package appstate

import (
	"errors"
	"fmt"
	"slices"
	"strings"
	"time"

	"git.julianfamily.org/keepassgo/internal/apiapproval"
	"git.julianfamily.org/keepassgo/internal/apitokens"
	"git.julianfamily.org/keepassgo/internal/vault"
	"git.julianfamily.org/keepassgo/internal/webdav"
)

type Section string

var (
	ErrAttachmentAlreadyExists = errors.New("attachment already exists")
	ErrAttachmentNotFound      = errors.New("attachment not found")
)

const (
	SectionEntries    Section = ""
	SectionTemplates  Section = "templates"
	SectionRecycleBin Section = "recycle-bin"
	SectionAPITokens  Section = "api-tokens"
	SectionAPIAudit   Section = "api-audit"
	SectionAbout      Section = "about"
)

type CurrentSession interface {
	Current() (vault.Model, error)
}

type MutableSession interface {
	CurrentSession
	Replace(vault.Model)
}

type LockableSession interface {
	CurrentSession
	Lock() error
	Unlock(vault.MasterKey) error
}

type MasterKeyChangeableSession interface {
	CurrentSession
	ChangeMasterKey(vault.MasterKey) error
}

type SaveableSession interface {
	CurrentSession
	Save() error
}

type SynchronizableSession interface {
	CurrentSession
	Synchronize() error
}

type AdvancedSynchronizableSession interface {
	CurrentSession
	SynchronizeFromLocal(string) error
	SynchronizeFromLocalBytes(string, []byte) error
	SynchronizeToLocal(string) error
	SynchronizeFromRemote(webdav.Client, string) error
	SynchronizeToRemote(webdav.Client, string) error
}

type CreateableSession interface {
	CurrentSession
	Create(vault.Model, vault.MasterKey) error
}

type OpenableSession interface {
	CurrentSession
	Open(string, vault.MasterKey) error
}

type SaveAsSession interface {
	CurrentSession
	SaveAs(string) error
}

type RemoteOpenableSession interface {
	CurrentSession
	OpenRemote(webdav.Client, string, vault.MasterKey) error
}

type SecurityConfigurableSession interface {
	ConfigureSecurity(vault.SecuritySettings) error
	SecuritySettings() vault.SecuritySettings
}

type ApprovalManager interface {
	Pending() []apiapproval.Request
	Resolve(string, apiapproval.Outcome) (apiapproval.Request, *apitokens.PolicyRule, error)
}

type State struct {
	Session         CurrentSession
	Approvals       ApprovalManager
	Section         Section
	CurrentPath     []string
	SearchQuery     string
	SelectedEntryID string
	Dirty           bool
	StatusMessage   string
	ErrorMessage    string
}

func (s *State) PendingApprovals() []apiapproval.Request {
	if s.Approvals == nil {
		return nil
	}
	return s.Approvals.Pending()
}

func (s *State) ResolveApproval(id string, outcome apiapproval.Outcome) error {
	if s.Approvals == nil {
		return fmt.Errorf("approval manager is not configured")
	}
	_, _, err := s.Approvals.Resolve(id, outcome)
	return err
}

func (s *State) APITokens() ([]apitokens.Token, error) {
	model, err := s.currentModel()
	if err != nil {
		return nil, err
	}
	return apitokens.Entries(model)
}

func (s *State) RemoteProfiles() ([]vault.RemoteProfile, error) {
	model, err := s.currentModel()
	if err != nil {
		return nil, err
	}
	profiles := slices.Clone(model.RemoteProfiles)
	slices.SortFunc(profiles, func(a, b vault.RemoteProfile) int {
		switch {
		case a.Name < b.Name:
			return -1
		case a.Name > b.Name:
			return 1
		case a.ID < b.ID:
			return -1
		case a.ID > b.ID:
			return 1
		default:
			return 0
		}
	})
	return profiles, nil
}

func (s *State) RemoteCredentialEntries() ([]vault.Entry, error) {
	model, err := s.currentModel()
	if err != nil {
		return nil, err
	}
	entries := slices.Clone(model.Entries)
	slices.SortFunc(entries, func(a, b vault.Entry) int {
		switch {
		case a.Title < b.Title:
			return -1
		case a.Title > b.Title:
			return 1
		case a.ID < b.ID:
			return -1
		case a.ID > b.ID:
			return 1
		default:
			return 0
		}
	})
	return entries, nil
}

