package tview import ( "math" "regexp" "strings" "sync" "unicode/utf8" "github.com/gdamore/tcell" ) // InputField is a one-line box (three lines if there is a title) where the // user can enter text. Use SetAcceptanceFunc() to accept or reject input, // SetChangedFunc() to listen for changes, and SetMaskCharacter() to hide input // from onlookers (e.g. for password input). // // The following keys can be used for navigation and editing: // // - Left arrow: Move left by one character. // - Right arrow: Move right by one character. // - Home, Ctrl-A, Alt-a: Move to the beginning of the line. // - End, Ctrl-E, Alt-e: Move to the end of the line. // - Alt-left, Alt-b: Move left by one word. // - Alt-right, Alt-f: Move right by one word. // - Backspace: Delete the character before the cursor. // - Delete: Delete the character after the cursor. // - Ctrl-K: Delete from the cursor to the end of the line. // - Ctrl-W: Delete the last word before the cursor. // - Ctrl-U: Delete the entire line. // // See https://github.com/rivo/tview/wiki/InputField for an example. type InputField struct { *Box // The text that was entered. text string // The text to be displayed before the input area. label string // The text to be displayed in the input area when "text" is empty. placeholder string // The label color. labelColor tcell.Color // The background color of the input area. fieldBackgroundColor tcell.Color // The text color of the input area. fieldTextColor tcell.Color // The text color of the placeholder. placeholderTextColor tcell.Color // The screen width of the label area. A value of 0 means use the width of // the label text. labelWidth int // The screen width of the input area. A value of 0 means extend as much as // possible. fieldWidth int // A character to mask entered text (useful for password fields). A value of 0 // disables masking. maskCharacter rune // The cursor position as a byte index into the text string. cursorPos int // The number of bytes of the text string skipped ahead while drawing. offset int // An optional autocomplete function which receives the current text of the // input field and returns a slice of strings to be displayed in a drop-down // selection. autocomplete func(text string) []string // The List object which shows the selectable autocomplete entries. If not // nil, the list's main texts represent the current autocomplete entries. autocompleteList *List autocompleteListMutex sync.Mutex // An optional function which may reject the last character that was entered. accept func(text string, ch rune) bool // An optional function which is called when the input has changed. changed func(text string) // An optional function which is called when the user indicated that they // are done entering text. The key which was pressed is provided (tab, // shift-tab, enter, or escape). done func(tcell.Key) // A callback function set by the Form class and called when the user leaves // this form item. finished func(tcell.Key) } // NewInputField returns a new input field. func NewInputField() *InputField { return &InputField{ Box: NewBox(), labelColor: Styles.SecondaryTextColor, fieldBackgroundColor: Styles.ContrastBackgroundColor, fieldTextColor: Styles.PrimaryTextColor, placeholderTextColor: Styles.ContrastSecondaryTextColor, } } // SetText sets the current text of the input field. func (i *InputField) SetText(text string) *InputField { i.text = text i.cursorPos = len(text) if i.changed != nil { i.changed(text) } return i } // GetText returns the current text of the input field. func (i *InputField) GetText() string { return i.text } // SetLabel sets the text to be displayed before the input area. func (i *InputField) SetLabel(label string) *InputField { i.label = label return i } // GetLabel returns the text to be displayed before the input area. func (i *InputField) GetLabel() string { return i.label } // SetLabelWidth sets the screen width of the label. A value of 0 will cause the // primitive to use the width of the label string. func (i *InputField) SetLabelWidth(width int) *InputField { i.labelWidth = width return i } // SetPlaceholder sets the text to be displayed