package app

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"sync"
	"time"

	"proxyctl/internal/profile"
	"proxyctl/internal/target"
)

type IntentKind int

const (
	CreateProfile IntentKind = iota + 1
	UpdateProfile
	DeleteProfile
	ActivateProfile
	RefreshTargets
	EnableTarget
	DisableTarget
	ApplyProfileToTarget
	ReapplyActiveProfile
	RestoreOriginal
)

type Intent struct {
	Kind              IntentKind
	Name              string
	Profile           profile.Profile
	Confirm           bool
	ConfirmationToken string
	TargetID          string
}

func confirmationToken(parts ...string) string {
	hash := sha256.New()
	for _, part := range parts {
		_, _ = hash.Write([]byte(part))
		_, _ = hash.Write([]byte{0})
	}
	return hex.EncodeToString(hash.Sum(nil))
}

// TargetActionKind identifies a Target action independently of display labels.
type TargetActionKind uint8

const (
	EnableTargetAction TargetActionKind = iota + 1
	DisableTargetAction
	ApplyProfileTargetAction
	ResolveDriftTargetAction
	ReapplyActiveProfileAction
	RestoreOriginalAction
)

// TargetAction exposes whether an intent is currently available and, when it
// is not, the reason presentation layers should show instead of ignoring it.
type TargetAction struct {
	Kind           TargetActionKind
	Available      bool
	DisabledReason string
}

type targetActionPolicy struct {
	kind            TargetActionKind
	intent          IntentKind
	state           target.State
	desired         bool
	primary         bool
	requiresProfile bool
	operation       string
}

var targetActionPolicies = []targetActionPolicy{
	{kind: EnableTargetAction, intent: EnableTarget, state: target.Disabled, desired: true, primary: true, requiresProfile: true, operation: "enable"},
	{kind: DisableTargetAction, intent: DisableTarget, state: target.Enabled, primary: true, operation: "disable"},
	{kind: ApplyProfileTargetAction, intent: ApplyProfileToTarget, state: target.External, desired: true, primary: true, requiresProfile: true, operation: "apply-Profile"},
	{kind: ResolveDriftTargetAction, state: target.Drifted, primary: true},
	{kind: ReapplyActiveProfileAction, intent: ReapplyActiveProfile, state: target.Drifted, desired: true, requiresProfile: true, operation: "reapply-Active-Profile"},
	{kind: RestoreOriginalAction, intent: RestoreOriginal, state: target.Drifted, operation: "restore-original"},
}

func targetActionPolicyForKind(kind TargetActionKind) (targetActionPolicy, bool) {
	for _, policy := range targetActionPolicies {
		if policy.kind == kind {
			return policy, true
		}
	}
	return targetActionPolicy{}, false
}

// Intent creates the Application intent represented by a structured Target
// action. Presentation layers use this as the sole action-to-intent boundary.
func (kind TargetActionKind) Intent(targetID string) (Intent, bool) {
	policy, ok := targetActionPolicyForKind(kind)
	if !ok || policy.intent == 0 {
		return Intent{}, false
	}
	return Intent{Kind: policy.intent, TargetID: targetID}, true
}

type TargetDetectionPhase uint8

const (
	// TargetReady is the zero value so snapshots supplied by non-progressive
	// Modules remain compatible with the established dashboard contract.
	TargetReady TargetDetectionPhase = iota
	TargetChecking
	TargetDetectionFailed
)

type TargetSnapshot struct {
	ID                     string
	Description            target.Description
	DetectionPhase         TargetDetectionPhase
	DetectionErr           error
	Available              bool
	AvailabilityEvidence   string
	State                  target.State
	Evidence               string
	PrimaryAction          TargetAction
	DriftResolutionActions []TargetAction
}

type Snapshot struct {
	Profiles      []profile.Profile
	ActiveProfile string
	Targets       []TargetSnapshot
}

type TargetProgress struct {
	TargetID string
	Phase    TargetProgressPhase
	State    target.State
	Evidence string
	Err      error
}

type Result struct {
	Snapshot            Snapshot
	Notice              string
	ConfirmationRequest *Confirmation
	Status              OperationStatus
	Progress            []TargetProgress
	FirstFailedTargetID string
	Err                 error
}

