package main

import (
	"context"
	"strings"

	"felis.lolicon.best/internal/cfsetup"

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

// sizeable is implemented by screens that need to know the terminal area
// available to them (after the root reserves space for the step rail). huh-based
// screens forward this to form.WithWidth/WithHeight; custom screens use it to
// avoid overflowing the frame.
type sizeable interface {
	setSize(width, height int)
}

// arrowNavigable is implemented by screens that don't need ←/→ for their own
// input (selects, summaries), so the root may repurpose those keys to walk back
// through completed steps. Text-input screens omit it and keep the arrows for
// cursor movement — that's the "don't fight the input fields" rule.
type arrowNavigable interface {
	arrowNavOK() bool
}

// ---- Connection methods ----

type connectMethod int

const (
	connectLocal connectMethod = iota
	connectCloudflare
	connectReverseProxy
)

func connectMethodLabel(m connectMethod) string {
	switch m {
	case connectCloudflare:
		return "Cloudflare Tunnel + Access"
	case connectReverseProxy:
		return "Reverse proxy (your own front)"
	default:
		return "Local only (NodePort + self-signed TLS)"
	}
}

// ---- Messages: sub-model → root ----

type preflightDoneMsg struct{}

type ownerResultMsg struct {
	username        string
	displayPassword string
	mode            string
	accountable     string
	auditWarning    string
	isOperator      bool // true when an Operator was added rather than the Owner provisioned
	err             error
}

// connectResultMsg is emitted by every connection method (the chooser for
// local, the edge model for Cloudflare, the reverse-proxy model for BYO). It is
// the single, method-agnostic outcome the root advances on.
type connectResultMsg struct {
	method        connectMethod
	panelHostname string
	adminHostname string
	edge          *cfsetup.Result // Cloudflare only
	guide         string          // reverse-proxy only
}

// goBackMsg returns from a connection sub-screen to the chooser.
type goBackMsg struct{}

func goBack() tea.Cmd { return func() tea.Msg { return goBackMsg{} } }

// reconfigureConnectMsg is sent from the re-run status screen to re-enter the
// connection chooser.
type reconfigureConnectMsg struct{}

// ---- rootModel: top-level session ----

type wizardStage int

const (
	stagePreflight wizardStage = iota
	stageOwner
	stageConnect
	stageSummary
	// stageMenu is the break-glass operation menu. It is appended last so the
	// setup-flow rail indices (Preflight…Done) are unshifted; the rail is suppressed
	// in break-glass mode, so this stage never reaches it.
	stageMenu
)

// setupRailSteps is the one progress rail shared by the whole first-run flow,
// spanning both bubbletea programs: the host-bootstrap installer is rail cell 0,
// and the post-install wizard owns cells 1–4. Defining it once keeps the two
// programs' breadcrumbs identical so the rail reads as a single continuous bar
// rather than restarting when the wizard takes over.
var setupRailSteps = []string{"Bootstrap", "Preflight", "Owner", "Connection", "Done"}

type rootModel struct {
	ctx context.Context

	screen tea.Model
	stage  wizardStage

	// reviewing is the index of a completed step the operator is looking back at
	// (read-only), or -1 when the live screen is in front. Driven by ←/→.
	reviewing int

	width  int
	height int

	result breakGlassResult
	err    error

	mode        consoleMode
	dbURL       string
	store       ownerStore
	osUser      string
	rootDomain  string
	adminHost   string
	panelHost   string
	accessAud   string
	adminExists bool
}

