fzf/src/options.go

package fzf

import (
	"fmt"
	"os"
	"regexp"
	"strconv"
	"strings"
	"unicode"

	"github.com/junegunn/fzf/src/algo"
	"github.com/junegunn/fzf/src/tui"

	"github.com/mattn/go-runewidth"
	"github.com/mattn/go-shellwords"
)

const usage = `usage: fzf [options]

  Search
    -x, --extended         Extended-search mode
                           (enabled by default; +x or --no-extended to disable)
    -e, --exact            Enable Exact-match
    -i                     Case-insensitive match (default: smart-case match)
    +i                     Case-sensitive match
    --scheme=SCHEME        Scoring scheme [default|path|history]
    --literal              Do not normalize latin script letters before matching
    -n, --nth=N[,..]       Comma-separated list of field index expressions
                           for limiting search scope. Each can be a non-zero
                           integer or a range expression ([BEGIN]..[END]).
    --with-nth=N[,..]      Transform the presentation of each line using
                           field index expressions
    -d, --delimiter=STR    Field delimiter regex (default: AWK-style)
    +s, --no-sort          Do not sort the result
    --tac                  Reverse the order of the input
    --disabled             Do not perform search
    --tiebreak=CRI[,..]    Comma-separated list of sort criteria to apply
                           when the scores are tied [length|chunk|begin|end|index]
                           (default: length)

  Interface
    -m, --multi[=MAX]      Enable multi-select with tab/shift-tab
    --no-mouse             Disable mouse
    --bind=KEYBINDS        Custom key bindings. Refer to the man page.
    --cycle                Enable cyclic scroll
    --keep-right           Keep the right end of the line visible on overflow
    --scroll-off=LINES     Number of screen lines to keep above or below when
                           scrolling to the top or to the bottom (default: 0)
    --no-hscroll           Disable horizontal scroll
    --hscroll-off=COLS     Number of screen columns to keep to the right of the
                           highlighted substring (default: 10)
    --filepath-word        Make word-wise movements respect path separators
    --jump-labels=CHARS    Label characters for jump and jump-accept

  Layout
    --height=[~]HEIGHT[%]  Display fzf window below the cursor with the given
                           height instead of using fullscreen.
                           If prefixed with '~', fzf will determine the height
                           according to the input size.
    --min-height=HEIGHT    Minimum height when --height is given in percent
                           (default: 10)
    --layout=LAYOUT        Choose layout: [default|reverse|reverse-list]
    --border[=STYLE]       Draw border around the finder
                           [rounded|sharp|horizontal|vertical|
                            top|bottom|left|right|none] (default: rounded)
    --border-label=LABEL   Label to print on the border
    --border-label-pos=COL Position of the border label
                           [POSITIVE_INTEGER: columns from left|
                            NEGATIVE_INTEGER: columns from right][:bottom]
                           (default: 0 or center)
    --margin=MARGIN        Screen margin (TRBL | TB,RL | T,RL,B | T,R,B,L)
    --padding=PADDING      Padding inside border (TRBL | TB,RL | T,RL,B | T,R,B,L)
    --info=STYLE           Finder info style [default|inline|hidden[:nosep]]
    --prompt=STR           Input prompt (default: '> ')
    --pointer=STR          Pointer to the current line (default: '>')
    --marker=STR           Multi-select marker (default: '>')
    --header=STR           String to print as header
    --header-lines=N       The first N lines of the input are treated as header
    --header-first         Print header before the prompt line
    --ellipsis=STR         Ellipsis to show when line is truncated (default: '..')

  Display
    --ansi                 Enable processing of ANSI color codes
    --tabstop=SPACES       Number of spaces for a tab character (default: 8)
    --color=COLSPEC        Base scheme (dark|light|16|bw) and/or custom colors
    --no-bold              Do not use bold text

  History
    --history=FILE         History file
    --history-size=N       Maximum number of history entries (default: 1000)

  Preview
    --preview=COMMAND      Command to preview highlighted line ({})
    --preview-window=OPT   Preview window layout (default: right:50%)
                           [up|down|left|right][,SIZE[%]]
                           [,[no]wrap][,[no]cycle][,[no]follow][,[no]hidden]
                           [,border-BORDER_OPT]
                           [,+SCROLL[OFFSETS][/DENOM]][,~HEADER_LINES]
                           [,default][,<SIZE_THRESHOLD(ALTERNATIVE_LAYOUT)]
    --preview-label=LABEL
    --preview-label-pos=N  Same as --border-label and --border-label-pos,
                           but for preview window

  Scripting
    -q, --query=STR        Start the finder with the given query
    -1, --select-1         Automatically select the only match
    -0, --exit-0           Exit immediately when there's no match
    -f, --filter=STR       Filter mode. Do not start interactive finder.
    --print-query          Print query as the first line
    --expect=KEYS          Comma-separated list of keys to complete fzf
    --read0                Read input delimited by ASCII NUL characters
    --print0               Print output delimited by ASCII NUL characters
    --sync                 Synchronous search for multi-staged filtering
    --version              Display version information and exit

  Environment variables
    FZF_DEFAULT_COMMAND    Default command to use when input is tty
    FZF_DEFAULT_OPTS       Default options
                           (e.g. '--layout=reverse --inline-info')

`

// Case denotes case-sensitivity of search
type Case int

// Case-sensitivities
const (
	CaseSmart Case = iota
	CaseIgnore
	CaseRespect
)

// Sort criteria
type criterion int

const (
	byScore criterion = iota
	byChunk
	byLength
	byBegin
	byEnd
)

type heightSpec struct {
	size    float64
	percent bool
	auto    bool
}

type sizeSpec struct {
	size    float64
	percent bool
}

func defaultMargin() [4]sizeSpec {
	return [4]sizeSpec{}
}

type windowPosition int

const (
	posUp windowPosition = iota
	posDown
	posLeft
	posRight
)

type layoutType int

const (
	layoutDefault layoutType = iota
	layoutReverse
	layoutReverseList
)

type infoLayout int
type infoStyle struct {
	layout    infoLayout
	separator bool
}

const (
	infoDefault infoLayout = iota
	infoInline
	infoHidden
)

type labelOpts struct {
	label  string
	column int
	bottom bool
}

type previewOpts struct {
	command     string
	position    windowPosition
	size        sizeSpec
	scroll      string
	hidden      bool
	wrap        bool
	cycle       bool
	follow      bool
	border      tui.BorderShape
	headerLines int
	threshold   int
	alternative *previewOpts
}

func parseLabelPosition(opts *labelOpts, arg string) {
	opts.column = 0
	opts.bottom = false
	for _, token := range splitRegexp.Split(strings.ToLower(arg), -1) {
		switch token {
		case "center":
			opts.column = 0
		case "bottom":
			opts.bottom = true
		case "top":
			opts.bottom = false
		default:
			opts.column = atoi(token)
		}
	}
}

func (a previewOpts) aboveOrBelow() bool {
	return a.size.size > 0 && (a.position == posUp || a.position == posDown)
}

func (a previewOpts) sameLayout(b previewOpts) bool {
	return a.size == b.size && a.position == b.position && a.border == b.border && a.hidden == b.hidden && a.threshold == b.threshold &&
		(a.alternative != nil && b.alternative != nil && a.alternative.sameLayout(*b.alternative) ||
			a.alternative == nil && b.alternative == nil)
}

func (a previewOpts) sameContentLayout(b previewOpts) bool {
	return a.wrap == b.wrap && a.headerLines == b.headerLines
}

