tcell-widgets/wdgt_textarea_field.go

/*
Copyright © Brian Buller <brian@bullercodeworks.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
package widgets

import (
	"fmt"
	"strings"

	wh "git.bullercodeworks.com/brian/tcell-widgets/helpers"
	"github.com/gdamore/tcell"
)

type TextAreaField struct {
	id    string
	style tcell.Style

	label string
	value string

	overwriteMode bool

	cursor    int
	visible   bool
	active    bool
	focusable bool
	x, y      int
	w, h      int

	filter   func(tcell.EventKey) bool
	onChange func(prev, curr string)

	keyMap *KeyMap
}

var _ Widget = (*TextAreaField)(nil)

func NewTextAreaField(id string, style tcell.Style) *TextAreaField {
	f := &TextAreaField{}
	f.Init(id, style)
	return f
}

func (w *TextAreaField) Init(id string, style tcell.Style) {
	w.id = id
	w.style = style
	w.visible = true
	w.filter = func(ev tcell.EventKey) bool {
		return wh.IsBS(ev) ||
			wh.KeyIsDisplayable(ev) ||
			wh.IsKey(tcell.KeyEnter)
	}
	w.keyMap = NewKeyMap(
		NewKey(BuildEK(tcell.KeyLeft), w.handleLeft),
		NewKey(BuildEK(tcell.KeyRight), w.handleRight),
		NewKey(BuildEK(tcell.KeyUp), w.handleUp),
		NewKey(BuildEK(tcell.KeyDown), w.handleDown),
		NewKey(BuildEK(tcell.KeyHome), w.handleHome),
		NewKey(BuildEK(tcell.KeyEnd), w.handleEnd),
		NewKey(BuildEK(tcell.KeyCtrlU), w.clearValueBeforeCursor),
	)
	w.focusable = true
}

func (w *TextAreaField) Id() string                         { return w.id }
func (w *TextAreaField) HandleResize(ev *tcell.EventResize) { w.w, w.h = ev.Size() }

func (w *TextAreaField) GetKeyMap() *KeyMap   { return w.keyMap }
func (w *TextAreaField) SetKeyMap(km *KeyMap) { w.keyMap = km }

func (w *TextAreaField) HandleKey(ev *tcell.EventKey) bool {
	if !w.active {
		return false
	}
	if wh.IsBS(*ev) {
		if w.overwriteMode {
			w.cursor--
			return true
		}
		return w.handleBackspace(ev)
	}
	if wh.IsKey(tcell.KeyEnter) {
		return w.handleEnter(ev)
	}
	if ev.Key() == tcell.KeyDelete {
		if w.cursor < len(w.value) {
			w.cursor++
			return w.handleBackspace(ev)
		}
	}
	if w.keyMap.Handle(ev) {
		return true
	}
	if w.filter != nil && !w.filter(*ev) {
		return false
	}
	if ev.Key() == tcell.KeyRune {
		var val string
		if w.overwriteMode {
			if w.value[w.cursor] == '\n' {
				// At a new line, we just insert
				val = fmt.Sprintf("%s%s\n", w.value[:w.cursor-1], string(ev.Rune()))
			} else {
				val = fmt.Sprintf("%s%s", w.value[:w.cursor], string(ev.Rune()))
			}
			if len(w.value) > w.cursor+1 {
				val = fmt.Sprintf("%s%s", val, w.value[w.cursor+1:])
			}
		} else {
			val = fmt.Sprintf("%s%s%s", w.value[:w.cursor], string(ev.Rune()), w.value[w.cursor:])
		}
		w.SetValue(val)
		w.cursor++
		return true
	}
	return false
}
func (w *TextAreaField) HandleTime(ev *tcell.EventTime) {}
func (w *TextAreaField) Draw(screen tcell.Screen) {
	if !w.visible {
		return
	}
	useStyle := w.style.Dim(!w.active)
	valueStyle := useStyle.Bold(w.active)
	x, y := w.x, w.y
	labelW := len(w.label)
	if labelW > 0 {
		wh.DrawText(w.x, w.y, w.label+": ", useStyle, screen)
		x = x + labelW + 2
		y++
	}
	lines := strings.Split(w.value, "\n")
	var byteCount int
	for li := range lines {
		ll := len(lines[li])
		if w.cursor >= byteCount && w.cursor < byteCount+ll {
			// Cursor is on this line
			crsPos := w.cursor - byteCount
			cursor := " "
			var pre, post string
			if ll > 0 {
				pre = lines[li][:crsPos]
				if crsPos < ll {
					cursor = string(lines[li][crsPos])
					post = lines[li][crsPos+1:]
				}
			}
			wh.DrawText(x, y, pre, valueStyle, screen)
			x += len(pre)
			if w.active {
				wh.DrawText(x, y, cursor, valueStyle.Reverse(true).Blink(true), screen)
			} else {
				wh.DrawText(x, y, cursor, valueStyle, screen)
			}
			x += 1
			wh.DrawText(x, y, post, valueStyle, screen)
		} else {
			// Cursor is not on this line
			wh.DrawText(x, y, w.value[i], valueStyle, screen)
		}
		byteCount += ll
		y++
		x = w.x
	}
}

