package app

import (
	"fmt"
	"sort"
	"strings"
	"unicode/utf8"

	"github.com/hjbdev/patterm/internal/preset"
)

// paletteAction is what the palette returns when the user picks an item.
type paletteAction struct {
	// kind: "spawn-agent" | "spawn-process" | "spawn-process-form" |
	//       "spawn-process-submit" | "spawn-terminal" | "switch" |
	//       "kill" | "quit" | "cancel" | "pad-delete" | "pad-rename" |
	//       "pad-rename-form" | "pad-rename-submit" | "pad-edit" |
	//       "agent-rename" | "agent-rename-form" | "agent-rename-submit" |
	//       "agent-close" | "proc-rename" | "proc-rename-form" |
	//       "proc-rename-submit" | "proc-delete" | "proc-stop" |
	//       "proc-restart" | "header"
	kind string

	// For spawn-agent / spawn-process, the preset to launch.
	preset *preset.Preset

	// For "switch" and "kill", the target child id.
	childID string

	// For "spawn-process-submit": the freeform command line the user
	// typed and the relaunch-on-exit flag they ticked.
	command  string
	relaunch bool

	// For pad-* actions, the scratchpad name to operate on.
	padName string

	// For *-rename-submit actions, the user-typed new name.
	newName string

	// For settings actions, the updated settings snapshot to persist.
	settings *settings
}

// Group ids order the section bands the palette renders when no query
// is active. Lower numbers render first; tie-broken matches in scored
// mode also fall back to group id so a tight Focused-section hit beats
// an equally tight Spawn-section hit.
const (
	groupFocused = iota
	groupOpen
	groupSpawn
	groupSettings
	groupQuit
)

var groupLabels = map[int]string{
	groupFocused:  "Focused",
	groupOpen:     "Open",
	groupSpawn:    "Spawn",
	groupSettings: "Settings",
	groupQuit:     "Quit",
}

type paletteItem struct {
	label  string
	hint   string
	action paletteAction
	group  int
	// matches lists rune indexes in label that should render bold during
	// scored mode so the user sees why a row matched.
	matches []int
}

// paletteMode toggles the palette between its fuzzy-picker UI and the
// freeform "spawn process" form. The form lives inside the palette so
// it shares the same modal-input contract (every byte intercepted; no
// PTY forwarding) without needing a second overlay.
type paletteMode int

const (
	paletteModePicker paletteMode = iota
	paletteModeSpawnForm
	paletteModeRenameForm
	paletteModeSettings
	paletteModeAutoSummary
	paletteModeSettingsInput
)

// spawnProcessForm is the state for the "Spawn process…" two-field
// form: a command line plus a "relaunch on exit" toggle. Tab cycles
// focus; space toggles the checkbox when it owns focus; Enter submits.
type spawnProcessForm struct {
	cmd      []rune
	relaunch bool
	field    int // 0 = command, 1 = relaunch checkbox
}

// renameForm is a one-field inline form used by the "Rename scratchpad /
// agent / process" context palette entries. The submit action kind
// determines what gets renamed; the target name (pad name or child id)
// is carried alongside so closePalette knows what to apply the new
// name to.
type renameForm struct {
	name        []rune
	subject     string // "pad" | "agent" | "proc"
	target      string // padName for "pad"; childID for "agent"/"proc"
	title       string // e.g. "Rename"
	subjectLine string // e.g. "scratchpad: notes.md" rendered above the input
}

type settingsInputForm struct {
	title    string
	field    string
	value    []rune
	subtitle string
}

// paletteState is the in-memory model for the overlay. SPEC §4: a
// single fuzzy-searchable list of commands scoped to the current focus.
type paletteState struct {
	query      []rune
	cursor     int
	children   []*Child
	focused    string
	focusedPad string
	presets    preset.Set
	settings   settings

	items []paletteItem

	mode          paletteMode
	form          *spawnProcessForm
	renameForm    *renameForm
	settingsInput *settingsInputForm

	// showHelp swaps the item list for a static keybinding cheat-sheet
	// until the next keystroke. Toggled by `?` in picker mode.
	showHelp bool
}

// macroPrefixes maps the palette macro prefix (without trailing space)
// to the paletteAction.kind values that should be retained when that
// macro is active. Typing `sw <query>` filters to switch entries only,
// `k <query>` to close entries, `sp <query>` to spawn entries.
var macroPrefixes = map[string][]string{
	"sw": {"switch"},
	"k":  {"kill", "agent-close", "proc-stop", "proc-delete"},
	"sp": {"spawn-agent", "spawn-process", "spawn-terminal", "spawn-process-form"},
}

// chipOrder is the cycle order for Tab / Shift-Tab when the user
// switches between filter categories from the chip strip. The empty
// string is the "All" chip.
var chipOrder = []string{"", "sw", "sp", "k"}

var chipLabels = map[string]string{
	"":   "All",
	"sw": "Open",
	"sp": "Spawn",
	"k":  "Close",
}

// detectMacro returns the macro keyword and the remaining query, or
// ("", original) if no macro is active. A macro is active when the
// query starts with one of the known prefixes followed by a space.
// Matching is case-insensitive but the returned `rest` preserves the
// user's original case so Tab-cycling chips doesn't downcase the text.
func detectMacro(q string) (macro, rest string) {
	lq := strings.ToLower(q)
	for k := range macroPrefixes {
		if len(lq) > len(k) && lq[:len(k)] == k && lq[len(k)] == ' ' {
			return k, q[len(k)+1:]
		}
	}
	return "", q
}

func findChildByID(children []*Child, id string) *Child {
	if id == "" {
		return nil
	}
	for _, c := range children {
		if c.ID == id {
			return c
		}
	}
	return nil
}

func newPalette(children []*Child, focused, focusedPad string, presets preset.Set, appSettings ...settings) *paletteState {
	st := defaultSettings()
	if len(appSettings) > 0 {
		st = appSettings[0].clone()
	}
	p := &paletteState{children: children, focused: focused, focusedPad: focusedPad, presets: presets, settings: st}
	p.rebuild()
	return p
}

func (p *paletteState) rebuild() {
	// Macro is resolved on the *original-case* query; the returned rest
	// keeps the user's casing intact (useful when Tab cycles chips).
	macro, rest := detectMacro(string(p.query))
	all := p.buildItems(macro)

	if rest == "" {
		// No textual filter: render with section headers between groups.
		p.items = itemsWithHeaders(all)
		p.clampCursor()
		return
	}

	needle := strings.ToLower(rest)
	type scored struct {
		it    paletteItem
		score int
		order int
	}
	scoredList := make([]scored, 0, len(all))
	for i, it := range all {
		s, matches := fuzzyScore(strings.ToLower(it.label), strings.ToLower(it.hint), needle)
		if s == 0 {
			continue
		}
		it.matches = matches
		scoredList = append(scoredList, scored{it: it, score: s, order: i})
	}
	sort.SliceStable(scoredList, func(i, j int) bool {
		if scoredList[i].score != scoredList[j].score {
			return scoredList[i].score > scoredList[j].score
		}
		if scoredList[i].it.group != scoredList[j].it.group {
			return scoredList[i].it.group < scoredList[j].it.group
		}
		return scoredList[i].order < scoredList[j].order
	})
	p.items = p.items[:0]
	for _, s := range scoredList {
		p.items = append(p.items, s.it)
	}
	p.clampCursor()
}

// buildItems assembles every selectable row in fixed group order
// (Focused → Open → Spawn → Quit). Headers are added by
// itemsWithHeaders for the no-query case; scored mode drops them.
// When macro is non-empty the result is filtered down to the kinds
// that macro retains.
func (p *paletteState) buildItems(macro string) []paletteItem {
	var out []paletteItem