// Options stores the values of command-line options
type Options struct {
	Fuzzy        bool
	FuzzyAlgo    algo.Algo
	Scheme       string
	Extended     bool
	Phony        bool
	Case         Case
	Normalize    bool
	Nth          []Range
	WithNth      []Range
	Delimiter    Delimiter
	Sort         int
	Tac          bool
	Criteria     []criterion
	Multi        int
	Ansi         bool
	Mouse        bool
	Theme        *tui.ColorTheme
	Black        bool
	Bold         bool
	Height       heightSpec
	MinHeight    int
	Layout       layoutType
	Cycle        bool
	KeepRight    bool
	Hscroll      bool
	HscrollOff   int
	ScrollOff    int
	FileWord     bool
	InfoStyle    infoStyle
	JumpLabels   string
	Prompt       string
	Pointer      string
	Marker       string
	Query        string
	Select1      bool
	Exit0        bool
	Filter       *string
	ToggleSort   bool
	Expect       map[tui.Event]string
	Keymap       map[tui.Event][]*action
	Preview      previewOpts
	PrintQuery   bool
	ReadZero     bool
	Printer      func(string)
	PrintSep     string
	Sync         bool
	History      *History
	Header       []string
	HeaderLines  int
	HeaderFirst  bool
	Ellipsis     string
	Margin       [4]sizeSpec
	Padding      [4]sizeSpec
	BorderShape  tui.BorderShape
	BorderLabel  labelOpts
	PreviewLabel labelOpts
	Unicode      bool
	Tabstop      int
	ClearOnExit  bool
	Version      bool
}

func defaultPreviewOpts(command string) previewOpts {
	return previewOpts{command, posRight, sizeSpec{50, true}, "", false, false, false, false, tui.BorderRounded, 0, 0, nil}
}

func defaultOptions() *Options {
	return &Options{
		Fuzzy:        true,
		FuzzyAlgo:    algo.FuzzyMatchV2,
		Scheme:       "default",
		Extended:     true,
		Phony:        false,
		Case:         CaseSmart,
		Normalize:    true,
		Nth:          make([]Range, 0),
		WithNth:      make([]Range, 0),
		Delimiter:    Delimiter{},
		Sort:         1000,
		Tac:          false,
		Criteria:     []criterion{byScore, byLength},
		Multi:        0,
		Ansi:         false,
		Mouse:        true,
		Theme:        tui.EmptyTheme(),
		Black:        false,
		Bold:         true,
		MinHeight:    10,
		Layout:       layoutDefault,
		Cycle:        false,
		KeepRight:    false,
		Hscroll:      true,
		HscrollOff:   10,
		ScrollOff:    0,
		FileWord:     false,
		InfoStyle:    infoStyle{layout: infoDefault, separator: true},
		JumpLabels:   defaultJumpLabels,
		Prompt:       "> ",
		Pointer:      ">",
		Marker:       ">",
		Query:        "",
		Select1:      false,
		Exit0:        false,
		Filter:       nil,
		ToggleSort:   false,
		Expect:       make(map[tui.Event]string),
		Keymap:       make(map[tui.Event][]*action),
		Preview:      defaultPreviewOpts(""),
		PrintQuery:   false,
		ReadZero:     false,
		Printer:      func(str string) { fmt.Println(str) },
		PrintSep:     "\n",
		Sync:         false,
		History:      nil,
		Header:       make([]string, 0),
		HeaderLines:  0,
		HeaderFirst:  false,
		Ellipsis:     "..",
		Margin:       defaultMargin(),
		Padding:      defaultMargin(),
		Unicode:      true,
		Tabstop:      8,
		BorderLabel:  labelOpts{},
		PreviewLabel: labelOpts{},
		ClearOnExit:  true,
		Version:      false}
}

func help(code int) {
	os.Stdout.WriteString(usage)
	os.Exit(code)
}

func errorExit(msg string) {
	os.Stderr.WriteString(msg + "\n")
	os.Exit(exitError)
}

func optString(arg string, prefixes ...string) (bool, string) {
	for _, prefix := range prefixes {
		if strings.HasPrefix(arg, prefix) {
			return true, arg[len(prefix):]
		}
	}
	return false, ""
}

func nextString(args []string, i *int, message string) string {
	if len(args) > *i+1 {
		*i++
	} else {
		errorExit(message)
	}
	return args[*i]
}

func optionalNextString(args []string, i *int) (bool, string) {
	if len(args) > *i+1 && !strings.HasPrefix(args[*i+1], "-") && !strings.HasPrefix(args[*i+1], "+") {
		*i++
		return true, args[*i]
	}
	return false, ""
}

func atoi(str string) int {
	num, err := strconv.Atoi(str)
	if err != nil {
		errorExit("not a valid integer: " + str)
	}
	return num
}

func atof(str string) float64 {
	num, err := strconv.ParseFloat(str, 64)
	if err != nil {
		errorExit("not a valid number: " + str)
	}
	return num
}

func nextInt(args []string, i *int, message string) int {
	if len(args) > *i+1 {
		*i++
	} else {
		errorExit(message)
	}
	return atoi(args[*i])
}

func optionalNumeric(args []string, i *int, defaultValue int) int {
	if len(args) > *i+1 {
		if strings.IndexAny(args[*i+1], "0123456789") == 0 {
			*i++
			return atoi(args[*i])
		}
	}
	return defaultValue
}

func splitNth(str string) []Range {
	if match, _ := regexp.MatchString("^[0-9,-.]+$", str); !match {
		errorExit("invalid format: " + str)
	}

	tokens := strings.Split(str, ",")
	ranges := make([]Range, len(tokens))
	for idx, s := range tokens {
		r, ok := ParseRange(&s)
		if !ok {
			errorExit("invalid format: " + str)
		}
		ranges[idx] = r
	}
	return ranges
}

func delimiterRegexp(str string) Delimiter {
	// Special handling of \t
	str = strings.Replace(str, "\\t", "\t", -1)

	// 1. Pattern does not contain any special character
	if regexp.QuoteMeta(str) == str {
		return Delimiter{str: &str}
	}

	rx, e := regexp.Compile(str)
	// 2. Pattern is not a valid regular expression
	if e != nil {
		return Delimiter{str: &str}
	}

	// 3. Pattern as regular expression. Slow.
	return Delimiter{regex: rx}
}

func isAlphabet(char uint8) bool {
	return char >= 'a' && char <= 'z'
}

func isNumeric(char uint8) bool {
	return char >= '0' && char <= '9'
}

func parseAlgo(str string) algo.Algo {
	switch str {
	case "v1":
		return algo.FuzzyMatchV1
	case "v2":
		return algo.FuzzyMatchV2
	default:
		errorExit("invalid algorithm (expected: v1 or v2)")
	}
	return algo.FuzzyMatchV2
}

func processScheme(opts *Options) {
	if !algo.Init(opts.Scheme) {
		errorExit("invalid scoring scheme (expected: default|path|history)")
	}
	if opts.Scheme == "history" {
		opts.Criteria = []criterion{byScore}
	}
}

func parseBorder(str string, optional bool) tui.BorderShape {
	switch str {
	case "rounded":
		return tui.BorderRounded
	case "sharp":
		return tui.BorderSharp
	case "bold":
		return tui.BorderBold
	case "double":
		return tui.BorderDouble
	case "horizontal":
		return tui.BorderHorizontal
	case "vertical":
		return tui.BorderVertical
	case "top":
		return tui.BorderTop
	case "bottom":
		return tui.BorderBottom
	case "left":
		return tui.BorderLeft
	case "right":
		return tui.BorderRight
	case "none":
		return tui.BorderNone
	default:
		if optional && str == "" {
			return tui.BorderRounded
		}
		errorExit("invalid border style (expected: rounded|sharp|bold|double|horizontal|vertical|top|bottom|left|right|none)")
	}
	return tui.BorderNone
}