type Module interface {
	Snapshot() Snapshot
	Dispatch(Intent) Result
}

type Application struct {
	store                profile.Store
	state                profile.State
	targets              []target.Target
	targetIDs            []string
	targetDescriptions   []target.Description
	availabilities       map[string]target.Availability
	inspections          map[string]target.Inspection
	mutationBlockReasons map[string]string
	detectionPhase       map[string]TargetDetectionPhase
	detectionErr         map[string]error
	detectionGeneration  uint64
	stateMu              sync.RWMutex
	dispatchMu           sync.Mutex
	interactiveMu        sync.Mutex
	interactiveOperation bool
	mutationLock         MutationLock
	logger               OperationLogger
}

func New(store profile.Store) (*Application, error) {
	return NewWithTargets(store, nil)
}

func NewWithTargets(store profile.Store, targets []target.Target) (*Application, error) {
	return NewWithTargetsAndLock(store, targets, nil)
}

// NewWithTargetsAndLock configures the cross-process lock used by every
// Profile or Target mutation. A nil lock is intended only for isolated tests.
func NewWithTargetsAndLock(store profile.Store, targets []target.Target, mutationLock MutationLock) (*Application, error) {
	return NewWithTargetsAndRuntime(store, targets, mutationLock, nil)
}

// NewWithTargetsAndRuntime configures shared mutation serialization and local
// operation diagnostics for production callers.
func NewWithTargetsAndRuntime(store profile.Store, targets []target.Target, mutationLock MutationLock, logger OperationLogger) (*Application, error) {
	state, err := store.Load()
	if err != nil {
		return nil, err
	}
	a := &Application{
		store:                store,
		state:                state,
		targets:              append([]target.Target(nil), targets...),
		availabilities:       make(map[string]target.Availability),
		inspections:          make(map[string]target.Inspection),
		mutationBlockReasons: make(map[string]string),
		detectionPhase:       make(map[string]TargetDetectionPhase),
		detectionErr:         make(map[string]error),
		mutationLock:         mutationLock,
		logger:               logger,
	}
	for _, adapter := range a.targets {
		id := adapter.ID()
		a.targetIDs = append(a.targetIDs, id)
		a.targetDescriptions = append(a.targetDescriptions, adapter.Description())
		a.detectionPhase[id] = TargetChecking
	}
	return a, nil
}

func (a *Application) Snapshot() Snapshot {
	a.stateMu.RLock()
	defer a.stateMu.RUnlock()
	return a.snapshotLocked()
}

func (a *Application) snapshotLocked() Snapshot {
	state := cloneState(a.state)
	snapshot := Snapshot{Profiles: state.Profiles, ActiveProfile: state.ActiveProfile}
	for i, id := range a.targetIDs {
		availability := a.availabilities[id]
		inspection := a.inspections[id]
		phase := a.detectionPhase[id]
		primary, resolution := contextualTargetActions(phase, availability.Available, inspection.State, state.ActiveProfile != "", a.mutationBlockReasons[id])
		snapshot.Targets = append(snapshot.Targets, TargetSnapshot{
			ID: id, Description: a.targetDescriptions[i], DetectionPhase: phase, DetectionErr: a.detectionErr[id],
			Available: availability.Available, AvailabilityEvidence: availability.Evidence, State: inspection.State, Evidence: inspection.Evidence,
			PrimaryAction: primary, DriftResolutionActions: resolution,
		})
	}
	return snapshot
}

func contextualTargetActions(phase TargetDetectionPhase, available bool, state target.State, hasActiveProfile bool, mutationBlockReason string) (TargetAction, []TargetAction) {
	primaryKind := primaryTargetActionKind(state)
	primary := TargetAction{Kind: primaryKind, Available: primaryKind != 0}
	if primaryKind == 0 {
		primary.DisabledReason = "Target actions are unavailable because this Target state is unknown"
	}
	if reason := targetActionDisabledReason(phase, available); reason != "" {
		primary.Available = false
		primary.DisabledReason = reason
	}
	if policy, ok := targetActionPolicyForKind(primaryKind); ok && primary.Available && policy.requiresProfile && !hasActiveProfile {
		primary.Available = false
		primary.DisabledReason = "This action is unavailable because there is no Active Profile; open Profile management first"
	}
	if primary.Available && mutationBlockReason != "" {
		primary.Available = false
		primary.DisabledReason = mutationBlockReason
	}
	if state != target.Drifted {
		return primary, nil
	}

