package service

import (
	"context"
	"errors"
	"fmt"
	"sort"
	"strings"
	"sync"

	"github.com/1Panel-dev/1Panel/agent/app/dto"
	"github.com/1Panel-dev/1Panel/agent/app/model"
	"github.com/1Panel-dev/1Panel/agent/app/repo"
	"github.com/1Panel-dev/1Panel/agent/app/task"
	"github.com/1Panel-dev/1Panel/agent/constant"
	"github.com/1Panel-dev/1Panel/agent/global"
	"github.com/1Panel-dev/1Panel/agent/i18n"
	"github.com/1Panel-dev/1Panel/agent/utils/firewall"
	"github.com/1Panel-dev/1Panel/agent/utils/firewall/docker_guard"
	"github.com/1Panel-dev/1Panel/agent/utils/firewall/filter"
	filterruntime "github.com/1Panel-dev/1Panel/agent/utils/firewall/filter/runtime"
	"github.com/1Panel-dev/1Panel/agent/utils/firewall/forwarding"
	firewallsync "github.com/1Panel-dev/1Panel/agent/utils/firewall/sync"
	"github.com/google/uuid"
	"gorm.io/gorm"
)

var (
	firewallRuleSyncTaskMu sync.Mutex
	firewallRuleSyncTaskID string
)

type firewallDatabaseSyncAdapter interface {
	previewRuleSync(context.Context, dto.FirewallRuleSyncRequest) (dto.FirewallRuleSyncPreview, error)
	syncRules(context.Context, dto.FirewallRuleSyncRequest) (dto.FirewallRuleSyncResult, error)
}

type firewallSyncRule struct {
	dto.FirewallRuleSyncItem
	desired  filter.DesiredRule
	observed *filter.ObservedRule
	done     bool
}

func firewallSyncSubsystem(value string) string {
	if value = strings.TrimSpace(value); value == "" {
		return "system"
	}
	return value
}

func (s *FirewallService) PreviewRuleSync(ctx context.Context, clientIP string, request dto.FirewallRuleSyncRequest) (dto.FirewallRuleSyncPreview, error) {
	switch firewallSyncSubsystem(request.Subsystem) {
	case "forwarding":
		return s.forwardingRuleSyncService().previewRuleSync(ctx, request)
	case "docker":
		return s.dockerRuleSyncService().previewRuleSync(ctx, request)
	}
	firewallRuleMutationMu.Lock()
	defer firewallRuleMutationMu.Unlock()
	_, rules, _, err := s.loadFirewallSyncRules(ctx, request)
	preview := dto.FirewallRuleSyncPreview{Subsystem: "system", TargetProvider: request.TargetProvider, Items: make([]dto.FirewallRuleSyncItem, 0, len(rules))}
	for _, rule := range rules {
		preview.Add(rule.FirewallRuleSyncItem)
	}
	return preview, err
}

func (s *FirewallService) loadFirewallSyncRules(ctx context.Context, request dto.FirewallRuleSyncRequest) (*filterruntime.Engine, []*firewallSyncRule, []filter.Snapshot, error) {
	if request.SourceProvider != "" || request.ResetSource {
		return nil, nil, nil, fmt.Errorf("%w: system synchronization reads rules from the database", filter.ErrInvalidRule)
	}
	if err := s.checkSelectedProvider(ctx, request.TargetProvider); err != nil {
		return nil, nil, nil, err
	}
	runtime, err := s.adapters.Resolve(request.TargetProvider)
	if err != nil {
		return nil, nil, nil, err
	}
	stored, err := s.rules.List(ctx)
	if err != nil {
		return nil, nil, nil, err
	}
	model.SortFirewallRules(stored, request.TargetProvider)
	ports, err := loadFirewallPortWhiteList()
	if err != nil {
		return nil, nil, nil, err
	}
	required, err := firewall.RequiredPortWhitelist(ports)
	if err != nil {
		return nil, nil, nil, err
	}
	whitelistDesired := whitelistRules(request.TargetProvider, firewall.ExpandPortWhitelist(customWhitelist(ports)), firewall.ExpandPortWhitelist(required))
	rules := make([]*firewallSyncRule, 0, len(stored))
	preservedMarkers := make(map[string]bool)
	compileFailed := false
	for _, record := range stored {
		desired, preserved, err := s.compileRestorableFirewallRules(ctx, record, request.TargetProvider)
		if err != nil {
			compileFailed = true
			rules = append(rules, &firewallSyncRule{FirewallRuleSyncItem: dto.FirewallRuleSyncItem{SourceUUID: record.UUID, Status: firewallsync.StatusBlocked, Reason: err.Error()}})
			continue
		}
		for _, rule := range preserved {
			preservedMarkers[rule.Marker] = true
		}
		for _, native := range desired {
			rule := native.Rule
			native.Protected = filter.RuleMatchesPortWhitelist(rule, ports)
			rules = append(rules, &firewallSyncRule{desired: native, FirewallRuleSyncItem: dto.FirewallRuleSyncItem{SourceUUID: record.UUID, Rule: &rule}})
		}
	}
	for _, candidate := range whitelistDesired {
		prepared, err := s.prepareCreate(ctx, request.TargetProvider, dto.FirewallRuleCreateItem{Rule: candidate})
		if err != nil {
			return nil, nil, nil, err
		}
		rule := prepared.request.Rule
		duplicate := false
		for _, existing := range rules {
			if existing.Rule != nil {
				if same, err := filter.SameRuleContent(*existing.Rule, rule); err == nil && same {
					duplicate = true
					break
				}
			}
		}
		if duplicate {
			continue
		}
		key, err := filter.RuleKey(rule)
		if err != nil {
			return nil, nil, nil, err
		}
		rule.UUID = uuid.NewSHA1(uuid.NameSpaceOID, []byte(key)).String()
		rules = append(rules, &firewallSyncRule{
			desired:              filter.DesiredRule{UUID: rule.UUID, Rule: rule, RuleKey: key, Origin: filter.RuleOriginCreated, Protected: true},
			FirewallRuleSyncItem: dto.FirewallRuleSyncItem{SourceUUID: rule.UUID, Rule: &rule},
		})
	}
	snapshots := make([]filter.Snapshot, 0)
	for _, scope := range filter.ManagedInputScopes(request.TargetProvider) {
		desired := make([]filter.DesiredRule, 0)
		scoped := make([]*firewallSyncRule, 0)
		byUUID := make(map[string]*firewallSyncRule)
		for _, rule := range rules {
			if rule.Rule != nil && rule.Rule.Scope.Key() == scope.Key() {
				scoped = append(scoped, rule)
				desired = append(desired, rule.desired)
				byUUID[rule.desired.Rule.UUID] = rule
			}
		}
		if compileFailed && len(desired) == 0 {
			continue
		}
		snapshot, err := runtime.ObserveMutation(ctx, scope)
		if errors.Is(err, filter.ErrFamilyUnavailable) {
			for _, rule := range scoped {
				rule.Status, rule.Reason = firewallsync.StatusBlocked, err.Error()
			}
			continue
		}
		if err != nil {
			return nil, nil, nil, err
		}
		snapshots = append(snapshots, snapshot)
		inventory, err := filter.MergeInventory(filter.InventoryMergeInput{Observed: snapshot.Rules, Desired: desired})
		if err != nil {
			return nil, nil, nil, err
		}
		matched := make(map[string]filter.InventoryItem)
		for _, item := range inventory {
			if item.Desired == nil {
				if compileFailed || item.Observed == nil || !strings.HasPrefix(item.Observed.Marker, "1panel-rule:") || preservedMarkers[item.Observed.Marker] {
					continue
				}
				observed := item.Observed
				if observed.Rule.Scope.Chain == filter.BasicBeforeChain {
					continue
				}
				rule := &firewallSyncRule{observed: observed, FirewallRuleSyncItem: dto.FirewallRuleSyncItem{
					SourceUUID: strings.TrimPrefix(observed.Marker, "1panel-rule:"), Rule: &observed.Rule, Status: firewallsync.StatusRemove,
					ReasonCode: firewallsync.ReasonManagedOnlyInTarget, Reason: firewallsync.ReasonMessage(firewallsync.ReasonManagedOnlyInTarget),
				}}
				if observed.Protected || observed.ParseStatus == filter.ParseStatusOpaque {
					rule.Status, rule.ReasonCode = firewallsync.StatusBlocked, firewallsync.ReasonUnsafeRemoval
					rule.Reason = firewallsync.ReasonMessage(rule.ReasonCode)
				}
				rules = append(rules, rule)
				continue
			}
			rule := byUUID[item.Desired.Rule.UUID]
			matched[item.Desired.Rule.UUID] = item
			rule.observed = item.Observed
			divergent := item.Observed != nil && item.Observed.Persistence != "" && item.Observed.Persistence != filter.PersistenceStatusConverged
			switch {
			case item.Match == filter.InventoryMatchExact && !divergent:
				rule.Status, rule.Reason = firewallsync.StatusExisting, "rule already matches database policy"
			case item.Match == filter.InventoryMatchMissing || item.Match == filter.InventoryMatchChanged || item.Match == filter.InventoryMatchExact:
				rule.Status, rule.Reason = firewallsync.StatusReady, "target rule differs from database policy"
				if item.Observed != nil && item.Observed.Protected {
					rule.Status, rule.Reason = firewallsync.StatusBlocked, filter.ErrProtectedRule.Error()
				}
			default:
				rule.Status, rule.Reason = firewallsync.StatusBlocked, fmt.Sprintf("target rule cannot be synchronized: %s", item.Match)
			}
		}
		ordered := make([]filter.InventoryItem, 0, len(scoped))
		for _, rule := range scoped {
			ordered = append(ordered, matched[rule.desired.Rule.UUID])
		}
		drifted := firewallsync.RuleOrder(snapshot, ordered)
		for _, rule := range scoped {
			if rule.desired.Protected || !drifted[rule.desired.Marker] {
				continue
			}
			if rule.Status == firewallsync.StatusExisting {
				rule.Status, rule.Reason = firewallsync.StatusReady, "managed rule order differs from database sequence"
			}
		}
	}
	return runtime, rules, snapshots, nil
}

