bubbles/textinput/textinput.go
Gabriel Nagy 588393fbf8 fix(textinput): set cursor on initial value
This reverts the code back to the logic from 4ce16e8 which fixed the
issue of the cursor not being moved when an initial value was set with
SetValue.

The fix regressed in 16053f4.
2022-07-05 09:16:19 -04:00

861 lines
20 KiB
Go

package textinput
import (
"context"
"strings"
"sync"
"time"
"unicode"
"github.com/atotto/clipboard"
tea "github.com/charmbracelet/bubbletea"
"github.com/charmbracelet/lipgloss"
rw "github.com/mattn/go-runewidth"
)
const defaultBlinkSpeed = time.Millisecond * 530
// Internal ID management for text inputs. Necessary for blink integrity when
// multiple text inputs are involved.
var (
lastID int
idMtx sync.Mutex
)
// Return the next ID we should use on the Model.
func nextID() int {
idMtx.Lock()
defer idMtx.Unlock()
lastID++
return lastID
}
// initialBlinkMsg initializes cursor blinking.
type initialBlinkMsg struct{}
// blinkMsg signals that the cursor should blink. It contains metadata that
// allows us to tell if the blink message is the one we're expecting.
type blinkMsg struct {
id int
tag int
}
// blinkCanceled is sent when a blink operation is canceled.
type blinkCanceled struct{}
// Internal messages for clipboard operations.
type pasteMsg string
type pasteErrMsg struct{ error }
// EchoMode sets the input behavior of the text input field.
type EchoMode int
const (
// EchoNormal displays text as is. This is the default behavior.
EchoNormal EchoMode = iota
// EchoPassword displays the EchoCharacter mask instead of actual
// characters. This is commonly used for password fields.
EchoPassword
// EchoNone displays nothing as characters are entered. This is commonly
// seen for password fields on the command line.
EchoNone
// EchoOnEdit.
)
// blinkCtx manages cursor blinking.
type blinkCtx struct {
ctx context.Context
cancel context.CancelFunc
}
// CursorMode describes the behavior of the cursor.
type CursorMode int
// Available cursor modes.
const (
CursorBlink CursorMode = iota
CursorStatic
CursorHide
)
// String returns a the cursor mode in a human-readable format. This method is
// provisional and for informational purposes only.
func (c CursorMode) String() string {
return [...]string{
"blink",
"static",
"hidden",
}[c]
}
// ValidateFunc is a function that returns an error if the input is invalid.
type ValidateFunc func(string) error
// Model is the Bubble Tea model for this text input element.
type Model struct {
Err error
// General settings.
Prompt string
Placeholder string
BlinkSpeed time.Duration
EchoMode EchoMode
EchoCharacter rune
// Styles. These will be applied as inline styles.
//
// For an introduction to styling with Lip Gloss see:
// https://github.com/charmbracelet/lipgloss
PromptStyle lipgloss.Style
TextStyle lipgloss.Style
BackgroundStyle lipgloss.Style
PlaceholderStyle lipgloss.Style
CursorStyle lipgloss.Style
// CharLimit is the maximum amount of characters this input element will
// accept. If 0 or less, there's no limit.
CharLimit int
// Width is the maximum number of characters that can be displayed at once.
// It essentially treats the text field like a horizontally scrolling
// viewport. If 0 or less this setting is ignored.
Width int
// The ID of this Model as it relates to other textinput Models.
id int
// The ID of the blink message we're expecting to receive.
blinkTag int
// Underlying text value.
value []rune
// focus indicates whether user input focus should be on this input
// component. When false, ignore keyboard input and hide the cursor.
focus bool
// Cursor blink state.
blink bool
// Cursor position.
pos int
// Used to emulate a viewport when width is set and the content is
// overflowing.
offset int
offsetRight int
// Used to manage cursor blink
blinkCtx *blinkCtx
// cursorMode determines the behavior of the cursor
cursorMode CursorMode
// Validate is a function that checks whether or not the text within the
// input is valid. If it is not valid, the `Err` field will be set to the
// error returned by the function. If the function is not defined, all
// input is considered valid.