func parseKeyChords(str string, message string) map[tui.Event]string {
	if len(str) == 0 {
		errorExit(message)
	}

	str = regexp.MustCompile("(?i)(alt-),").ReplaceAllString(str, "$1"+string([]rune{escapedComma}))
	tokens := strings.Split(str, ",")
	if str == "," || strings.HasPrefix(str, ",,") || strings.HasSuffix(str, ",,") || strings.Contains(str, ",,,") {
		tokens = append(tokens, ",")
	}

	chords := make(map[tui.Event]string)
	for _, key := range tokens {
		if len(key) == 0 {
			continue // ignore
		}
		key = strings.ReplaceAll(key, string([]rune{escapedComma}), ",")
		lkey := strings.ToLower(key)
		add := func(e tui.EventType) {
			chords[e.AsEvent()] = key
		}
		switch lkey {
		case "up":
			add(tui.Up)
		case "down":
			add(tui.Down)
		case "left":
			add(tui.Left)
		case "right":
			add(tui.Right)
		case "enter", "return":
			add(tui.CtrlM)
		case "space":
			chords[tui.Key(' ')] = key
		case "bspace", "bs":
			add(tui.BSpace)
		case "ctrl-space":
			add(tui.CtrlSpace)
		case "ctrl-^", "ctrl-6":
			add(tui.CtrlCaret)
		case "ctrl-/", "ctrl-_":
			add(tui.CtrlSlash)
		case "ctrl-\\":
			add(tui.CtrlBackSlash)
		case "ctrl-]":
			add(tui.CtrlRightBracket)
		case "change":
			add(tui.Change)
		case "backward-eof":
			add(tui.BackwardEOF)
		case "start":
			add(tui.Start)
		case "alt-enter", "alt-return":
			chords[tui.CtrlAltKey('m')] = key
		case "alt-space":
			chords[tui.AltKey(' ')] = key
		case "alt-bs", "alt-bspace":
			add(tui.AltBS)
		case "alt-up":
			add(tui.AltUp)
		case "alt-down":
			add(tui.AltDown)
		case "alt-left":
			add(tui.AltLeft)
		case "alt-right":
			add(tui.AltRight)
		case "tab":
			add(tui.Tab)
		case "btab", "shift-tab":
			add(tui.BTab)
		case "esc":
			add(tui.ESC)
		case "del":
			add(tui.Del)
		case "home":
			add(tui.Home)
		case "end":
			add(tui.End)
		case "insert":
			add(tui.Insert)
		case "pgup", "page-up":
			add(tui.PgUp)
		case "pgdn", "page-down":
			add(tui.PgDn)
		case "alt-shift-up", "shift-alt-up":
			add(tui.AltSUp)
		case "alt-shift-down", "shift-alt-down":
			add(tui.AltSDown)
		case "alt-shift-left", "shift-alt-left":
			add(tui.AltSLeft)
		case "alt-shift-right", "shift-alt-right":
			add(tui.AltSRight)
		case "shift-up":
			add(tui.SUp)
		case "shift-down":
			add(tui.SDown)
		case "shift-left":
			add(tui.SLeft)
		case "shift-right":
			add(tui.SRight)
		case "left-click":
			add(tui.LeftClick)
		case "right-click":
			add(tui.RightClick)
		case "double-click":
			add(tui.DoubleClick)
		case "f10":
			add(tui.F10)
		case "f11":
			add(tui.F11)
		case "f12":
			add(tui.F12)
		default:
			runes := []rune(key)
			if len(key) == 10 && strings.HasPrefix(lkey, "ctrl-alt-") && isAlphabet(lkey[9]) {
				chords[tui.CtrlAltKey(rune(key[9]))] = key
			} else if len(key) == 6 && strings.HasPrefix(lkey, "ctrl-") && isAlphabet(lkey[5]) {
				add(tui.EventType(tui.CtrlA.Int() + int(lkey[5]) - 'a'))
			} else if len(runes) == 5 && strings.HasPrefix(lkey, "alt-") {
				r := runes[4]
				switch r {
				case escapedColon:
					r = ':'
				case escapedComma:
					r = ','
				case escapedPlus:
					r = '+'
				}
				chords[tui.AltKey(r)] = key
			} else if len(key) == 2 && strings.HasPrefix(lkey, "f") && key[1] >= '1' && key[1] <= '9' {
				add(tui.EventType(tui.F1.Int() + int(key[1]) - '1'))
			} else if len(runes) == 1 {
				chords[tui.Key(runes[0])] = key
			} else {
				errorExit("unsupported key: " + key)
			}
		}
	}
	return chords
}

func parseTiebreak(str string) []criterion {
	criteria := []criterion{byScore}
	hasIndex := false
	hasChunk := false
	hasLength := false
	hasBegin := false
	hasEnd := false
	check := func(notExpected *bool, name string) {
		if *notExpected {
			errorExit("duplicate sort criteria: " + name)
		}
		if hasIndex {
			errorExit("index should be the last criterion")
		}
		*notExpected = true
	}
	for _, str := range strings.Split(strings.ToLower(str), ",") {
		switch str {
		case "index":
			check(&hasIndex, "index")
		case "chunk":
			check(&hasChunk, "chunk")
			criteria = append(criteria, byChunk)
		case "length":
			check(&hasLength, "length")
			criteria = append(criteria, byLength)
		case "begin":
			check(&hasBegin, "begin")
			criteria = append(criteria, byBegin)
		case "end":
			check(&hasEnd, "end")
			criteria = append(criteria, byEnd)
		default:
			errorExit("invalid sort criterion: " + str)
		}
	}
	if len(criteria) > 4 {
		errorExit("at most 3 tiebreaks are allowed: " + str)
	}
	return criteria
}

func dupeTheme(theme *tui.ColorTheme) *tui.ColorTheme {
	dupe := *theme
	return &dupe
}

func parseTheme(defaultTheme *tui.ColorTheme, str string) *tui.ColorTheme {
	theme := dupeTheme(defaultTheme)
	rrggbb := regexp.MustCompile("^#[0-9a-fA-F]{6}$")
	for _, str := range strings.Split(strings.ToLower(str), ",") {
		switch str {
		case "dark":
			theme = dupeTheme(tui.Dark256)
		case "light":
			theme = dupeTheme(tui.Light256)
		case "16":
			theme = dupeTheme(tui.Default16)
		case "bw", "no":
			theme = tui.NoColorTheme()
		default:
			fail := func() {
				errorExit("invalid color specification: " + str)
			}
			// Color is disabled
			if theme == nil {
				continue
			}

			components := strings.Split(str, ":")
			if len(components) < 2 {
				fail()
			}