	// Group 0: Focused — context-aware actions for whatever owns focus.
	// A focused scratchpad shadows any focused child.
	switch {
	case p.focusedPad != "":
		name := p.focusedPad
		out = append(out,
			paletteItem{label: "Delete scratchpad: " + name, hint: "remove the file from disk",
				action: paletteAction{kind: "pad-delete", padName: name}, group: groupFocused},
			paletteItem{label: "Rename scratchpad: " + name, hint: "inline rename · enter to commit",
				action: paletteAction{kind: "pad-rename-form", padName: name}, group: groupFocused},
			paletteItem{label: "Edit scratchpad: " + name, hint: "open in external editor (zed)",
				action: paletteAction{kind: "pad-edit", padName: name}, group: groupFocused},
		)
	case p.focused != "":
		if c := findChildByID(p.children, p.focused); c != nil {
			name := c.DisplayName()
			switch c.Kind {
			case KindAgent:
				out = append(out,
					paletteItem{label: "Rename agent: " + name, hint: "inline rename · enter to commit",
						action: paletteAction{kind: "agent-rename-form", childID: c.ID}, group: groupFocused},
					paletteItem{label: "Close agent: " + name, hint: "SIGTERM " + strings.Join(c.Argv, " "),
						action: paletteAction{kind: "agent-close", childID: c.ID}, group: groupFocused},
				)
			default:
				out = append(out,
					paletteItem{label: "Rename process: " + name, hint: "inline rename · enter to commit",
						action: paletteAction{kind: "proc-rename-form", childID: c.ID}, group: groupFocused},
					paletteItem{label: "Delete process: " + name, hint: "remove entry; SIGKILL if alive",
						action: paletteAction{kind: "proc-delete", childID: c.ID}, group: groupFocused},
					paletteItem{label: "Stop process: " + name, hint: "SIGTERM · keep entry for restart",
						action: paletteAction{kind: "proc-stop", childID: c.ID}, group: groupFocused},
					paletteItem{label: "Restart process: " + name, hint: "SIGTERM then start with same argv",
						action: paletteAction{kind: "proc-restart", childID: c.ID}, group: groupFocused},
				)
			}
		}
	}

	// Group 1: Open — switch entries for every running child. Dead
	// agents are filtered out (no restart path); dead command processes
	// remain so they can be restarted. The currently-focused child is
	// marked with a leading ▶ instead of the older "• … (current)" suffix
	// so the row reads cleaner.
	for _, c := range p.children {
		if c.Kind == KindAgent && c.Status() != StatusRunning {
			continue
		}
		label := "Switch to " + c.DisplayName()
		hint := strings.Join(c.Argv, " ")
		if c.ID == p.focused {
			label = "▶ " + label
		}
		if c.Status() != StatusRunning {
			label = label + "  [" + string(c.Status()) + "]"
		}
		out = append(out, paletteItem{
			label:  label,
			hint:   hint,
			action: paletteAction{kind: "switch", childID: c.ID},
			group:  groupOpen,
		})
	}

	// Group 2: Spawn — every way to launch something new. Verbs are
	// unified on "Spawn" for consistency; the trailing "…" plus the
	// `(custom)` suffix on the freeform row signals it opens a form.
	for _, pr := range p.presets.Agents {
		out = append(out, paletteItem{
			label:  "Spawn agent: " + pr.Name,
			hint:   strings.Join(pr.Argv, " "),
			action: paletteAction{kind: "spawn-agent", preset: pr},
			group:  groupSpawn,
		})
	}
	for _, pr := range p.presets.Processes {
		out = append(out, paletteItem{
			label:  "Spawn process: " + pr.Name,
			hint:   strings.Join(pr.Argv, " "),
			action: paletteAction{kind: "spawn-process", preset: pr},
			group:  groupSpawn,
		})
	}
	out = append(out, paletteItem{
		label:  "Spawn terminal",
		hint:   "bare interactive $SHELL · removed on exit",
		action: paletteAction{kind: "spawn-terminal"},
		group:  groupSpawn,
	})
	out = append(out, paletteItem{
		label:  "Spawn process… (custom)",
		hint:   "freeform · sh -lc · optional relaunch",
		action: paletteAction{kind: "spawn-process-form"},
		group:  groupSpawn,
	})

	// Group 3: Settings.
	out = append(out, paletteItem{
		label:  "Open Settings",
		hint:   "configure agents and auto-summary",
		action: paletteAction{kind: "settings-open"},
		group:  groupSettings,
	})

	// Group 4: Quit.
	out = append(out, paletteItem{
		label:  "Quit",
		hint:   "exit patterm; SIGTERM every child",
		action: paletteAction{kind: "quit"},
		group:  groupQuit,
	})

	if macro != "" {
		retain := macroPrefixes[macro]
		filtered := out[:0:0]
		for _, it := range out {
			for _, k := range retain {
				if it.action.kind == k {
					filtered = append(filtered, it)
					break
				}
			}
		}
		out = filtered
	}
	return out
}

// itemsWithHeaders splices a non-selectable header row in front of
// each new group so the (unfiltered) list reads as scannable bands.
func itemsWithHeaders(items []paletteItem) []paletteItem {
	if len(items) == 0 {
		return nil
	}
	result := make([]paletteItem, 0, len(items)+4)
	currentGroup := -1
	for _, it := range items {
		if it.group != currentGroup {
			currentGroup = it.group
			label, ok := groupLabels[it.group]
			if !ok {
				label = ""
			}
			result = append(result, paletteItem{
				label:  "── " + label + " ──",
				action: paletteAction{kind: "header"},
				group:  it.group,
			})
		}
		result = append(result, it)
	}
	return result
}

// fuzzyScore ranks a candidate label against the lowercase needle.
// Returns (score, matchPositions). score==0 means no match. Higher is
// better. matchPositions are rune indexes inside the label that should
// render bold when displayed.
func fuzzyScore(label, hint, needle string) (int, []int) {
	if needle == "" {
		return 1, nil
	}
	needleRunes := utf8.RuneCountInString(needle)

	if strings.HasPrefix(label, needle) {
		pos := make([]int, needleRunes)
		for i := range pos {
			pos[i] = i
		}
		return 1000 + needleRunes, pos
	}

	if byteIdx := wordBoundaryIndex(label, needle); byteIdx >= 0 {
		return 500 + needleRunes, runeRange(label, byteIdx, len(needle))
	}

	if byteIdx := strings.Index(label, needle); byteIdx >= 0 {
		return 250 + needleRunes, runeRange(label, byteIdx, len(needle))
	}

	if strings.Contains(hint, needle) {
		return 100 + needleRunes, nil
	}

	// Scattered fuzzy match: characters of needle appear in order in
	// label. Lowest-value bucket, recorded so the user sees something
	// highlighted in the rendered row.
	pos := make([]int, 0, needleRunes)
	runeIdx := 0
	needleIdx := 0
	nr := []rune(needle)
	for _, r := range label {
		if needleIdx < len(nr) && r == nr[needleIdx] {
			pos = append(pos, runeIdx)
			needleIdx++
		}
		runeIdx++
	}
	if needleIdx == len(nr) {
		return 10 * needleRunes, pos
	}
	return 0, nil
}

// wordBoundaryIndex returns the byte index of the first occurrence of
// needle in label that starts at a word boundary (label start, or
// after one of " -_:./"), or -1 if no boundary match exists.
func wordBoundaryIndex(label, needle string) int {
	idx := 0
	for idx <= len(label)-len(needle) {
		next := strings.Index(label[idx:], needle)
		if next < 0 {
			return -1
		}
		abs := idx + next
		if abs == 0 {
			return abs
		}
		prev := label[abs-1]
		if prev == ' ' || prev == '-' || prev == '_' || prev == ':' || prev == '.' || prev == '/' {
			return abs
		}
		idx = abs + 1
	}
	return -1
}

// runeRange converts a (byteStart, byteCount) span inside s into the
// list of rune indexes covered. ASCII labels collapse to byteStart..
// byteStart+byteCount-1; multi-byte runes are accounted for correctly.
func runeRange(s string, byteStart, byteCount int) []int {
	var out []int
	runeIdx := 0
	for byteI := range s {
		if byteI >= byteStart && byteI < byteStart+byteCount {
			out = append(out, runeIdx)
		}
		if byteI >= byteStart+byteCount {
			break
		}
		runeIdx++
	}
	return out
}

// kitty functional keycodes.
const (
	kittyKeyUp   = 57352
	kittyKeyDown = 57353
	kittyKeyHome = 57371
	kittyKeyEnd  = 57368
)

// peekArrowEvent classifies the CSI sequence at chunk[i:] as Up ('U'),
// Down ('D'), or none (0) and returns the byte length of that sequence.
// Used by the palette input loop to suppress duplicate adjacent
// arrow events some terminals emit for a single physical keypress
// (either two legacy `CSI B` in a row, or a legacy + kitty pair).
func peekArrowEvent(chunk []byte, i int) (nav byte, advance int) {
	if i >= len(chunk) || chunk[i] != 0x1b {
		return 0, 0
	}
	n := csiLen(chunk, i)
	if n == 0 {
		return 0, 0
	}
	final := chunk[i+n-1]
	switch final {
	case 'A':
		return 'U', n
	case 'B':
		return 'D', n
	case 'u':
		k, ok := decodeCSIu(string(chunk[i+2 : i+n-1]))
		if !ok || k.event != 1 {
			return 0, n
		}
		switch k.key {
		case kittyKeyUp:
			return 'U', n
		case kittyKeyDown:
			return 'D', n
		}
	}
	return 0, 0
}

