package cli

import (
	"context"
	"fmt"
	"io"
	"net"
	"net/mail"
	"os"
	"strings"
	"sync"
	"time"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"

	joinpkg "gitea.mynodes.xyz/ilker/llmgw/internal/join"
	"gitea.mynodes.xyz/ilker/llmgw/internal/onboard"
	"gitea.mynodes.xyz/ilker/llmgw/internal/pgha"
	"gitea.mynodes.xyz/ilker/llmgw/internal/preflight"
)

// The setup screens: what a bare `llmgw` shows on a machine with nothing
// installed. One machine, or three for high availability — this one as the
// control plane and etcd's third vote, two more for the store under Patroni —
// with every machine checked before anything is installed on any of them.
//
// The other machines are reached with Go's own ssh rather than the system's,
// so a password can be typed here when there is no key; it is held in memory
// for the run and written nowhere. A sudo password, likewise, is used once to
// let the user sudo for the length of the install, and that is taken back
// when it finishes.

type setupPage int

const (
	pWelcome setupPage = iota
	pAdmin
	pMachines
	// pWait shows the codes for machines joining rather than logged into,
	// until they have all dialled in.
	pWait
	pCheck
	pPlan
	pRun
)

// How a database machine is logged into.
const (
	authAgent = iota
	authKey
	authPassword
	// authJoin is no login at all: the machine runs `llmgw join` with a code
	// shown here and dials out to this one.
	authJoin
	authCount
)

var authNames = [authCount]string{"ssh agent", "key file", "password", "join code"}

// Fields of one database machine, in order.
const (
	mfAddr = iota
	mfUser
	mfAuth
	mfSecret
	mfSudo
	mfCount
)

type dbMachine struct {
	addr, user, secret, sudo textField
	auth                     int
	// For a machine joining: its code, and it once it has dialled in.
	code   string
	joined *joinpkg.Remote
	arrive <-chan *joinpkg.Remote
}

// visible reports whether a field is shown, and so can be moved to: a joining
// machine is asked nothing but how it joins.
func (d dbMachine) visible(f int) bool {
	switch {
	case d.auth == authJoin:
		return f == mfAuth
	case f == mfSecret:
		return d.auth != authAgent
	}
	return true
}

// dbConn is a database machine as it is reached, whichever way.
type dbConn struct {
	remote onboard.Remote
	addr   string
	ssh    *onboard.GoSSH
	joined *joinpkg.Remote
}

func newDBMachine(n int) dbMachine {
	f := func(ph string, mask bool) textField {
		t := newTextField()
		t.Placeholder, t.Mask, t.CharLimit, t.Width = ph, mask, 200, 34
		return t
	}
	m := dbMachine{
		addr:   f(fmt.Sprintf("10.0.0.%d or db%d.internal", 10+n, n), false),
		user:   f("ubuntu", false),
		secret: f("", true),
		sudo:   f("only if sudo asks for one", true),
	}
	if os.Getenv("SSH_AUTH_SOCK") == "" {
		m.auth = authKey
	}
	return m
}

// field is the text field at a machine's position, nil for the selector.
func (d *dbMachine) field(i int) *textField {
	switch i {
	case mfAddr:
		return &d.addr
	case mfUser:
		return &d.user
	case mfSecret:
		return &d.secret
	case mfSudo:
		return &d.sudo
	}
	return nil
}

// Messages from the work behind the screens.
type (
	checkDoneMsg struct{ rep preflight.Report }
	joinedMsg    struct {
		i int
		r *joinpkg.Remote
	}
)