when the input text is empty. func (i *InputField) SetPlaceholder(text string) *InputField { i.placeholder = text return i } // SetLabelColor sets the color of the label. func (i *InputField) SetLabelColor(color tcell.Color) *InputField { i.labelColor = color return i } // SetFieldBackgroundColor sets the background color of the input area. func (i *InputField) SetFieldBackgroundColor(color tcell.Color) *InputField { i.fieldBackgroundColor = color return i } // SetFieldTextColor sets the text color of the input area. func (i *InputField) SetFieldTextColor(color tcell.Color) *InputField { i.fieldTextColor = color return i } // SetPlaceholderTextColor sets the text color of placeholder text. func (i *InputField) SetPlaceholderTextColor(color tcell.Color) *InputField { i.placeholderTextColor = color return i } // SetFormAttributes sets attributes shared by all form items. func (i *InputField) SetFormAttributes(labelWidth int, labelColor, bgColor, fieldTextColor, fieldBgColor tcell.Color) FormItem { i.labelWidth = labelWidth i.labelColor = labelColor i.backgroundColor = bgColor i.fieldTextColor = fieldTextColor i.fieldBackgroundColor = fieldBgColor return i } // SetFieldWidth sets the screen width of the input area. A value of 0 means // extend as much as possible. func (i *InputField) SetFieldWidth(width int) *InputField { i.fieldWidth = width return i } // GetFieldWidth returns this primitive's field width. func (i *InputField) GetFieldWidth() int { return i.fieldWidth } // SetMaskCharacter sets a character that masks user input on a screen. A value // of 0 disables masking. func (i *InputField) SetMaskCharacter(mask rune) *InputField { i.maskCharacter = mask return i } // SetAutocompleteFunc sets an autocomplete callback function which may return // strings to be selected from a drop-down based on the current text of the // input field. The drop-down appears only if len(entries) > 0. The callback is // invoked in this function and whenever the current text changes or when // Autocomplete() is called. Entries are cleared when the user selects an entry // or presses Escape. func (i *InputField) SetAutocompleteFunc(callback func(currentText string) (entries []string)) *InputField { i.autocomplete = callback i.Autocomplete() return i } // Autocomplete invokes the autocomplete callback (if there is one). If the // length of the returned autocomplete entries slice is greater than 0, the // input field will present the user with a corresponding drop-down list the // next time the input field is drawn. // // It is safe to call this function from any goroutine. Note that the input // field is not redrawn automatically unless called from the main goroutine // (e.g. in response to events). func (i *InputField) Autocomplete() *InputField { i.autocompleteListMutex.Lock() defer i.autocompleteListMutex.Unlock() if i.autocomplete == nil { return i } // Do we have any autocomplete entries? entries := i.autocomplete(i.text) if len(entries) == 0 { // No entries, no list. i.autocompleteList = nil return i } // Make a list if we have none. if i.autocompleteList == nil { i.autocompleteList = NewList() i.autocompleteList.ShowSecondaryText(false). SetMainTextColor(Styles.PrimitiveBackgroundColor). SetSelectedTextColor(Styles.PrimitiveBackgroundColor). SetSelectedBackgroundColor(Styles.PrimaryTextColor). SetHighlightFullLine(true). SetBackgroundColor(Styles.MoreContrastBackgroundColor) } // Fill it with the entries. currentEntry := -1 i.autocompleteList.Clear() for index, entry := range entries { i.autocompleteList.AddItem(entry, "", 0, nil) if currentEntry < 0 && entry == i.text { currentEntry = index } } // Set the selection if we have one. if currentEntry >= 0 { i.autocompleteList.SetCurrentItem(currentEntry) } return i } // SetAcceptanceFunc sets a handler which may reject the last character that was // entered (by returning false). // // This package defines a number of variables prefixed with InputField which may // be used for common input (e.g. numbers, maximum text length). func (i *InputField) SetAcceptanceFunc(handler func(textToCheck string, lastChar rune) bool) *InputField { i.accept = handler return i } // SetChangedFunc sets a handler which is called whenever the text of the input // field has changed. It receives the current text (after the change). func (i *InputField) SetChangedFunc(handler func(text string)) *InputField { i.changed = handler return i } // SetDoneFunc sets a handler which is called when the user is done entering // text. The callback function is provided with the key that was pressed, which // is one of the following: // // - KeyEnter: Done entering text. // - KeyEscape: Abort text input. // - KeyTab: Move to the next field. // - KeyBacktab: Move to the previous field. func (i *InputField) SetDoneFunc(handler func(key tcell.Key)) *InputField { i.done = handler return i } // SetFinishedFunc sets a callback invoked when the user leaves this form item. func (i *InputField) SetFinishedFunc(handler func(key tcell.Key)) FormItem { i.finished = handler return i } // Draw draws this primitive onto the screen. func (i *InputField) Draw(screen tcell.Screen) { i.Box.Draw(screen) // Prepare x, y, width, height := i.GetInnerRect() rightLimit := x + width if height < 1 || rightLimit <= x { return } // Draw label. if i.labelWidth > 0 { labelWidth := i.labelWidth if labelWidth > rightLimit-x { labelWidth = rightLimit - x } Print(screen, i.label, x, y, labelWidth, AlignLeft, i.labelColor) x += labelWidth } else { _, drawnWidth := Print(screen, i.label, x, y, rightLimit-x, AlignLeft, i.labelColor) x += drawnWidth } // Draw input area. fieldWidth := i.fieldWidth if fieldWidth == 0 { fieldWidth = math.MaxInt32 } if rightLimit-x < fieldWidth { fieldWidth = rightLimit - x } fieldStyle := tcell.StyleDefault.Background(i.fieldBackgroundColor) for index := 0; index < fieldWidth; index++ { screen.SetContent(x+index, y, ' ', nil, fieldStyle) } // Text. var cursorScreenPos int text := i.text if text == "" && i.placeholder != "" { // Draw placeholder text. Print(screen, Escape(i.placeholder), x, y, fieldWidth, AlignLeft, i.placeholderTextColor) i.offset = 0 } else { // Draw entered text. if i.maskCharacter > 0 { text = strings.Repeat(string(i.maskCharacter), utf8.RuneCountInString(i.text)) } if fieldWidth >= stringWidth(text) { // We have enough space for the full text. Print(screen, Escape(text), x, y, fieldWidth, AlignLeft, i.fieldTextColor) i.offset = 0 iterateString(text, func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { if textPos >= i.cursorPos { return true } cursorScreenPos += screenWidth return false }) } else { // The text doesn't fit. Where is the cursor? if i.cursorPos < 0 { i.cursorPos = 0 } else if i.cursorPos > len(text) { i.cursorPos = len(text) } // Shift the text so the cursor is inside the field. var shiftLeft int if i.offset > i.cursorPos { i.offset = i.cursorPos } else if subWidth := stringWidth(text[i.offset:i.cursorPos]); subWidth > fieldWidth-1 { shiftLeft = subWidth - fieldWidth + 1 } currentOffset := i.offset iterateString(text, func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { if textPos >= currentOffset { if shiftLeft > 0 { i.offset = textPos + textWidth shiftLeft -= screenWidth } else { if textPos+textWidth > i.cursorPos { return true } cursorScreenPos += screenWidth } } return false }) Print(screen, Escape(text[i.offset:]), x, y, fieldWidth, AlignLeft, i.fieldTextColor) } } // Draw autocomplete list. i.autocompleteListMutex.Lock() defer i.autocompleteListMutex.Unlock() if i.autocompleteList != nil { // How much space do we need? lheight := i.autocompleteList.GetItemCount() lwidth := 0 for index := 0; index < lheight; index++ { entry, _ := i.autocompleteList.GetItemText(index) width := TaggedStringWidth(entry) if width > lwidth { lwidth = width } } // We prefer to drop down but if there is no space, maybe drop up? lx := x ly := y + 1 _, sheight := screen.Size() if ly+lheight >= sheight && ly-2 > lheight-ly { ly = y - lheight if ly < 0 { ly = 0 } } if ly+lheight >= sheight { lheight = sheight - ly } i.autocompleteList.SetRect(lx, ly, lwidth, lheight) i.autocompleteList.Draw(screen) } // Set cursor. if i.focus.HasFocus() { screen.ShowCursor(x+cursorScreenPos, y) } } // InputHandler returns the handler for this primitive. func (i *InputField) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) { return i.