func (s *FirewallService) syncRules(ctx context.Context, _ string, request dto.FirewallRuleSyncRequest, t *task.Task) (result dto.FirewallRuleSyncResult, err error) {
	if request.SourceProvider != "" || request.ResetSource {
		return result, fmt.Errorf("%w: system synchronization reads rules from the database", filter.ErrInvalidRule)
	}
	if err := s.checkSelectedProvider(ctx, request.TargetProvider); err != nil {
		return result, err
	}
	whitelistErr := s.SyncPortWhitelist(ctx)
	if t != nil {
		t.LogWithStatus(i18n.GetMsgByKey("FirewallSyncWhitelistStep"), whitelistErr)
	}
	if whitelistErr != nil {
		return result, whitelistErr
	}
	firewallRuleMutationMu.Lock()
	defer firewallRuleMutationMu.Unlock()
	result = dto.FirewallRuleSyncResult{Subsystem: "system", TargetProvider: request.TargetProvider}
	if err := ctx.Err(); err != nil {
		return result, err
	}
	runtime, rules, snapshots, err := s.loadFirewallSyncRules(ctx, request)
	if err != nil {
		return result, err
	}

	created, removed, unexecuted := 0, 0, 0
	stopped := make(map[string]error)
	failedRemovals := make(map[string]error)
	var firewalldFinalSnapshot *filter.Snapshot
	record := func(operation string, rule *firewallSyncRule, cause error, skipped bool) {
		item := rule.FirewallRuleSyncItem
		if operation == "TaskDelete" && rule.observed != nil {
			item.Rule = &rule.observed.Rule
		}
		switch {
		case skipped:
			result.Skipped++
			unexecuted++
			rule.done = true
		case cause != nil:
			appendDatabaseSyncFailure(&result, item, cause)
			rule.done = true
			if operation == "TaskDelete" {
				failedRemovals[rule.SourceUUID] = cause
			}
		case operation == "TaskDelete":
			removed++
			if rule.Status == firewallsync.StatusRemove {
				result.Removed++
				rule.done = true
			}
		case operation == "TaskCreate":
			created++
			result.Succeeded++
			rule.done = true
		default:
			result.Skipped++
			rule.done = true
		}
		if t == nil {
			return
		}
		label := fmt.Sprintf("%s %s", i18n.GetMsgByKey(operation), item.SourceUUID)
		if r := item.Rule; r != nil {
			label += fmt.Sprintf(" [%s] %s %s:%s -> %s:%s %s", r.Scope.Key(), r.Protocol, r.SourceAddress, r.SourcePort, r.DestinationAddress, r.DestinationPort, r.Action)
		}
		if skipped {
			t.Logf("%s %s: %v", label, i18n.GetMsgByKey("FirewallCreateRuleSkipped"), cause)
		} else if operation == task.TaskSync && cause == nil {
			t.Logf("%s %s", label, i18n.GetMsgByKey("FirewallSyncRuleUnchanged"))
		} else {
			t.LogWithStatus(label, cause)
		}
	}
	defer func() {
		if t != nil {
			t.Log(i18n.GetMsgWithMap("FirewallSyncOperationsResult", map[string]interface{}{"created": created, "removed": removed, "failed": result.Failed, "skipped": unexecuted, "unchanged": result.Skipped - unexecuted}))
		}
	}()
	blocked := false
	for _, rule := range rules {
		if rule.Status != firewallsync.StatusRemove {
			result.Total++
		}
		if rule.Status == firewallsync.StatusBlocked {
			blocked = true
			record("TaskSync", rule, errors.New(rule.Reason), false)
		}
	}
	if blocked {
		for _, rule := range rules {
			if !rule.done {
				record("TaskSync", rule, filter.ErrRuleOperation, true)
			}
		}
		return result, nil
	}
	for _, rule := range rules {
		if rule.Status == firewallsync.StatusExisting {
			record("TaskSync", rule, nil, false)
		}
	}
	for _, operation := range []filter.ChangeOperation{filter.ChangeDelete, filter.ChangeCreate} {
		name := "TaskCreate"
		if operation == filter.ChangeDelete {
			name = "TaskDelete"
		}
		for _, initial := range snapshots {
			scope := initial.Scope
			queue := make([]*firewallSyncRule, 0)
			for _, rule := range rules {
				if rule.done || rule.Rule.Scope.Key() != scope.Key() {
					continue
				}
				if operation == filter.ChangeDelete && rule.observed != nil || operation == filter.ChangeCreate && rule.Status == firewallsync.StatusReady {
					queue = append(queue, rule)
				}
			}
			if operation == filter.ChangeDelete {
				sort.SliceStable(queue, func(i, j int) bool {
					return syncObservedPosition(queue[i].observed) > syncObservedPosition(queue[j].observed)
				})
			}
			if scope.Provider == filter.ProviderFirewalld && operation == filter.ChangeCreate && len(failedRemovals) == 0 && stopped[scope.Key()] == nil {
				firewalldFinalSnapshot = syncFirewalldCreates(ctx, runtime, initial, removed > 0, queue, t, record)
				continue
			}
			markers := make([]string, 0)
			for _, candidate := range rules {
				if candidate.Rule != nil && candidate.Rule.Scope.Key() == scope.Key() && candidate.desired.Marker != "" {