// handleInput consumes one keystroke from chunk[i:] and updates palette
// state. advance is how many bytes the keystroke occupies. Returning
// done=true tells the caller the palette is finished and action
// describes what to do next.
func (p *paletteState) handleInput(chunk []byte, i int) (action paletteAction, done bool, advance int) {
	if p.mode == paletteModeSpawnForm {
		return p.handleFormInput(chunk, i)
	}
	if p.mode == paletteModeRenameForm {
		return p.handleRenameInput(chunk, i)
	}
	if p.mode == paletteModeSettings {
		return p.handleSettingsInput(chunk, i)
	}
	if p.mode == paletteModeAutoSummary {
		return p.handleAutoSummaryInput(chunk, i)
	}
	if p.mode == paletteModeSettingsInput {
		return p.handleSettingsTextInput(chunk, i)
	}

	b := chunk[i]

	// Help overlay: any keystroke dismisses it back to the picker. We
	// consume CSI sequences as one unit so a long arrow encoding doesn't
	// leave dangling bytes in the input stream.
	if p.showHelp {
		p.showHelp = false
		if b == 0x1b {
			if n := csiLen(chunk, i); n > 0 {
				return paletteAction{}, false, n
			}
			return paletteAction{}, false, 1
		}
		return paletteAction{}, false, 1
	}

	if b == 0x1b {
		// Alt-digit (ESC then '1'-'9') is the quick-pick accelerator —
		// jump straight to the Nth visible selectable item.
		if i+1 < len(chunk) && chunk[i+1] >= '1' && chunk[i+1] <= '9' {
			n := int(chunk[i+1] - '0')
			if a, ok := p.quickPick(n); ok {
				return a, true, 2
			}
			return paletteAction{}, false, 2
		}
		if n := csiLen(chunk, i); n > 0 {
			return p.handleCSI(chunk[i+2:i+n-1], chunk[i+n-1], n)
		}
		// Bare ESC (no CSI follow-up): cancel.
		return paletteAction{kind: "cancel"}, true, 1
	}
	switch b {
	case '\r', '\n':
		return p.acceptOrEnterForm(1)
	case 0x7f, 0x08:
		p.backspace()
	case '\t':
		p.cycleChip(+1)
	case 0x15: // Ctrl-U
		p.clearQuery()
	case 0x0e: // Ctrl-N
		p.cursorDown()
	case 0x10: // Ctrl-P
		p.cursorUp()
	case 0x18: // Ctrl-X — inline close on a Switch entry.
		if a, ok := p.killCurrentSwitch(); ok {
			return a, true, 1
		}
	case 0x0b: // Ctrl-K inside palette is a no-op (would re-open); ignore.
	case 0x16: // Ctrl-V literal-paste — ignore in palette.
	case '?':
		if len(p.query) == 0 {
			p.showHelp = true
			return paletteAction{}, false, 1
		}
		p.query = append(p.query, '?')
		p.rebuild()
	default:
		if b >= 0x20 && b < 0x7f {
			p.query = append(p.query, rune(b))
			p.rebuild()
		}
	}
	return paletteAction{}, false, 1
}

// acceptOrEnterForm wraps accept(): if the chosen item opens the
// spawn-process form or one of the rename forms, transition into form
// mode instead of returning done=true. The advance count is what the
// caller already consumed for the Enter keystroke.
func (p *paletteState) acceptOrEnterForm(adv int) (paletteAction, bool, int) {
	a := p.accept()
	switch a.kind {
	case "", "header":
		// Cursor parked on a header (or empty list) — Enter is a no-op
		// rather than closing the palette.
		return paletteAction{}, false, adv
	case "spawn-process-form":
		p.mode = paletteModeSpawnForm
		p.form = &spawnProcessForm{}
		return paletteAction{}, false, adv
	case "settings-open":
		p.mode = paletteModeSettings
		p.query = nil
		p.cursor = 0
		p.rebuildSettings()
		return paletteAction{}, false, adv
	case "pad-rename-form":
		p.enterRenameForm("pad", a.padName, a.padName, "scratchpad: "+a.padName)
		return paletteAction{}, false, adv
	case "agent-rename-form", "proc-rename-form":
		subject := "agent"
		subjLabel := "agent: "
		if a.kind == "proc-rename-form" {
			subject = "proc"
			subjLabel = "process: "
		}
		current := ""
		if c := findChildByID(p.children, a.childID); c != nil {
			current = c.DisplayName()
		}
		p.enterRenameForm(subject, a.childID, current, subjLabel+current)
		return paletteAction{}, false, adv
	}
	return a, true, adv
}

func (p *paletteState) enterRenameForm(subject, target, current, subjectLine string) {
	p.mode = paletteModeRenameForm
	p.renameForm = &renameForm{
		name:        []rune(current),
		subject:     subject,
		target:      target,
		title:       "Rename",
		subjectLine: subjectLine,
	}
}

func (p *paletteState) handleCSI(params []byte, final byte, n int) (paletteAction, bool, int) {
	switch final {
	case 'A':
		p.cursorUp()
		return paletteAction{}, false, n
	case 'B':
		p.cursorDown()
		return paletteAction{}, false, n
	case 'H':
		p.cursorHome()
		return paletteAction{}, false, n
	case 'F':
		p.cursorEnd()
		return paletteAction{}, false, n
	case 'Z':
		// Shift-Tab — cycle chip backwards.
		p.cycleChip(-1)
		return paletteAction{}, false, n
	case 'u':
		k, ok := decodeCSIu(string(params))
		if !ok || k.event != 1 {
			// Repeat / release events, or malformed: ignore.
			return paletteAction{}, false, n
		}
		switch k.key {
		case 13: // Enter
			return p.acceptOrEnterForm(n)
		case 27: // Escape
			return paletteAction{kind: "cancel"}, true, n
		case 9: // Tab
			if k.mods == 2 {
				p.cycleChip(-1)
			} else {
				p.cycleChip(+1)
			}
			return paletteAction{}, false, n
		case 127, 8: // Backspace
			p.backspace()
		case kittyKeyUp:
			p.cursorUp()
		case kittyKeyDown:
			p.cursorDown()
		case kittyKeyHome:
			p.cursorHome()
		case kittyKeyEnd:
			p.cursorEnd()
		default:
			// Ctrl-modified character keys.
			if k.mods == 5 {
				switch k.key {
				case 'u':
					p.clearQuery()
				case 'n':
					p.cursorDown()
				case 'p':
					p.cursorUp()
				case 'x':
					if a, ok := p.killCurrentSwitch(); ok {
						return a, true, n
					}
				}
				return paletteAction{}, false, n
			}
			// Alt-digit via kitty.
			if k.mods == 3 && k.key >= '1' && k.key <= '9' {
				if a, ok := p.quickPick(int(k.key - '0')); ok {
					return a, true, n
				}
				return paletteAction{}, false, n
			}
			// Unmodified printable ASCII typed via CSI u (flag 8): treat
			// as a query keystroke.
			if k.mods == 1 && k.key >= 0x20 && k.key < 0x7f {
				if k.key == '?' && len(p.query) == 0 {
					p.showHelp = true
					return paletteAction{}, false, n
				}
				p.query = append(p.query, rune(k.key))
				p.rebuild()
			}
		}
		return paletteAction{}, false, n
	}
	// Anything else (~, function keys, etc.): consume silently.
	return paletteAction{}, false, n
}

// handleFormInput drives the spawn-process form. Tab cycles fields,
// space toggles the relaunch checkbox when it has focus, Enter submits,
// Esc cancels. Ctrl-R toggles relaunch regardless of focused field so
// the user doesn't have to leave the command line to set it.
func (p *paletteState) handleFormInput(chunk []byte, i int) (paletteAction, bool, int) {
	b := chunk[i]
	if b == 0x1b {
		if n := csiLen(chunk, i); n > 0 {
			return p.handleFormCSI(chunk[i+2:i+n-1], chunk[i+n-1], n)
		}
		return paletteAction{kind: "cancel"}, true, 1
	}
	switch b {
	case '\r', '\n':
		return p.submitForm(), true, 1
	case '\t':
		p.cycleFormField()
	case 0x7f, 0x08:
		p.formBackspace()
	case 0x12: // Ctrl-R — toggle relaunch in either field.
		p.form.relaunch = !p.form.relaunch
	case ' ':
		if p.form.field == 1 {
			p.form.relaunch = !p.form.relaunch
		} else {
			p.form.cmd = append(p.form.cmd, ' ')
		}
	default:
		if b >= 0x20 && b < 0x7f && p.form.field == 0 {
			p.form.cmd = append(p.form.cmd, rune(b))
		}
	}
	return paletteAction{}, false, 1
}

func (p *paletteState) handleFormCSI(params []byte, final byte, n int) (paletteAction, bool, int) {
	switch final {
	case 'A', 'B':
		// Arrow up/down cycles field.
		p.cycleFormField()
		return paletteAction{}, false, n
	case 'u':
		k, ok := decodeCSIu(string(params))
		if !ok || k.event != 1 {
			return paletteAction{}, false, n
		}
		switch k.key {
		case 13:
			return p.submitForm(), true, n
		case 27:
			return paletteAction{kind: "cancel"}, true, n
		case 9:
			p.cycleFormField()
		case 127, 8:
			p.formBackspace()
		case ' ':
			if p.form.field == 1 {
				p.form.relaunch = !p.form.relaunch
			}
		default:
			if k.mods == 5 && k.key == 'r' {
				p.form.relaunch = !p.form.relaunch
				return paletteAction{}, false, n
			}
			if k.mods == 1 && k.key >= 0x20 && k.key < 0x7f && p.form.field == 0 {
				p.form.cmd = append(p.form.cmd, rune(k.key))
			}
		}
	}
	return paletteAction{}, false, n
}