func (s *State) IssueAPIToken(name, clientName string, expiresAt *time.Time, now time.Time) (apitokens.Token, string, error) {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return apitokens.Token{}, "", fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return apitokens.Token{}, "", err
	}
	token, secret, err := apitokens.Issue(name, clientName, expiresAt, now)
	if err != nil {
		return apitokens.Token{}, "", err
	}
	apitokens.Upsert(&model, token)
	session.Replace(model)
	s.Dirty = true
	return token, secret, nil
}

func (s *State) RotateAPIToken(id string, now time.Time) (apitokens.Token, string, error) {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return apitokens.Token{}, "", fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return apitokens.Token{}, "", err
	}
	token, err := apitokens.Find(model, id)
	if err != nil {
		return apitokens.Token{}, "", err
	}
	token, secret, err := apitokens.Rotate(token, now)
	if err != nil {
		return apitokens.Token{}, "", err
	}
	apitokens.Upsert(&model, token)
	session.Replace(model)
	s.Dirty = true
	return token, secret, nil
}

func (s *State) UpsertAPIToken(token apitokens.Token) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return err
	}
	apitokens.Upsert(&model, token)
	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) DisableAPIToken(id string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return err
	}
	token, err := apitokens.Find(model, id)
	if err != nil {
		return err
	}
	apitokens.Upsert(&model, apitokens.Disable(token))
	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) RevokeAPIToken(id string, when time.Time) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return err
	}
	token, err := apitokens.Find(model, id)
	if err != nil {
		return err
	}
	apitokens.Upsert(&model, apitokens.Revoke(token, when))
	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) DeleteAPIToken(id string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return err
	}
	if err := apitokens.Delete(&model, id); err != nil {
		return err
	}
	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) SecuritySettings() (vault.SecuritySettings, error) {
	security, ok := s.Session.(SecurityConfigurableSession)
	if !ok {
		return vault.SecuritySettings{}, fmt.Errorf("session does not expose security settings")
	}
	return security.SecuritySettings(), nil
}

func (s *State) ConfigureSecurity(settings vault.SecuritySettings) error {
	security, ok := s.Session.(SecurityConfigurableSession)
	if !ok {
		return fmt.Errorf("session does not expose security settings")
	}
	if err := security.ConfigureSecurity(settings); err != nil {
		return err
	}
	s.Dirty = true
	return nil
}

func (s *State) ShowSection(section Section) {
	s.Section = section
	s.CurrentPath = nil
	s.SelectedEntryID = ""
}

func (s *State) SetSearchQuery(query string) {
	s.SearchQuery = query
}

func (s *State) BeginNewEntry() {
	s.SelectedEntryID = ""
	s.StatusMessage = ""
	s.ErrorMessage = ""
}

func (s *State) SetActionResult(label string, err error) {
	if err != nil {
		s.ErrorMessage = err.Error()
		s.StatusMessage = ""
		return
	}

	s.ErrorMessage = ""
	s.StatusMessage = label + " complete"
}

func (s *State) VisibleEntries() ([]vault.Entry, error) {
	model, err := s.currentModel()
	if err != nil {
		return nil, err
	}

	entries := s.entriesForSection(model)
	if strings.TrimSpace(s.SearchQuery) != "" {
		return filterEntries(entries, s.SearchQuery), nil
	}

	if s.Section == SectionEntries {
		return entriesInPath(model.Entries, s.CurrentPath), nil
	}
	if s.Section == SectionRecycleBin || len(s.CurrentPath) == 0 {
		return entries, nil
	}

	return entriesInPath(entries, s.CurrentPath), nil
}

func (s *State) ChildGroups() ([]string, error) {
	if strings.TrimSpace(s.SearchQuery) != "" {
		return nil, nil
	}

	model, err := s.currentModel()
	if err != nil {
		return nil, err
	}

	if s.Section != SectionEntries {
		if s.Section == SectionTemplates && len(s.CurrentPath) == 0 {
			return childGroups(s.entriesForSection(model), []string{"Templates"}), nil
		}
		return childGroups(s.entriesForSection(model), s.CurrentPath), nil
	}

	return model.ChildGroups(s.CurrentPath), nil
}

func (s *State) SelectVisibleIndex(index int) error {
	entries, err := s.VisibleEntries()
	if err != nil {
		return err
	}
	if index < 0 || index >= len(entries) {
		return fmt.Errorf("visible index %d out of range", index)
	}

	s.SelectedEntryID = entries[index].ID
	return nil
}

func (s *State) ToggleVisibleIndex(index int) error {
	entries, err := s.VisibleEntries()
	if err != nil {
		return err
	}
	if index < 0 || index >= len(entries) {
		return fmt.Errorf("visible index %d out of range", index)
	}

	if s.SelectedEntryID == entries[index].ID {
		s.SelectedEntryID = ""
		return nil
	}