	var resolution []TargetAction
	for _, policy := range targetActionPolicies {
		if policy.state != target.Drifted || policy.primary || policy.intent == 0 {
			continue
		}
		action := TargetAction{Kind: policy.kind, Available: true}
		if policy.requiresProfile && !hasActiveProfile {
			action.Available = false
			action.DisabledReason = "Reapply Active Profile is unavailable because there is no Active Profile; open Profile management first"
		}
		if reason := targetActionDisabledReason(phase, available); reason != "" {
			action.Available = false
			action.DisabledReason = reason
		}
		if action.Available && mutationBlockReason != "" {
			action.Available = false
			action.DisabledReason = mutationBlockReason
		}
		resolution = append(resolution, action)
	}
	return primary, resolution
}

func primaryTargetActionKind(state target.State) TargetActionKind {
	for _, policy := range targetActionPolicies {
		if policy.primary && policy.state == state {
			return policy.kind
		}
	}
	return 0
}

func targetActionDisabledReason(phase TargetDetectionPhase, available bool) string {
	switch phase {
	case TargetChecking:
		return "Target actions are unavailable while this Target is still being checked"
	case TargetDetectionFailed:
		return "Target actions are unavailable because this Target check failed; refresh Targets to retry"
	default:
		if !available {
			return "Target actions are unavailable because this Target is unavailable"
		}
		return ""
	}
}

type targetDetectionOutcome struct {
	targetID            string
	detection           target.Detection
	mutationBlockReason string
}

type targetDetectionUpdate struct {
	snapshot Snapshot
	targetID string
	complete bool
}

func (a *Application) beginTargetDetection(ctx context.Context) (Snapshot, <-chan targetDetectionUpdate) {
	a.stateMu.Lock()
	a.detectionGeneration++
	generation := a.detectionGeneration
	for _, id := range a.targetIDs {
		a.detectionPhase[id] = TargetChecking
		a.detectionErr[id] = nil
	}
	active := activeProfile(a.state)
	checking := a.snapshotLocked()
	a.stateMu.Unlock()

	updates := make(chan targetDetectionUpdate, len(a.targets)+1)
	outcomes := make(chan targetDetectionOutcome, len(a.targets))
	for i, adapter := range a.targets {
		adapter, id := adapter, a.targetIDs[i]
		go func() {
			outcomes <- targetDetectionOutcome{
				targetID: id, detection: detectTarget(ctx, adapter, active),
				mutationBlockReason: mutationBlockReason(ctx, adapter),
			}
		}()
	}
	go func() {
		defer close(updates)
		for range a.targets {
			outcome := <-outcomes
			a.stateMu.Lock()
			if generation != a.detectionGeneration {
				a.stateMu.Unlock()
				continue
			}
			phase := TargetReady
			if outcome.detection.Err != nil {
				phase = TargetDetectionFailed
			}
			a.availabilities[outcome.targetID] = outcome.detection.Availability
			a.inspections[outcome.targetID] = outcome.detection.Inspection
			a.mutationBlockReasons[outcome.targetID] = outcome.mutationBlockReason
			a.detectionPhase[outcome.targetID] = phase
			a.detectionErr[outcome.targetID] = outcome.detection.Err
			update := targetDetectionUpdate{snapshot: a.snapshotLocked(), targetID: outcome.targetID}
			// The buffered send cannot wait on a consumer and happens before a
			// newer Begin call can make this generation stale.
			updates <- update
			a.stateMu.Unlock()
		}
		a.stateMu.Lock()
		if generation == a.detectionGeneration {
			updates <- targetDetectionUpdate{snapshot: a.snapshotLocked(), complete: true}
		}
		a.stateMu.Unlock()
	}()
	return checking, updates
}

func detectTarget(ctx context.Context, adapter target.Target, active *profile.Profile) target.Detection {
	if detector, ok := adapter.(target.Detector); ok {
		return detector.Detect(ctx, active)
	}
	return target.Detection{
		Availability: adapter.Availability(ctx),
		Inspection:   adapter.Inspect(ctx, active),
	}
}

func mutationBlockReason(ctx context.Context, adapter target.Target) string {
	authorizer, ok := adapter.(target.MutationAuthorizer)
	if !ok {
		return ""
	}
	check := authorizer.MutationAuthority(ctx)
	if check.OK {
		return ""
	}
	if check.Evidence == "" {
		return "The current process does not have authority to change this Target"
	}
	return check.Evidence
}

func (a *Application) Dispatch(intent Intent) Result {
	ctx, cancel := context.WithTimeout(context.Background(), operationTimeout)
	defer cancel()
	return a.dispatch(ctx, intent, nil)
}