// handleRenameInput drives the single-field rename form. Enter commits
// the typed name, Esc cancels back out of the palette entirely (same
// semantics as the spawn form so the user has one mental model).
func (p *paletteState) handleRenameInput(chunk []byte, i int) (paletteAction, bool, int) {
	b := chunk[i]
	if b == 0x1b {
		if n := csiLen(chunk, i); n > 0 {
			return p.handleRenameCSI(chunk[i+2:i+n-1], chunk[i+n-1], n)
		}
		return paletteAction{kind: "cancel"}, true, 1
	}
	switch b {
	case '\r', '\n':
		return p.submitRename(), true, 1
	case 0x7f, 0x08:
		p.renameBackspace()
	case 0x15: // Ctrl-U
		if p.renameForm != nil {
			p.renameForm.name = p.renameForm.name[:0]
		}
	default:
		if b >= 0x20 && b < 0x7f && p.renameForm != nil {
			p.renameForm.name = append(p.renameForm.name, rune(b))
		}
	}
	return paletteAction{}, false, 1
}

func (p *paletteState) handleRenameCSI(params []byte, final byte, n int) (paletteAction, bool, int) {
	switch final {
	case 'u':
		k, ok := decodeCSIu(string(params))
		if !ok || k.event != 1 {
			return paletteAction{}, false, n
		}
		switch k.key {
		case 13:
			return p.submitRename(), true, n
		case 27:
			return paletteAction{kind: "cancel"}, true, n
		case 127, 8:
			p.renameBackspace()
		default:
			if k.mods == 5 && k.key == 'u' {
				if p.renameForm != nil {
					p.renameForm.name = p.renameForm.name[:0]
				}
				return paletteAction{}, false, n
			}
			if k.mods == 1 && k.key >= 0x20 && k.key < 0x7f && p.renameForm != nil {
				p.renameForm.name = append(p.renameForm.name, rune(k.key))
			}
		}
	}
	return paletteAction{}, false, n
}

func (p *paletteState) renameBackspace() {
	if p.renameForm != nil && len(p.renameForm.name) > 0 {
		p.renameForm.name = p.renameForm.name[:len(p.renameForm.name)-1]
	}
}

func (p *paletteState) submitRename() paletteAction {
	if p.renameForm == nil {
		return paletteAction{kind: "cancel"}
	}
	newName := strings.TrimSpace(string(p.renameForm.name))
	if newName == "" {
		return paletteAction{kind: "cancel"}
	}
	var kind string
	switch p.renameForm.subject {
	case "pad":
		kind = "pad-rename-submit"
		return paletteAction{kind: kind, padName: p.renameForm.target, newName: newName}
	case "agent":
		kind = "agent-rename-submit"
	case "proc":
		kind = "proc-rename-submit"
	default:
		return paletteAction{kind: "cancel"}
	}
	return paletteAction{kind: kind, childID: p.renameForm.target, newName: newName}
}

func (p *paletteState) cycleFormField() {
	p.form.field++
	if p.form.field > 1 {
		p.form.field = 0
	}
}

func (p *paletteState) formBackspace() {
	if p.form.field == 0 && len(p.form.cmd) > 0 {
		p.form.cmd = p.form.cmd[:len(p.form.cmd)-1]
	}
}

func (p *paletteState) submitForm() paletteAction {
	cmd := strings.TrimSpace(string(p.form.cmd))
	if cmd == "" {
		return paletteAction{kind: "cancel"}
	}
	return paletteAction{
		kind:     "spawn-process-submit",
		command:  cmd,
		relaunch: p.form.relaunch,
	}
}

func (p *paletteState) accept() paletteAction {
	if p.cursor < 0 || p.cursor >= len(p.items) {
		return paletteAction{kind: "cancel"}
	}
	it := p.items[p.cursor]
	if it.action.kind == "header" {
		return paletteAction{kind: "header"}
	}
	return it.action
}

// quickPick selects the Nth visible non-header item (1-indexed) and
// returns its accepted action. Returns (_, false) if N is out of range
// or if the resolved action would only open a sub-form (which would
// leave the palette in an inconsistent state for a one-shot keystroke).
func (p *paletteState) quickPick(n int) (paletteAction, bool) {
	if n <= 0 {
		return paletteAction{}, false
	}
	seen := 0
	for i, it := range p.items {
		if it.action.kind == "header" {
			continue
		}
		seen++
		if seen == n {
			p.cursor = i
			a, done, _ := p.acceptOrEnterForm(0)
			if !done {
				return paletteAction{}, false
			}
			return a, true
		}
	}
	return paletteAction{}, false
}

// killCurrentSwitch fires a "kill" action against the child the cursor
// is parked on, but only if that cursor row is a Switch entry. Used by
// Ctrl-X so the user can close a non-focused child without leaving the
// palette.
func (p *paletteState) killCurrentSwitch() (paletteAction, bool) {
	if p.cursor < 0 || p.cursor >= len(p.items) {
		return paletteAction{}, false
	}
	it := p.items[p.cursor]
	if it.action.kind != "switch" {
		return paletteAction{}, false
	}
	return paletteAction{kind: "kill", childID: it.action.childID}, true
}

// cycleChip rotates the active macro filter by dir (±1). Empty macro
// is "All"; otherwise the query is rewritten to "<macro> <rest>" so
// the existing macro pipeline does the actual filtering.
func (p *paletteState) cycleChip(dir int) {
	cur, rest := detectMacro(string(p.query))
	idx := 0
	for i, c := range chipOrder {
		if c == cur {
			idx = i
			break
		}
	}
	next := chipOrder[(idx+dir+len(chipOrder))%len(chipOrder)]
	if next == "" {
		p.query = []rune(rest)
	} else {
		p.query = []rune(next + " " + rest)
	}
	p.rebuild()
}

// backspace deletes the last rune, with one special case: if the
// query is exactly a macro keyword plus its trailing space (e.g. "sw "),
// backspace drops the whole macro back to empty rather than leaving
// "sw" which would now read as a literal search term.
func (p *paletteState) backspace() {
	if len(p.query) == 0 {
		return
	}
	q := string(p.query)
	if len(q) >= 2 && q[len(q)-1] == ' ' {
		if _, ok := macroPrefixes[q[:len(q)-1]]; ok {
			p.query = p.query[:0]
			p.rebuild()
			return
		}
	}
	p.query = p.query[:len(p.query)-1]
	p.rebuild()
}

func (p *paletteState) clearQuery() {
	p.query = p.query[:0]
	p.rebuild()
}

func (p *paletteState) cursorUp() {
	if len(p.items) == 0 {
		return
	}
	for i := p.cursor - 1; i >= 0; i-- {
		if p.items[i].action.kind != "header" {
			p.cursor = i
			return
		}
	}
}

func (p *paletteState) cursorDown() {
	if len(p.items) == 0 {
		return
	}
	for i := p.cursor + 1; i < len(p.items); i++ {
		if p.items[i].action.kind != "header" {
			p.cursor = i
			return
		}
	}
}

func (p *paletteState) cursorHome() {
	for i := 0; i < len(p.items); i++ {
		if p.items[i].action.kind != "header" {
			p.cursor = i
			return
		}
	}
}

func (p *paletteState) cursorEnd() {
	for i := len(p.items) - 1; i >= 0; i-- {
		if p.items[i].action.kind != "header" {
			p.cursor = i
			return
		}
	}
}

func (p *paletteState) clampCursor() {
	if len(p.items) == 0 {
		p.cursor = 0
		return
	}
	if p.cursor >= len(p.items) {
		p.cursor = len(p.items) - 1
	}
	if p.cursor < 0 {
		p.cursor = 0
	}
	if p.items[p.cursor].action.kind == "header" {
		// Prefer moving down to the next selectable row; fall back to up.
		for i := p.cursor + 1; i < len(p.items); i++ {
			if p.items[i].action.kind != "header" {
				p.cursor = i
				return
			}
		}
		for i := p.cursor - 1; i >= 0; i-- {
			if p.items[i].action.kind != "header" {
				p.cursor = i
				return
			}
		}
	}
}