					markers = append(markers, candidate.desired.Marker)
				}
			}
			for start := 0; start < len(queue); {
				rule := queue[start]
				cause := stopped[scope.Key()]
				if operation == filter.ChangeCreate && cause == nil {
					for id, err := range failedRemovals {
						if id == rule.SourceUUID || strings.HasPrefix(id, rule.SourceUUID+"-") {
							cause = err
							break
						}
					}
				}
				if cause != nil {
					record(name, rule, cause, true)
					start++
					continue
				}
				snapshot := initial
				err := ctx.Err()
				if err == nil {
					snapshot, err = runtime.ObserveMutation(ctx, scope)
				}
				unreadable := err != nil
				end := start + 1
				if supportsNativeRuleBatch(scope.Provider) && (operation == filter.ChangeDelete || len(snapshot.Rules) == 0) && len(failedRemovals) == 0 {
					end = min(start+filter.MaxAtomicExpansion, len(queue))
				}
				batch := queue[start:end]
				changes := make([]filter.DesiredChange, 0, len(batch))
				for _, entry := range batch {
					if err != nil {
						break
					}
					if operation == filter.ChangeDelete {
						var change filter.DesiredChange
						change, err = firewallsync.DeleteChange(snapshot, *entry.observed, entry.desired)
						changes = append(changes, change)
					} else {
						after := *entry.Rule
						after.OrderIndex = nil
						if len(batch) == 1 && scope.Provider != filter.ProviderFirewalld {
							after.OrderIndex = firewallsync.InsertionPosition(snapshot, markers, entry.desired.Marker)
						}
						changes = append(changes, filter.DesiredChange{Operation: operation, After: &after, Append: scope.Provider == filter.ProviderUFW && after.OrderIndex == nil})
					}
				}
				if err == nil {
					_, err = runtime.ExecuteSync(ctx, snapshot, changes)
				}
				for _, entry := range batch {
					record(name, entry, err, false)
				}
				if err != nil && (operation == filter.ChangeDelete || scope.Provider != filter.ProviderFirewalld || unreadable || firewallCreateUnavailable(err)) {
					stopped[scope.Key()] = err
				}
				start = end
			}
		}
	}
	if firewalldFinalSnapshot != nil && result.Failed == 0 && created > 0 {
		verifyErr := verifyFirewalldSyncSnapshot(*firewalldFinalSnapshot, rules)
		if t != nil {
			t.LogWithStatus(i18n.GetWithName("FirewallSyncStep", string(request.TargetProvider)), verifyErr)
		}
		if verifyErr != nil {
			return result, verifyErr
		}
	}
	return result, nil
}

func syncFirewalldCreates(
	ctx context.Context,
	runtime *filterruntime.Engine,
	initial filter.Snapshot,
	refresh bool,
	queue []*firewallSyncRule,
	t *task.Task,
	record func(string, *firewallSyncRule, error, bool),
) *filter.Snapshot {
	if len(queue) == 0 {
		return nil
	}
	planner, readErr := runtime.NewCreatePlanner(initial)
	if readErr != nil {
		for _, entry := range queue {
			record(task.TaskCreate, entry, readErr, false)
		}
		return nil
	}
	pending := make([]*firewallSyncRule, 0, len(queue))
	for index, entry := range queue {
		if refresh {
			var snapshot filter.Snapshot
			snapshot, readErr = runtime.ObserveMutation(ctx, initial.Scope)
			if readErr == nil {
				planner, readErr = runtime.NewCreatePlanner(snapshot)
			}
			if readErr != nil {
				record(task.TaskCreate, entry, readErr, false)
				for _, remaining := range queue[index+1:] {
					record(task.TaskCreate, remaining, readErr, true)
				}
				break
			}
			refresh = false
		}
		if t != nil {
			t.Logf("[%d/%d] %s %s", index+1, len(queue), i18n.GetMsgByKey(task.TaskCreate), entry.SourceUUID)
		}
		after := *entry.Rule
		after.OrderIndex = nil
		_, err := runtime.ExecutePlannedCreate(ctx, planner, filter.DesiredChange{
			Operation: filter.ChangeCreate, After: &after, CommandOnly: true,
		})
		if err != nil {
			record(task.TaskCreate, entry, err, false)
			if firewallCreateUnavailable(err) {
				for _, remaining := range queue[index+1:] {
					record(task.TaskCreate, remaining, err, true)
				}
				break
			}
			refresh = true
			continue
		}
		pending = append(pending, entry)
	}
	var actual filter.Snapshot
	if readErr == nil {
		actual, readErr = runtime.ObserveMutation(ctx, initial.Scope)
	}
	if readErr != nil {
		for _, entry := range pending {
			record(task.TaskCreate, entry, readErr, false)
		}
		return nil
	}
	states := firewalldRuleStates(actual)
	for _, entry := range pending {
		key, err := filter.RuleKey(*entry.Rule)
		if err == nil && states[key] != 1 {
			err = filter.ErrVerificationFailed
		}
		record(task.TaskCreate, entry, err, false)
	}
	return &actual
}