func (a *Application) dispatch(ctx context.Context, intent Intent, publish func(Result)) Result {
	// Serialize local mutation workflows even when tests intentionally omit the
	// cross-process MutationLock.
	a.dispatchMu.Lock()
	defer a.dispatchMu.Unlock()

	if a.mutationLock != nil {
		unlock, err := a.mutationLock.Lock(ctx)
		if err != nil {
			return Result{Snapshot: a.Snapshot(), Err: fmt.Errorf("lock proxyctl mutation: %w", err)}
		}
		defer unlock()
	}
	// A different process may have changed the persisted Active Profile since
	// this Application was constructed. Reload only after the global mutation
	// lock is held, before selecting a Profile or invoking a Target. Load is
	// deliberately separate from Store.Mutate so no Profile-store lock is nested.
	fresh, err := a.store.Load()
	if err != nil {
		return Result{Snapshot: a.Snapshot(), Err: fmt.Errorf("reload Profile state for mutation: %w", err)}
	}
	a.replaceState(fresh)
	if intent.Kind == ActivateProfile {
		a.refreshInspections(ctx)
	}
	if isTargetMutationIntent(intent.Kind) {
		return a.setTargetDesired(ctx, intent, publish)
	}
	if intent.Kind == RefreshTargets {
		return a.refreshTargets(ctx, publish)
	}
	if intent.Kind == ActivateProfile {
		return a.activateProfile(ctx, intent, publish)
	}
	var notice string
	next, err := a.store.Mutate(func(current profile.State) (profile.State, error) {
		var mutationErr error
		switch intent.Kind {
		case CreateProfile:
			current, notice, mutationErr = create(current, intent.Profile)
		case UpdateProfile:
			current, notice, mutationErr = update(current, intent.Name, intent.Profile)
		case DeleteProfile:
			current, notice, mutationErr = deleteProfile(current, intent.Name, intent.Confirm)
		default:
			mutationErr = errors.New("unsupported Profile action")
		}
		return current, mutationErr
	})
	if err == nil {
		a.replaceState(next)
		a.refreshInspections(ctx)
	} else {
		var committed *profile.CommitError
		if errors.As(err, &committed) {
			// Rename committed next before directory durability reporting failed.
			// Prefer that state even if the required verification reload also fails.
			a.replaceState(next)
			reloaded, loadErr := a.store.Load()
			if loadErr != nil {
				err = errors.Join(err, fmt.Errorf("reload committed Profile configuration: %w", loadErr))
			} else {
				a.replaceState(reloaded)
			}
		}
	}
	return Result{Snapshot: a.Snapshot(), Notice: notice, Err: err}
}

func (a *Application) activateProfile(ctx context.Context, intent Intent, publish func(Result)) Result {
	state := a.stateCopy()
	if index(state, intent.Name) < 0 {
		return Result{Snapshot: a.Snapshot(), Err: fmt.Errorf("Profile %q does not exist", intent.Name)}
	}
	if state.ActiveProfile == intent.Name {
		return Result{Snapshot: a.Snapshot(), Notice: fmt.Sprintf("Profile %q is already Active", intent.Name)}
	}

	inspections := a.inspectionsCopy()
	var enabled []int
	var warnings []string
	confirmationScope := []string{"activate-profile", intent.Name}
	for i, adapter := range a.targets {
		id := a.targetIDs[i]
		if inspections[id].State != target.Enabled {
			continue
		}
		enabled = append(enabled, i)
		confirmationScope = append(confirmationScope, id)
		if warning := adapter.Confirmation(true); warning != "" {
			detail := a.targetDescriptions[i].Name + ": " + warning
			warnings = append(warnings, detail)
			confirmationScope = append(confirmationScope, detail)
		} else {
			confirmationScope = append(confirmationScope, "")
		}
	}
	token := confirmationToken(confirmationScope...)
	if len(warnings) > 0 && (!intent.Confirm || intent.ConfirmationToken != token) {
		confirmation := &Confirmation{
			Title: "Confirm Active Profile change", Summary: "Changing the Active Profile has high-impact Target effects.",
			Details: warnings, ConfirmLabel: "Change Profile", CancelLabel: "Cancel", HighImpact: true, Token: token,
		}
		return Result{Snapshot: a.Snapshot(), ConfirmationRequest: confirmation,
			Status: OperationStatus{Summary: confirmation.Title}}
	}