			mergeAttr := func(cattr *tui.ColorAttr) {
				for _, component := range components[1:] {
					switch component {
					case "regular":
						cattr.Attr = tui.AttrRegular
					case "bold", "strong":
						cattr.Attr |= tui.Bold
					case "dim":
						cattr.Attr |= tui.Dim
					case "italic":
						cattr.Attr |= tui.Italic
					case "underline":
						cattr.Attr |= tui.Underline
					case "blink":
						cattr.Attr |= tui.Blink
					case "reverse":
						cattr.Attr |= tui.Reverse
					case "strikethrough":
						cattr.Attr |= tui.StrikeThrough
					case "black":
						cattr.Color = tui.Color(0)
					case "red":
						cattr.Color = tui.Color(1)
					case "green":
						cattr.Color = tui.Color(2)
					case "yellow":
						cattr.Color = tui.Color(3)
					case "blue":
						cattr.Color = tui.Color(4)
					case "magenta":
						cattr.Color = tui.Color(5)
					case "cyan":
						cattr.Color = tui.Color(6)
					case "white":
						cattr.Color = tui.Color(7)
					case "bright-black", "gray", "grey":
						cattr.Color = tui.Color(8)
					case "bright-red":
						cattr.Color = tui.Color(9)
					case "bright-green":
						cattr.Color = tui.Color(10)
					case "bright-yellow":
						cattr.Color = tui.Color(11)
					case "bright-blue":
						cattr.Color = tui.Color(12)
					case "bright-magenta":
						cattr.Color = tui.Color(13)
					case "bright-cyan":
						cattr.Color = tui.Color(14)
					case "bright-white":
						cattr.Color = tui.Color(15)
					case "":
					default:
						if rrggbb.MatchString(component) {
							cattr.Color = tui.HexToColor(component)
						} else {
							ansi32, err := strconv.Atoi(component)
							if err != nil || ansi32 < -1 || ansi32 > 255 {
								fail()
							}
							cattr.Color = tui.Color(ansi32)
						}
					}
				}
			}
			switch components[0] {
			case "query", "input":
				mergeAttr(&theme.Input)
			case "disabled":
				mergeAttr(&theme.Disabled)
			case "fg":
				mergeAttr(&theme.Fg)
			case "bg":
				mergeAttr(&theme.Bg)
			case "preview-fg":
				mergeAttr(&theme.PreviewFg)
			case "preview-bg":
				mergeAttr(&theme.PreviewBg)
			case "fg+":
				mergeAttr(&theme.Current)
			case "bg+":
				mergeAttr(&theme.DarkBg)
			case "gutter":
				mergeAttr(&theme.Gutter)
			case "hl":
				mergeAttr(&theme.Match)
			case "hl+":
				mergeAttr(&theme.CurrentMatch)
			case "border":
				mergeAttr(&theme.Border)
			case "separator":
				mergeAttr(&theme.Separator)
			case "label":
				mergeAttr(&theme.BorderLabel)
			case "prompt":
				mergeAttr(&theme.Prompt)
			case "spinner":
				mergeAttr(&theme.Spinner)
			case "info":
				mergeAttr(&theme.Info)
			case "pointer":
				mergeAttr(&theme.Cursor)
			case "marker":
				mergeAttr(&theme.Selected)
			case "header":
				mergeAttr(&theme.Header)
			default:
				fail()
			}
		}
	}
	return theme
}

var (
	executeRegexp *regexp.Regexp
	splitRegexp   *regexp.Regexp
)

func firstKey(keymap map[tui.Event]string) tui.Event {
	for k := range keymap {
		return k
	}
	return tui.EventType(0).AsEvent()
}

const (
	escapedColon = 0
	escapedComma = 1
	escapedPlus  = 2
)

func init() {
	// Backreferences are not supported.
	// "~!@#$%^&*;/|".each_char.map { |c| Regexp.escape(c) }.map { |c| "#{c}[^#{c}]*#{c}" }.join('|')
	executeRegexp = regexp.MustCompile(
		`(?si)[:+](execute(?:-multi|-silent)?|reload|preview|change-prompt|change-preview-window|change-preview|(?:re|un)bind):.+|[:+](execute(?:-multi|-silent)?|reload|preview|change-prompt|change-preview-window|change-preview|(?:re|un)bind)(\([^)]*\)|\[[^\]]*\]|~[^~]*~|![^!]*!|@[^@]*@|\#[^\#]*\#|\$[^\$]*\$|%[^%]*%|\^[^\^]*\^|&[^&]*&|\*[^\*]*\*|;[^;]*;|/[^/]*/|\|[^\|]*\|)`)
	splitRegexp = regexp.MustCompile("[,:]+")
}

func parseKeymap(keymap map[tui.Event][]*action, str string) {
	masked := executeRegexp.ReplaceAllStringFunc(str, func(src string) string {
		symbol := ":"
		if strings.HasPrefix(src, "+") {
			symbol = "+"
		}
		prefix := symbol + "execute"
		if strings.HasPrefix(src[1:], "reload") {
			prefix = symbol + "reload"
		} else if strings.HasPrefix(src[1:], "change-preview-window") {
			prefix = symbol + "change-preview-window"
		} else if strings.HasPrefix(src[1:], "change-preview") {
			prefix = symbol + "change-preview"
		} else if strings.HasPrefix(src[1:], "preview") {
			prefix = symbol + "preview"
		} else if strings.HasPrefix(src[1:], "unbind") {
			prefix = symbol + "unbind"
		} else if strings.HasPrefix(src[1:], "rebind") {
			prefix = symbol + "rebind"
		} else if strings.HasPrefix(src[1:], "change-prompt") {
			prefix = symbol + "change-prompt"
		} else if src[len(prefix)] == '-' {
			c := src[len(prefix)+1]
			if c == 's' || c == 'S' {
				prefix += "-silent"
			} else {
				prefix += "-multi"
			}
		}
		return prefix + "(" + strings.Repeat(" ", len(src)-len(prefix)-2) + ")"
	})
	masked = strings.Replace(masked, "::", string([]rune{escapedColon, ':'}), -1)
	masked = strings.Replace(masked, ",:", string([]rune{escapedComma, ':'}), -1)
	masked = strings.Replace(masked, "+:", string([]rune{escapedPlus, ':'}), -1)

	idx := 0
	for _, pairStr := range strings.Split(masked, ",") {
		origPairStr := str[idx : idx+len(pairStr)]
		idx += len(pairStr) + 1

		pair := strings.SplitN(pairStr, ":", 2)
		if len(pair) < 2 {
			errorExit("bind action not specified: " + origPairStr)
		}
		var key tui.Event
		if len(pair[0]) == 1 && pair[0][0] == escapedColon {
			key = tui.Key(':')
		} else if len(pair[0]) == 1 && pair[0][0] == escapedComma {
			key = tui.Key(',')
		} else if len(pair[0]) == 1 && pair[0][0] == escapedPlus {
			key = tui.Key('+')
		} else {
			keys := parseKeyChords(pair[0], "key name required")
			key = firstKey(keys)
		}