func newRootModel(ctx context.Context, store ownerStore, dbURL, rootDomain, adminHostname, panelHostname, accessAud, osUser string, adminExists bool, mode consoleMode) *rootModel {
	rm := &rootModel{
		ctx:         ctx,
		reviewing:   -1,
		dbURL:       dbURL,
		store:       store,
		osUser:      osUser,
		rootDomain:  rootDomain,
		adminHost:   adminHostname,
		panelHost:   panelHostname,
		accessAud:   accessAud,
		adminExists: adminExists,
		mode:        mode,
		result: breakGlassResult{
			osUser:        osUser,
			rootDomain:    rootDomain,
			adminHostname: adminHostname,
		},
	}
	if mode == consoleModeBreakGlass {
		if adminExists {
			// A staff account exists, so account operations are peers: open on the menu
			// (provision/reset Owner, or add Operator).
			rm.stage = stageMenu
			rm.screen = newMenuModel()
		} else {
			// Fresh machine: bootstrapping the first Owner is the only sensible op, so skip
			// the menu and go straight to it (offering "add Operator" here would mint a
			// staff account the login gate still rejects).
			rm.stage = stageOwner
			rm.screen = newOwnerModel(ctx, store, osUser, adminExists)
		}
	} else {
		rm.stage = stagePreflight
		rm.screen = newPreflightModel(dbURL, rootDomain)
	}
	return rm
}

func (m *rootModel) Init() tea.Cmd {
	return m.screen.Init()
}

func (m *rootModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	// Rail navigation claims ←/→ before anything else sees them. While reviewing
	// it owns every key so nothing leaks into the live screen underneath;
	// otherwise it only takes ← (to enter review) and lets the rest fall through.
	if key, ok := msg.(tea.KeyMsg); ok {
		if handled, model, cmd := m.handleRailKey(key); handled {
			return model, cmd
		}
	}

	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width, m.height = msg.Width, msg.Height
		m.pushSize()
		return m, nil

	case preflightDoneMsg:
		if m.adminExists {
			// Re-run: setup already happened. Land on the status screen.
			return m.showStatus()
		}
		m.stage = stageOwner
		return m.adopt(newOwnerModel(m.ctx, m.store, m.osUser, false))

	case menuChoiceMsg:
		// The break-glass menu picked an account operation; build its screen. Both reuse
		// stageOwner (the rail is suppressed in break-glass, so the stage is only a label).
		m.stage = stageOwner
		switch msg.op {
		case bgAddOperator:
			return m.adopt(newOperatorModel(m.ctx, m.store, m.osUser))
		default:
			return m.adopt(newOwnerModel(m.ctx, m.store, m.osUser, m.adminExists))
		}

	case ownerResultMsg:
		if msg.err != nil {
			m.err = msg.err
			return m, tea.Quit
		}
		m.result.provisioned = true
		m.result.isOperator = msg.isOperator
		m.result.username = msg.username
		m.result.displayPassword = msg.displayPassword
		m.result.mode = msg.mode
		m.result.accountable = msg.accountable
		m.result.auditWarning = msg.auditWarning
		if m.mode == consoleModeBreakGlass {
			return m, tea.Quit
		}
		m.adminExists = true
		m.stage = stageConnect
		return m.adopt(newConnectChooserModel(m.rootDomain, m.adminHost, m.panelHost))

	case connectResultMsg:
		m.applyConnectResult(msg)
		return m.showSummary()

	case goBackMsg:
		m.stage = stageConnect
		return m.adopt(newConnectChooserModel(m.rootDomain, m.adminHost, m.panelHost))

	case reconfigureConnectMsg:
		m.stage = stageConnect
		return m.adopt(newConnectChooserModel(m.rootDomain, m.adminHost, m.panelHost))
	}

	if m.screen != nil {
		newScreen, cmd := m.screen.Update(msg)
		if newScreen != nil && newScreen != m.screen {
			adopted, initCmd := m.adopt(newScreen)
			return adopted, tea.Batch(cmd, initCmd)
		}
		return m, cmd
	}
	return m, nil
}

// adopt installs a new screen, hands it the current size, and returns its Init.
// Centralizing screen swaps here guarantees every screen is sized before its
// first View — the fix for the rail being clipped off the top of the frame.
func (m *rootModel) adopt(s tea.Model) (tea.Model, tea.Cmd) {
	m.screen = s
	m.reviewing = -1 // every stage change drops back to the live screen
	m.pushSize()
	return m, s.Init()
}