// progRef lets work started from Update send to the program it runs in.
type progRef struct{ p *tea.Program }

type setupModel struct {
	ref *progRef

	page   setupPage
	host   string
	ips    []string
	choice int // 0 one machine, 1 high availability

	admin, names textField
	afocus       int // admin, names, next

	db     [2]dbMachine
	mfocus int // over both machines' fields, then the check button

	conns    []dbConn
	listener *joinpkg.Listener
	report   preflight.Report
	checking bool

	in       *serverInit
	run      initModel
	finished bool
	log      *[]string
	logMu    *sync.Mutex

	spin    spinnerModel
	formErr string
	width   int
	height  int
	// scroll is how far the panel is scrolled, reset with each page.
	scroll int
	quit   bool
	// single is the choice of one machine: the screen closes and init's own
	// form takes over.
	single bool
}

func newSetupModel(host string, ips []string) setupModel {
	admin := newTextField()
	admin.Placeholder, admin.CharLimit, admin.Width = "you@example.com", 200, 40
	names := newTextField()
	names.Placeholder, names.CharLimit, names.Width = "llm.example.com, 203.0.113.10", 400, 40
	return setupModel{
		ref: &progRef{}, host: host, ips: ips, admin: admin, names: names,
		db: [2]dbMachine{newDBMachine(1), newDBMachine(2)}, spin: newSpinner(), width: 100, height: 30,
		log: &[]string{}, logMu: &sync.Mutex{},
	}
}

func (m setupModel) Init() tea.Cmd { return m.spin.Tick }

func (m setupModel) thisAddr() string {
	if len(m.ips) > 0 {
		return m.ips[0]
	}
	return m.host
}

func (m setupModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width, m.height = msg.Width, msg.Height
		m.run.width = msg.Width - navWidth - 6
	case spinTickMsg:
		var cmd tea.Cmd
		m.spin, cmd = m.spin.Update(msg)
		m.run.spin = m.spin
		return m, cmd
	case checkDoneMsg:
		m.checking, m.report = false, msg.rep
	case joinedMsg:
		m.db[msg.i].joined = msg.r
		if m.page == pWait && m.allJoined() {
			m.page = pCheck
			cmd := m.startCheck()
			return m, cmd
		}
	case initLineMsg:
		m.run.addLine(string(msg))
	case initDoneMsg:
		m.run.done, m.run.err, m.finished = true, msg.err, true
	case tea.KeyMsg:
		if msg.Type == tea.KeyCtrlC {
			m.quit = true
			return m, tea.Quit
		}
		before := m.page
		next, cmd := m.key(msg)
		if nm := next.(setupModel); nm.page != before {
			// A new page starts at its top.
			nm.scroll = 0
			return nm, cmd
		}
		return next, cmd
	}
	return m, nil
}

func (m setupModel) key(k tea.KeyMsg) (tea.Model, tea.Cmd) {
	// A dialog open takes the next key, whatever it is, to close it.
	if m.formErr != "" {
		m.formErr = ""
		return m, nil
	}
	switch k.Type {
	case tea.KeyPgDown:
		m.scroll += max(1, m.height-8)
		return m, nil
	case tea.KeyPgUp:
		m.scroll = max(0, m.scroll-max(1, m.height-8))
		return m, nil
	}
	if k.Type == tea.KeyEsc && m.page > pWelcome && m.page < pRun && !m.checking {
		m.page--
		if m.page == pWait {
			m.page = pMachines
		}
		m.formErr = ""
		return m, nil
	}
	switch m.page {
	case pWelcome:
		switch k.String() {
		case "up", "down", "tab", "k", "j":
			m.choice = 1 - m.choice
		case "enter":
			if m.choice == 0 {
				m.single = true
				return m, tea.Quit
			}
			m.page = pAdmin
			m.afocus = 0
			m.admin.Focus()
		}
	case pAdmin:
		return m.adminKey(k)
	case pMachines:
		return m.machinesKey(k)
	case pCheck:
		switch k.String() {
		case "r":
			if !m.checking {
				cmd := m.startCheck()
				return m, cmd
			}
		case "enter":
			if !m.checking && m.report.Worst() < preflight.Fail {
				m.page = pPlan
			}
		}
	case pPlan:
		if k.String() == "enter" {
			m.page = pRun
			cmd := m.startRun()
			return m, cmd
		}
	case pRun:
		if m.finished && (k.String() == "q" || k.String() == "enter") {
			return m, tea.Quit
		}
	}
	return m, nil
}