Validate ValidateFunc
}
// New creates a new model with default settings.
func New() Model {
return Model{
Prompt: "> ",
BlinkSpeed: defaultBlinkSpeed,
EchoCharacter: '*',
CharLimit: 0,
PlaceholderStyle: lipgloss.NewStyle().Foreground(lipgloss.Color("240")),
id: nextID(),
value: nil,
focus: false,
blink: true,
pos: 0,
cursorMode: CursorBlink,
blinkCtx: &blinkCtx{
ctx: context.Background(),
},
}
}
// NewModel creates a new model with default settings.
//
// Deprecated. Use New instead.
var NewModel = New
// SetValue sets the value of the text input.
func (m *Model) SetValue(s string) {
if m.Validate != nil {
if err := m.Validate(s); err != nil {
m.Err = err
return
}
}
m.Err = nil
runes := []rune(s)
if m.CharLimit > 0 && len(runes) > m.CharLimit {
m.value = runes[:m.CharLimit]
} else {
m.value = runes
}
if m.pos == 0 || m.pos > len(m.value) {
m.setCursor(len(m.value))
}
m.handleOverflow()
}
// Value returns the value of the text input.
func (m Model) Value() string {
return string(m.value)
}
// Cursor returns the cursor position.
func (m Model) Cursor() int {
return m.pos
}
// Blink returns whether or not to draw the cursor.
func (m Model) Blink() bool {
return m.blink
}
// SetCursor moves the cursor to the given position. If the position is
// out of bounds the cursor will be moved to the start or end accordingly.
func (m *Model) SetCursor(pos int) {
m.setCursor(pos)
}
// setCursor moves the cursor to the given position and returns whether or not
// the cursor blink should be reset. If the position is out of bounds the
// cursor will be moved to the start or end accordingly.
func (m *Model) setCursor(pos int) bool {
m.pos = clamp(pos, 0, len(m.value))
m.handleOverflow()
// Show the cursor unless it's been explicitly hidden
m.blink = m.cursorMode == CursorHide
// Reset cursor blink if necessary
return m.cursorMode == CursorBlink
}
// CursorStart moves the cursor to the start of the input field.
func (m *Model) CursorStart() {
m.cursorStart()
}
// cursorStart moves the cursor to the start of the input field and returns
// whether or not the curosr blink should be reset.
func (m *Model) cursorStart() bool {
return m.setCursor(0)
}
// CursorEnd moves the cursor to the end of the input field.
func (m *Model) CursorEnd() {
m.cursorEnd()
}
// CursorMode returns the model's cursor mode. For available cursor modes, see
// type CursorMode.
func (m Model) CursorMode() CursorMode {
return m.cursorMode
}
// SetCursorMode sets the model's cursor mode. This method returns a command.
//
// For available cursor modes, see type CursorMode.
func (m *Model) SetCursorMode(mode CursorMode) tea.Cmd {
m.cursorMode = mode
m.blink = m.cursorMode == CursorHide || !m.focus
if mode == CursorBlink {
return Blink
}
return nil
}
// cursorEnd moves the cursor to the end of the input field and returns whether
// the cursor should blink should reset.
func (m *Model) cursorEnd() bool {
return m.setCursor(len(m.value))
}
// Focused returns the focus state on the model.
func (m Model) Focused() bool {
return m.focus
}
// Focus sets the focus state on the model. When the model is in focus it can
// receive keyboard input and the cursor will be hidden.
func (m *Model) Focus() tea.Cmd {
m.focus = true
m.blink = m.cursorMode == CursorHide // show the cursor unless we've explicitly hidden it
if m.cursorMode == CursorBlink && m.focus {
return m.blinkCmd()
}
return nil
}
// Blur removes the focus state on the model. When the model is blurred it can
// not receive keyboard input and the cursor will be hidden.
func (m *Model) Blur() {
m.focus = false
m.blink = true
}
// Reset sets the input to its default state with no input. Returns whether
// or not the cursor blink should reset.
func (m *Model) Reset() bool {
m.value = nil
return m.setCursor(0)
}
// handle a clipboard paste event, if supported. Returns whether or not the
// cursor blink should reset.
func (m *Model) handlePaste(v string) bool {
paste := []rune(v)
var availSpace int
if m.CharLimit > 0 {
availSpace = m.CharLimit - len(m.value)
}
// If the char limit's been reached cancel
if m.CharLimit > 0 && availSpace <= 0 {
return false
}
// If there's not enough space to paste the whole thing cut the pasted
// runes down so they'll fit
if m.CharLimit > 0 && availSpace < len(paste) {
paste = paste[:len(paste)-availSpace]
}
// Stuff before and after the cursor
head := m.value[:m.pos]
tailSrc := m.value[m.pos:]
tail := make([]rune, len(tailSrc))
copy(tail, tailSrc)
oldPos := m.pos
// Insert pasted runes
for _, r := range paste {
head = append(head, r)
m.pos++
if m.CharLimit > 0 {
availSpace--
if availSpace <= 0 {
break
}
}
}
// Put it all back together
value := append(head, tail...)