func firewalldRuleStates(snapshot filter.Snapshot) map[string]int {
	states := make(map[string]int, len(snapshot.Rules))
	for _, observed := range snapshot.Rules {
		if observed.ParseStatus != filter.ParseStatusSupported || observed.Persistence != filter.PersistenceStatusConverged {
			continue
		}
		if key, err := filter.RuleKey(observed.Rule); err == nil {
			states[key]++
		}
	}
	return states
}

func verifyFirewalldSyncSnapshot(snapshot filter.Snapshot, rules []*firewallSyncRule) error {
	states := firewalldRuleStates(snapshot)
	for _, entry := range rules {
		if entry.Status == firewallsync.StatusRemove {
			continue
		}
		if entry.Rule == nil {
			return filter.ErrVerificationFailed
		}
		key, err := filter.RuleKey(*entry.Rule)
		if err != nil {
			return err
		}
		if states[key] != 1 {
			return fmt.Errorf("%w: %s", filter.ErrVerificationFailed, entry.SourceUUID)
		}
	}
	return nil
}

func syncObservedPosition(rule *filter.ObservedRule) int {
	if rule.Locator.Position != nil {
		return *rule.Locator.Position
	}
	return 0
}

func (s *FirewallService) restoreStoredFirewallRules(ctx context.Context, provider filter.Provider, t *task.Task) error {
	result, err := s.syncRules(ctx, "", dto.FirewallRuleSyncRequest{TargetProvider: provider}, t)
	if err != nil {
		return fmt.Errorf("restore database firewall rules: %w", err)
	}
	failures := make([]error, 0, len(result.Errors))
	for _, failure := range result.Errors {
		failures = append(failures, fmt.Errorf("rule %s: %s", failure.SourceUUID, failure.Error))
	}
	return errors.Join(failures...)
}

func (s *FirewallService) SyncRules(
	ctx context.Context,
	clientIP string,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncResult, error) {
	switch firewallSyncSubsystem(request.Subsystem) {
	case "forwarding":
		return s.forwardingRuleSyncService().syncRules(ctx, request)
	case "docker":
		return s.dockerRuleSyncService().syncRules(ctx, request)
	default:
		return s.syncSystemRules(ctx, clientIP, request)
	}
}

func (s *FirewallService) syncSystemRules(
	ctx context.Context,
	clientIP string,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncResult, error) {
	if err := lockFirewallLifecycleIdle(); err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	defer firewallLifecycleTaskMu.Unlock()
	firewallRuleSyncTaskMu.Lock()
	defer firewallRuleSyncTaskMu.Unlock()

	running, err := currentFirewallRuleSyncTaskLocked()
	if err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	if running.Executing {
		return dto.FirewallRuleSyncResult{
			Subsystem:      firewallSyncSubsystem(request.Subsystem),
			TargetProvider: request.TargetProvider,
			TaskID:         running.TaskID,
			Queued:         true,
		}, nil
	}
	if firewallSyncSubsystem(request.Subsystem) != "system" {
		return dto.FirewallRuleSyncResult{}, fmt.Errorf("%w: firewall synchronization tasks are only available for the system firewall", filter.ErrInvalidRule)
	}
	taskItem, err := task.NewTask(firewallTaskName(task.TaskSync, firewallTaskHost, string(request.TargetProvider)), task.TaskSync, task.TaskScopeFirewall, "", 0)
	if err != nil {
		return dto.FirewallRuleSyncResult{}, fmt.Errorf("create firewall sync task: %w", err)
	}
	taskItem.AddSubTaskWithOps(i18n.GetWithName("FirewallSyncStep", string(request.TargetProvider)), func(t *task.Task) error {
		result, err := s.syncRules(t.TaskCtx, clientIP, request, t)
		if err != nil {
			return err
		}
		if result.Failed > 0 {
			return errors.New(i18n.GetMsgWithMap("FirewallSyncFailed", map[string]interface{}{"failed": result.Failed}))
		}
		return nil
	}, nil, 0, 0)

	if err := repo.NewITaskRepo().Save(context.Background(), taskItem.Task); err != nil {
		taskItem.LogFailedWithErr(taskItem.Name, err)
		closeUnstartedFirewallTask(taskItem)
		return dto.FirewallRuleSyncResult{}, fmt.Errorf("save firewall sync task: %w", err)
	}
	firewallRuleSyncTaskID = taskItem.TaskID
	go func() {
		defer func() {
			firewallRuleSyncTaskMu.Lock()
			if firewallRuleSyncTaskID == taskItem.TaskID {
				firewallRuleSyncTaskID = ""
			}
			firewallRuleSyncTaskMu.Unlock()
		}()
		if err := taskItem.Execute(); err != nil && global.LOG != nil {
			global.LOG.Errorf("firewall sync task %s failed: %v", taskItem.TaskID, err)
		}
	}()
	return dto.FirewallRuleSyncResult{
		Subsystem:      "system",
		TargetProvider: request.TargetProvider,
		TaskID:         taskItem.TaskID,
		Queued:         true,
	}, nil
}

func (s *FirewallService) CurrentRuleSyncTask() (dto.FirewallRuleSyncTask, error) {
	firewallRuleSyncTaskMu.Lock()
	defer firewallRuleSyncTaskMu.Unlock()
	return currentFirewallRuleSyncTaskLocked()
}

func currentFirewallRuleSyncTaskLocked() (dto.FirewallRuleSyncTask, error) {
	if firewallRuleSyncTaskID != "" {
		return dto.FirewallRuleSyncTask{TaskID: firewallRuleSyncTaskID, Executing: true}, nil
	}
	if global.TaskDB == nil {
		return dto.FirewallRuleSyncTask{}, nil
	}
	taskRepo := repo.NewITaskRepo()
	record, err := taskRepo.GetFirst(
		repo.WithByStatus(constant.StatusExecuting),
		repo.WithByType(task.TaskScopeFirewall),
		taskRepo.WithOperate(task.TaskSync),
	)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return dto.FirewallRuleSyncTask{}, nil
		}
		return dto.FirewallRuleSyncTask{}, err
	}
	return dto.FirewallRuleSyncTask{TaskID: record.ID, Executing: true}, nil
}