func (m setupModel) adminKey(k tea.KeyMsg) (tea.Model, tea.Cmd) {
	move := func(d int) {
		m.afocus = (m.afocus + d + 3) % 3
		m.admin.Blur()
		m.names.Blur()
		switch m.afocus {
		case 0:
			m.admin.Focus()
		case 1:
			m.names.Focus()
		}
	}
	switch k.Type {
	case tea.KeyTab, tea.KeyDown:
		move(1)
		return m, nil
	case tea.KeyShiftTab, tea.KeyUp:
		move(-1)
		return m, nil
	case tea.KeyEnter:
		if m.afocus < 2 {
			move(1)
			return m, nil
		}
		if _, err := mail.ParseAddress(strings.TrimSpace(m.admin.Value())); err != nil {
			m.formErr = "the administrator's email is needed, and that is not one"
			m.afocus = 0
			move(0)
			return m, nil
		}
		m.formErr = ""
		m.page, m.mfocus = pMachines, 0
		m.db[0].addr.Focus()
		return m, nil
	}
	var cmd tea.Cmd
	switch m.afocus {
	case 0:
		m.admin, cmd = m.admin.Update(k)
	case 1:
		m.names, cmd = m.names.Update(k)
	}
	return m, cmd
}

func (m *setupModel) focusMachine() {
	for i := range m.db {
		for f := 0; f < mfCount; f++ {
			if t := m.db[i].field(f); t != nil {
				t.Blur()
			}
		}
	}
	if m.mfocus < 2*mfCount {
		if t := m.db[m.mfocus/mfCount].field(m.mfocus % mfCount); t != nil {
			t.Focus()
		}
	}
}

func (m setupModel) machinesKey(k tea.KeyMsg) (tea.Model, tea.Cmd) {
	n := 2*mfCount + 1
	switch k.Type {
	case tea.KeyTab, tea.KeyDown:
		m.step(1, n)
		return m, nil
	case tea.KeyShiftTab, tea.KeyUp:
		m.step(-1, n)
		return m, nil
	case tea.KeyEnter:
		if m.mfocus < 2*mfCount {
			m.step(1, n)
			return m, nil
		}
		if err := m.validateMachines(); err != "" {
			m.formErr = err
			return m, nil
		}
		m.formErr = ""
		if cmd, waiting := m.startJoins(); waiting {
			m.page = pWait
			return m, cmd
		}
		m.page = pCheck
		cmd := m.startCheck()
		return m, cmd
	}
	if m.mfocus == 2*mfCount {
		return m, nil
	}
	d := &m.db[m.mfocus/mfCount]
	if m.mfocus%mfCount == mfAuth {
		switch k.String() {
		case "left", "h":
			d.auth = (d.auth + authCount - 1) % authCount
		case "right", "l", " ":
			d.auth = (d.auth + 1) % authCount
		}
		if d.auth != authJoin && d.joined != nil {
			_ = d.joined.Close()
			d.joined, d.code, d.arrive = nil, "", nil
		}
		d.secret.SetValue("")
		d.secret.Mask = d.auth == authPassword
		d.secret.Placeholder = map[int]string{authKey: "/root/.ssh/id_ed25519", authPassword: "the user's ssh password"}[d.auth]
		return m, nil
	}
	var cmd tea.Cmd
	t := d.field(m.mfocus % mfCount)
	*t, cmd = t.Update(k)
	return m, cmd
}

// step moves the focus over the fields that are shown.
func (m *setupModel) step(d, n int) {
	for range n {
		m.mfocus = (m.mfocus + d + n) % n
		if m.mfocus == 2*mfCount || m.db[m.mfocus/mfCount].visible(m.mfocus%mfCount) {
			break
		}
	}
	m.focusMachine()
}

func (m setupModel) allJoined() bool {
	for _, d := range m.db {
		if d.auth == authJoin && d.joined == nil {
			return false
		}
	}
	return true
}