// visibleSelectableCount returns the total non-header items in p.items.
func (p *paletteState) visibleSelectableCount() int {
	n := 0
	for _, it := range p.items {
		if it.action.kind != "header" {
			n++
		}
	}
	return n
}

// selectableIndex returns the 1-based index of the cursor among
// selectable (non-header) items, or 0 if cursor is on a header / empty.
func (p *paletteState) selectableIndex() int {
	if p.cursor < 0 || p.cursor >= len(p.items) {
		return 0
	}
	n := 0
	for i := 0; i <= p.cursor; i++ {
		if p.items[i].action.kind != "header" {
			n++
		}
	}
	return n
}

// focusedSubject returns the short context string shown in the title
// bar — "on: <child>" / "pad: <name>" / "" — so the user knows which
// focus the context-section is targeting.
func (p *paletteState) focusedSubject() string {
	if p.focusedPad != "" {
		return "pad: " + p.focusedPad
	}
	if p.focused != "" {
		if c := findChildByID(p.children, p.focused); c != nil {
			return "on: " + c.DisplayName()
		}
	}
	return ""
}

func (p *paletteState) rebuildSettings() {
	items := []paletteItem{{
		label:  "Agents / Auto-summarization",
		hint:   "provider, models, cadence, test",
		action: paletteAction{kind: "settings-auto-summary"},
		group:  groupSettings,
	}}
	q := strings.TrimSpace(strings.ToLower(string(p.query)))
	if q == "" {
		p.items = items
		p.cursor = 0
		return
	}
	p.items = p.items[:0]
	for _, it := range items {
		if strings.Contains(strings.ToLower(it.label+" "+it.hint), q) {
			p.items = append(p.items, it)
		}
	}
	p.clampCursor()
}

func (p *paletteState) handleSettingsInput(chunk []byte, i int) (paletteAction, bool, int) {
	b := chunk[i]
	if b == 0x1b {
		if n := csiLen(chunk, i); n > 0 {
			final := chunk[i+n-1]
			switch final {
			case 'A':
				p.cursorUp()
			case 'B':
				p.cursorDown()
			}
			return paletteAction{}, false, n
		}
		return paletteAction{kind: "cancel"}, true, 1
	}
	switch b {
	case '\r', '\n':
		if len(p.items) == 0 {
			return paletteAction{}, false, 1
		}
		a := p.items[p.cursor].action
		if a.kind == "settings-auto-summary" {
			p.mode = paletteModeAutoSummary
			p.cursor = 0
			return paletteAction{}, false, 1
		}
	case 0x7f, 0x08:
		p.backspace()
		p.rebuildSettings()
	case 0x15:
		p.query = nil
		p.rebuildSettings()
	case 0x0e:
		p.cursorDown()
	case 0x10:
		p.cursorUp()
	default:
		if b >= 0x20 && b < 0x7f {
			p.query = append(p.query, rune(b))
			p.rebuildSettings()
		}
	}
	return paletteAction{}, false, 1
}

func (p *paletteState) handleAutoSummaryInput(chunk []byte, i int) (paletteAction, bool, int) {
	b := chunk[i]
	if b == 0x1b {
		if n := csiLen(chunk, i); n > 0 {
			final := chunk[i+n-1]
			switch final {
			case 'A':
				p.cursor--
				if p.cursor < 0 {
					p.cursor = len(autoSummaryRows()) - 1
				}
			case 'B':
				p.cursor++
				if p.cursor >= len(autoSummaryRows()) {
					p.cursor = 0
				}
			}
			return paletteAction{}, false, n
		}
		return paletteAction{kind: "cancel"}, true, 1
	}
	switch b {
	case '\r', '\n':
		return p.activateAutoSummaryRow()
	case 0x0e:
		p.cursor++
	case 0x10:
		p.cursor--
	}
	if p.cursor < 0 {
		p.cursor = len(autoSummaryRows()) - 1
	}
	if p.cursor >= len(autoSummaryRows()) {
		p.cursor = 0
	}
	return paletteAction{}, false, 1
}

func (p *paletteState) handleSettingsTextInput(chunk []byte, i int) (paletteAction, bool, int) {
	if p.settingsInput == nil {
		p.mode = paletteModeAutoSummary
		return paletteAction{}, false, 1
	}
	b := chunk[i]
	if b == 0x1b {
		if n := csiLen(chunk, i); n > 0 {
			return paletteAction{}, false, n
		}
		p.mode = paletteModeAutoSummary
		return paletteAction{}, false, 1
	}
	switch b {
	case '\r', '\n':
		p.applySettingsInput()
		p.mode = paletteModeAutoSummary
	case 0x7f, 0x08:
		if len(p.settingsInput.value) > 0 {
			p.settingsInput.value = p.settingsInput.value[:len(p.settingsInput.value)-1]
		}
	case 0x15:
		p.settingsInput.value = nil
	default:
		if b >= 0x20 && b < 0x7f {
			p.settingsInput.value = append(p.settingsInput.value, rune(b))
		}
	}
	return paletteAction{}, false, 1
}

type autoSummaryRow struct {
	key   string
	label string
}

func autoSummaryRows() []autoSummaryRow {
	return []autoSummaryRow{
		{key: "enabled", label: "Enabled"},
		{key: "provider", label: "Provider"},
		{key: "codex_model", label: "Codex model"},
		{key: "opencode_model", label: "OpenCode model"},
		{key: "claude_model", label: "Claude model"},
		{key: "cadence", label: "Cadence"},
		{key: "test", label: "Test summarizer"},
		{key: "run_now", label: "Summarize current top-level agent now"},
		{key: "save", label: "Save settings"},
		{key: "cancel", label: "Cancel"},
		{key: "back", label: "Back to Settings"},
	}
}

func (p *paletteState) activateAutoSummaryRow() (paletteAction, bool, int) {
	rows := autoSummaryRows()
	if p.cursor < 0 || p.cursor >= len(rows) {
		return paletteAction{}, false, 1
	}
	switch rows[p.cursor].key {
	case "enabled":
		p.settings.AutoSummary.Enabled = !p.settings.AutoSummary.Enabled
	case "provider":
		switch p.settings.AutoSummary.Provider {
		case "codex":
			p.settings.AutoSummary.Provider = "opencode"
		case "opencode":
			p.settings.AutoSummary.Provider = "claude"
		default:
			p.settings.AutoSummary.Provider = "codex"
		}
	case "codex_model", "opencode_model", "claude_model":
		provider := strings.TrimSuffix(rows[p.cursor].key, "_model")
		p.settingsInput = &settingsInputForm{
			title:    provider + " model",
			field:    rows[p.cursor].key,
			value:    []rune(p.settings.AutoSummary.modelFor(provider)),
			subtitle: "model flag passed to " + provider,
		}
		p.mode = paletteModeSettingsInput
	case "cadence":
		switch p.settings.AutoSummary.Cadence {
		case "5m":
			p.settings.AutoSummary.Cadence = "15m"
		case "15m":
			p.settings.AutoSummary.Cadence = "30m"
		default:
			p.settings.AutoSummary.Cadence = "5m"
		}
	case "test":
		return p.settingsAction("settings-test"), true, 1
	case "run_now":
		return p.settingsAction("settings-run-now"), true, 1
	case "save":
		return p.settingsAction("settings-close"), true, 1
	case "cancel":
		return paletteAction{kind: "cancel"}, true, 1
	case "back":
		p.mode = paletteModeSettings
		p.cursor = 0
		p.query = nil
		p.rebuildSettings()
	}
	p.settings.normalize()
	return paletteAction{}, false, 1
}

func (p *paletteState) applySettingsInput() {
	if p.settingsInput == nil {
		return
	}
	val := strings.TrimSpace(string(p.settingsInput.value))
	if val == "" {
		return
	}
	if p.settings.AutoSummary.Models == nil {
		p.settings.AutoSummary.Models = defaultSummaryModels()
	}
	switch p.settingsInput.field {
	case "codex_model":
		p.settings.AutoSummary.Models["codex"] = val
	case "opencode_model":
		p.settings.AutoSummary.Models["opencode"] = val
	case "claude_model":
		p.settings.AutoSummary.Models["claude"] = val
	}
	p.settings.normalize()
}

func (p *paletteState) settingsCloseAction() paletteAction {
	return p.settingsAction("settings-close")
}

