
			result.Warnings = append(result.Warnings, fmt.Sprintf("%s：%s", name, warning))
		}
	}
	if len(defaultRouteInterfaces) > 1 {
		result.Valid = false
		result.Errors = append(result.Errors, fmt.Sprintf("只能有一个网口配置默认网关，当前检测到多个默认网关：%s。", strings.Join(defaultRouteInterfaces, "、")))
	}
	return result
}

func hasDefaultRouteConfig(input model.InterfaceConfig) bool {
	if input.Dhcp4 {
		return false
	}
	for _, route := range input.Routes {
		if strings.TrimSpace(route.To) == "default" && strings.TrimSpace(route.Via) != "" {
			return true
		}
	}
	return false
}

func (s *Server) addManagementAddressWarning(result *model.ValidateResponse, input model.InterfaceConfig) {
	managementInterface := s.currentManagementInterface()
	if managementInterface == "" || strings.TrimSpace(input.Interface) != managementInterface {
		return
	}
	addManagementAddressWarning(result, input)
}

func addManagementAddressWarning(result *model.ValidateResponse, input model.InterfaceConfig) {
	if hasLinkLocalAddress(input) {
		return
	}
	result.Warnings = append(result.Warnings, "直连接口未配置 169.254 链路本地地址，可能导致客户端无法通过维护链路发现或连接设备。")
}

func hasLinkLocalAddress(input model.InterfaceConfig) bool {
	addresses := input.Addresses
	if len(addresses) == 0 && strings.TrimSpace(input.IP) != "" {
		addresses = []model.InterfaceAddressConfig{{IP: strings.TrimSpace(input.IP), Prefix: input.Prefix}}
	}
	for _, address := range addresses {
		ip := net.ParseIP(strings.TrimSpace(address.IP))
		if ip == nil {
			continue
		}
		ipv4 := ip.To4()
		if ipv4 != nil && ipv4[0] == 169 && ipv4[1] == 254 {
			return true
		}
	}
	return false
}

func (s *Server) rollbackAppliedConfig(taskID string, filePath string, backupPath string, reason string) {
	s.log.Warn("apply confirmation failed, restoring netplan file", "task_id", taskID, "file", filePath, "reason", reason)
	_ = s.netplanSvc.Restore(filePath, backupPath)
	_ = s.applySvc.Apply()
	s.logNetplanFile(taskID, filePath, "netplan restored after confirmation failure")
	s.taskSvc.Update(taskID, "rolled_back", "rolling_back", fmt.Sprintf("%s，已自动回滚。", reason), true)
}

func (s *Server) registerApplyControl(taskID string) applyControl {
	control := applyControl{confirm: make(chan struct{}, 1), cancel: make(chan struct{}, 1)}
	s.confirmMu.Lock()
	s.applyControls[taskID] = control
	s.confirmMu.Unlock()
	return control
}

func (s *Server) unregisterApplyControl(taskID string) {
	s.confirmMu.Lock()
	delete(s.applyControls, taskID)
	s.confirmMu.Unlock()
}

func (s *Server) confirmApply(taskID string) bool {
	s.confirmMu.Lock()
	control, ok := s.applyControls[taskID]
	s.confirmMu.Unlock()
	if !ok {
		return false
	}
	select {
	case control.confirm <- struct{}{}:
	default:
	}
	return true
}

func (s *Server) cancelApply(taskID string) bool {
	s.confirmMu.Lock()
	control, ok := s.applyControls[taskID]
	s.confirmMu.Unlock()
	if !ok {
		return false
	}
	select {
	case control.cancel <- struct{}{}:
	default:
	}
	return true
}

func (s *Server) logNetplanFile(taskID string, filePath string, message string) {
	data, err := os.ReadFile(filePath)
	if err != nil {
		s.log.Error("failed to read netplan file for logging", "task_id", taskID, "file", filePath, "error", err.Error())
		return
	}
	s.log.Info(message, "task_id", taskID, "file", filePath, "content", string(data))
}

func (s *Server) runSystemTask(taskID string, action string) {
	detail := "正在发送系统指令。"
	if action == "reboot" {
		detail = "正在发送重启指令。"
	} else if action == "shutdown" {
		detail = "正在发送关机指令。"
	}
	s.taskSvc.Update(taskID, "running", "executing", detail, false)

	var err error
	switch action {
	case "reboot":
		err = s.systemSvc.Reboot()
	case "shutdown":
		err = s.systemSvc.Shutdown()
	default:
		err = fmt.Errorf("unsupported system action: %s", action)
	}
	if err != nil {
		s.log.Error("system action failed", "action", action, "error", err.Error())
		s.taskSvc.Update(taskID, "failed", "executing", err.Error(), false)
		return
	}

	completedDetail := "系统指令已发送。"
	if action == "reboot" {
		completedDetail = "系统重启指令已发送。"
	} else if action == "shutdown" {
		completedDetail = "系统关机指令已发送。"
	}
	s.taskSvc.Update(taskID, "success", "completed", completedDetail, false)
}

func (s *Server) interfaceExists(name string) bool {
	data, err := s.interfaceSvc.List()
	if err != nil {
		return false
	}
	for _, item := range data.Interfaces {
		if item.SystemName == name {
			return true
		}
	}
	return false
}

func (s *Server) currentManagementInterface() string {
	data, err := s.interfaceSvc.List()
	if err != nil {
		return ""
	}
	return data.ManagementInterface
}

func writeJSON(w http.ResponseWriter, status int, payload model.APIResponse) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(payload)
}

func hasRootPrivileges() bool {
	return os.Geteuid() == 0
}

func formatAddresses(input model.InterfaceConfig) string {
	addresses := input.Addresses
	if len(addresses) == 0 && strings.TrimSpace(input.IP) != "" {
		addresses = []model.InterfaceAddressConfig{{IP: input.IP, Prefix: input.Prefix}}
	}
	items := make([]string, 0, len(addresses))
	for _, address := range addresses {
		items = append(items, fmt.Sprintf("%s/%d", strings.TrimSpace(address.IP), address.Prefix))
	}
	return strings.Join(items, ",")
}

func formatRoutes(input model.InterfaceConfig) string {
	routes := input.Routes
	if len(routes) == 0 && strings.TrimSpace(input.Gateway) != "" {
		routes = []model.InterfaceRouteConfig{{To: "default", Via: input.Gateway}}
	}
	items := make([]string, 0, len(routes))
	for _, route := range routes {
		items = append(items, fmt.Sprintf("%s via %s", strings.TrimSpace(route.To), strings.TrimSpace(route.Via)))
	}
	return strings.Join(items, ",")
}