package ui

import (
	"context"
	"time"

	"charm.land/bubbles/v2/help"
	"charm.land/bubbles/v2/key"
	"charm.land/bubbles/v2/list"
	"charm.land/bubbles/v2/spinner"
	"charm.land/bubbles/v2/viewport"
	tea "charm.land/bubbletea/v2"
	"charm.land/lipgloss/v2"

	"git.morlana.online/f.weber/vault-tui/internal/auth"
	"git.morlana.online/f.weber/vault-tui/internal/cli"
	"git.morlana.online/f.weber/vault-tui/internal/token"
	"git.morlana.online/f.weber/vault-tui/internal/ui/keys"
	"git.morlana.online/f.weber/vault-tui/internal/ui/theme"
	"git.morlana.online/f.weber/vault-tui/internal/vault"
)

type screen int

const (
	scrAuth screen = iota
	scrMounts
	scrBrowser
	scrSecret
	scrEditor
	scrVersions
)

// frame is one entry in the navigation stack. Not every field is used by
// every screen kind; see the per-screen handlers in the other files in
// this package.
type frame struct {
	scr   screen
	mount vault.Mount
	path  string // relative path: browser's current dir, or the secret path
}

// confirmSpec describes a pending destructive action, rendered as a
// centered overlay (see overlay.go) rather than appended below the
// current screen.
type confirmSpec struct {
	title      string
	body       string
	danger     bool
	typeToConf string // if non-empty, the user must type this text to confirm
	input      string
	onConfirm  func() tea.Cmd
}

// authState holds everything the auth screen needs across its three
// sub-phases (method picker -> credential form -> waiting on a
// multi-step login such as OIDC or Okta).
type authState struct {
	phase   int // 0=picker 1=form 2=waiting
	methods []auth.Method
	cursor  int
	method  auth.Method
	mount   string
	inputs  []textInputField
	focus   int
	events  chan auth.Event
	cancel  context.CancelFunc
	authURL string
	status  []string
	err     error
}

type textInputField struct {
	field auth.Field
	input textInput
}

// profileState drives the profile-switch overlay (screen_profile.go).
type profileState struct {
	open   bool
	names  []string
	cursor int
}

type Model struct {
	ctx context.Context
	a   *cli.App
	svc *vault.Service

	styles *theme.Styles
	keys   *keys.KeyMap
	help   help.Model
	spin   spinner.Model

	lay     layout
	loading bool

	toast    *toast
	toastSeq int

	stack []frame
	auth  authState

	list       list.Model
	listReady  bool
	listSelect string // remembered selected item's label, restored after a reload

	secret       *vault.Secret
	secretMask   map[string]bool
	secretKeys   []string // sorted cache of secret.Data's keys, rebuilt on load
	secretCursor int
	secretVP     viewport.Model
	clipSeq      int

	editName    textInput
	editKeys    []textInput
	editVals    []textInput
	editFocus   int
	editIsNew   bool
	editMount   vault.Mount
	editPath    string
	editSecret  *vault.Secret
	editSnap    string // serialized snapshot at open, for the unsaved-changes guard
	editConfirm bool   // pending "discard unsaved changes?" on esc

	versions       []vault.VersionMeta
	versionsCursor int

	confirm  *confirmSpec
	profile  profileState
	helpOpen bool

	tokenInfo *token.Info
	quitting  bool
}

func newModel(ctx context.Context, a *cli.App) (*Model, error) {
	isDark := theme.IsDark(a.File.Theme, a.Settings.Appearance)
	mono := theme.NoColor(a.Settings.NoColor)
	styles := theme.Build(a.File.Theme, isDark, mono)

	km := keys.Default()
	if err := km.Apply(a.File.Keys); err != nil {
		return nil, err
	}
	if a.Settings.ReadOnly {
		km.DisableWrites()
	}

	sp := spinner.New(spinner.WithSpinner(spinner.MiniDot))
	hp := help.New()
	hp.Styles = styles.HelpStyles()

	m := &Model{
		ctx:        ctx,
		a:          a,
		svc:        a.Service(),
		styles:     styles,
		keys:       km,
		help:       hp,
		spin:       sp,
		secretMask: map[string]bool{},
	}
	return m, nil
}

func (m *Model) Init() tea.Cmd {
	return tea.Batch(m.startAuth(), m.spin.Tick, tickCmd())
}

func tickCmd() tea.Cmd {
	return tea.Tick(30*time.Second, func(t time.Time) tea.Msg { return tickMsg(t) })
}

func (m *Model) top() screen {
	if len(m.stack) == 0 {
		return scrAuth
	}
	return m.stack[len(m.stack)-1].scr
}

func (m *Model) push(f frame) { m.stack = append(m.stack, f) }

func (m *Model) pop() (frame, bool) {
	if len(m.stack) == 0 {
		return frame{}, false
	}
	f := m.stack[len(m.stack)-1]
	m.stack = m.stack[:len(m.stack)-1]
	return f, true
}

func (m *Model) currentFrame() frame {
	if len(m.stack) == 0 {
		return frame{scr: scrMounts}
	}
	return m.stack[len(m.stack)-1]
}