func (p *paletteState) settingsAction(kind string) paletteAction {
	st := p.settings.clone()
	return paletteAction{kind: kind, settings: &st}
}

func (p *paletteState) renderSettings(out writeFlusher, cols, rows int) {
	p.renderSimplePicker(out, cols, rows, "Settings", "esc cancel", "search settings")
}

func (p *paletteState) renderSimplePicker(out writeFlusher, cols, rows int, title, hint, placeholder string) {
	width, leftPad, content := paletteBox(cols)
	maxItems := rows - 7
	if maxItems > 10 {
		maxItems = 10
	}
	if maxItems < 1 {
		maxItems = 1
	}
	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")
	row := 2
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + title + styleReset + styleBorder + " " + strings.Repeat("─", max(2, width-visibleLen(title)-visibleLen(hint)-9)) + " " + styleHint + hint + styleReset + styleBorder + " ─╮" + styleReset)
	row++
	query := string(p.query)
	if query == "" {
		query = styleDim + placeholder + styleReset
	}
	pad := content - 2 - visibleLen(query)
	if pad < 0 {
		pad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + styleAccent + "❯" + styleReset + " " + query + strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
	row++
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++
	p.renderItemRows(&b, &row, leftPad, width, content, maxItems)
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++
	footer := styleHint + "↵ open · esc cancel · ↑↓ navigate" + styleReset
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + footer + strings.Repeat(" ", max(0, content-visibleLen(footer))) + " " + styleBorder + "│" + styleReset)
	row++
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)
	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

func (p *paletteState) renderAutoSummary(out writeFlusher, cols, rows int) {
	width, leftPad, content := paletteBox(cols)
	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")
	row := 2
	title := "Auto-summarization"
	hint := "esc cancel"
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + title + styleReset + styleBorder + " " + strings.Repeat("─", max(2, width-visibleLen(title)-visibleLen(hint)-9)) + " " + styleHint + hint + styleReset + styleBorder + " ─╮" + styleReset)
	row++
	lines := p.autoSummaryDisplayRows()
	for i, line := range lines {
		moveTo(&b, row, leftPad)
		prefix := "  "
		if i == p.cursor {
			prefix = styleAccent + "▎" + styleReset + " "
			line = styleBold + line + styleReset
		}
		pad := content - visibleLen(prefix) - visibleLen(line)
		if pad < 0 {
			pad = 0
		}
		b.WriteString(styleBorder + "│" + styleReset + " " + prefix + line + strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
		row++
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++
	footer := styleHint + "↵ edit/toggle · save row commits · esc cancel" + styleReset
	if visibleLen(footer) > content {
		footer = clipRunes(footer, content-1) + "…"
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + footer + strings.Repeat(" ", max(0, content-visibleLen(footer))) + " " + styleBorder + "│" + styleReset)
	row++
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)
	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

func (p *paletteState) autoSummaryDisplayRows() []string {
	a := p.settings.AutoSummary
	enabled := "off"
	if a.Enabled {
		enabled = "on"
	}
	values := map[string]string{
		"enabled":        enabled,
		"provider":       a.Provider,
		"codex_model":    a.modelFor("codex"),
		"opencode_model": a.modelFor("opencode"),
		"claude_model":   a.modelFor("claude"),
		"cadence":        a.Cadence + " minimum after activity",
	}
	var out []string
	for _, row := range autoSummaryRows() {
		if v, ok := values[row.key]; ok {
			out = append(out, row.label+": "+v)
		} else {
			out = append(out, row.label)
		}
	}
	return out
}

func (p *paletteState) renderSettingsInput(out writeFlusher, cols, rows int) {
	if p.settingsInput == nil {
		p.settingsInput = &settingsInputForm{title: "Setting"}
	}
	width, leftPad, content := paletteBox(cols)
	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")
	row := 2
	title := p.settingsInput.title
	hint := "esc cancel"
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + title + styleReset + styleBorder + " " + strings.Repeat("─", max(2, width-visibleLen(title)-visibleLen(hint)-9)) + " " + styleHint + hint + styleReset + styleBorder + " ─╮" + styleReset)
	row++
	if p.settingsInput.subtitle != "" {
		sub := p.settingsInput.subtitle
		if visibleLen(sub) > content {
			sub = clipRunes(sub, content-1) + "…"
		}
		moveTo(&b, row, leftPad)
		b.WriteString(styleBorder + "│" + styleReset + " " + styleHint + sub + styleReset + strings.Repeat(" ", max(0, content-visibleLen(sub))) + " " + styleBorder + "│" + styleReset)
		row++
	}
	value := string(p.settingsInput.value)
	if visibleLen(value) > content-2 {
		value = clipRunes(value, content-3) + "…"
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + styleAccent + "❯" + styleReset + " " + value + strings.Repeat(" ", max(0, content-2-visibleLen(value))) + " " + styleBorder + "│" + styleReset)
	inputRow := row
	row++
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++
	footer := styleHint + "↵ save · esc cancel · ⌃u clear" + styleReset
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + footer + strings.Repeat(" ", max(0, content-visibleLen(footer))) + " " + styleBorder + "│" + styleReset)
	row++
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)
	moveTo(&b, inputRow, leftPad+4+visibleLen(value))
	b.WriteString("\x1b[?25h")
	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

func paletteBox(cols int) (width, leftPad, content int) {
	if cols < 32 {
		cols = 32
	}
	width = cols - 8
	if width > 72 {
		width = 72
	}
	if width < 40 {
		width = cols - 2
	}
	if width < 32 {
		width = 32
	}
	leftPad = (cols - width) / 2
	if leftPad < 1 {
		leftPad = 1
	}
	content = width - 4
	return width, leftPad, content
}

// render draws the palette onto out. Layout is a rounded box with a
// title bar, query line, chip strip, divider, item list, divider, and
// footer. The caller is responsible for the screen clear before the
// first render.
func (p *paletteState) render(out writeFlusher, cols, rows int) {
	if p.mode == paletteModeSpawnForm {
		p.renderForm(out, cols, rows)
		return
	}
	if p.mode == paletteModeRenameForm {
		p.renderRename(out, cols, rows)
		return
	}
	if p.mode == paletteModeSettings {
		p.renderSettings(out, cols, rows)
		return
	}
	if p.mode == paletteModeAutoSummary {
		p.renderAutoSummary(out, cols, rows)
		return
	}
	if p.mode == paletteModeSettingsInput {
		p.renderSettingsInput(out, cols, rows)
		return
	}
	if cols < 32 {
		cols = 32
	}
	if rows < 10 {
		rows = 10
	}
	width := cols - 8
	if width > 72 {
		width = 72
	}
	if width < 40 {
		width = cols - 2
	}
	if width < 32 {
		width = 32
	}
	leftPad := (cols - width) / 2
	if leftPad < 1 {
		leftPad = 1
	}
	content := width - 4 // visible cells between the " " padding on each side

	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")

	row := 2
	titleText := "patterm"
	subject := p.focusedSubject()
	keyHint := "Ctrl-K"
	// Right-side title contents: optional subject then "Ctrl-K".
	subjLen := utf8.RuneCountInString(subject)
	keyLen := utf8.RuneCountInString(keyHint)
	rightVisible := keyLen
	if subjLen > 0 {
		rightVisible += subjLen + 2 // "  " separator
	}
	dashes := width - 3 - len(titleText) - 1 - 1 - rightVisible - 3
	// If the title-bar can't fit the subject, drop it.
	if dashes < 2 && subjLen > 0 {
		subject = ""
		subjLen = 0
		rightVisible = keyLen
		dashes = width - 3 - len(titleText) - 1 - 1 - rightVisible - 3
	}
	if dashes < 2 {
		dashes = 2
	}
	var rightStr string
	if subject != "" {
		rightStr = styleHint + subject + styleReset + "  " + styleHint + keyHint + styleReset
	} else {
		rightStr = styleHint + keyHint + styleReset
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + titleText + styleReset + styleBorder + " " +
		strings.Repeat("─", dashes) + " " + rightStr + styleBorder + " ─╮" + styleReset)
	row++

	queryStr := string(p.query)
	queryRow := row
	qLen := utf8.RuneCountInString(queryStr)
	qPad := content - 2 - qLen
	if qPad < 0 {
		qPad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + styleAccent + "❯" + styleReset + " " + queryStr +
		strings.Repeat(" ", qPad) + " " + styleBorder + "│" + styleReset)
	row++