	next, err := a.store.Mutate(func(current profile.State) (profile.State, error) {
		next, _, mutationErr := activate(current, intent.Name)
		return next, mutationErr
	})
	if err != nil {
		var committed *profile.CommitError
		if errors.As(err, &committed) {
			a.replaceState(next)
			if reloaded, loadErr := a.store.Load(); loadErr != nil {
				err = errors.Join(err, fmt.Errorf("reload committed Profile configuration: %w", loadErr))
			} else {
				a.replaceState(reloaded)
			}
		}
		return Result{Snapshot: a.Snapshot(), Err: err}
	}
	a.replaceState(next)
	active := a.activeProfile()
	// The Active Profile has changed before any Target write begins. Re-inspect
	// without the state lock, then publish all observations atomically.
	observed := make(map[string]target.Inspection, len(a.targets))
	for i, adapter := range a.targets {
		observed[a.targetIDs[i]] = adapter.Inspect(ctx, active)
	}
	a.replaceInspections(observed)

	var progress []TargetProgress
	var failures []error
	updated := make(map[string]bool, len(enabled))
	for _, targetIndex := range enabled {
		adapter := a.targets[targetIndex]
		id := a.targetIDs[targetIndex]
		name := a.targetDescriptions[targetIndex].Name
		updated[id] = true
		if publish != nil {
			publish(Result{Snapshot: a.Snapshot(), Progress: []TargetProgress{{TargetID: id, Phase: TargetProgressRunning, State: a.inspection(id).State}}, Notice: "Updating " + name + " Target",
				Status: OperationStatus{Summary: "Updating " + name + " Target", TargetID: id}})
		}
		operation := adapter.SetDesired(ctx, true, active)
		inspection := operation.Inspection
		var safeErr error
		if operation.Err != nil {
			// A failure-returned inspection may predate a partial write. Always
			// inspect explicitly against the new Active Profile before publishing.
			inspection = adapter.Inspect(ctx, active)
			safeErr = fmt.Errorf("%s (fresh inspection: %s — %s)", profile.RedactText(operation.Err.Error()), inspection.State, profile.RedactText(inspection.Evidence))
		}
		a.replaceInspection(id, inspection)
		if a.logger != nil {
			outcome, detail := "success", inspection.Evidence
			if safeErr != nil {
				outcome, detail = "failure", safeErr.Error()
			}
			if logErr := a.logger.Write(LogEntry{Time: time.Now(), Operation: "switch-Active-Profile", Target: id, Result: outcome, Detail: RedactLogDetail(detail)}); logErr != nil {
				safeErr = errors.Join(safeErr, fmt.Errorf("write %s Target operation log: %w", name, logErr))
			}
		}
		progressPhase := TargetProgressSucceeded
		if safeErr != nil {
			progressPhase = TargetProgressFailed
		}
		item := TargetProgress{TargetID: id, Phase: progressPhase, State: inspection.State, Evidence: inspection.Evidence, Err: safeErr}
		progress = append(progress, item)
		if publish != nil {
			status := OperationStatus{Summary: name + " Target update completed", TargetID: id}
			if safeErr != nil {
				status = OperationStatus{Summary: name + " Target update failed", TargetID: id}
			}
			publish(Result{Snapshot: a.Snapshot(), Progress: []TargetProgress{item}, Notice: name + " Target update completed", Status: status, Err: safeErr})
		}
		if safeErr != nil {
			failures = append(failures, fmt.Errorf("%s Target: %w", name, safeErr))
		}
	}
	// Re-inspect Targets which were not part of the transition so any managed
	// configuration is interpreted against the new Active Profile as well.
	remaining := make(map[string]target.Inspection)
	for i, adapter := range a.targets {
		id := a.targetIDs[i]
		if !updated[id] {
			remaining[id] = adapter.Inspect(ctx, active)
		}
	}
	a.mergeInspections(remaining)
	result := Result{Snapshot: a.Snapshot(), Progress: progress, Notice: fmt.Sprintf("Activated Profile %q", intent.Name),
		Status: OperationStatus{Summary: fmt.Sprintf("Activated Profile %q", intent.Name)}}
	if len(failures) > 0 {
		result.Err = errors.Join(failures...)
		result.Notice = fmt.Sprintf("Activated Profile %q with %d Target update failure(s); successful updates were kept and no global rollback was attempted", intent.Name, len(failures))
		result.Status = OperationStatus{Summary: fmt.Sprintf("Activated Profile %q with %d Target update failure(s)", intent.Name, len(failures))}
		for _, item := range progress {
			if item.Err != nil {
				result.FirstFailedTargetID = item.TargetID
				result.Status.TargetID = item.TargetID
				break
			}
		}
	}
	return result
}