// overlayActive reports whether anything should render on top of the
// current screen instead of routing input to it.
func (m *Model) overlayActive() bool {
	return m.confirm != nil || m.profile.open || m.helpOpen
}

func (m *Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.lay = computeLayout(msg.Width, msg.Height)
		m.help.SetWidth(m.lay.w - 2)
		m.resizeList()
		m.resizeSecretViewport()
		return m, nil

	case tea.KeyPressMsg:
		if key.Matches(msg, m.keys.ForceQuit) {
			m.quitting = true
			return m, tea.Quit
		}
		if m.confirm != nil {
			return m.updateConfirm(msg)
		}
		if m.profile.open {
			return m.updateProfilePicker(msg)
		}
		if m.helpOpen {
			return m.updateHelp(msg)
		}
		if !m.textInputActive() {
			if key.Matches(msg, m.keys.Help) {
				m.helpOpen = true
				return m, nil
			}
			if key.Matches(msg, m.keys.Profiles) && m.top() != scrAuth && len(m.a.File.Profiles) > 1 {
				return m.openProfilePicker()
			}
			if key.Matches(msg, m.keys.Logout) && m.top() != scrAuth {
				return m.confirmLogout()
			}
		}

	case tickMsg:
		cmds := []tea.Cmd{tickCmd()}
		if m.a.Client.Token() != "" {
			cmds = append(cmds, m.refreshTokenInfo())
		}
		return m, tea.Batch(cmds...)

	case tokenInfoMsg:
		if msg.err == nil {
			m.tokenInfo = msg.info
		}
		return m, nil

	case toastExpireMsg:
		m.clearExpiredToast(msg)
		return m, nil

	case logoutDoneMsg:
		if msg.err != nil {
			return m, m.notify(toastErr, "logout: %v", msg.err)
		}
		m.a.Client.ClearToken()
		m.tokenInfo = nil
		return m, tea.Batch(m.notify(toastSuccess, "logged out"), m.startAuth())

	case errMsg:
		m.loading = false
		return m, m.notify(toastErr, "%v", msg.err)

	case statusMsg:
		return m, m.notify(toastInfo, "%s", msg.text)

	case spinner.TickMsg:
		var cmd tea.Cmd
		m.spin, cmd = m.spin.Update(msg)
		return m, cmd
	}

	switch m.top() {
	case scrAuth:
		return m.updateAuth(msg)
	case scrMounts, scrBrowser:
		return m.updateBrowser(msg)
	case scrSecret:
		return m.updateSecret(msg)
	case scrEditor:
		return m.updateEditor(msg)
	case scrVersions:
		return m.updateVersions(msg)
	}
	return m, nil
}

func (m *Model) View() tea.View {
	if m.lay.tooSmall {
		v := tea.NewView(m.viewTooSmall())
		v.AltScreen = true
		v.WindowTitle = "vault-tui"
		return v
	}

	var body string
	var sh screenHelp
	switch m.top() {
	case scrAuth:
		body, sh = m.viewAuth(), m.keys.AuthHelp()
	case scrMounts, scrBrowser:
		body, sh = m.viewBrowser(), m.keys.BrowserHelp()
	case scrSecret:
		body, sh = m.viewSecret(), m.keys.SecretHelp()
	case scrEditor:
		body, sh = m.viewEditor(), m.keys.EditorHelp()
	case scrVersions:
		body, sh = m.viewVersions(), m.keys.VersionsHelp()
	}

	content := lipgloss.JoinVertical(lipgloss.Left, m.viewHeader(), fit(body, m.lay.w, m.lay.bodyH), m.viewFooter(sh))

	if m.confirm != nil {
		content = m.overlay(content, m.viewConfirm())
	}
	if m.profile.open {
		content = m.overlay(content, m.viewProfilePicker())
	}
	if m.helpOpen {
		content = m.overlay(content, m.viewHelp())
	}

	v := tea.NewView(content)
	v.AltScreen = true
	v.WindowTitle = "vault-tui — " + m.a.Settings.Profile
	return v
}

func (m *Model) refreshTokenInfo() tea.Cmd {
	return func() tea.Msg {
		info, err := token.Lookup(m.ctx, m.a.Client)
		return tokenInfoMsg{info: info, err: err}
	}
}