// handleRailKey implements ←/→ navigation of the step rail. While reviewing a
// completed step it owns every key (so nothing leaks into the live screen);
// otherwise it claims only ← to enter review, and only when the active screen
// doesn't need the arrows for its own text input.
func (m *rootModel) handleRailKey(k tea.KeyMsg) (bool, tea.Model, tea.Cmd) {
	if m.reviewing >= 0 {
		switch k.String() {
		case "ctrl+c":
			return true, m, tea.Quit
		case "left":
			if m.reviewing > 0 {
				m.reviewing--
			}
			return true, m, nil
		case "right":
			m.reviewing++
			if m.reviewing >= int(m.stage) {
				m.reviewing = -1 // caught up to the live step
			}
			return true, m, nil
		case "esc", "enter":
			m.reviewing = -1
			return true, m, nil
		default:
			return true, m, nil // swallow everything else while reviewing
		}
	}
	if k.String() == "left" && m.canEnterReview() {
		m.reviewing = int(m.stage) - 1
		return true, m, nil
	}
	return false, m, nil
}

// canEnterReview reports whether the live screen will yield ←/→ to the rail.
func (m *rootModel) canEnterReview() bool {
	if m.mode != consoleModeSetup || m.adminExistsAtStart() || m.stage == 0 {
		return false
	}
	n, ok := m.screen.(arrowNavigable)
	return ok && n.arrowNavOK()
}

// displayStage is the rail position currently shown — the reviewed step when
// looking back, otherwise the live stage.
func (m *rootModel) displayStage() int {
	if m.reviewing >= 0 {
		return m.reviewing
	}
	return int(m.stage)
}

// reviewBody renders a read-only recap of an already-completed step. Steps in
// this wizard commit as you finish them (the Owner account and its one-time
// password are created on submit), so review is deliberately look-only — there
// is no re-editing a step you've passed.
func (m *rootModel) reviewBody(stage int) string {
	var b strings.Builder
	switch wizardStage(stage) {
	case stagePreflight:
		b.WriteString(tuiOK.Render("✓ Preflight") + "\n")
		b.WriteString(tuiHint.Render("Control plane verified before configuration."))
	case stageOwner:
		b.WriteString(tuiOK.Render("✓ Owner account") + "\n")
		if m.result.username != "" {
			b.WriteString(tuiLabel.Render("username  ") + m.result.username + "\n")
		}
		b.WriteString(tuiHint.Render("Created and recorded. The one-time password was shown on the Owner step."))
	case stageConnect:
		b.WriteString(tuiOK.Render("✓ Connection") + "\n")
		b.WriteString(tuiLabel.Render("method    ") + connectMethodLabel(m.result.connectMethod) + "\n")
		if m.result.panelURL != "" {
			b.WriteString(tuiLabel.Render("panel     ") + m.result.panelURL)
		}
	}
	b.WriteString("\n\n" + tuiHint.Render("read-only · ") + tuiLabel.Render("←/→") +
		tuiHint.Render(" walk steps · ") + tuiLabel.Render("esc") + tuiHint.Render(" back"))
	return b.String()
}

// pushSize gives the active screen the area left after the step rail.
func (m *rootModel) pushSize() {
	if m.height == 0 {
		return
	}
	if s, ok := m.screen.(sizeable); ok {
		// Reserve one extra row: huh renders a hair taller than its WithHeight
		// budget (the help line sits outside it). Clipping the rail off the top is
		// the bug we're fixing, so we round the budget down — a blank bottom row is
		// invisible, an overflowed top is not.
		avail := m.height - m.chromeHeight() - 1
		if avail < 1 {
			avail = 1
		}
		s.setSize(m.width, avail)
	}
}

// chromeHeight is the number of rows the root paints around the screen — the
// rail plus its blank separator, or 0 when the rail is hidden.
func (m *rootModel) chromeHeight() int {
	if m.mode != consoleModeSetup || m.adminExistsAtStart() {
		return 0
	}
	return lipgloss.Height(m.railWithHint()) + 1
}

func (m *rootModel) View() string {
	if m.screen == nil {
		return ""
	}
	if m.mode == consoleModeSetup && !m.adminExistsAtStart() {
		body := m.screen.View()
		if m.reviewing >= 0 {
			body = m.reviewBody(m.reviewing)
		}
		return m.railWithHint() + "\n\n" + body
	}
	return m.screen.View()
}