func (w *TextAreaField) SetStyle(s tcell.Style) { w.style = s }
func (w *TextAreaField) Active() bool           { return w.active }
func (w *TextAreaField) SetActive(a bool) bool {
	w.active = a
	return w.active
}
func (w *TextAreaField) Visible() bool     { return w.visible }
func (w *TextAreaField) SetVisible(a bool) { w.visible = a }
func (w *TextAreaField) SetX(x int)        { w.x = x }
func (w *TextAreaField) SetY(y int)        { w.y = y }
func (w *TextAreaField) GetX() int         { return w.x }
func (w *TextAreaField) GetY() int         { return w.y }
func (w *TextAreaField) GetPos() Coord     { return Coord{X: w.x, Y: w.y} }
func (w *TextAreaField) SetPos(c Coord)    { w.x, w.y = c.X, c.Y }
func (w *TextAreaField) SetW(wd int)       { w.w = wd }
func (w *TextAreaField) SetH(h int)        { w.h = h }
func (w *TextAreaField) GetW() int         { return w.w }
func (w *TextAreaField) GetH() int         { return w.h }
func (w *TextAreaField) WantW() int {
	vM := wh.Max(40, len(w.value))
	if len(w.label) > 0 {
		return len(w.label) + vM + 3
	}
	return vM
}

func (w *TextAreaField) WantH() int { return 1 }
func (w *TextAreaField) SetSize(c Coord) {
	w.SetW(c.X)
	w.SetH(c.Y)
}
func (w *TextAreaField) Focusable() bool     { return w.focusable }
func (w *TextAreaField) SetFocusable(b bool) { w.focusable = b }
func (w *TextAreaField) MinW() int           { return len(w.label) + len(w.value) }
func (w *TextAreaField) MinH() int           { return 1 }

/* Non-Widget-Interface Functions */
func (w *TextAreaField) handleEnter(_ *tcell.EventKey) bool {
	st := w.cursor
	w.SetValue(w.value[:w.cursor] + "\n" + w.value[w.cursor+1:])
	return true
}
func (w *TextAreaField) handleBackspace(_ *tcell.EventKey) bool {
	st := w.cursor
	if w.cursor > 0 {
		w.cursor--
	}
	if w.cursor < len(w.value) {
		w.SetValue(w.value[:w.cursor] + w.value[w.cursor+1:])
	}
	if st != w.cursor {
		return true
	}
	return false
}

func (w *TextAreaField) getLine(n int) (string, error) {
	if n < 0 {
		return "", errors.New("invalid line specified")
	}
	pts := strings.Split(w.value, "\n")
	if len(
}

func (w *TextAreaField) getCursorPosOnLine() (int, string) {
	pts := strings.Split(w.value, "\n")
	var wrk int
	for i := range pts {
		if w.cursor < wrk+len(pts[i]) {
			return w.cursor - wrk, pts[i]
		}
	}
	return -1, ""
}

func (w *TextAreaField) handleUp(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, find equivilant 'x' on previous line
	pos, ln := w.getCursorPosOnLine()
	if pos == w.cursor {
		w.cursor = 0
		return true
	}

	return false
}
func (w *TextAreaField) handleDown(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, find equivilant 'x' on next line
	return false
}

func (w *TextAreaField) handleLeft(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, if pos on line is 0, go to end of previous line
	return false
}

func (w *TextAreaField) handleRight(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, if pos on line is end, go to beg of next line
	return false
}

func (w *TextAreaField) clearValueBeforeCursor(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, clear before cursor
	return true
}

func (w *TextAreaField) handleHome(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, go to beg of it
	w.cursorX = 0
	return true
}

func (w *TextAreaField) handleEnd(ev *tcell.EventKey) bool {
	// TODO: Split up value into lines, find current line, go to end of it
	w.cursorX = len(w.value[w.cursorY])
	return true
}

func (w *TextAreaField) SetLabel(l string) { w.label = l }
func (w *TextAreaField) Label() string     { return w.label }
func (w *TextAreaField) SetValue(v string) {
	prev := w.value
	w.value = v
	w.doOnChange(prev, v)
	if w.cursor > len(v) {
		w.cursor = len(v)
	}
	if w.cursor < 0 {
		w.cursor = 0
	}
}
func (w *TextAreaField) Value() string { return w.value }

func (w *TextAreaField) SetOnChange(v func(prev, curr string)) { w.onChange = v }
func (w *TextAreaField) doOnChange(prev, curr string) {
	if w.onChange != nil {
		w.onChange(prev, curr)
	}
}

func (w *TextAreaField) SetFilter(f func(ev tcell.EventKey) bool) {
	w.filter = func(ev tcell.EventKey) bool {
		// We always want to make sure we allow backspace.
		if wh.IsBS(ev) || wh.IsKey(tcell.KeyEnter) {
			return true
		}

		// We also always want to make sure it's displayable
		if !wh.KeyIsDisplayable(ev) {
			return false
		}
		return f(ev)
	}
}
func (w *TextAreaField) SetOverwrite(b bool) { w.overwriteMode = b }