m.SetValue(string(value))
if m.Err != nil {
m.pos = oldPos
}
// Reset blink state if necessary and run overflow checks
return m.setCursor(m.pos)
}
// If a max width is defined, perform some logic to treat the visible area
// as a horizontally scrolling viewport.
func (m *Model) handleOverflow() {
if m.Width <= 0 || rw.StringWidth(string(m.value)) <= m.Width {
m.offset = 0
m.offsetRight = len(m.value)
return
}
// Correct right offset if we've deleted characters
m.offsetRight = min(m.offsetRight, len(m.value))
if m.pos < m.offset {
m.offset = m.pos
w := 0
i := 0
runes := m.value[m.offset:]
for i < len(runes) && w <= m.Width {
w += rw.RuneWidth(runes[i])
if w <= m.Width+1 {
i++
}
}
m.offsetRight = m.offset + i
} else if m.pos >= m.offsetRight {
m.offsetRight = m.pos
w := 0
runes := m.value[:m.offsetRight]
i := len(runes) - 1
for i > 0 && w < m.Width {
w += rw.RuneWidth(runes[i])
if w <= m.Width {
i--
}
}
m.offset = m.offsetRight - (len(runes) - 1 - i)
}
}
// deleteBeforeCursor deletes all text before the cursor. Returns whether or
// not the cursor blink should be reset.
func (m *Model) deleteBeforeCursor() bool {
m.value = m.value[m.pos:]
m.offset = 0
return m.setCursor(0)
}
// deleteAfterCursor deletes all text after the cursor. Returns whether or not
// the cursor blink should be reset. If input is masked delete everything after
// the cursor so as not to reveal word breaks in the masked input.
func (m *Model) deleteAfterCursor() bool {
m.value = m.value[:m.pos]
return m.setCursor(len(m.value))
}
// deleteWordLeft deletes the word left to the cursor. Returns whether or not
// the cursor blink should be reset.
func (m *Model) deleteWordLeft() bool {
if m.pos == 0 || len(m.value) == 0 {
return false
}
if m.EchoMode != EchoNormal {
return m.deleteBeforeCursor()
}
// Linter note: it's critical that we acquire the initial cursor position
// here prior to altering it via SetCursor() below. As such, moving this
// call into the corresponding if clause does not apply here.
oldPos := m.pos //nolint:ifshort
blink := m.setCursor(m.pos - 1)
for unicode.IsSpace(m.value[m.pos]) {
if m.pos <= 0 {
break
}
// ignore series of whitespace before cursor
blink = m.setCursor(m.pos - 1)
}
for m.pos > 0 {
if !unicode.IsSpace(m.value[m.pos]) {
blink = m.setCursor(m.pos - 1)
} else {
if m.pos > 0 {
// keep the previous space
blink = m.setCursor(m.pos + 1)
}
break
}
}
if oldPos > len(m.value) {
m.value = m.value[:m.pos]
} else {
m.value = append(m.value[:m.pos], m.value[oldPos:]...)
}
return blink
}
// deleteWordRight deletes the word right to the cursor. Returns whether or not
// the cursor blink should be reset. If input is masked delete everything after
// the cursor so as not to reveal word breaks in the masked input.
func (m *Model) deleteWordRight() bool {
if m.pos >= len(m.value) || len(m.value) == 0 {
return false
}
if m.EchoMode != EchoNormal {
return m.deleteAfterCursor()
}
oldPos := m.pos
m.setCursor(m.pos + 1)
for unicode.IsSpace(m.value[m.pos]) {
// ignore series of whitespace after cursor
m.setCursor(m.pos + 1)
if m.pos >= len(m.value) {
break
}
}
for m.pos < len(m.value) {
if !unicode.IsSpace(m.value[m.pos]) {
m.setCursor(m.pos + 1)
} else {
break
}
}
if m.pos > len(m.value) {
m.value = m.value[:oldPos]
} else {
m.value = append(m.value[:oldPos], m.value[m.pos:]...)