	s.SelectedEntryID = entries[index].ID
	return nil
}

func (s *State) currentModel() (vault.Model, error) {
	if s.Session == nil {
		return vault.Model{}, nil
	}
	return s.Session.Current()
}

func (s *State) entriesForSection(model vault.Model) []vault.Entry {
	switch s.Section {
	case SectionTemplates:
		return slices.Clone(model.Templates)
	case SectionRecycleBin:
		return slices.Clone(model.RecycleBin)
	case SectionAPITokens, SectionAPIAudit, SectionAbout:
		return nil
	default:
		return slices.Clone(model.Entries)
	}
}

func (s State) SearchPathContext(entry vault.Entry) string {
	path := slices.Clone(entry.Path)
	switch s.Section {
	case SectionTemplates:
		if len(path) == 0 || path[0] != "Templates" {
			path = append([]string{"Templates"}, path...)
		}
	case SectionRecycleBin:
		path = append([]string{"Recycle Bin"}, path...)
	}
	return strings.Join(path, " / ")
}

func entriesInPath(entries []vault.Entry, path []string) []vault.Entry {
	var out []vault.Entry
	for _, entry := range entries {
		if slices.Equal(entry.Path, path) {
			out = append(out, entry)
		}
	}
	slices.SortFunc(out, func(a, b vault.Entry) int {
		switch {
		case a.Title < b.Title:
			return -1
		case a.Title > b.Title:
			return 1
		default:
			return 0
		}
	})
	return out
}

func filterEntries(entries []vault.Entry, query string) []vault.Entry {
	query = strings.TrimSpace(strings.ToLower(query))
	if query == "" {
		return nil
	}

	var out []vault.Entry
	for _, entry := range entries {
		haystack := strings.ToLower(
			entry.Title + " " +
				entry.Username + " " +
				entry.URL + " " +
				strings.Join(entry.Path, " "),
		)
		if !strings.Contains(haystack, query) {
			continue
		}
		out = append(out, entry)
	}
	slices.SortFunc(out, func(a, b vault.Entry) int {
		switch {
		case a.Title < b.Title:
			return -1
		case a.Title > b.Title:
			return 1
		default:
			return 0
		}
	})
	return out
}

func childGroups(entries []vault.Entry, path []string) []string {
	seen := map[string]bool{}
	var groups []string
	for _, entry := range entries {
		if len(path) > len(entry.Path) {
			continue
		}
		if !slices.Equal(entry.Path[:len(path)], path) {
			continue
		}
		if len(entry.Path) == len(path) {
			continue
		}
		group := entry.Path[len(path)]
		if seen[group] {
			continue
		}
		seen[group] = true
		groups = append(groups, group)
	}
	slices.Sort(groups)
	return groups
}

func (s *State) DeleteSelectedEntry() error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.DeleteEntry(s.SelectedEntryID); err != nil {
		return err
	}

	session.Replace(model)
	s.SelectedEntryID = ""
	s.Dirty = true
	return nil
}

func (s *State) RestoreEntry(id string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.RestoreEntry(id); err != nil {
		return err
	}

	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) UpsertEntry(entry vault.Entry) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	model.UpsertEntry(entry)
	session.Replace(model)
	s.SelectedEntryID = entry.ID
	s.Dirty = true
	return nil
}

func (s *State) UpsertTemplate(entry vault.Entry) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	model.UpsertTemplate(entry)
	session.Replace(model)
	s.SelectedEntryID = entry.ID
	s.Dirty = true
	return nil
}

func (s *State) InstantiateTemplate(templateID string, overrides vault.Entry) (vault.Entry, error) {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return vault.Entry{}, fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return vault.Entry{}, err
	}

	entry, err := model.InstantiateTemplate(templateID, overrides)
	if err != nil {
		return vault.Entry{}, err
	}

	session.Replace(model)
	s.SelectedEntryID = entry.ID
	s.Dirty = true
	return entry, nil
}

func (s *State) DeleteTemplate(id string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.DeleteTemplate(id); err != nil {
		return err
	}

	session.Replace(model)
	if s.SelectedEntryID == id {
		s.SelectedEntryID = ""
	}
	s.Dirty = true
	return nil
}

func (s *State) DuplicateSelectedEntry(duplicateID string) (vault.Entry, error) {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return vault.Entry{}, fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return vault.Entry{}, err
	}

	duplicate, err := model.DuplicateEntry(s.SelectedEntryID, duplicateID)
	if err != nil {
		return vault.Entry{}, err
	}

	session.Replace(model)
	s.SelectedEntryID = duplicate.ID
	s.Dirty = true
	return duplicate, nil
}

func (s *State) RestoreSelectedEntryVersion(historyIndex int) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.RestoreEntryVersion(s.SelectedEntryID, historyIndex); err != nil {
		return err
	}