// startJoins listens for the machines that join with a code, makes their
// codes, and waits for them; it says whether there is anything to wait for.
func (m *setupModel) startJoins() (tea.Cmd, bool) {
	var cmds []tea.Cmd
	for i := range m.db {
		d := &m.db[i]
		if d.auth != authJoin || d.joined != nil {
			continue
		}
		if m.listener == nil {
			// On the address the codes name, not every interface: a code is
			// a credential, and the port it is spent on need not face more
			// than the network the machines join from.
			addr := net.JoinHostPort(m.thisAddr(), fmt.Sprint(joinpkg.DefaultPort))
			l, err := joinpkg.Listen(addr, addr, time.Hour)
			if err != nil {
				m.formErr = err.Error()
				return nil, false
			}
			m.listener = l
		}
		if d.arrive == nil {
			c, ch := m.listener.Code("database")
			d.code, d.arrive = c.String(), ch
		}
		ch, i := d.arrive, i
		cmds = append(cmds, func() tea.Msg { return joinedMsg{i, <-ch} })
	}
	return tea.Batch(cmds...), len(cmds) > 0
}

func (m setupModel) validateMachines() string {
	seen := map[string]bool{m.thisAddr(): true, m.host: true}
	for i, d := range m.db {
		if d.auth == authJoin {
			continue
		}
		addr := strings.TrimSpace(d.addr.Value())
		switch {
		case addr == "":
			return fmt.Sprintf("database machine %d has no address", i+1)
		case seen[addr]:
			return fmt.Sprintf("%s is given twice, or is this machine: the three must be different machines", addr)
		case strings.TrimSpace(d.user.Value()) == "":
			return fmt.Sprintf("database machine %d has no user to log in as", i+1)
		case d.auth != authAgent && d.secret.Value() == "":
			return fmt.Sprintf("database machine %d needs its %s", i+1, authNames[d.auth])
		}
		seen[addr] = true
	}
	return ""
}

// startCheck connects to the database machines and runs the checks on all
// three, this one included.
func (m *setupModel) startCheck() tea.Cmd {
	for _, c := range m.conns {
		if c.ssh != nil {
			_ = c.ssh.Close()
		}
	}
	m.conns = nil
	machines := []preflight.Machine{{
		Name: m.host + " (this machine)", Addr: m.thisAddr(), Local: true, Remote: pgha.Local{},
		Roles: []preflight.Role{preflight.RoleControl, preflight.RoleWitness},
	}}
	for _, d := range m.db {
		if d.auth == authJoin {
			m.conns = append(m.conns, dbConn{remote: d.joined, addr: d.joined.Addr, joined: d.joined})
			machines = append(machines, preflight.Machine{Name: d.joined.Hostname + " (" + d.joined.Addr + ", joined)",
				Addr: d.joined.Addr, Roles: []preflight.Role{preflight.RoleDatabase}, Remote: d.joined})
			continue
		}
		g := &onboard.GoSSH{
			Addr: strings.TrimSpace(d.addr.Value()), User: strings.TrimSpace(d.user.Value()),
			UseAgent: d.auth == authAgent, SudoPassword: d.sudo.Value(),
		}
		switch d.auth {
		case authKey:
			g.KeyFile = strings.TrimSpace(d.secret.Value())
		case authPassword:
			g.Password = d.secret.Value()
		}
		m.conns = append(m.conns, dbConn{remote: g, addr: g.Addr, ssh: g})
		machines = append(machines, preflight.Machine{Name: g.Addr, Addr: g.Addr,
			Roles: []preflight.Role{preflight.RoleDatabase}, Remote: g})
	}
	m.checking = true
	m.report = preflight.Report{}
	conns := m.conns
	return func() tea.Msg {
		rep := preflight.Run(context.Background(), machines)
		// A sudo that asks for a password is fine with one given: the
		// install grants itself sudo with it.
		for i := range rep.Findings {
			f := &rep.Findings[i]
			if f.Check == "sudo" && f.Level == preflight.Warn {
				for _, c := range conns {
					g := c.ssh
					switch {
					case g == nil || g.Addr != f.Machine:
					case g.SudoPassword == "":
						f.Level = preflight.Fail
						f.Fix = "give this user's sudo password on the previous screen"
					default:
						f.Level = preflight.OK
						f.Detail = "with the password given"
						f.Fix = ""
					}
				}
			}
		}
		return checkDoneMsg{rep}
	}
}