		idx2 := len(pair[0]) + 1
		specs := strings.Split(pair[1], "+")
		actions := make([]*action, 0, len(specs))
		appendAction := func(types ...actionType) {
			actions = append(actions, toActions(types...)...)
		}
		prevSpec := ""
		for specIndex, maskedSpec := range specs {
			spec := origPairStr[idx2 : idx2+len(maskedSpec)]
			idx2 += len(maskedSpec) + 1
			spec = prevSpec + spec
			specLower := strings.ToLower(spec)
			switch specLower {
			case "ignore":
				appendAction(actIgnore)
			case "beginning-of-line":
				appendAction(actBeginningOfLine)
			case "abort":
				appendAction(actAbort)
			case "accept":
				appendAction(actAccept)
			case "accept-non-empty":
				appendAction(actAcceptNonEmpty)
			case "print-query":
				appendAction(actPrintQuery)
			case "refresh-preview":
				appendAction(actRefreshPreview)
			case "replace-query":
				appendAction(actReplaceQuery)
			case "backward-char":
				appendAction(actBackwardChar)
			case "backward-delete-char":
				appendAction(actBackwardDeleteChar)
			case "backward-delete-char/eof":
				appendAction(actBackwardDeleteCharEOF)
			case "backward-word":
				appendAction(actBackwardWord)
			case "clear-screen":
				appendAction(actClearScreen)
			case "delete-char":
				appendAction(actDeleteChar)
			case "delete-char/eof":
				appendAction(actDeleteCharEOF)
			case "deselect":
				appendAction(actDeselect)
			case "end-of-line":
				appendAction(actEndOfLine)
			case "cancel":
				appendAction(actCancel)
			case "clear-query":
				appendAction(actClearQuery)
			case "clear-selection":
				appendAction(actClearSelection)
			case "forward-char":
				appendAction(actForwardChar)
			case "forward-word":
				appendAction(actForwardWord)
			case "jump":
				appendAction(actJump)
			case "jump-accept":
				appendAction(actJumpAccept)
			case "kill-line":
				appendAction(actKillLine)
			case "kill-word":
				appendAction(actKillWord)
			case "unix-line-discard", "line-discard":
				appendAction(actUnixLineDiscard)
			case "unix-word-rubout", "word-rubout":
				appendAction(actUnixWordRubout)
			case "yank":
				appendAction(actYank)
			case "backward-kill-word":
				appendAction(actBackwardKillWord)
			case "toggle-down":
				appendAction(actToggle, actDown)
			case "toggle-up":
				appendAction(actToggle, actUp)
			case "toggle-in":
				appendAction(actToggleIn)
			case "toggle-out":
				appendAction(actToggleOut)
			case "toggle-all":
				appendAction(actToggleAll)
			case "toggle-search":
				appendAction(actToggleSearch)
			case "select":
				appendAction(actSelect)
			case "select-all":
				appendAction(actSelectAll)
			case "deselect-all":
				appendAction(actDeselectAll)
			case "close":
				appendAction(actClose)
			case "toggle":
				appendAction(actToggle)
			case "down":
				appendAction(actDown)
			case "up":
				appendAction(actUp)
			case "first", "top":
				appendAction(actFirst)
			case "last":
				appendAction(actLast)
			case "page-up":
				appendAction(actPageUp)
			case "page-down":
				appendAction(actPageDown)
			case "half-page-up":
				appendAction(actHalfPageUp)
			case "half-page-down":
				appendAction(actHalfPageDown)
			case "previous-history":
				appendAction(actPreviousHistory)
			case "next-history":
				appendAction(actNextHistory)
			case "toggle-preview":
				appendAction(actTogglePreview)
			case "toggle-preview-wrap":
				appendAction(actTogglePreviewWrap)
			case "toggle-sort":
				appendAction(actToggleSort)
			case "preview-top":
				appendAction(actPreviewTop)
			case "preview-bottom":
				appendAction(actPreviewBottom)
			case "preview-up":
				appendAction(actPreviewUp)
			case "preview-down":
				appendAction(actPreviewDown)
			case "preview-page-up":
				appendAction(actPreviewPageUp)
			case "preview-page-down":
				appendAction(actPreviewPageDown)
			case "preview-half-page-up":
				appendAction(actPreviewHalfPageUp)
			case "preview-half-page-down":
				appendAction(actPreviewHalfPageDown)
			case "enable-search":
				appendAction(actEnableSearch)
			case "disable-search":
				appendAction(actDisableSearch)
			case "put":
				if key.Type == tui.Rune && unicode.IsGraphic(key.Char) {
					appendAction(actRune)
				} else {
					errorExit("unable to put non-printable character: " + pair[0])
				}
			default:
				t := isExecuteAction(specLower)
				if t == actIgnore {
					if specIndex == 0 && specLower == "" {
						actions = append(keymap[key], actions...)
					} else {
						errorExit("unknown action: " + spec)
					}
				} else {
					var offset int
					switch t {
					case actReload:
						offset = len("reload")
					case actPreview:
						offset = len("preview")
					case actChangePreviewWindow:
						offset = len("change-preview-window")
					case actChangePreview:
						offset = len("change-preview")
					case actChangePrompt:
						offset = len("change-prompt")
					case actUnbind:
						offset = len("unbind")
					case actRebind:
						offset = len("rebind")
					case actExecuteSilent:
						offset = len("execute-silent")
					case actExecuteMulti:
						offset = len("execute-multi")
					default:
						offset = len("execute")
					}
					var actionArg string
					if spec[offset] == ':' {
						if specIndex == len(specs)-1 {
							actionArg = spec[offset+1:]
							actions = append(actions, &action{t: t, a: actionArg})
						} else {
							prevSpec = spec + "+"
							continue
						}
					} else {
						actionArg = spec[offset+1 : len(spec)-1]
						actions = append(actions, &action{t: t, a: actionArg})
					}
					if t == actUnbind || t == actRebind {
						parseKeyChords(actionArg, spec[0:offset]+" target required")
					}
				}
			}
			prevSpec = ""
		}
		keymap[key] = actions
	}
}

func isExecuteAction(str string) actionType {
	matches := executeRegexp.FindAllStringSubmatch(":"+str, -1)
	if matches == nil || len(matches) != 1 {
		return actIgnore
	}
	prefix := matches[0][1]
	if len(prefix) == 0 {
		prefix = matches[0][2]
	}
	switch prefix {
	case "reload":
		return actReload
	case "unbind":
		return actUnbind
	case "rebind":
		return actRebind
	case "preview":
		return actPreview
	case "change-preview-window":
		return actChangePreviewWindow
	case "change-preview":
		return actChangePreview
	case "change-prompt":
		return actChangePrompt
	case "execute":
		return actExecute
	case "execute-silent":
		return actExecuteSilent
	case "execute-multi":
		return actExecuteMulti
	}
	return actIgnore
}

func parseToggleSort(keymap map[tui.Event][]*action, str string) {
	keys := parseKeyChords(str, "key name required")
	if len(keys) != 1 {
		errorExit("multiple keys specified")
	}
	keymap[firstKey(keys)] = toActions(actToggleSort)
}

func strLines(str string) []string {
	return strings.Split(strings.TrimSuffix(str, "\n"), "\n")
}

func parseSize(str string, maxPercent float64, label string) sizeSpec {
	var val float64
	percent := strings.HasSuffix(str, "%")
	if percent {
		val = atof(str[:len(str)-1])
		if val < 0 {
			errorExit(label + " must be non-negative")
		}
		if val > maxPercent {
			errorExit(fmt.Sprintf("%s too large (max: %d%%)", label, int(maxPercent)))
		}
	} else {
		if strings.Contains(str, ".") {
			errorExit(label + " (without %) must be a non-negative integer")
		}

		val = float64(atoi(str))
		if val < 0 {
			errorExit(label + " must be non-negative")
		}
	}
	return sizeSpec{val, percent}
}

func parseHeight(str string) heightSpec {
	heightSpec := heightSpec{}
	if strings.HasPrefix(str, "~") {
		heightSpec.auto = true
		str = str[1:]
	}

	size := parseSize(str, 100, "height")
	heightSpec.size = size.size
	heightSpec.percent = size.percent
	return heightSpec
}

func parseLayout(str string) layoutType {
	switch str {
	case "default":
		return layoutDefault
	case "reverse":
		return layoutReverse
	case "reverse-list":
		return layoutReverseList
	default:
		errorExit("invalid layout (expected: default / reverse / reverse-list)")
	}
	return layoutDefault
}

func parseInfoStyle(str string) infoStyle {
	layout := infoDefault
	separator := true

	for _, token := range splitRegexp.Split(strings.ToLower(str), -1) {
		switch token {
		case "default":
			layout = infoDefault
		case "inline":
			layout = infoInline
		case "hidden":
			layout = infoHidden
		case "nosep":
			separator = false
		case "sep":
			separator = true
		default:
			errorExit("invalid info style (expected: default|inline|hidden[:nosep])")
		}
	}
	return infoStyle{layout: layout, separator: separator}
}