	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) Lock() error {
	session, ok := s.Session.(LockableSession)
	if !ok {
		return fmt.Errorf("session is not lockable")
	}

	if err := session.Lock(); err != nil {
		return err
	}

	s.SelectedEntryID = ""
	return nil
}

func (s *State) Unlock(key vault.MasterKey) error {
	session, ok := s.Session.(LockableSession)
	if !ok {
		return fmt.Errorf("session is not lockable")
	}

	return session.Unlock(key)
}

func (s *State) ChangeMasterKey(key vault.MasterKey) error {
	session, ok := s.Session.(MasterKeyChangeableSession)
	if !ok {
		return fmt.Errorf("session does not support master key changes")
	}

	if err := session.ChangeMasterKey(key); err != nil {
		return err
	}

	s.Dirty = true
	return nil
}

func (s *State) EnterGroup(name string) {
	s.CurrentPath = append(append([]string(nil), s.CurrentPath...), name)
	s.SelectedEntryID = ""
}

func (s *State) NavigateToPath(path []string) {
	s.CurrentPath = append([]string(nil), path...)
	s.SelectedEntryID = ""
}

func (s *State) Save() error {
	session, ok := s.Session.(SaveableSession)
	if !ok {
		return fmt.Errorf("session is not saveable")
	}

	if err := session.Save(); err != nil {
		return err
	}

	s.Dirty = false
	return nil
}

func (s *State) Synchronize() error {
	session, ok := s.Session.(SynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not synchronizable")
	}

	if err := session.Synchronize(); err != nil {
		return err
	}

	s.Dirty = false
	return nil
}

func (s *State) SynchronizeFromLocal(path string) error {
	session, ok := s.Session.(AdvancedSynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not advanced-synchronizable")
	}
	if err := session.SynchronizeFromLocal(path); err != nil {
		return err
	}
	s.Dirty = false
	return nil
}

func (s *State) SynchronizeFromLocalBytes(name string, content []byte) error {
	session, ok := s.Session.(AdvancedSynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not advanced-synchronizable")
	}
	if err := session.SynchronizeFromLocalBytes(name, content); err != nil {
		return err
	}
	s.Dirty = false
	return nil
}

func (s *State) SynchronizeToLocal(path string) error {
	session, ok := s.Session.(AdvancedSynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not advanced-synchronizable")
	}
	if err := session.SynchronizeToLocal(path); err != nil {
		return err
	}
	s.Dirty = true
	return nil
}

func (s *State) SynchronizeFromRemote(client webdav.Client, path string) error {
	session, ok := s.Session.(AdvancedSynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not advanced-synchronizable")
	}
	if err := session.SynchronizeFromRemote(client, path); err != nil {
		return err
	}
	s.Dirty = false
	return nil
}

func (s *State) SynchronizeToRemote(client webdav.Client, path string) error {
	session, ok := s.Session.(AdvancedSynchronizableSession)
	if !ok {
		return fmt.Errorf("session is not advanced-synchronizable")
	}
	if err := session.SynchronizeToRemote(client, path); err != nil {
		return err
	}
	s.Dirty = true
	return nil
}

func (s *State) CreateVault(key vault.MasterKey) error {
	session, ok := s.Session.(CreateableSession)
	if !ok {
		return fmt.Errorf("session is not createable")
	}

	if err := session.Create(vault.Model{}, key); err != nil {
		return err
	}

	s.CurrentPath = nil
	s.SelectedEntryID = ""
	s.Dirty = false
	return nil
}

func (s *State) OpenVault(path string, key vault.MasterKey) error {
	session, ok := s.Session.(OpenableSession)
	if !ok {
		return fmt.Errorf("session is not openable")
	}

	if err := session.Open(path, key); err != nil {
		return err
	}

	s.CurrentPath = nil
	s.SelectedEntryID = ""
	s.Dirty = false
	return nil
}

func (s *State) SaveAs(path string) error {
	session, ok := s.Session.(SaveAsSession)
	if !ok {
		return fmt.Errorf("session is not save-as capable")
	}

	if err := session.SaveAs(path); err != nil {
		return err
	}

	s.Dirty = false
	return nil
}

func (s *State) OpenRemoteVault(client webdav.Client, path string, key vault.MasterKey) error {
	session, ok := s.Session.(RemoteOpenableSession)
	if !ok {
		return fmt.Errorf("session is not remote-openable")
	}