// targets are the database machines as user@address, for the command line.
func (m setupModel) targets() []string {
	var out []string
	for _, d := range m.db {
		if d.joined != nil {
			out = append(out, "root@"+d.joined.Addr)
			continue
		}
		out = append(out, strings.TrimSpace(d.user.Value())+"@"+strings.TrimSpace(d.addr.Value()))
	}
	return out
}

func (m setupModel) namesList() []string {
	var out []string
	for _, h := range strings.Split(m.names.Value(), ",") {
		if h = strings.TrimSpace(h); h != "" {
			out = append(out, h)
		}
	}
	return out
}

// command is what this setup is on the command line, for doing it again
// from a script — with keys in place, since a password cannot be given there.
func (m setupModel) command() string {
	parts := []string{"sudo --preserve-env=SSH_AUTH_SOCK llmgw server init",
		"--admin " + strings.TrimSpace(m.admin.Value())}
	for _, h := range m.namesList() {
		parts = append(parts, "--host "+h)
	}
	for _, t := range m.targets() {
		parts = append(parts, "--patroni "+t)
	}
	parts = append(parts, "--no-node", "--no-model")
	return strings.Join(parts, " \\\n    ")
}

// startRun installs: sudo granted where it asks for a password, the control
// plane here, the store on the other two, then sudo taken back.
func (m *setupModel) startRun() tea.Cmd {
	in := newDefaultServerInit()
	in.admin = strings.TrimSpace(m.admin.Value())
	in.hosts = m.namesList()
	in.patroni = m.targets()
	// The control plane of a replicated setup is not where models run;
	// nodes are added once it is up.
	in.noNode, in.noModel = true, true
	m.in = &in
	m.run = newInitModel(&in, nil, false)
	m.run.running, m.run.width, m.run.spin = true, m.width, m.spin
	ref, conns, logp, mu, listener := m.ref, m.conns, m.log, m.logMu, m.listener
	return func() tea.Msg {
		send := func(l string) {
			mu.Lock()
			*logp = append(*logp, l)
			mu.Unlock()
			ref.p.Send(initLineMsg(l))
		}
		in.out = &lineWriter{send: send}
		err := func() error {
			ctx := context.Background()
			for _, c := range conns {
				if c.ssh != nil {
					fmt.Fprintf(in.out, "  ..    sudo on %s\n", c.addr)
					if err := c.ssh.PrepareSudo(ctx); err != nil {
						return err
					}
				}
				out, err := c.remote.Run(ctx, "hostname", nil)
				if err != nil {
					return fmt.Errorf("%s: %v", c.addr, err)
				}
				ip, err := ipv4Of(c.addr)
				if err != nil {
					return err
				}
				in.patroniNodes = append(in.patroniNodes, pgha.Node{
					Member: pgha.Member{Name: strings.TrimSpace(string(out)), IP: ip}, Remote: c.remote})
			}
			return in.run(ctx)
		}()
		// Whatever happened: a sudo grant taken back, a joined machine's
		// `llmgw join` told it is done, the port for joining closed.
		for _, c := range conns {
			if c.ssh != nil {
				_ = c.ssh.Close()
			}
			if c.joined != nil {
				_ = c.joined.Close()
			}
		}
		if listener != nil {
			_ = listener.Close()
		}
		return initDoneMsg{err}
	}
}

// setupSteps are the sidebar's steps, by page.
var setupSteps = []struct {
	label string
	page  setupPage
}{
	{"Start", pWelcome}, {"Administrator", pAdmin}, {"Machines", pMachines},
	{"Checks", pCheck}, {"Plan", pPlan}, {"Install", pRun},
}