	// Chip strip — visual mirror of the typed-prefix macros. Active
	// chip is wrapped in [ ] and styled accent+bold; inactive chips
	// fade to styleHint. The user can also drive this with Tab.
	activeChip, _ := detectMacro(string(p.query))
	chipStr := renderChips(activeChip)
	chipVisible := visibleLen(chipStr)
	chipPad := content - chipVisible
	if chipPad < 0 {
		chipPad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + chipStr +
		strings.Repeat(" ", chipPad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++

	maxItems := rows - 7
	if maxItems > 12 {
		maxItems = 12
	}
	if maxItems < 1 {
		maxItems = 1
	}

	if p.showHelp {
		p.renderHelpRows(&b, &row, leftPad, width, content, maxItems)
	} else {
		p.renderItemRows(&b, &row, leftPad, width, content, maxItems)
	}

	// Bottom divider with scroll indicator when there are more items
	// above or below the visible window.
	moveTo(&b, row, leftPad)
	div := middleDivider(width, p.scrollIndicator(maxItems))
	b.WriteString(styleBorder + div + styleReset)
	row++

	footer := pickerFooter(p.visibleSelectableCount(), p.selectableIndex())
	fLen := visibleLen(footer)
	fPad := content - fLen
	if fPad < 0 {
		fPad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + footer +
		strings.Repeat(" ", fPad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)

	// Park the real terminal cursor at the end of the query so it
	// blinks naturally in place of the old underscore stub. Help
	// overlay hides the cursor since there's nothing to type into.
	if !p.showHelp {
		moveTo(&b, queryRow, leftPad+4+qLen)
		b.WriteString("\x1b[?25h")
	} else {
		b.WriteString("\x1b[?25l")
	}

	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

// renderChips returns the chip strip with the active chip wrapped in
// [brackets] and styled accent+bold. Inactive chips render in hint
// gray separated by two spaces.
func renderChips(active string) string {
	var sb strings.Builder
	for i, k := range chipOrder {
		if i > 0 {
			sb.WriteString("  ")
		}
		label := chipLabels[k]
		if k == active {
			sb.WriteString(styleAccent + styleBold + "[" + label + "]" + styleReset)
		} else {
			sb.WriteString(styleHint + " " + label + " " + styleReset)
		}
	}
	return sb.String()
}

// pickerFooter returns the styled footer string; appends a "cur/total"
// counter on the right when the list has anything selectable.
func pickerFooter(total, cur int) string {
	left := styleHint + "↵ run  ·  esc close  ·  ↑↓ navigate  ·  tab filter  ·  ? help" + styleReset
	if total == 0 {
		return left
	}
	return left + styleHint + fmt.Sprintf("  ·  %d/%d", cur, total) + styleReset
}

// middleDivider returns the divider that separates the item list from
// the footer. When extra is non-empty (a "▼ 3 more" indicator) it is
// embedded inside the divider.
func middleDivider(width int, extra string) string {
	if extra == "" {
		return "├" + strings.Repeat("─", width-2) + "┤"
	}
	tag := " " + extra + " "
	tagVisible := visibleLen(tag)
	dashes := width - 2 - tagVisible
	if dashes < 2 {
		return "├" + strings.Repeat("─", width-2) + "┤"
	}
	leftDashes := 2
	rightDashes := dashes - leftDashes
	return "├" + strings.Repeat("─", leftDashes) + tag + strings.Repeat("─", rightDashes) + "┤"
}

// scrollIndicator returns a "▼ N more" / "▲ N above" / "" string for
// the middle divider, signalling that there are items above or below
// the visible window.
func (p *paletteState) scrollIndicator(maxItems int) string {
	if len(p.items) == 0 {
		return ""
	}
	start, end := p.viewWindow(maxItems)
	above := start
	below := len(p.items) - end
	switch {
	case above > 0 && below > 0:
		return styleHint + fmt.Sprintf("▲ %d  ▼ %d", above, below) + styleReset
	case above > 0:
		return styleHint + fmt.Sprintf("▲ %d above", above) + styleReset
	case below > 0:
		return styleHint + fmt.Sprintf("▼ %d more", below) + styleReset
	}
	return ""
}

// viewWindow returns the [start, end) slice indexes into p.items that
// are currently rendered. The cursor is always inside the window.
func (p *paletteState) viewWindow(maxItems int) (int, int) {
	start := 0
	if p.cursor >= maxItems {
		start = p.cursor - maxItems + 1
	}
	end := start + maxItems
	if end > len(p.items) {
		end = len(p.items)
	}
	return start, end
}

// renderItemRows paints the picker's item area into b. row is advanced
// past every row written (including filler rows that keep the box
// height constant).
func (p *paletteState) renderItemRows(b *strings.Builder, row *int, leftPad, width, content, maxItems int) {
	start, end := p.viewWindow(maxItems)

	for i := 0; i < maxItems; i++ {
		moveTo(b, *row, leftPad)
		if start+i >= end {
			if len(p.items) == 0 && i == 0 {
				msg := styleDim + "no matches  ·  ⌫ to widen" + styleReset
				msgVisible := visibleLen(msg)
				pad := content - 2 - msgVisible
				if pad < 0 {
					pad = 0
				}
				b.WriteString(styleBorder + "│" + styleReset + "   " + msg +
					strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
			} else {
				b.WriteString(styleBorder + "│" + styleReset + strings.Repeat(" ", width-2) +
					styleBorder + "│" + styleReset)
			}
			*row++
			continue
		}

		it := p.items[start+i]
		if it.action.kind == "header" {
			b.WriteString(renderHeaderRow(it.label, width, content))
			*row++
			continue
		}

		isSel := (start + i) == p.cursor
		avail := content - 2 // 2 cells reserved for the selection indicator

		label := it.label
		hint := it.hint
		matches := it.matches
		labelLen := utf8.RuneCountInString(label)
		hintLen := utf8.RuneCountInString(hint)

		if labelLen > avail {
			label = clipRunes(label, avail-1) + "…"
			labelLen = utf8.RuneCountInString(label)
			hint = ""
			hintLen = 0
			matches = trimMatches(matches, labelLen-1)
		} else if hintLen > 0 {
			gap := avail - labelLen - hintLen
			if gap < 3 {
				budget := avail - labelLen - 3
				if budget > 1 {
					hint = clipRunes(hint, budget-1) + "…"
					hintLen = utf8.RuneCountInString(hint)
				} else {
					hint = ""
					hintLen = 0
				}
			}
		}
		gap := avail - labelLen - hintLen
		if gap < 0 {
			gap = 0
		}

		var indicator, labelStr, hintStr string
		if isSel {
			indicator = styleAccent + "▎" + styleReset + " "
		} else {
			indicator = "  "
		}
		labelStr = styleLabel(label, matches, isSel)
		if hint != "" {
			hintStr = styleHint + hint + styleReset
		}

		b.WriteString(styleBorder + "│" + styleReset + " " + indicator + labelStr +
			strings.Repeat(" ", gap) + hintStr + " " + styleBorder + "│" + styleReset)
		*row++
	}
}

// renderHeaderRow renders a non-selectable section label like
// "── Focused ──────". The header uses dim color so it visually
// recedes from the selectable rows above and below.
func renderHeaderRow(label string, width, content int) string {
	visible := utf8.RuneCountInString(label)
	if visible > content {
		label = clipRunes(label, content)
		visible = utf8.RuneCountInString(label)
	}
	pad := content - visible
	if pad < 0 {
		pad = 0
	}
	return styleBorder + "│" + styleReset + " " + styleHint + label + styleReset +
		strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset
}

// styleLabel renders label with any rune positions in matches bolded
// in accent. When selected the un-matched portion still bolds via
// styleBold so the whole row visually pops.
func styleLabel(label string, matches []int, selected bool) string {
	base := ""
	if selected {
		base = styleBold
	}
	if len(matches) == 0 {
		if base == "" {
			return label
		}
		return base + label + styleReset
	}
	set := make(map[int]bool, len(matches))
	for _, m := range matches {
		set[m] = true
	}
	var sb strings.Builder
	if base != "" {
		sb.WriteString(base)
	}
	runeIdx := 0
	inHl := false
	for _, r := range label {
		want := set[runeIdx]
		if want && !inHl {
			sb.WriteString(styleAccent + styleBold)
			inHl = true
		} else if !want && inHl {
			sb.WriteString(styleReset)
			if base != "" {
				sb.WriteString(base)
			}
			inHl = false
		}
		sb.WriteRune(r)
		runeIdx++
	}
	sb.WriteString(styleReset)
	return sb.String()
}

// trimMatches drops match positions that no longer fall within the
// (possibly truncated) label rune count.
func trimMatches(matches []int, limit int) []int {
	if limit <= 0 {
		return nil
	}
	out := matches[:0:0]
	for _, m := range matches {
		if m < limit {
			out = append(out, m)
		}
	}
	if len(out) == 0 {
		return nil
	}
	return out
}