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) { // Trigger changed events. currentText := i.text defer func() { if i.text != currentText { i.Autocomplete() if i.changed != nil { i.changed(i.text) } } }() // Movement functions. home := func() { i.cursorPos = 0 } end := func() { i.cursorPos = len(i.text) } moveLeft := func() { iterateStringReverse(i.text[:i.cursorPos], func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { i.cursorPos -= textWidth return true }) } moveRight := func() { iterateString(i.text[i.cursorPos:], func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { i.cursorPos += textWidth return true }) } moveWordLeft := func() { i.cursorPos = len(regexp.MustCompile(`\S+\s*$`).ReplaceAllString(i.text[:i.cursorPos], "")) } moveWordRight := func() { i.cursorPos = len(i.text) - len(regexp.MustCompile(`^\s*\S+\s*`).ReplaceAllString(i.text[i.cursorPos:], "")) } // Add character function. Returns whether or not the rune character is // accepted. add := func(r rune) bool { newText := i.text[:i.cursorPos] + string(r) + i.text[i.cursorPos:] if i.accept != nil && !i.accept(newText, r) { return false } i.text = newText i.cursorPos += len(string(r)) return true } // Finish up. finish := func(key tcell.Key) { if i.done != nil { i.done(key) } if i.finished != nil { i.finished(key) } } // Process key event. i.autocompleteListMutex.Lock() defer i.autocompleteListMutex.Unlock() switch key := event.Key(); key { case tcell.KeyRune: // Regular character. if event.Modifiers()&tcell.ModAlt > 0 { // We accept some Alt- key combinations. switch event.Rune() { case 'a': // Home. home() case 'e': // End. end() case 'b': // Move word left. moveWordLeft() case 'f': // Move word right. moveWordRight() default: if !add(event.Rune()) { return } } } else { // Other keys are simply accepted as regular characters. if !add(event.Rune()) { return } } case tcell.KeyCtrlU: // Delete all. i.text = "" i.cursorPos = 0 case tcell.KeyCtrlK: // Delete until the end of the line. i.text = i.text[:i.cursorPos] case tcell.KeyCtrlW: // Delete last word. lastWord := regexp.MustCompile(`\S+\s*$`) newText := lastWord.ReplaceAllString(i.text[:i.cursorPos], "") + i.text[i.cursorPos:] i.cursorPos -= len(i.text) - len(newText) i.text = newText case tcell.KeyBackspace, tcell.KeyBackspace2: // Delete character before the cursor. iterateStringReverse(i.text[:i.cursorPos], func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { i.text = i.text[:textPos] + i.text[textPos+textWidth:] i.cursorPos -= textWidth return true }) if i.offset >= i.cursorPos { i.offset = 0 } case tcell.KeyDelete: // Delete character after the cursor. iterateString(i.text[i.cursorPos:], func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { i.text = i.text[:i.cursorPos] + i.text[i.cursorPos+textWidth:] return true }) case tcell.KeyLeft: if event.Modifiers()&tcell.ModAlt > 0 { moveWordLeft() } else { moveLeft() } case tcell.KeyRight: if event.Modifiers()&tcell.ModAlt > 0 { moveWordRight() } else { moveRight() } case tcell.KeyHome, tcell.KeyCtrlA: home() case tcell.KeyEnd, tcell.KeyCtrlE: end() case tcell.KeyEnter, tcell.KeyEscape: // We might be done. if i.autocompleteList != nil { i.autocompleteList = nil } else { finish(key) } case tcell.KeyDown, tcell.KeyTab: // Autocomplete selection. if i.autocompleteList != nil { count := i.autocompleteList.GetItemCount() newEntry := i.autocompleteList.GetCurrentItem() + 1 if newEntry >= count { newEntry = 0 } i.autocompleteList.SetCurrentItem(newEntry) currentText, _ = i.autocompleteList.GetItemText(newEntry) // Don't trigger changed function twice. i.SetText(currentText) } else { finish(key) } case tcell.KeyUp, tcell.KeyBacktab: // Autocomplete selection. if i.autocompleteList != nil { newEntry := i.autocompleteList.GetCurrentItem() - 1 if newEntry < 0 { newEntry = i.autocompleteList.GetItemCount() - 1 } i.autocompleteList.SetCurrentItem(newEntry) currentText, _ = i.autocompleteList.GetItemText(newEntry) // Don't trigger changed function twice. i.SetText(currentText) } else { finish(key) } } }) }