func (m setupModel) View() string {
	at := m.page
	if at == pWait {
		at = pMachines
	}
	var nav []navItem
	for _, st := range setupSteps {
		if m.choice == 0 && st.page > pWelcome {
			break
		}
		state := "todo"
		switch {
		case st.page < at || (st.page == pRun && m.finished && m.run.err == nil):
			state = "done"
		case st.page == at:
			state = "current"
		}
		nav = append(nav, navItem{Label: st.label, State: state})
	}
	title, body, keys := m.pageView()
	f := frame{
		Width: m.width, Height: m.height,
		Title: "llmgw setup", Where: m.host + " · " + m.thisAddr(),
		NavTitle: "Steps", Nav: nav,
		PanelTitle: title, Body: body, Scroll: m.scroll, Keys: keys,
	}
	if m.formErr != "" {
		f.DialogTitle, f.Dialog = "Not yet", m.formErr+"\n\n"+sDim.Render("any key to go back")
	}
	return f.render()
}

// pageView is the panel for the page: its title, what is in it, and its keys.
func (m setupModel) pageView() (string, string, string) {
	switch m.page {
	case pWelcome:
		return "Start", m.welcomeView(), "↑↓ choose · Enter go on · Ctrl+C leave"
	case pAdmin:
		return "Administrator", m.adminView(), "Tab/↑↓ move · Enter next · Esc back · Ctrl+C leave"
	case pMachines:
		return "Database machines", m.machinesView(), "Tab/↑↓ move · ←→ how to log in · Enter next · Esc back · PgUp/PgDn scroll"
	case pWait:
		return "Waiting for machines to join", m.waitView(), "Esc back · PgUp/PgDn scroll · Ctrl+C leave"
	case pCheck:
		keys := "R check again · Esc back · PgUp/PgDn scroll"
		if !m.checking && m.report.Worst() < preflight.Fail {
			keys = "Enter see the plan · " + keys
		}
		return "Checks", m.checkView(), keys
	case pPlan:
		return "Plan", m.planView(), "Enter install · Esc back · PgUp/PgDn scroll · Ctrl+C leave"
	}
	v := m.run.View()
	if i := strings.Index(v, "\n\n"); i >= 0 {
		v = v[i+2:] // init's own title; the frame has one
	}
	keys := "Ctrl+C stop"
	if m.finished {
		keys = "Enter or Q leave · PgUp/PgDn scroll"
		if m.run.err == nil {
			v += "\n" + sDim.Render("The same, from a script, with ssh keys in place:") + "\n" + m.command() + "\n"
		}
	}
	return "Install", v, keys
}

func (m setupModel) welcomeView() string {
	var b strings.Builder
	fmt.Fprintf(&b, "\n  Nothing of llmgw is installed on %s.\n\n", lipgloss.NewStyle().Bold(true).Render(m.host))
	opt := func(i int, title, detail string) {
		mark := "( )"
		if m.choice == i {
			mark = "(" + sOK.Render("•") + ")"
			title = fSelected.Render(title)
		}
		fmt.Fprintf(&b, "  %s %s\n      %s\n\n", mark, title, sDim.Render(detail))
	}
	opt(0, "One machine", "This machine runs everything: control plane, model mirror,\n      and models if it has room.")
	opt(1, "High availability — three machines",
		"This one is the control plane; two more keep the store, replicated,\n      so losing any one machine loses nothing.")
	return b.String()
}

func (m setupModel) adminView() string {
	var b strings.Builder
	label := func(i int, s string) string {
		if m.afocus == i {
			return fSelected.Render("› " + s)
		}
		return "  " + s
	}
	b.WriteString("\n")
	fmt.Fprintf(&b, "%s\n    %s\n    %s\n\n", label(0, "Administrator's email"), m.admin.View(),
		sDim.Render("A password is generated and shown once, at the end."))
	fmt.Fprintf(&b, "%s\n    %s\n    %s\n\n", label(1, "Other names nodes will reach this machine by"), m.names.View(),
		sDim.Render("Known: "+strings.Join(append([]string{m.host}, m.ips...), ", ")+". Add a DNS name or a floating address."))
	b.WriteString(button(m.afocus == 2, "Next") + "\n")
	return b.String()
}