func parsePreviewWindow(opts *previewOpts, input string) {
	tokenRegex := regexp.MustCompile(`[:,]*(<([1-9][0-9]*)\(([^)<]+)\)|[^,:]+)`)
	sizeRegex := regexp.MustCompile("^[0-9]+%?$")
	offsetRegex := regexp.MustCompile(`^(\+{-?[0-9]+})?([+-][0-9]+)*(-?/[1-9][0-9]*)?$`)
	headerRegex := regexp.MustCompile("^~(0|[1-9][0-9]*)$")
	tokens := tokenRegex.FindAllStringSubmatch(input, -1)
	var alternative string
	for _, match := range tokens {
		if len(match[2]) > 0 {
			opts.threshold = atoi(match[2])
			alternative = match[3]
			continue
		}
		token := match[1]
		switch token {
		case "":
		case "default":
			*opts = defaultPreviewOpts(opts.command)
		case "hidden":
			opts.hidden = true
		case "nohidden":
			opts.hidden = false
		case "wrap":
			opts.wrap = true
		case "nowrap":
			opts.wrap = false
		case "cycle":
			opts.cycle = true
		case "nocycle":
			opts.cycle = false
		case "up", "top":
			opts.position = posUp
		case "down", "bottom":
			opts.position = posDown
		case "left":
			opts.position = posLeft
		case "right":
			opts.position = posRight
		case "rounded", "border", "border-rounded":
			opts.border = tui.BorderRounded
		case "sharp", "border-sharp":
			opts.border = tui.BorderSharp
		case "border-bold":
			opts.border = tui.BorderBold
		case "border-double":
			opts.border = tui.BorderDouble
		case "noborder", "border-none":
			opts.border = tui.BorderNone
		case "border-horizontal":
			opts.border = tui.BorderHorizontal
		case "border-vertical":
			opts.border = tui.BorderVertical
		case "border-up", "border-top":
			opts.border = tui.BorderTop
		case "border-down", "border-bottom":
			opts.border = tui.BorderBottom
		case "border-left":
			opts.border = tui.BorderLeft
		case "border-right":
			opts.border = tui.BorderRight
		case "follow":
			opts.follow = true
		case "nofollow":
			opts.follow = false
		default:
			if headerRegex.MatchString(token) {
				opts.headerLines = atoi(token[1:])
			} else if sizeRegex.MatchString(token) {
				opts.size = parseSize(token, 99, "window size")
			} else if offsetRegex.MatchString(token) {
				opts.scroll = token
			} else {
				errorExit("invalid preview window option: " + token)
			}
		}
	}
	if len(alternative) > 0 {
		alternativeOpts := *opts
		opts.alternative = &alternativeOpts
		opts.alternative.hidden = false
		opts.alternative.alternative = nil
		parsePreviewWindow(opts.alternative, alternative)
	}
}

func parseMargin(opt string, margin string) [4]sizeSpec {
	margins := strings.Split(margin, ",")
	checked := func(str string) sizeSpec {
		return parseSize(str, 49, opt)
	}
	switch len(margins) {
	case 1:
		m := checked(margins[0])
		return [4]sizeSpec{m, m, m, m}
	case 2:
		tb := checked(margins[0])
		rl := checked(margins[1])
		return [4]sizeSpec{tb, rl, tb, rl}
	case 3:
		t := checked(margins[0])
		rl := checked(margins[1])
		b := checked(margins[2])
		return [4]sizeSpec{t, rl, b, rl}
	case 4:
		return [4]sizeSpec{
			checked(margins[0]), checked(margins[1]),
			checked(margins[2]), checked(margins[3])}
	default:
		errorExit("invalid " + opt + ": " + margin)
	}
	return defaultMargin()
}