	if err := session.OpenRemote(client, path, key); err != nil {
		return err
	}

	s.CurrentPath = nil
	s.SelectedEntryID = ""
	s.Dirty = false
	return nil
}

func (s *State) OpenBoundRemoteVault(binding RemoteBinding, key vault.MasterKey) error {
	model, err := s.currentModel()
	if err != nil {
		return err
	}

	resolved, err := binding.Resolve(model)
	if err != nil {
		return err
	}

	client := webdav.Client{
		BaseURL:  resolved.Profile.BaseURL,
		Username: resolved.Credentials.Username,
		Password: resolved.Credentials.Password,
	}
	return s.OpenRemoteVault(client, resolved.Profile.Path, key)
}

func (s *State) ConfigureRemoteBinding(input RemoteBindingInput) (RemoteBinding, error) {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return RemoteBinding{}, fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return RemoteBinding{}, err
	}

	binding, err := ConfigureRemoteBinding(&model, input)
	if err != nil {
		return RemoteBinding{}, err
	}

	session.Replace(model)
	s.Dirty = true
	return binding, nil
}

func (s *State) RemoveRemoteBinding(binding RemoteBinding) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := RemoveRemoteBinding(&model, binding); err != nil {
		return err
	}

	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) CreateGroup(name string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	model.CreateGroup(s.CurrentPath, name)
	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) MoveCurrentGroup(parent []string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}
	model, err := session.Current()
	if err != nil {
		return err
	}
	current := append([]string(nil), s.CurrentPath...)
	if err := model.MoveGroup(current, parent); err != nil {
		return err
	}
	session.Replace(model)
	if len(current) > 0 {
		s.CurrentPath = append(append([]string(nil), parent...), current[len(current)-1])
	}
	s.Dirty = true
	return nil
}

func (s *State) RenameCurrentGroup(newName string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.RenameGroup(s.CurrentPath, newName); err != nil {
		return err
	}

	session.Replace(model)
	if len(s.CurrentPath) > 0 {
		s.CurrentPath = append(append([]string(nil), s.CurrentPath[:len(s.CurrentPath)-1]...), newName)
	}
	s.Dirty = true
	return nil
}

func (s *State) MoveSelectedEntry(path []string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.MoveEntry(s.SelectedEntryID, path); err != nil {
		return err
	}

	session.Replace(model)
	s.Dirty = true
	return nil
}

func (s *State) DeleteCurrentGroup() error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	if err := model.DeleteGroup(s.CurrentPath); err != nil {
		return err
	}

	session.Replace(model)
	if len(s.CurrentPath) > 0 {
		s.CurrentPath = append([]string(nil), s.CurrentPath[:len(s.CurrentPath)-1]...)
	}
	s.SelectedEntryID = ""
	s.Dirty = true
	return nil
}

func (s *State) AddAttachmentToSelectedEntry(name string, content []byte) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	for i := range model.Entries {
		if model.Entries[i].ID != s.SelectedEntryID {
			continue
		}
		if model.Entries[i].Attachments == nil {
			model.Entries[i].Attachments = map[string][]byte{}
		}
		if _, exists := model.Entries[i].Attachments[name]; exists {
			return ErrAttachmentAlreadyExists
		}
		model.Entries[i].Attachments[name] = append([]byte(nil), content...)
		session.Replace(model)
		s.Dirty = true
		return nil
	}

	return vault.ErrEntryNotFound
}

func (s *State) ReplaceAttachmentOnSelectedEntry(name string, content []byte) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	for i := range model.Entries {
		if model.Entries[i].ID != s.SelectedEntryID {
			continue
		}
		if _, exists := model.Entries[i].Attachments[name]; !exists {
			return ErrAttachmentNotFound
		}
		model.Entries[i].Attachments[name] = append([]byte(nil), content...)
		session.Replace(model)
		s.Dirty = true
		return nil
	}

	return vault.ErrEntryNotFound
}

func (s *State) DeleteAttachmentFromSelectedEntry(name string) error {
	session, ok := s.Session.(MutableSession)
	if !ok {
		return fmt.Errorf("session is not mutable")
	}

	model, err := session.Current()
	if err != nil {
		return err
	}

	for i := range model.Entries {
		if model.Entries[i].ID != s.SelectedEntryID {
			continue
		}
		if _, exists := model.Entries[i].Attachments[name]; !exists {
			return ErrAttachmentNotFound
		}
		delete(model.Entries[i].Attachments, name)
		if len(model.Entries[i].Attachments) == 0 {
			model.Entries[i].Attachments = nil
		}
		session.Replace(model)
		s.Dirty = true
		return nil
	}

	return vault.ErrEntryNotFound
}