// adminExistsAtStart reports whether this run began with an Owner already
// present (a re-run). The rail only makes sense for the first-run linear wizard.
func (m *rootModel) adminExistsAtStart() bool {
	// adminExists flips true once we provision the Owner mid-run; the rail should
	// keep showing through the connect/summary stages of that same first run. So
	// only suppress the rail when the Owner pre-existed AND we never provisioned.
	return m.adminExists && !m.result.provisioned
}

func (m *rootModel) rail() string {
	// Bootstrap is rail cell 0 and is always done by the time the wizard runs (an
	// open DB is the proof), so the wizard's own stages render starting at cell 1.
	return tuiStepRail(setupRailSteps, m.displayStage()+1)
}

// railWithHint appends a discoverability hint when ←/→ can walk the rail — while
// reviewing, or on a live screen that yields the arrows.
func (m *rootModel) railWithHint() string {
	r := m.rail()
	switch {
	case m.reviewing >= 0:
		// Mid-review both directions move; → eventually returns to the live step.
		r += tuiRailSep.Render("    ") + tuiRailTodo.Render("←/→ review steps")
	case m.canEnterReview():
		// At the live frontier only ← does anything — there's nothing ahead, so
		// don't advertise → and have it silently no-op.
		r += tuiRailSep.Render("    ") + tuiRailTodo.Render("← review steps")
	}
	return r
}

// applyConnectResult records the chosen connection outcome onto the result.
func (m *rootModel) applyConnectResult(msg connectResultMsg) {
	m.result.connectMethod = msg.method
	if msg.panelHostname != "" {
		m.result.panelHostname = msg.panelHostname
	}
	if msg.adminHostname != "" {
		m.result.adminHostname = msg.adminHostname
	}
	switch msg.method {
	case connectCloudflare:
		m.result.connectConfigured = true
		m.result.edgeConfigured = true
		if msg.edge != nil {
			m.result.edgeAud = msg.edge.AccessAud
			m.result.edgeRoutedHosts = msg.edge.RoutedHostnames
			m.result.edgeConfigPath = msg.edge.ConfigPath
		}
	case connectReverseProxy:
		m.result.connectConfigured = true
		m.result.reverseProxyGuide = msg.guide
	}
	m.result.panelURL = panelURLFor(msg.method, msg.panelHostname, m.rootDomain)
}

func (m *rootModel) showSummary() (tea.Model, tea.Cmd) {
	m.stage = stageSummary
	routed := m.result.edgeRoutedHosts
	if len(routed) == 0 && m.result.connectMethod == connectReverseProxy && m.result.panelHostname != "" {
		routed = []string{m.result.panelHostname}
	}
	return m.adopt(&summaryModel{
		panelURL:      m.result.panelURL,
		ownerUsername: m.result.username,
		ownerPassword: m.result.displayPassword,
		accessLabel:   connectMethodLabel(m.result.connectMethod),
		routedHosts:   routed,
		localHint:     m.result.connectMethod == connectLocal,
	})
}

// showStatus is the re-run landing: prove the backend is up, then point the
// operator at the panel without forcing any reconfiguration.
func (m *rootModel) showStatus() (tea.Model, tea.Cmd) {
	m.stage = stageSummary
	method := connectLocal
	accessLabel := "configured (manage in panel)"
	if m.accessAud != "" {
		method = connectCloudflare
		accessLabel = connectMethodLabel(connectCloudflare)
	}
	m.result.panelURL = panelURLFor(method, m.panelHost, m.rootDomain)
	return m.adopt(&summaryModel{
		panelURL:     m.result.panelURL,
		accessLabel:  accessLabel,
		alreadySetUp: true,
		localHint:    m.accessAud == "" && rootDomainEmbeddedIP(m.rootDomain) != "",
	})
}

func panelURLFor(method connectMethod, panelHostname, rootDomain string) string {
	if method != connectLocal && panelHostname != "" {
		return "https://" + panelHostname
	}
	return localPanelURL(rootDomain)
}