func whitelistRules(provider filter.Provider, ports, required []firewall.SystemPort) []filter.FirewallRule {
	rules := make([]filter.FirewallRule, 0, len(ports)+len(required))
	for _, port := range required {
		rule := systemPortRule(provider, port)
		if isDirectFirewallProvider(provider) {
			rule.Scope.Chain = filter.BasicBeforeChain
		}
		rules = append(rules, rule)
	}
	for _, port := range ports {
		rules = append(rules, systemPortRule(provider, port))
	}
	return rules
}

func (s *FirewallService) SyncPortWhitelist(ctx context.Context) error {
	firewallWhitelistMu.Lock()
	defer firewallWhitelistMu.Unlock()
	filterruntime.InvalidateInventory()
	defer filterruntime.InvalidateInventory()
	ports, err := loadFirewallPortWhiteList()
	if err != nil {
		return err
	}
	required, err := firewall.RequiredPortWhitelist(ports)
	if err != nil {
		return err
	}
	provider, err := s.selectedProvider(ctx)
	if err != nil {
		return err
	}
	rules := whitelistRules(provider, firewall.ExpandPortWhitelist(customWhitelist(ports)), firewall.ExpandPortWhitelist(required))
	activeFamilies := make(map[filter.Family]bool)
	if isDirectFirewallProvider(provider) {
		for _, rule := range rules {
			family := rule.Scope.Family
			if _, checked := activeFamilies[family]; checked {
				continue
			}
			initialized, bound, err := loadSystemFirewallFamilyStatus(string(provider), string(family))
			if err != nil {
				return err
			}
			activeFamilies[family] = initialized && bound
		}
	} else if len(rules) > 0 {
		client, err := s.baseClient()
		if err != nil {
			return err
		}
		active, err := client.Status()
		if err != nil || !active {
			return err
		}
	}
	prepared := make([]preparedFirewallRuleCreate, 0, len(rules))
	var failures []error
	for _, rule := range rules {
		if err := ctx.Err(); err != nil {
			return err
		}
		if isDirectFirewallProvider(provider) && !activeFamilies[rule.Scope.Family] {
			continue
		}
		port := firewall.SystemPort{Family: string(rule.Scope.Family), Port: rule.DestinationPort, Protocol: rule.Protocol, SourceAddress: rule.SourceAddress}
		item, err := s.prepareCreate(ctx, provider, dto.FirewallRuleCreateItem{
			Rule: rule, SourceKind: constant.FirewallRuleSourceSecurity, SourceID: systemPortSourceID(port),
		})
		if err != nil {
			failures = append(failures, fmt.Errorf("prepare whitelist rule %s: %w", firewall.SystemPortKey(port), err))
			continue
		}
		prepared = append(prepared, item)
	}
	if len(failures) > 0 {
		return errors.Join(failures...)
	}
	if provider == filter.ProviderUFW && len(prepared) > 0 {
		return s.syncUFWPortWhitelist(ctx, prepared)
	}

	for _, item := range prepared {
		if err := ctx.Err(); err != nil {
			return err
		}
		if err := s.addWhitelistRule(ctx, item); err != nil {
			rule := item.request.Rule
			failures = append(failures, fmt.Errorf("add whitelist rule %s %s/%s [%s]: %w", rule.Scope.Family, rule.DestinationPort, rule.Protocol, rule.SourceAddress, err))
		}
	}
	return errors.Join(failures...)
}

func (s *FirewallService) syncUFWPortWhitelist(ctx context.Context, prepared []preparedFirewallRuleCreate) error {
	firewallRuleMutationMu.Lock()
	defer firewallRuleMutationMu.Unlock()
	runtime := prepared[0].runtime
	snapshots, err := runtime.ObserveScopes(ctx, filter.ManagedInputScopes(filter.ProviderUFW))
	if err != nil {
		return err
	}
	for itemIndex, item := range prepared {
		if err := ctx.Err(); err != nil {
			return err
		}
		rule := item.request.Rule
		var snapshot *filter.Snapshot
		for index := range snapshots {
			if snapshots[index].Scope.Key() == rule.Scope.Key() {
				snapshot = &snapshots[index]
				break
			}
		}
		if snapshot == nil {
			return fmt.Errorf("%w: missing UFW whitelist scope %s", filter.ErrInventoryUnavailable, rule.Scope.Key())
		}
		for _, notice := range snapshot.Notices {
			if notice.Code == filter.ScopeNoticeManagedScopeInactive || notice.Code == filter.ScopeNoticeManagedScopeMissing {
				return filter.ErrProviderUnavailable
			}
		}
		added, err := s.addWhitelistRuleFromSnapshot(ctx, item, *snapshot)
		if err != nil {
			return fmt.Errorf("add whitelist rule %s %s/%s [%s]: %w", rule.Scope.Family, rule.DestinationPort, rule.Protocol, rule.SourceAddress, err)
		}
		if !added {
			continue
		}

		if itemIndex+1 < len(prepared) {
			if err := ctx.Err(); err != nil {
				return err
			}
			snapshots, err = runtime.ObserveScopes(ctx, filter.ManagedInputScopes(filter.ProviderUFW))
			if err != nil {
				return err
			}
		}
	}
	return nil
}

func (s *FirewallService) addWhitelistRule(ctx context.Context, prepared preparedFirewallRuleCreate) error {
	firewallRuleMutationMu.Lock()
	defer firewallRuleMutationMu.Unlock()
	if err := ctx.Err(); err != nil {
		return err
	}
	rule, runtime := prepared.request.Rule, prepared.runtime
	snapshot, err := runtime.ObserveMutation(ctx, rule.Scope)
	if err != nil {
		return err
	}
	_, err = s.addWhitelistRuleFromSnapshot(ctx, prepared, snapshot)
	return err
}