// button is a [ Label ] that shows when it has the focus.
func button(focused bool, label string) string {
	if focused {
		return "  " + fBar.Render(" "+label+" ")
	}
	return "  " + lipgloss.NewStyle().Bold(true).Render("[ "+label+" ]")
}

func (m setupModel) machinesView() string {
	var b strings.Builder
	b.WriteString("\n  The two machines that keep the store: Ubuntu 22.04/24.04 or Debian 12.\n" +
		"  PostgreSQL, Patroni and etcd are installed on them.\n\n")
	for i, d := range m.db {
		base := i * mfCount
		// Padded before it is coloured: the colour's escape codes count
		// toward a width and threw the focused row out of line.
		label := func(f int, s string) string {
			s = fmt.Sprintf("%-15s", s)
			if m.mfocus == base+f {
				return fSelected.Render("› " + s)
			}
			return "  " + s
		}
		fmt.Fprintf(&b, "  %s\n", lipgloss.NewStyle().Bold(true).Render(fmt.Sprintf("Database machine %d", i+1)))
		if d.visible(mfAddr) {
			fmt.Fprintf(&b, "  %s %s\n", label(mfAddr, "Address"), d.addr.View())
			fmt.Fprintf(&b, "  %s %s\n", label(mfUser, "User"), d.user.View())
		}
		var auth []string
		for a := 0; a < authCount; a++ {
			if a == d.auth {
				auth = append(auth, "("+sOK.Render("•")+") "+authNames[a])
			} else {
				auth = append(auth, "( ) "+sDim.Render(authNames[a]))
			}
		}
		fmt.Fprintf(&b, "  %s   %s\n", label(mfAuth, "Log in with"), strings.Join(auth, "  "))
		if d.visible(mfSecret) {
			fmt.Fprintf(&b, "  %s %s\n", label(mfSecret, strings.ToUpper(authNames[d.auth][:1])+authNames[d.auth][1:]), d.secret.View())
		}
		if d.visible(mfSudo) {
			fmt.Fprintf(&b, "  %s %s\n", label(mfSudo, "Sudo password"), d.sudo.View())
		}
		if d.auth == authJoin {
			b.WriteString("      " + sDim.Render("Nothing logs into it: it runs llmgw join with a code shown next.") + "\n")
		}
		b.WriteString("\n")
	}
	b.WriteString(button(m.mfocus == 2*mfCount, "Check the three machines") + "\n\n")
	b.WriteString("  " + sDim.Render("Passwords are kept in memory only, for this setup.") + "\n")
	return b.String()
}

func (m setupModel) waitView() string {
	var b strings.Builder
	fmt.Fprintf(&b, "\n  On each machine below, as root. It dials this machine on port %d;\n  nothing dials in. Each code is for one machine and good for an hour.\n\n", joinpkg.DefaultPort)
	for i, d := range m.db {
		if d.auth != authJoin {
			continue
		}
		title := lipgloss.NewStyle().Bold(true).Render(fmt.Sprintf("Database machine %d", i+1))
		if d.joined != nil {
			fmt.Fprintf(&b, "  %s  %s joined as %s (%s)\n\n", title, sOK.Render("✓"), d.joined.Hostname, d.joined.Addr)
			continue
		}
		fmt.Fprintf(&b, "  %s  %s waiting\n", title, m.spin.View())
		b.WriteString("  " + sDim.Render("without llmgw yet:") + "\n")
		for _, l := range joinInstall() {
			b.WriteString("    " + strings.ReplaceAll(l, "\n", "\n    ") + "\n")
		}
		b.WriteString("  " + sDim.Render("then:") + "\n    sudo llmgw join " + d.code + "\n\n")
	}
	return b.String()
}