func parseOptions(opts *Options, allArgs []string) {
	var historyMax int
	if opts.History == nil {
		historyMax = defaultHistoryMax
	} else {
		historyMax = opts.History.maxSize
	}
	setHistory := func(path string) {
		h, e := NewHistory(path, historyMax)
		if e != nil {
			errorExit(e.Error())
		}
		opts.History = h
	}
	setHistoryMax := func(max int) {
		historyMax = max
		if historyMax < 1 {
			errorExit("history max must be a positive integer")
		}
		if opts.History != nil {
			opts.History.maxSize = historyMax
		}
	}
	validateJumpLabels := false
	validatePointer := false
	validateMarker := false
	for i := 0; i < len(allArgs); i++ {
		arg := allArgs[i]
		switch arg {
		case "-h", "--help":
			help(exitOk)
		case "-x", "--extended":
			opts.Extended = true
		case "-e", "--exact":
			opts.Fuzzy = false
		case "--extended-exact":
			// Note that we now don't have --no-extended-exact
			opts.Fuzzy = false
			opts.Extended = true
		case "+x", "--no-extended":
			opts.Extended = false
		case "+e", "--no-exact":
			opts.Fuzzy = true
		case "-q", "--query":
			opts.Query = nextString(allArgs, &i, "query string required")
		case "-f", "--filter":
			filter := nextString(allArgs, &i, "query string required")
			opts.Filter = &filter
		case "--literal":
			opts.Normalize = false
		case "--no-literal":
			opts.Normalize = true
		case "--algo":
			opts.FuzzyAlgo = parseAlgo(nextString(allArgs, &i, "algorithm required (v1|v2)"))
		case "--scheme":
			opts.Scheme = strings.ToLower(nextString(allArgs, &i, "scoring scheme required (default|path|history)"))
		case "--expect":
			for k, v := range parseKeyChords(nextString(allArgs, &i, "key names required"), "key names required") {
				opts.Expect[k] = v
			}
		case "--no-expect":
			opts.Expect = make(map[tui.Event]string)
		case "--enabled", "--no-phony":
			opts.Phony = false
		case "--disabled", "--phony":
			opts.Phony = true
		case "--tiebreak":
			opts.Criteria = parseTiebreak(nextString(allArgs, &i, "sort criterion required"))
		case "--bind":
			parseKeymap(opts.Keymap, nextString(allArgs, &i, "bind expression required"))
		case "--color":
			_, spec := optionalNextString(allArgs, &i)
			if len(spec) == 0 {
				opts.Theme = tui.EmptyTheme()
			} else {
				opts.Theme = parseTheme(opts.Theme, spec)
			}
		case "--toggle-sort":
			parseToggleSort(opts.Keymap, nextString(allArgs, &i, "key name required"))
		case "-d", "--delimiter":
			opts.Delimiter = delimiterRegexp(nextString(allArgs, &i, "delimiter required"))
		case "-n", "--nth":
			opts.Nth = splitNth(nextString(allArgs, &i, "nth expression required"))
		case "--with-nth":
			opts.WithNth = splitNth(nextString(allArgs, &i, "nth expression required"))
		case "-s", "--sort":
			opts.Sort = optionalNumeric(allArgs, &i, 1)
		case "+s", "--no-sort":
			opts.Sort = 0
		case "--tac":
			opts.Tac = true
		case "--no-tac":
			opts.Tac = false
		case "-i":
			opts.Case = CaseIgnore
		case "+i":
			opts.Case = CaseRespect
		case "-m", "--multi":
			opts.Multi = optionalNumeric(allArgs, &i, maxMulti)
		case "+m", "--no-multi":
			opts.Multi = 0
		case "--ansi":
			opts.Ansi = true
		case "--no-ansi":
			opts.Ansi = false
		case "--no-mouse":
			opts.Mouse = false
		case "+c", "--no-color":
			opts.Theme = tui.NoColorTheme()
		case "+2", "--no-256":
			opts.Theme = tui.Default16
		case "--black":
			opts.Black = true
		case "--no-black":
			opts.Black = false
		case "--bold":
			opts.Bold = true
		case "--no-bold":
			opts.Bold = false
		case "--layout":
			opts.Layout = parseLayout(
				nextString(allArgs, &i, "layout required (default / reverse / reverse-list)"))
		case "--reverse":
			opts.Layout = layoutReverse
		case "--no-reverse":
			opts.Layout = layoutDefault
		case "--cycle":
			opts.Cycle = true
		case "--no-cycle":
			opts.Cycle = false
		case "--keep-right":
			opts.KeepRight = true
		case "--no-keep-right":
			opts.KeepRight = false
		case "--hscroll":
			opts.Hscroll = true
		case "--no-hscroll":
			opts.Hscroll = false
		case "--hscroll-off":
			opts.HscrollOff = nextInt(allArgs, &i, "hscroll offset required")
		case "--scroll-off":
			opts.ScrollOff = nextInt(allArgs, &i, "scroll offset required")
		case "--filepath-word":
			opts.FileWord = true
		case "--no-filepath-word":
			opts.FileWord = false
		case "--info":
			opts.InfoStyle = parseInfoStyle(
				nextString(allArgs, &i, "info style required"))
		case "--no-info":
			opts.InfoStyle.layout = infoHidden
		case "--inline-info":
			opts.InfoStyle.layout = infoInline
		case "--no-inline-info":
			opts.InfoStyle.layout = infoDefault
		case "--jump-labels":
			opts.JumpLabels = nextString(allArgs, &i, "label characters required")
			validateJumpLabels = true
		case "-1", "--select-1":
			opts.Select1 = true
		case "+1", "--no-select-1":
			opts.Select1 = false
		case "-0", "--exit-0":
			opts.Exit0 = true
		case "+0", "--no-exit-0":
			opts.Exit0 = false
		case "--read0":
			opts.ReadZero = true
		case "--no-read0":
			opts.ReadZero = false
		case "--print0":
			opts.Printer = func(str string) { fmt.Print(str, "\x00") }
			opts.PrintSep = "\x00"
		case "--no-print0":
			opts.Printer = func(str string) { fmt.Println(str) }
			opts.PrintSep = "\n"
		case "--print-query":
			opts.PrintQuery = true
		case "--no-print-query":
			opts.PrintQuery = false
		case "--prompt":
			opts.Prompt = nextString(allArgs, &i, "prompt string required")
		case "--pointer":
			opts.Pointer = nextString(allArgs, &i, "pointer sign string required")
			validatePointer = true
		case "--marker":
			opts.Marker = nextString(allArgs, &i, "selected sign string required")
			validateMarker = true
		case "--sync":
			opts.Sync = true
		case "--no-sync":
			opts.Sync = false
		case "--async":
			opts.Sync = false
		case "--no-history":
			opts.History = nil
		case "--history":
			setHistory(nextString(allArgs, &i, "history file path required"))
		case "--history-size":
			setHistoryMax(nextInt(allArgs, &i, "history max size required"))
		case "--no-header":
			opts.Header = []string{}
		case "--no-header-lines":
			opts.HeaderLines = 0
		case "--header":
			opts.Header = strLines(nextString(allArgs, &i, "header string required"))
		case "--header-lines":
			opts.HeaderLines = atoi(
				nextString(allArgs, &i, "number of header lines required"))
		case "--header-first":
			opts.HeaderFirst = true
		case "--no-header-first":
			opts.HeaderFirst = false
		case "--ellipsis":
			opts.Ellipsis = nextString(allArgs, &i, "ellipsis string required")
		case "--preview":
			opts.Preview.command = nextString(allArgs, &i, "preview command required")
		case "--no-preview":
			opts.Preview.command = ""
		case "--preview-window":
			parsePreviewWindow(&opts.Preview,
				nextString(allArgs, &i, "preview window layout required: [up|down|left|right][,SIZE[%]][,border-BORDER_OPT][,wrap][,cycle][,hidden][,+SCROLL[OFFSETS][/DENOM]][,~HEADER_LINES][,default]"))
		case "--height":
			opts.Height = parseHeight(nextString(allArgs, &i, "height required: [~]HEIGHT[%]"))
		case "--min-height":
			opts.MinHeight = nextInt(allArgs, &i, "height required: HEIGHT")
		case "--no-height":
			opts.Height = heightSpec{}
		case "--no-margin":
			opts.Margin = defaultMargin()
		case "--no-padding":
			opts.Padding = defaultMargin()
		case "--no-border":
			opts.BorderShape = tui.BorderNone
		case "--border":
			hasArg, arg := optionalNextString(allArgs, &i)
			opts.BorderShape = parseBorder(arg, !hasArg)
		case "--no-border-label":
			opts.BorderLabel.label = ""
		case "--border-label":
			opts.BorderLabel.label = nextString(allArgs, &i, "label required")
		case "--border-label-pos":
			pos := nextString(allArgs, &i, "label position required (positive or negative integer or 'center')")
			parseLabelPosition(&opts.BorderLabel, pos)
		case "--no-preview-label":
			opts.PreviewLabel.label = ""
		case "--preview-label":
			opts.PreviewLabel.label = nextString(allArgs, &i, "preview label required")
		case "--preview-label-pos":
			pos := nextString(allArgs, &i, "preview label position required (positive or negative integer or 'center')")
			parseLabelPosition(&opts.PreviewLabel, pos)
		case "--no-unicode":
			opts.Unicode = false
		case "--unicode":
			opts.Unicode = true
		case "--margin":
			opts.Margin = parseMargin(
				"margin",
				nextString(allArgs, &i, "margin required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
		case "--padding":
			opts.Padding = parseMargin(
				"padding",
				nextString(allArgs, &i, "padding required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
		case "--tabstop":
			opts.Tabstop = nextInt(allArgs, &i, "tab stop required")
		case "--clear":
			opts.ClearOnExit = true
		case "--no-clear":
			opts.ClearOnExit = false
		case "--version":
			opts.Version = true
		case "--":
			// Ignored
		default:
			if match, value := optString(arg, "--algo="); match {
				opts.FuzzyAlgo = parseAlgo(value)
			} else if match, value := optString(arg, "--scheme="); match {
				opts.Scheme = strings.ToLower(value)
			} else if match, value := optString(arg, "-q", "--query="); match {
				opts.Query = value
			} else if match, value := optString(arg, "-f", "--filter="); match {
				opts.Filter = &value
			} else if match, value := optString(arg, "-d", "--delimiter="); match {
				opts.Delimiter = delimiterRegexp(value)
			} else if match, value := optString(arg, "--border="); match {
				opts.BorderShape = parseBorder(value, false)
			} else if match, value := optString(arg, "--border-label="); match {
				opts.BorderLabel.label = value
			} else if match, value := optString(arg, "--border-label-pos="); match {
				parseLabelPosition(&opts.BorderLabel, value)
			} else if match, value := optString(arg, "--preview-label="); match {
				opts.PreviewLabel.label = value
			} else if match, value := optString(arg, "--preview-label-pos="); match {
				parseLabelPosition(&opts.PreviewLabel, value)
			} else if match, value := optString(arg, "--prompt="); match {
				opts.Prompt = value
			} else if match, value := optString(arg, "--pointer="); match {
				opts.Pointer = value
				validatePointer = true
			} else if match, value := optString(arg, "--marker="); match {
				opts.Marker = value
				validateMarker = true
			} else if match, value := optString(arg, "-n", "--nth="); match {
				opts.Nth = splitNth(value)
			} else if match, value := optString(arg, "--with-nth="); match {
				opts.WithNth = splitNth(value)
			} else if match, _ := optString(arg, "-s", "--sort="); match {
				opts.Sort = 1 // Don't care
			} else if match, value := optString(arg, "-m", "--multi="); match {
				opts.Multi = atoi(value)
			} else if match, value := optString(arg, "--height="); match {
				opts.Height = parseHeight(value)
			} else if match, value := optString(arg, "--min-height="); match {
				opts.MinHeight = atoi(value)
			} else if match, value := optString(arg, "--layout="); match {
				opts.Layout = parseLayout(value)
			} else if match, value := optString(arg, "--info="); match {
				opts.InfoStyle = parseInfoStyle(value)
			} else if match, value := optString(arg, "--toggle-sort="); match {
				parseToggleSort(opts.Keymap, value)
			} else if match, value := optString(arg, "--expect="); match {
				for k, v := range parseKeyChords(value, "key names required") {
					opts.Expect[k] = v
				}
			} else if match, value := optString(arg, "--tiebreak="); match {
				opts.Criteria = parseTiebreak(value)
			} else if match, value := optString(arg, "--color="); match {
				opts.Theme = parseTheme(opts.Theme, value)
			} else if match, value := optString(arg, "--bind="); match {
				parseKeymap(opts.Keymap, value)
			} else if match, value := optString(arg, "--history="); match {
				setHistory(value)
			} else if match, value := optString(arg, "--history-size="); match {
				setHistoryMax(atoi(value))
			} else if match, value := optString(arg, "--header="); match {
				opts.Header = strLines(value)
			} else if match, value := optString(arg, "--header-lines="); match {
				opts.HeaderLines = atoi(value)
			} else if match, value := optString(arg, "--ellipsis="); match {
				opts.Ellipsis = value
			} else if match, value := optString(arg, "--preview="); match {
				opts.Preview.command = value
			} else if match, value := optString(arg, "--preview-window="); match {
				parsePreviewWindow(&opts.Preview, value)
			} else if match, value := optString(arg, "--margin="); match {
				opts.Margin = parseMargin("margin", value)
			} else if match, value := optString(arg, "--padding="); match {
				opts.Padding = parseMargin("padding", value)
			} else if match, value := optString(arg, "--tabstop="); match {
				opts.Tabstop = atoi(value)
			} else if match, value := optString(arg, "--hscroll-off="); match {
				opts.HscrollOff = atoi(value)
			} else if match, value := optString(arg, "--scroll-off="); match {
				opts.ScrollOff = atoi(value)
			} else if match, value := optString(arg, "--jump-labels="); match {
				opts.JumpLabels = value
				validateJumpLabels = true
			} else {
				errorExit("unknown option: " + arg)
			}
		}
	}