func (s *FirewallService) addWhitelistRuleFromSnapshot(ctx context.Context, prepared preparedFirewallRuleCreate, snapshot filter.Snapshot) (bool, error) {
	rule, runtime := prepared.request.Rule, prepared.runtime
	for _, observed := range snapshot.Rules {
		if observed.ParseStatus == filter.ParseStatusSupported {
			if same, err := filter.SameRuleContent(rule, observed.Rule); err == nil && same {
				return false, nil
			}
		}
	}
	if err := filter.CheckObservedRuleCollisions(snapshot, rule, nil); err != nil {
		return false, err
	}
	if rule.Scope.Chain == filter.BasicBeforeChain {
		position := int64(1)
		rule.OrderIndex = &position
		rule.UUID = uuid.NewString()
		return true, runtime.ExecuteCreate(ctx, snapshot, []filter.DesiredChange{{Operation: filter.ChangeCreate, After: &rule}})
	}
	stored, err := s.rules.List(ctx)
	if err != nil {
		return false, err
	}
	model.SortFirewallRules(stored, rule.Scope.Provider)
	markers := make([]string, 0, len(stored))
	var existing *filter.DesiredRule
	var firstSequence *int64
	for _, record := range stored {
		compiled, err := s.compileStoredFirewallRules(ctx, record, rule.Scope.Provider)
		if err != nil {
			if isFirewallPolicyIncompatible(err) {
				continue
			}
			return false, err
		}
		for _, candidate := range compiled {
			if candidate.Rule.Scope.Key() == rule.Scope.Key() && candidate.Marker != "" {
				markers = append(markers, candidate.Marker)
				if firstSequence == nil && record.Sequence != nil {
					firstSequence = record.Sequence
				}
			}
			if err := filter.CheckRuleCollision(rule, candidate.Rule); errors.Is(err, filter.ErrRuleOperation) {
				copy := candidate
				existing = &copy
			} else if err != nil {
				return false, err
			}
		}
	}
	if existing != nil {
		existing.Rule.OrderIndex = firewallsync.InsertionPosition(snapshot, markers, existing.Marker)
		return true, runtime.ExecuteCreate(ctx, snapshot, []filter.DesiredChange{{
			Operation: filter.ChangeCreate, After: &existing.Rule,
			Append: rule.Scope.Provider == filter.ProviderUFW && existing.Rule.OrderIndex == nil,
		}})
	}
	if rule.Scope.Provider != filter.ProviderFirewalld {
		position := int64(1)
		rule.OrderIndex = &position
		record, err := firewallRuleModelForCreate(rule, prepared.request, constant.FirewallRuleOriginCreated)
		if err != nil {
			return false, err
		}
		sequence := model.FirewallRuleSequenceStep
		if firstSequence != nil {
			sequence = *firstSequence - model.FirewallRuleSequenceStep
		}
		record.UUID, record.Sequence = uuid.NewString(), &sequence
		rule.UUID = record.UUID
		if err := runtime.ExecuteCreate(ctx, snapshot, []filter.DesiredChange{{Operation: filter.ChangeCreate, After: &rule}}); err != nil {
			return false, firewallCreateExecutionError(err)
		}
		return true, s.saveFirewallRule(ctx, &record)
	}
	return true, s.applyCreateRules(ctx, runtime, snapshot, stored, []preparedFirewallRuleCreate{prepared})[0]
}

type forwardingRuleSyncCandidate struct {
	rule forwarding.Rule
	err  error
}

func (s *ForwardingService) loadRuleSyncCandidates(
	ctx context.Context,
	targetProvider filter.Provider,
) (*forwarding.Manager, []forwardingRuleSyncCandidate, []forwarding.Rule, bool, error) {
	target, err := s.managerFactory()
	if err != nil {
		return nil, nil, nil, false, err
	}
	if target.Name() != string(targetProvider) {
		return nil, nil, nil, false, fmt.Errorf(
			"%w: selected forwarding backend is %s, requested target is %s",
			filter.ErrProviderUnavailable, target.Name(), targetProvider,
		)
	}
	stored, err := s.rules.List(ctx)
	if err != nil {
		return nil, nil, nil, false, err
	}
	candidates := make([]forwardingRuleSyncCandidate, 0, len(stored))
	for _, record := range stored {
		rule := forwarding.Rule{
			Family: record.Family, Protocol: record.Protocol, Port: record.Port, TargetIP: record.TargetIP,
			TargetPort: record.TargetPort, Interface: record.Interface,
		}
		normalized, normalizeErr := forwarding.NormalizeRule(rule)
		candidates = append(candidates, forwardingRuleSyncCandidate{rule: normalized, err: normalizeErr})
	}
	targetStatus, err := target.Status()
	if err != nil {
		return nil, nil, nil, false, err
	}
	targetRules := make([]forwarding.Rule, 0)
	if targetStatus.IsInit {
		targetRules, err = target.List("", "")
		if err != nil {
			return nil, nil, nil, false, err
		}
		targetRules, err = normalizeForwardingRuntimeRules(targetRules)
		if err != nil {
			return nil, nil, nil, false, err
		}
	}
	return target, candidates, targetRules, targetStatus.IsInit, nil
}

func verifyForwardingRuleSync(target *forwarding.Manager, desired []forwarding.Rule) error {
	actual, err := target.List("", "")
	if err != nil {
		return fmt.Errorf("verify synchronized forwarding rules: %w", err)
	}
	actual, err = normalizeForwardingRuntimeRules(actual)
	if err != nil {
		return fmt.Errorf("verify synchronized forwarding rules: %w", err)
	}
	if !firewallsync.StatesEqual(actual, desired, func(rule forwarding.Rule) string { return rule.Identity() }) {
		return fmt.Errorf("verify synchronized forwarding rules: target rules do not match the database")
	}
	return nil
}

func normalizeForwardingRuntimeRules(rules []forwarding.Rule) ([]forwarding.Rule, error) {
	normalized := make([]forwarding.Rule, 0, len(rules))
	for _, rule := range rules {
		item, err := forwarding.NormalizeRule(rule)
		if err != nil {
			return nil, fmt.Errorf("normalize target forwarding rule %s: %w", rule.Identity(), err)
		}
		normalized = append(normalized, item)
	}
	return normalized, nil
}

func forwardingRuleSyncDTO(rule forwarding.Rule) *dto.ForwardRule {
	return &dto.ForwardRule{
		Family: rule.Family, Protocol: rule.Protocol, Port: rule.Port, TargetIP: rule.TargetIP,
		TargetPort: rule.TargetPort, Interface: rule.Interface,
	}
}

func (s *ForwardingService) previewRuleSync(
	ctx context.Context,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncPreview, error) {
	targetProvider, err := databaseRuleSyncTarget(request, "forwarding")
	if err != nil {
		return dto.FirewallRuleSyncPreview{}, err
	}
	target, candidates, targetRules, _, err := s.loadRuleSyncCandidates(ctx, targetProvider)
	if err != nil {
		return dto.FirewallRuleSyncPreview{}, err
	}
	return forwardingSyncPreview(filter.Provider(target.Name()), candidates, targetRules), nil
}

func (s *ForwardingService) syncRules(
	ctx context.Context,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncResult, error) {
	forwardingMutationMu.Lock()
	defer forwardingMutationMu.Unlock()