}
return m.setCursor(oldPos)
}
// wordLeft moves the cursor one word to the left. Returns whether or not the
// cursor blink should be reset. If input is masked, move input to the start
// so as not to reveal word breaks in the masked input.
func (m *Model) wordLeft() bool {
if m.pos == 0 || len(m.value) == 0 {
return false
}
if m.EchoMode != EchoNormal {
return m.cursorStart()
}
blink := false
i := m.pos - 1
for i >= 0 {
if unicode.IsSpace(m.value[i]) {
blink = m.setCursor(m.pos - 1)
i--
} else {
break
}
}
for i >= 0 {
if !unicode.IsSpace(m.value[i]) {
blink = m.setCursor(m.pos - 1)
i--
} else {
break
}
}
return blink
}
// wordRight moves the cursor one word to the right. Returns whether or not the
// cursor blink should be reset. If the input is masked, move input to the end
// so as not to reveal word breaks in the masked input.
func (m *Model) wordRight() bool {
if m.pos >= len(m.value) || len(m.value) == 0 {
return false
}
if m.EchoMode != EchoNormal {
return m.cursorEnd()
}
blink := false
i := m.pos
for i < len(m.value) {
if unicode.IsSpace(m.value[i]) {
blink = m.setCursor(m.pos + 1)
i++
} else {
break
}
}
for i < len(m.value) {
if !unicode.IsSpace(m.value[i]) {
blink = m.setCursor(m.pos + 1)
i++
} else {
break
}
}
return blink
}
func (m Model) echoTransform(v string) string {
switch m.EchoMode {
case EchoPassword:
return strings.Repeat(string(m.EchoCharacter), rw.StringWidth(v))
case EchoNone:
return ""
default:
return v
}
}
// Update is the Bubble Tea update loop.
func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
if !m.focus {
m.blink = true
return m, nil
}
var resetBlink bool
switch msg := msg.(type) {
case tea.KeyMsg:
switch msg.Type {
case tea.KeyBackspace: // delete character before cursor
m.Err = nil
if msg.Alt {
resetBlink = m.deleteWordLeft()
} else {
if len(m.value) > 0 {
m.value = append(m.value[:max(0, m.pos-1)], m.value[m.pos:]...)
if m.pos > 0 {
resetBlink = m.setCursor(m.pos - 1)
}
}
}
case tea.KeyLeft, tea.KeyCtrlB:
if msg.Alt { // alt+left arrow, back one word
resetBlink = m.wordLeft()
break
}
if m.pos > 0 { // left arrow, ^F, back one character
resetBlink = m.setCursor(m.pos - 1)
}
case tea.KeyRight, tea.KeyCtrlF:
if msg.Alt { // alt+right arrow, forward one word
resetBlink = m.wordRight()
break
}
if m.pos < len(m.value) { // right arrow, ^F, forward one character
resetBlink = m.setCursor(m.pos + 1)
}
case tea.KeyCtrlW: // ^W, delete word left of cursor
resetBlink = m.deleteWordLeft()
case tea.KeyHome, tea.KeyCtrlA: // ^A, go to beginning
resetBlink = m.cursorStart()
case tea.KeyDelete, tea.KeyCtrlD: // ^D, delete char under cursor
if len(m.value) > 0 && m.pos < len(m.value) {
m.value = append(m.value[:m.pos], m.value[m.pos+1:]...)
}
case tea.KeyCtrlE, tea.KeyEnd: // ^E, go to end
resetBlink = m.cursorEnd()
case tea.KeyCtrlK: // ^K, kill text after cursor
resetBlink = m.deleteAfterCursor()
case tea.KeyCtrlU: // ^U, kill text before cursor
resetBlink = m.deleteBeforeCursor()
case tea.KeyCtrlV: // ^V paste
return m, Paste
case tea.KeyRunes, tea.KeySpace: // input regular characters
if msg.Alt && len(msg.Runes) == 1 {
if msg.Runes[0] == 'd' { // alt+d, delete word right of cursor
resetBlink = m.deleteWordRight()
break
}
if msg.Runes[0] == 'b' { // alt+b, back one word
resetBlink = m.wordLeft()
break
}
if msg.Runes[0] == 'f' { // alt+f, forward one word
resetBlink = m.wordRight()
break
}
}
// Input a regular character
if m.CharLimit <= 0 || len(m.value) < m.CharLimit {
runes := msg.Runes
value := make([]rune, len(m.value))
copy(value, m.value)
value = append(value[:m.pos], append(runes, value[m.pos:]...)...)