// renderHelpRows paints the help cheat-sheet in place of the item list
// when showHelp is active.
func (p *paletteState) renderHelpRows(b *strings.Builder, row *int, leftPad, width, content, maxItems int) {
	lines := []struct{ key, desc string }{
		{"↵", "run selected"},
		{"esc", "close palette"},
		{"↑ ↓", "navigate (also ⌃p / ⌃n)"},
		{"tab / ⇧tab", "cycle filter chip"},
		{"home / end", "jump to first / last"},
		{"alt-1..9", "quick-pick that visible row"},
		{"⌃x", "close child (on a Switch row)"},
		{"⌃u", "clear query"},
		{"sw·sp·k <q>", "macro filters (same as chips)"},
		{"⌫", "delete · widen results"},
		{"?", "this help · any key to close"},
	}
	for i := 0; i < maxItems; i++ {
		moveTo(b, *row, leftPad)
		if i >= len(lines) {
			b.WriteString(styleBorder + "│" + styleReset + strings.Repeat(" ", width-2) +
				styleBorder + "│" + styleReset)
			*row++
			continue
		}
		ln := lines[i]
		keyPart := styleAccent + ln.key + styleReset
		descPart := styleHint + ln.desc + styleReset
		visible := utf8.RuneCountInString(ln.key) + 3 + utf8.RuneCountInString(ln.desc)
		pad := content - 2 - visible
		if pad < 0 {
			pad = 0
		}
		b.WriteString(styleBorder + "│" + styleReset + "  " + keyPart + "   " + descPart +
			strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
		*row++
	}
}

// renderForm paints the "Spawn process…" two-field form. Layout
// mirrors the picker (centered rounded box) so the user feels like
// they're still inside the palette. Cursor parks at the active field
// so it blinks where the next byte will land.
func (p *paletteState) renderForm(out writeFlusher, cols, rows int) {
	if p.form == nil {
		p.form = &spawnProcessForm{}
	}
	if cols < 32 {
		cols = 32
	}
	if rows < 10 {
		rows = 10
	}
	width := cols - 8
	if width > 72 {
		width = 72
	}
	if width < 40 {
		width = cols - 2
	}
	if width < 32 {
		width = 32
	}
	leftPad := (cols - width) / 2
	if leftPad < 1 {
		leftPad = 1
	}
	content := width - 4

	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")

	row := 2
	title := "Spawn process"
	hint := "esc cancel"
	dashes := width - 3 - len(title) - 1 - 1 - len(hint) - 3
	if dashes < 2 {
		dashes = 2
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + title + styleReset + styleBorder + " " +
		strings.Repeat("─", dashes) + " " + styleHint + hint + styleReset + styleBorder + " ─╮" + styleReset)
	row++

	cmdStr := string(p.form.cmd)
	cmdLen := utf8.RuneCountInString(cmdStr)
	pad := content - 2 - cmdLen
	if pad < 0 {
		pad = 0
		cmdStr = clipRunes(cmdStr, content-2)
		cmdLen = utf8.RuneCountInString(cmdStr)
	}
	prompt := "❯"
	if p.form.field == 0 {
		prompt = styleAccent + "❯" + styleReset
	} else {
		prompt = styleDim + "❯" + styleReset
	}
	cmdRow := row
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + prompt + " " + cmdStr +
		strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++

	box := "[ ]"
	if p.form.relaunch {
		box = "[x]"
	}
	check := "  " + box + " Relaunch on exit"
	if p.form.field == 1 {
		check = styleAccent + "▎" + styleReset + " " + styleBold + box + styleReset + " Relaunch on exit"
	}
	checkLen := visibleLen(check)
	cpad := content - checkLen
	if cpad < 0 {
		cpad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + check +
		strings.Repeat(" ", cpad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++

	footer := styleHint + "↵ spawn · esc cancel · tab cycle · ⌃r relaunch · runs via sh -lc" + styleReset
	fLen := visibleLen(footer)
	fpad := content - fLen
	if fpad < 0 {
		fpad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + footer +
		strings.Repeat(" ", fpad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)

	// Park the cursor on the command line if that field is focused.
	if p.form.field == 0 {
		moveTo(&b, cmdRow, leftPad+4+cmdLen)
		b.WriteString("\x1b[?25h")
	} else {
		b.WriteString("\x1b[?25l")
	}

	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

// renderRename paints the single-field rename form. The subject (e.g.
// "scratchpad: notes.md") lives on its own dim row above the input so
// long names don't get cut off in the title bar.
func (p *paletteState) renderRename(out writeFlusher, cols, rows int) {
	if p.renameForm == nil {
		p.renameForm = &renameForm{}
	}
	if cols < 32 {
		cols = 32
	}
	if rows < 10 {
		rows = 10
	}
	width := cols - 8
	if width > 72 {
		width = 72
	}
	if width < 40 {
		width = cols - 2
	}
	if width < 32 {
		width = 32
	}
	leftPad := (cols - width) / 2
	if leftPad < 1 {
		leftPad = 1
	}
	content := width - 4

	var b strings.Builder
	b.WriteString("\x1b[?25l\x1b[H\x1b[2J\x1b[3J")

	row := 2
	title := p.renameForm.title
	if title == "" {
		title = "Rename"
	}
	hint := "esc cancel"
	titleLen := utf8.RuneCountInString(title)
	dashes := width - 3 - titleLen - 1 - 1 - len(hint) - 3
	if dashes < 2 {
		dashes = 2
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╭─ " + styleActive + title + styleReset + styleBorder + " " +
		strings.Repeat("─", dashes) + " " + styleHint + hint + styleReset + styleBorder + " ─╮" + styleReset)
	row++

	// Subject line — "scratchpad: foo.md" / "agent: codex" / "process: dev".
	subj := p.renameForm.subjectLine
	if subj != "" {
		subjLen := utf8.RuneCountInString(subj)
		if subjLen > content {
			subj = clipRunes(subj, content-1) + "…"
			subjLen = utf8.RuneCountInString(subj)
		}
		spad := content - subjLen
		if spad < 0 {
			spad = 0
		}
		moveTo(&b, row, leftPad)
		b.WriteString(styleBorder + "│" + styleReset + " " + styleHint + subj + styleReset +
			strings.Repeat(" ", spad) + " " + styleBorder + "│" + styleReset)
		row++
	}

	nameStr := string(p.renameForm.name)
	nameLen := utf8.RuneCountInString(nameStr)
	pad := content - 2 - nameLen
	if pad < 0 {
		pad = 0
		nameStr = clipRunes(nameStr, content-2)
		nameLen = utf8.RuneCountInString(nameStr)
	}
	nameRow := row
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + styleAccent + "❯" + styleReset + " " + nameStr +
		strings.Repeat(" ", pad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "├" + strings.Repeat("─", width-2) + "┤" + styleReset)
	row++

	footer := "↵ commit · esc cancel · ⌃u clear"
	fLen := utf8.RuneCountInString(footer)
	fpad := content - fLen
	if fpad < 0 {
		fpad = 0
	}
	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "│" + styleReset + " " + styleHint + footer + styleReset +
		strings.Repeat(" ", fpad) + " " + styleBorder + "│" + styleReset)
	row++

	moveTo(&b, row, leftPad)
	b.WriteString(styleBorder + "╰" + strings.Repeat("─", width-2) + "╯" + styleReset)

	moveTo(&b, nameRow, leftPad+4+nameLen)
	b.WriteString("\x1b[?25h")

	_, _ = out.Write([]byte(b.String()))
	_ = out.Flush()
}

func clipRunes(s string, n int) string {
	if n <= 0 {
		return ""
	}
	count := 0
	for i := range s {
		if count == n {
			return s[:i]
		}
		count++
	}
	return s
}

type writeFlusher interface {
	Write(p []byte) (int, error)
	Flush() error
}

type writeFlusherBase interface {
	Write(p []byte) (int, error)
}

type nopFlusher struct{ io writeFlusherBase }

func wrapWriter(w writeFlusherBase) writeFlusher { return nopFlusher{io: w} }
func (n nopFlusher) Write(p []byte) (int, error) { return n.io.Write(p) }
func (n nopFlusher) Flush() error                { return nil }

func moveTo(b *strings.Builder, row, col int) {
	fmt.Fprintf(b, "\x1b[%d;%dH", row, col)
}

func padRight(s string, width int) string {
	w := width - visibleLen(s)
	if w <= 0 {
		return s
	}
	return s + strings.Repeat(" ", w)
}

func visibleLen(s string) int {
	n := 0
	in := false
	for _, r := range s {
		if r == 0x1b {
			in = true
			continue
		}
		if in {
			if r == 'm' || r == 'H' {
				in = false
			}
			continue
		}
		n++
	}
	return n
}

func countAnsi(s string) int {
	return len(s) - visibleLen(s)
}