	targetProvider, err := databaseRuleSyncTarget(request, "forwarding")
	if err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	target, candidates, targetRules, targetInitialized, err := s.loadRuleSyncCandidates(ctx, targetProvider)
	if err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	preview := forwardingSyncPreview(filter.Provider(target.Name()), candidates, targetRules)
	desired := make([]forwarding.Rule, 0, len(candidates))
	for _, candidate := range candidates {
		if candidate.err == nil {
			desired = append(desired, candidate.rule)
		}
	}
	if preview.Blocked > 0 {
		return firewallSyncResult(preview, nil, false), nil
	}
	if len(desired) == 0 && !targetInitialized {
		return firewallSyncResult(preview, nil, true), nil
	}
	reconcileErr := func() error {
		if len(desired) > 0 {
			if err := s.persistForwardingEnabled(); err != nil {
				return err
			}
			if err := s.activateManager(target); err != nil {
				return err
			}
		}
		if err := target.Reconcile(desired); err != nil {
			return err
		}
		return verifyForwardingRuleSync(target, desired)
	}()
	result := firewallSyncResult(preview, reconcileErr, true)
	recordForwardingSyncError(reconcileErr)
	if reconcileErr != nil {
		if preview.Ready == 0 {
			return result, reconcileErr
		}
		return result, nil
	}
	return result, nil
}

func forwardingSyncPreview(
	target filter.Provider,
	candidates []forwardingRuleSyncCandidate,
	actual []forwarding.Rule,
) dto.FirewallRuleSyncPreview {
	desired := make([]firewallsync.Desired[forwarding.Rule, dto.FirewallRuleSyncItem], 0, len(candidates))
	for _, candidate := range candidates {
		desired = append(desired, firewallsync.Desired[forwarding.Rule, dto.FirewallRuleSyncItem]{
			Value: candidate.rule,
			Payload: dto.FirewallRuleSyncItem{
				SourceUUID: candidate.rule.Identity(), ForwardRule: forwardingRuleSyncDTO(candidate.rule),
			},
			Err: candidate.err,
		})
	}
	return firewallDiffPreview(
		"forwarding", target, desired, actual,
		func(rule forwarding.Rule) string { return rule.Identity() },
		func(rule forwarding.Rule) dto.FirewallRuleSyncItem {
			return dto.FirewallRuleSyncItem{SourceUUID: rule.Identity(), ForwardRule: forwardingRuleSyncDTO(rule)}
		},
	)
}

func (s *FirewallService) forwardingRuleSyncService() firewallDatabaseSyncAdapter {
	if s.forwardingSync == nil {
		return newForwardingService()
	}
	return s.forwardingSync
}

func (s *DockerPortGuardService) loadRuleSyncCandidates(
	ctx context.Context,
	request dto.FirewallRuleSyncRequest,
) (string, []model.DockerPortGuardPolicy, dockerGuardRuntime, error) {
	targetProvider, err := databaseRuleSyncTarget(request, "Docker")
	if err != nil {
		return "", nil, nil, err
	}
	target := string(targetProvider)
	selected, err := s.selectedRuleSyncBackend(ctx)
	if err != nil {
		return "", nil, nil, err
	}
	if target != selected {
		return "", nil, nil, fmt.Errorf(
			"%w: selected Docker firewall backend is %s, requested target is %s",
			filter.ErrProviderUnavailable, selected, target,
		)
	}
	policies, err := s.policies.ListManaged(ctx)
	if err != nil {
		return "", nil, nil, err
	}
	return target, policies, s.guardRuntime(target), nil
}

func (s *DockerPortGuardService) selectedRuleSyncBackend(ctx context.Context) (string, error) {
	if global.DB != nil {
		selected, _ := settingRepo.GetValueByKey(constant.FirewallDockerBackendKey)
		selected = strings.ToLower(strings.TrimSpace(selected))
		if selected == constant.FirewallProviderIptables || selected == constant.FirewallProviderNftables {
			return selected, nil
		}
	}
	if s.client == nil {
		return "", fmt.Errorf("%w: Docker firewall backend is unavailable", ErrDockerUnavailable)
	}
	cli, err := s.client()
	if err != nil {
		return "", fmt.Errorf("%w: %v", ErrDockerUnavailable, err)
	}
	defer cli.Close()
	info, err := cli.Info(ctx)
	if err != nil {
		return "", fmt.Errorf("%w: %v", ErrDockerUnavailable, err)
	}
	return selectedDockerFirewallBackend(dockerFirewallBackend(info)), nil
}

func dockerGuardPoliciesFromModels(policies []model.DockerPortGuardPolicy) []docker_guard.Policy {
	result := make([]docker_guard.Policy, 0, len(policies))
	for _, policy := range policies {
		result = append(result, dockerGuardPolicyFromModel(policy))
	}
	return result
}

func dockerGuardRuleSyncDTO(policy model.DockerPortGuardPolicy) *dto.DockerPortGuardEndpoint {
	return &dto.DockerPortGuardEndpoint{
		Family: policy.Family, HostIP: policy.HostIP, HostPort: policy.HostPort, Protocol: policy.Protocol,
		PolicyUUID: policy.UUID, Mode: policy.Mode, Sources: docker_guard.DecodeSources(policy.Sources), Description: policy.Description,
		TrafficPath: dockerTrafficPathUnknown, ManagementTarget: dockerManagementNeedsDiagnosis,
		ManagementReason: dockerReasonNoMatchingPath,
	}
}

func dockerGuardRuntimeRuleSyncDTO(policy docker_guard.Policy) *dto.DockerPortGuardEndpoint {
	return &dto.DockerPortGuardEndpoint{
		Family: policy.Family, HostIP: policy.HostIP, HostPort: policy.HostPort, Protocol: policy.Protocol,
		PolicyUUID: policy.UUID, Mode: policy.Mode, Sources: append([]string(nil), policy.Sources...),
		TrafficPath: dockerTrafficPathUnknown, ManagementTarget: dockerManagementNeedsDiagnosis,
		ManagementReason: dockerReasonNoMatchingPath,
	}
}

func dockerGuardReadOnlyRuleSyncDTO(policy docker_guard.ReadOnlyPolicy) *dto.DockerPortGuardEndpoint {
	return &dto.DockerPortGuardEndpoint{
		Family: policy.Policy.Family, HostIP: policy.Policy.HostIP, HostPort: policy.Policy.HostPort,
		Protocol: policy.Policy.Protocol, PolicyUUID: dockerGuardReadOnlyPolicyUUID(policy), Sources: append([]string(nil), policy.Policy.Sources...),
		NativeAction: policy.Action, ReadOnly: true, TrafficPath: dockerTrafficPathUnknown,
		ManagementTarget: dockerManagementNeedsDiagnosis, ManagementReason: dockerReasonNoMatchingPath,
	}
}

func (s *DockerPortGuardService) previewRuleSync(
	ctx context.Context,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncPreview, error) {
	target, policies, runtime, err := s.loadRuleSyncCandidates(ctx, request)
	if err != nil {
		return dto.FirewallRuleSyncPreview{}, err
	}
	targetInventory, err := runtime.ListPolicies()
	if err != nil {
		return dto.FirewallRuleSyncPreview{}, err
	}
	return dockerSyncPreview(filter.Provider(target), policies, targetInventory), nil
}