func activeProfile(state profile.State) *profile.Profile {
	for i := range state.Profiles {
		if state.Profiles[i].Name == state.ActiveProfile {
			value := state.Profiles[i]
			value.Bypass = append([]string(nil), value.Bypass...)
			return &value
		}
	}
	return nil
}

func (a *Application) activeProfile() *profile.Profile {
	a.stateMu.RLock()
	defer a.stateMu.RUnlock()
	return activeProfile(a.state)
}

func (a *Application) stateCopy() profile.State {
	a.stateMu.RLock()
	defer a.stateMu.RUnlock()
	return cloneState(a.state)
}

func (a *Application) replaceState(state profile.State) {
	a.stateMu.Lock()
	defer a.stateMu.Unlock()
	a.detectionGeneration++
	a.state = cloneState(state)
}

func (a *Application) inspectionsCopy() map[string]target.Inspection {
	a.stateMu.RLock()
	defer a.stateMu.RUnlock()
	result := make(map[string]target.Inspection, len(a.inspections))
	for id, inspection := range a.inspections {
		result[id] = inspection
	}
	return result
}

func (a *Application) inspection(id string) target.Inspection {
	a.stateMu.RLock()
	defer a.stateMu.RUnlock()
	return a.inspections[id]
}

func (a *Application) replaceInspection(id string, inspection target.Inspection) {
	a.stateMu.Lock()
	defer a.stateMu.Unlock()
	a.detectionGeneration++
	a.inspections[id] = inspection
}

// publishTargetDetection atomically replaces all availability, inspection, and
// failure fields from one targeted check. Detect runs before this method, so no
// Application state mutex is held while adapter code executes.
func (a *Application) publishTargetDetection(id string, detection target.Detection, mutationBlockReason string) Snapshot {
	a.stateMu.Lock()
	defer a.stateMu.Unlock()
	a.detectionGeneration++
	a.availabilities[id] = detection.Availability
	a.inspections[id] = detection.Inspection
	a.mutationBlockReasons[id] = mutationBlockReason
	a.detectionErr[id] = detection.Err
	a.detectionPhase[id] = TargetReady
	if detection.Err != nil {
		a.detectionPhase[id] = TargetDetectionFailed
	}
	return a.snapshotLocked()
}

func (a *Application) replaceInspections(inspections map[string]target.Inspection) {
	a.stateMu.Lock()
	defer a.stateMu.Unlock()
	a.detectionGeneration++
	for _, id := range a.targetIDs {
		a.inspections[id] = inspections[id]
	}
}

func (a *Application) mergeInspections(inspections map[string]target.Inspection) {
	if len(inspections) == 0 {
		return
	}
	a.stateMu.Lock()
	defer a.stateMu.Unlock()
	a.detectionGeneration++
	for id, inspection := range inspections {
		a.inspections[id] = inspection
	}
}

func targetByID(snapshot Snapshot, id string) (TargetSnapshot, string) {
	for _, item := range snapshot.Targets {
		if item.ID == id {
			name := item.Description.Name
			if name == "" {
				name = id
			}
			return item, name
		}
	}
	return TargetSnapshot{ID: id}, id
}

func (a *Application) refreshTargets(ctx context.Context, publish func(Result)) Result {
	checking, updates := a.beginTargetDetection(ctx)
	if publish != nil {
		progress := make([]TargetProgress, 0, len(checking.Targets))
		for _, item := range checking.Targets {
			progress = append(progress, TargetProgress{TargetID: item.ID, Phase: TargetProgressRunning, State: item.State})
		}
		publish(Result{Snapshot: checking, Status: OperationStatus{Summary: "Checking Target availability and state"}, Progress: progress})
	}
	var failures []error
	firstFailed := ""
	final := checking
	for update := range updates {
		final = update.snapshot
		if update.complete {
			continue
		}
		item, name := targetByID(update.snapshot, update.targetID)
		progress := TargetProgress{TargetID: update.targetID, Phase: TargetProgressSucceeded, State: item.State, Evidence: item.Evidence}
		status := OperationStatus{Summary: "Checked " + name + " Target", TargetID: update.targetID}
		if item.DetectionPhase == TargetDetectionFailed {
			progress.Phase = TargetProgressFailed
			progress.Err = item.DetectionErr
			status.Summary = "Could not check " + name + " Target"
			if item.DetectionErr != nil {
				failures = append(failures, fmt.Errorf("%s Target: %w", name, item.DetectionErr))
			}
			if firstFailed == "" {
				firstFailed = update.targetID
			}
		}
		if publish != nil {
			publish(Result{Snapshot: update.snapshot, Status: status, Progress: []TargetProgress{progress}, Err: progress.Err})
		}
	}
	result := Result{Snapshot: final, Notice: "Target availability and state checks completed", Status: OperationStatus{Summary: "Target availability and state checks completed"}}
	if len(failures) > 0 {
		result.Err = errors.Join(failures...)
		result.FirstFailedTargetID = firstFailed
		result.Status = OperationStatus{Summary: "Some Target checks failed", TargetID: firstFailed}
	}
	return result
}