m.SetValue(string(value))
if m.Err == nil {
resetBlink = m.setCursor(m.pos + len(runes))
}
}
}
case initialBlinkMsg:
// We accept all initialBlinkMsgs genrated by the Blink command.
if m.cursorMode != CursorBlink || !m.focus {
return m, nil
}
cmd := m.blinkCmd()
return m, cmd
case blinkMsg:
// We're choosy about whether to accept blinkMsgs so that our cursor
// only exactly when it should.
// Is this model blinkable?
if m.cursorMode != CursorBlink || !m.focus {
return m, nil
}
// Were we expecting this blink message?
if msg.id != m.id || msg.tag != m.blinkTag {
return m, nil
}
var cmd tea.Cmd
if m.cursorMode == CursorBlink {
m.blink = !m.blink
cmd = m.blinkCmd()
}
return m, cmd
case blinkCanceled: // no-op
return m, nil
case pasteMsg:
resetBlink = m.handlePaste(string(msg))
case pasteErrMsg:
m.Err = msg
}
var cmd tea.Cmd
if resetBlink {
cmd = m.blinkCmd()
}
m.handleOverflow()
return m, cmd
}
// View renders the textinput in its current state.
func (m Model) View() string {
// Placeholder text
if len(m.value) == 0 && m.Placeholder != "" {
return m.placeholderView()
}
styleText := m.TextStyle.Inline(true).Render
value := m.value[m.offset:m.offsetRight]
pos := max(0, m.pos-m.offset)
v := styleText(m.echoTransform(string(value[:pos])))
if pos < len(value) {
v += m.cursorView(m.echoTransform(string(value[pos]))) // cursor and text under it
v += styleText(m.echoTransform(string(value[pos+1:]))) // text after cursor
} else {
v += m.cursorView(" ")
}
// If a max width and background color were set fill the empty spaces with
// the background color.
valWidth := rw.StringWidth(string(value))
if m.Width > 0 && valWidth <= m.Width {
padding := max(0, m.Width-valWidth)
if valWidth+padding <= m.Width && pos < len(value) {
padding++
}
v += styleText(strings.Repeat(" ", padding))
}
return m.PromptStyle.Render(m.Prompt) + v
}
// placeholderView returns the prompt and placeholder view, if any.
func (m Model) placeholderView() string {
var (
v string
p = m.Placeholder
style = m.PlaceholderStyle.Inline(true).Render
)
// Cursor
if m.blink {
v += m.cursorView(style(p[:1]))
} else {
v += m.cursorView(p[:1])
}
// The rest of the placeholder text
v += style(p[1:])
return m.PromptStyle.Render(m.Prompt) + v
}
// cursorView styles the cursor.
func (m Model) cursorView(v string) string {
if m.blink {
return m.TextStyle.Render(v)
}
return m.CursorStyle.Inline(true).Reverse(true).Render(v)
}
// blinkCmd is an internal command used to manage cursor blinking.
func (m *Model) blinkCmd() tea.Cmd {
if m.cursorMode != CursorBlink {
return nil
}
if m.blinkCtx != nil && m.blinkCtx.cancel != nil {
m.blinkCtx.cancel()
}
ctx, cancel := context.WithTimeout(m.blinkCtx.ctx, m.BlinkSpeed)
m.blinkCtx.cancel = cancel
m.blinkTag++
return func() tea.Msg {
defer cancel()
<-ctx.Done()
if ctx.Err() == context.DeadlineExceeded {
return blinkMsg{id: m.id, tag: m.blinkTag}
}
return blinkCanceled{}
}
}
// Blink is a command used to initialize cursor blinking.
func Blink() tea.Msg {
return initialBlinkMsg{}
}
// Paste is a command for pasting from the clipboard into the text input.
func Paste() tea.Msg {
str, err := clipboard.ReadAll()
if err != nil {
return pasteErrMsg{err}
}
return pasteMsg(str)
}
func clamp(v, low, high int) int {
if high < low {
low, high = high, low
}
return min(high, max(low, v))
}
func min(a, b int) int {
if a < b {
return a
}
return b
}
func max(a, b int) int {
if a > b {
return a
}
return b
}