func (m setupModel) checkView() string {
	var b strings.Builder
	b.WriteString("\n")
	if m.checking {
		b.WriteString("  " + m.spin.View() + " checking the three machines…\n")
		return b.String()
	}
	switch m.report.Worst() {
	case preflight.Fail:
		b.WriteString("  " + sBad.Render("✗ Fix what is marked ✗, then check again (R).") + "\n")
	case preflight.Warn:
		b.WriteString("  " + sWarn.Render("! It can go ahead; what is marked ! is worth a look.") + "\n")
	default:
		b.WriteString("  " + sOK.Render("✓ All three are ready.") + "\n")
	}
	machine := ""
	for _, f := range m.report.Findings {
		if f.Machine != machine {
			machine = f.Machine
			b.WriteString("\n  " + lipgloss.NewStyle().Bold(true).Render(machine) + "\n")
		}
		mark := sOK.Render("✓")
		switch f.Level {
		case preflight.Warn:
			mark = sWarn.Render("!")
		case preflight.Fail:
			mark = sBad.Render("✗")
		}
		fmt.Fprintf(&b, "    %s %-13s %s\n", mark, f.Check, f.Detail)
		if f.Level != preflight.OK && f.Fix != "" {
			b.WriteString("                    " + sDim.Render(f.Fix) + "\n")
		}
	}
	return b.String()
}

func (m setupModel) planView() string {
	var b strings.Builder
	b.WriteString("\n  What will be installed:\n\n")
	fmt.Fprintf(&b, "  %s  %s\n      %s\n", lipgloss.NewStyle().Bold(true).Render(m.host), sDim.Render(m.thisAddr()),
		"control plane and gateway, model mirror, etcd (the third vote)")
	fmt.Fprintf(&b, "      administrator %s\n", strings.TrimSpace(m.admin.Value()))
	granted := false
	for _, d := range m.db {
		addr := strings.TrimSpace(d.addr.Value())
		if d.joined != nil {
			addr = d.joined.Hostname + "  " + sDim.Render(d.joined.Addr+", joined")
		}
		fmt.Fprintf(&b, "  %s\n      PostgreSQL under Patroni, etcd\n", lipgloss.NewStyle().Bold(true).Render(addr))
		granted = granted || d.sudo.Value() != ""
	}
	b.WriteString("\n  The store is replicated from the first to the second; if the primary is lost\n" +
		"  the standby takes over in about thirty seconds, and the control plane follows.\n")
	if granted {
		b.WriteString("  " + sDim.Render("Where a sudo password was given, the user may sudo without it until the\n  install finishes, and not after.") + "\n")
	}
	b.WriteString("\n  " + sDim.Render("The same from a script, with ssh keys in place:") + "\n")
	for _, l := range strings.Split(m.command(), "\n") {
		b.WriteString("  " + l + "\n")
	}
	for _, d := range m.db {
		if d.joined != nil {
			b.WriteString("  " + sDim.Render("(a machine that joined with a code needs ssh for that)") + "\n")
			break
		}
	}
	b.WriteString("\n" + button(true, "Enter to install") + "\n")
	return b.String()
}

// runSetupTUI is the setup screens, until they finish or hand over to init's
// own form for one machine.
func runSetupTUI(ctx context.Context, out io.Writer) error {
	host, _ := os.Hostname()
	var ips []string
	for _, ip := range localAddrs() {
		if ip.To4() != nil {
			ips = append(ips, ip.String())
		}
	}
	m := newSetupModel(host, ips)
	p := tea.NewProgram(m, tea.WithOutput(out), tea.WithAltScreen())
	m.ref.p = p
	final, err := p.Run()
	if err != nil {
		return err
	}
	fm := final.(setupModel)
	if fm.single {
		in := newDefaultServerInit()
		in.out = out
		return in.runInitTUI(ctx, out)
	}
	if fm.page < pRun {
		return nil
	}
	fmt.Fprintln(out)
	if fm.run.err != nil {
		fm.logMu.Lock()
		fmt.Fprintln(out, strings.Join(*fm.log, "\n"))
		fm.logMu.Unlock()
		return fm.run.err
	}
	if !fm.finished {
		return fmt.Errorf("left while installing; running llmgw again finishes what was started")
	}
	if fm.run.password != "" {
		fmt.Fprintf(out, "Administrator %s, password %s (shown once)\n\n", fm.in.admin, fm.run.password)
	}
	fmt.Fprintln(out, "Next: add nodes from the console — run llmgw again — or with")
	fmt.Fprintln(out, "  sudo llmgw node add <user>@<address>")
	return nil
}