func (s *DockerPortGuardService) syncRules(
	ctx context.Context,
	request dto.FirewallRuleSyncRequest,
) (dto.FirewallRuleSyncResult, error) {
	dockerPortGuardServiceMu.Lock()
	defer dockerPortGuardServiceMu.Unlock()

	target, policies, targetRuntime, err := s.loadRuleSyncCandidates(ctx, request)
	if err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	runtimePolicies := dockerGuardPoliciesFromModels(policies)
	targetInventory, err := targetRuntime.ListPolicies()
	if err != nil {
		return dto.FirewallRuleSyncResult{}, err
	}
	preview := dockerSyncPreview(filter.Provider(target), policies, targetInventory)
	for _, item := range preview.Items {
		if item.Status == firewallsync.StatusBlocked && item.ReasonCode != firewallsync.ReasonReadOnlyRule {
			return firewallSyncResult(preview, nil, false), nil
		}
	}
	if preview.Ready == 0 && preview.Removed == 0 {
		return firewallSyncResult(preview, nil, false), nil
	}
	reconcileErr := func() error {
		if err := s.replaceRuntimeReadOnlyPolicies(ctx, targetInventory.ReadOnly); err != nil {
			return err
		}
		if err := docker_guard.ReconcileTarget(target, runtimePolicies, targetRuntime); err != nil {
			return err
		}
		if err := docker_guard.Verify(targetRuntime, runtimePolicies, targetInventory.ReadOnly); err != nil {
			return err
		}
		if len(policies) == 0 {
			return nil
		}
		if err := settingRepo.UpdateOrCreate(constant.FirewallDockerBackendKey, target); err != nil {
			return err
		}
		return settingRepo.UpdateOrCreate(constant.FirewallDockerPortGuardStatusKey, constant.StatusEnable)
	}()
	result := firewallSyncResult(preview, reconcileErr, true)
	recordDockerPortGuardReconcileError(reconcileErr)
	if reconcileErr != nil {
		return result, reconcileErr
	}
	return result, nil
}

func dockerSyncPreview(
	target filter.Provider,
	policies []model.DockerPortGuardPolicy,
	inventory docker_guard.PolicyInventory,
) dto.FirewallRuleSyncPreview {
	desired := make([]firewallsync.Desired[docker_guard.Policy, dto.FirewallRuleSyncItem], 0, len(policies))
	for _, policy := range policies {
		desired = append(desired, firewallsync.Desired[docker_guard.Policy, dto.FirewallRuleSyncItem]{
			Value:   dockerGuardPolicyFromModel(policy),
			Payload: dto.FirewallRuleSyncItem{SourceUUID: policy.UUID, DockerRule: dockerGuardRuleSyncDTO(policy)},
		})
	}
	preview := firewallDiffPreview(
		"docker", target, desired, inventory.Policies, docker_guard.PolicySyncKey,
		func(policy docker_guard.Policy) dto.FirewallRuleSyncItem {
			return dto.FirewallRuleSyncItem{SourceUUID: policy.UUID, DockerRule: dockerGuardRuntimeRuleSyncDTO(policy)}
		},
	)
	for _, policy := range inventory.ReadOnly {
		preview.Add(dto.FirewallRuleSyncItem{
			SourceUUID: dockerGuardReadOnlyPolicyUUID(policy),
			DockerRule: dockerGuardReadOnlyRuleSyncDTO(policy),
			Status:     firewallsync.StatusBlocked,
			ReasonCode: firewallsync.ReasonReadOnlyRule,
			Reason:     firewallsync.ReasonMessage(firewallsync.ReasonReadOnlyRule),
		})
	}
	return preview
}

func (s *FirewallService) dockerRuleSyncService() firewallDatabaseSyncAdapter {
	if s.dockerSync == nil {
		return newDockerPortGuardService()
	}
	return s.dockerSync
}

func databaseRuleSyncTarget(request dto.FirewallRuleSyncRequest, subsystem string) (filter.Provider, error) {
	if request.SourceProvider != "" {
		return "", fmt.Errorf("%w: %s synchronization reads rules from the database and does not accept a source provider", filter.ErrInvalidRule, subsystem)
	}
	if request.ResetSource {
		return "", fmt.Errorf("%w: %s synchronization does not have a source firewall to reset", filter.ErrInvalidRule, subsystem)
	}
	if request.TargetProvider != filter.ProviderIptables && request.TargetProvider != filter.ProviderNftables {
		return "", fmt.Errorf("%w: %s synchronization only supports iptables and nftables targets", filter.ErrInvalidRule, subsystem)
	}
	return request.TargetProvider, nil
}

func appendDatabaseSyncFailure(result *dto.FirewallRuleSyncResult, item dto.FirewallRuleSyncItem, err error) {
	if err == nil {
		err = errors.New("database synchronization failed")
	}
	result.Failed++
	result.Errors = append(result.Errors, dto.FirewallRuleSyncFailure{
		SourceUUID: item.SourceUUID,
		Rule:       item.Rule, ForwardRule: item.ForwardRule, DockerRule: item.DockerRule,
		Error: err.Error(),
	})
}

func firewallDiffPreview[T any](subsystem string, target filter.Provider, desired []firewallsync.Desired[T, dto.FirewallRuleSyncItem], actual []T, key func(T) string, actualItem func(T) dto.FirewallRuleSyncItem) dto.FirewallRuleSyncPreview {
	preview := dto.FirewallRuleSyncPreview{Subsystem: subsystem, TargetProvider: target, Items: make([]dto.FirewallRuleSyncItem, 0)}
	for _, item := range firewallsync.Diff(desired, actual, key, actualItem) {
		row := item.Payload
		row.Status, row.ReasonCode, row.Reason = item.Status, item.ReasonCode, item.Reason
		preview.Add(row)
	}
	return preview
}

func firewallSyncResult(preview dto.FirewallRuleSyncPreview, cause error, executed bool) dto.FirewallRuleSyncResult {
	result := dto.FirewallRuleSyncResult{Subsystem: preview.Subsystem, TargetProvider: preview.TargetProvider}
	for _, item := range preview.Items {
		if item.Status != firewallsync.StatusRemove {
			result.Total++
		}
		switch item.Status {
		case firewallsync.StatusExisting:
			result.Skipped++
		case firewallsync.StatusBlocked:
			appendDatabaseSyncFailure(&result, item, errors.New(item.Reason))
		case firewallsync.StatusReady:
			if executed {
				if cause != nil {
					appendDatabaseSyncFailure(&result, item, cause)
				} else {
					result.Succeeded++
				}
			}
		case firewallsync.StatusRemove:
			if executed && cause == nil {
				result.Removed++
			}
		}
	}
	return result
}