func (a *Application) refreshInspections(ctx context.Context) {
	active := a.activeProfile()
	inspections := make(map[string]target.Inspection, len(a.targets))
	for i, adapter := range a.targets {
		inspections[a.targetIDs[i]] = adapter.Inspect(ctx, active)
	}
	a.replaceInspections(inspections)
}

func isTargetMutationIntent(kind IntentKind) bool {
	for _, policy := range targetActionPolicies {
		if policy.intent == kind {
			return true
		}
	}
	return false
}

func requestedTargetAction(intent Intent) (TargetActionKind, bool) {
	for _, policy := range targetActionPolicies {
		if policy.intent == intent.Kind {
			return policy.kind, true
		}
	}
	return 0, false
}

func structuredTargetAction(selected TargetSnapshot, kind TargetActionKind) (TargetAction, bool) {
	if selected.PrimaryAction.Kind == kind {
		return selected.PrimaryAction, true
	}
	for _, action := range selected.DriftResolutionActions {
		if action.Kind == kind {
			return action, true
		}
	}
	return TargetAction{}, false
}

func validateTargetAction(intent Intent, selected TargetSnapshot) (targetActionPolicy, error) {
	kind, ok := requestedTargetAction(intent)
	if !ok {
		return targetActionPolicy{}, fmt.Errorf("Target %q action is no longer available because its state is %s", selected.ID, selected.State)
	}
	action, ok := structuredTargetAction(selected, kind)
	if !ok {
		return targetActionPolicy{}, fmt.Errorf("Target %q action is no longer available because its state is %s", selected.ID, selected.State)
	}
	if !action.Available {
		return targetActionPolicy{}, errors.New(action.DisabledReason)
	}
	policy, _ := targetActionPolicyForKind(kind)
	return policy, nil
}

func (a *Application) setTargetDesired(ctx context.Context, intent Intent, publish func(Result)) Result {
	selectedIndex := -1
	for i, id := range a.targetIDs {
		if id == intent.TargetID {
			selectedIndex = i
			break
		}
	}
	if selectedIndex < 0 {
		return Result{Snapshot: a.Snapshot(), Err: fmt.Errorf("Target %q does not exist", intent.TargetID)}
	}
	selected := a.targets[selectedIndex]
	active := a.activeProfile()
	// This targeted check runs inside dispatch serialization and immediately
	// before action validation. Adapter calls happen without stateMu; the full
	// outcome is then published under one lock before policy is derived.
	detection := detectTarget(ctx, selected, active)
	snapshot := a.publishTargetDetection(intent.TargetID, detection, mutationBlockReason(ctx, selected))
	selectedSnapshot := snapshot.Targets[selectedIndex]
	policy, err := validateTargetAction(intent, selectedSnapshot)
	if err != nil {
		return Result{Snapshot: snapshot, Err: err}
	}
	if warning := selected.Confirmation(policy.desired); warning != "" {
		token := confirmationToken("target", intent.TargetID, fmt.Sprint(intent.Kind), fmt.Sprint(selectedSnapshot.State), fmt.Sprint(policy.desired), warning)
		if !intent.Confirm || intent.ConfirmationToken != token {
			confirmation := &Confirmation{Title: "Confirm " + a.targetDescriptions[selectedIndex].Name + " Target change", Summary: warning,
				ConfirmLabel: "Continue", CancelLabel: "Cancel", HighImpact: true, Token: token}
			return Result{Snapshot: a.Snapshot(), ConfirmationRequest: confirmation,
				Status: OperationStatus{Summary: confirmation.Title, TargetID: intent.TargetID}}
		}
	}
	if publish != nil {
		publish(Result{Snapshot: snapshot, Progress: []TargetProgress{{TargetID: intent.TargetID, Phase: TargetProgressRunning, State: selectedSnapshot.State}},
			Status: OperationStatus{Summary: "Updating " + a.targetDescriptions[selectedIndex].Name + " Target", TargetID: intent.TargetID}})
	}
	result := selected.SetDesired(ctx, policy.desired, active)
	inspection := result.Inspection
	if result.Err != nil {
		inspection = selected.Inspect(ctx, active)
	}
	a.replaceInspection(intent.TargetID, inspection)
	outcome, detail := "success", inspection.Evidence
	if result.Err != nil {
		outcome, detail = "failure", result.Err.Error()
	}
	if a.logger != nil {
		if logErr := a.logger.Write(LogEntry{Time: time.Now(), Operation: policy.operation, Target: intent.TargetID, Result: outcome, Detail: RedactLogDetail(detail)}); logErr != nil {
			result.Err = errors.Join(result.Err, fmt.Errorf("write Target operation log: %w", logErr))
		}
	}
	notice := ""
	progressPhase := TargetProgressSucceeded
	status := OperationStatus{TargetID: intent.TargetID}
	if result.Err == nil {
		notice = fmt.Sprintf("%s Target is now %s", a.targetDescriptions[selectedIndex].Name, inspection.State)
		status.Summary = notice
	} else {
		progressPhase = TargetProgressFailed
		status.Summary = a.targetDescriptions[selectedIndex].Name + " Target update failed"
	}
	progress := TargetProgress{TargetID: intent.TargetID, Phase: progressPhase, State: inspection.State, Evidence: inspection.Evidence, Err: result.Err}
	return Result{Snapshot: a.Snapshot(), Notice: notice, Status: status, Progress: []TargetProgress{progress}, FirstFailedTargetID: map[bool]string{true: intent.TargetID}[result.Err != nil], Err: result.Err}
}