	if opts.HeaderLines < 0 {
		errorExit("header lines must be a non-negative integer")
	}

	if opts.HscrollOff < 0 {
		errorExit("hscroll offset must be a non-negative integer")
	}

	if opts.ScrollOff < 0 {
		errorExit("scroll offset must be a non-negative integer")
	}

	if opts.Tabstop < 1 {
		errorExit("tab stop must be a positive integer")
	}

	if len(opts.JumpLabels) == 0 {
		errorExit("empty jump labels")
	}

	if validateJumpLabels {
		for _, r := range opts.JumpLabels {
			if r < 32 || r > 126 {
				errorExit("non-ascii jump labels are not allowed")
			}
		}
	}

	if validatePointer {
		if err := validateSign(opts.Pointer, "pointer"); err != nil {
			errorExit(err.Error())
		}
	}

	if validateMarker {
		if err := validateSign(opts.Marker, "marker"); err != nil {
			errorExit(err.Error())
		}
	}
}

func validateSign(sign string, signOptName string) error {
	if sign == "" {
		return fmt.Errorf("%v cannot be empty", signOptName)
	}
	if runewidth.StringWidth(sign) > 2 {
		return fmt.Errorf("%v display width should be up to 2", signOptName)
	}
	return nil
}

func postProcessOptions(opts *Options) {
	if !opts.Version && !tui.IsLightRendererSupported() && opts.Height.size > 0 {
		errorExit("--height option is currently not supported on this platform")
	}
	// Default actions for CTRL-N / CTRL-P when --history is set
	if opts.History != nil {
		if _, prs := opts.Keymap[tui.CtrlP.AsEvent()]; !prs {
			opts.Keymap[tui.CtrlP.AsEvent()] = toActions(actPreviousHistory)
		}
		if _, prs := opts.Keymap[tui.CtrlN.AsEvent()]; !prs {
			opts.Keymap[tui.CtrlN.AsEvent()] = toActions(actNextHistory)
		}
	}

	// Extend the default key map
	previewEnabled := len(opts.Preview.command) > 0 || hasPreviewAction(opts)
	keymap := defaultKeymap()
	for key, actions := range opts.Keymap {
		var lastChangePreviewWindow *action
		for _, act := range actions {
			switch act.t {
			case actToggleSort:
				// To display "+S"/"-S" on info line
				opts.ToggleSort = true
			case actChangePreviewWindow:
				lastChangePreviewWindow = act
				if !previewEnabled {
					// Doesn't matter
					continue
				}
				opts := previewOpts{}
				for _, arg := range strings.Split(act.a, "|") {
					// Make sure that each expression is valid
					parsePreviewWindow(&opts, arg)
				}
			}
		}

		// Re-organize actions so that we only keep the last change-preview-window
		// and it comes first in the list.
		//  *  change-preview-window(up,+10)+preview(sleep 3; cat {})+change-preview-window(up,+20)
		//  -> change-preview-window(up,+20)+preview(sleep 3; cat {})
		if lastChangePreviewWindow != nil {
			reordered := []*action{lastChangePreviewWindow}
			for _, act := range actions {
				if act.t != actChangePreviewWindow {
					reordered = append(reordered, act)
				}
			}
			actions = reordered
		}
		keymap[key] = actions
	}
	opts.Keymap = keymap

	if opts.Height.auto {
		for _, s := range []sizeSpec{opts.Margin[0], opts.Margin[2]} {
			if s.percent {
				errorExit("adaptive height is not compatible with top/bottom percent margin")
			}
		}
		for _, s := range []sizeSpec{opts.Padding[0], opts.Padding[2]} {
			if s.percent {
				errorExit("adaptive height is not compatible with top/bottom percent padding")
			}
		}
	}

	// If we're not using extended search mode, --nth option becomes irrelevant
	// if it contains the whole range
	if !opts.Extended || len(opts.Nth) == 1 {
		for _, r := range opts.Nth {
			if r.begin == rangeEllipsis && r.end == rangeEllipsis {
				opts.Nth = make([]Range, 0)
				return
			}
		}
	}

	if opts.Bold {
		theme := opts.Theme
		boldify := func(c tui.ColorAttr) tui.ColorAttr {
			dup := c
			if !theme.Colored {
				dup.Attr |= tui.Bold
			} else if (c.Attr & tui.AttrRegular) == 0 {
				dup.Attr |= tui.Bold
			}
			return dup
		}
		theme.Current = boldify(theme.Current)
		theme.CurrentMatch = boldify(theme.CurrentMatch)
		theme.Prompt = boldify(theme.Prompt)
		theme.Input = boldify(theme.Input)
		theme.Cursor = boldify(theme.Cursor)
		theme.Spinner = boldify(theme.Spinner)
	}

	if opts.Scheme != "default" {
		processScheme(opts)
	}
}

func expectsArbitraryString(opt string) bool {
	switch opt {
	case "-q", "--query", "-f", "--filter", "--header", "--prompt":
		return true
	}
	return false
}

// ParseOptions parses command-line options
func ParseOptions() *Options {
	opts := defaultOptions()

	for idx, arg := range os.Args[1:] {
		if arg == "--version" && (idx == 0 || idx > 0 && !expectsArbitraryString(os.Args[idx])) {
			opts.Version = true
			return opts
		}
	}

	// Options from Env var
	words, _ := shellwords.Parse(os.Getenv("FZF_DEFAULT_OPTS"))
	if len(words) > 0 {
		parseOptions(opts, words)
	}

	// Options from command-line arguments
	parseOptions(opts, os.Args[1:])

	postProcessOptions(opts)
	return opts
}