func create(state profile.State, input profile.Profile) (profile.State, string, error) {
	p, err := profile.ValidateAndNormalize(input)
	if err != nil {
		return state, "", err
	}
	if index(state, p.Name) >= 0 {
		return state, "", fmt.Errorf("a Profile named %q already exists", p.Name)
	}
	next := cloneState(state)
	next.Profiles = append(next.Profiles, p)
	return next, fmt.Sprintf("Created Profile %q", p.Name), nil
}

func activate(state profile.State, name string) (profile.State, string, error) {
	if index(state, name) < 0 {
		return state, "", fmt.Errorf("Profile %q does not exist", name)
	}
	next := cloneState(state)
	next.ActiveProfile = name
	return next, fmt.Sprintf("Activated Profile %q", name), nil
}

func update(state profile.State, originalName string, input profile.Profile) (profile.State, string, error) {
	profileIndex := index(state, originalName)
	if profileIndex < 0 {
		return state, "", fmt.Errorf("Profile %q does not exist", originalName)
	}
	p, err := profile.ValidateAndNormalize(input)
	if err != nil {
		return state, "", err
	}
	if other := index(state, p.Name); other >= 0 && other != profileIndex {
		return state, "", fmt.Errorf("a Profile named %q already exists", p.Name)
	}
	next := cloneState(state)
	next.Profiles[profileIndex] = p
	if next.ActiveProfile == originalName {
		next.ActiveProfile = p.Name
	}
	return next, fmt.Sprintf("Updated Profile %q", p.Name), nil
}

func deleteProfile(state profile.State, name string, confirm bool) (profile.State, string, error) {
	profileIndex := index(state, name)
	if profileIndex < 0 {
		return state, "", fmt.Errorf("Profile %q does not exist", name)
	}
	if len(state.Profiles) == 1 && !confirm {
		return state, "", errors.New("deleting the final Profile requires confirmation")
	}
	next := cloneState(state)
	next.Profiles = append(next.Profiles[:profileIndex], next.Profiles[profileIndex+1:]...)
	if next.ActiveProfile == name {
		next.ActiveProfile = ""
	}
	return next, fmt.Sprintf("Deleted Profile %q", name), nil
}

func index(state profile.State, name string) int {
	for i := range state.Profiles {
		if state.Profiles[i].Name == name {
			return i
		}
	}
	return -1
}

func cloneState(state profile.State) profile.State {
	state.Profiles = append([]profile.Profile(nil), state.Profiles...)
	for i := range state.Profiles {
		state.Profiles[i].Bypass = append([]string(nil), state.Profiles[i].Bypass...)
	}
	return state
}