Split ex line text handling into dedicated widget

1 files changed, 136 insertions, 0 deletions

diff --git a/lib/ui/textinput.go b/lib/ui/textinput.go
new file mode 100644
index 0000000..aff520b
--- /dev/null
+++ b/lib/ui/textinput.go
@@ -0,0 +1,136 @@
+package ui
+
+import (
+	"github.com/gdamore/tcell"
+	"github.com/mattn/go-runewidth"
+)
+
+// TODO: Attach history and tab completion providers
+// TODO: scrolling
+
+type TextInput struct {
+	Invalidatable
+	cells  int
+	ctx    *Context
+	focus  bool
+	index  int
+	prompt string
+	scroll int
+	text   []rune
+}
+
+// Creates a new TextInput. TextInputs will render a "textbox" in the entire
+// context they're given, and process keypresses to build a string from user
+// input.
+func NewTextInput() *TextInput {
+	return &TextInput{
+		cells: -1,
+		text:  []rune{},
+	}
+}
+
+func (ti *TextInput) Prompt(prompt string) *TextInput {
+	ti.prompt = prompt
+	return ti
+}
+
+func (ti *TextInput) String() string {
+	return string(ti.text)
+}
+
+func (ti *TextInput) Invalidate() {
+	ti.DoInvalidate(ti)
+}
+
+func (ti *TextInput) Draw(ctx *Context) {
+	ti.ctx = ctx // gross
+	ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ', tcell.StyleDefault)
+	ctx.Printf(0, 0, tcell.StyleDefault, "%s%s", ti.prompt, string(ti.text))
+	cells := runewidth.StringWidth(string(ti.text[:ti.index]))
+	if cells != ti.cells {
+		ctx.SetCursor(cells+1, 0)
+	}
+}
+
+func (ti *TextInput) Focus(focus bool) {
+	ti.focus = focus
+	if focus && ti.ctx != nil {
+		cells := runewidth.StringWidth(string(ti.text[:ti.index]))
+		ti.ctx.SetCursor(cells+1, 0)
+	}
+}
+
+func (ti *TextInput) insert(ch rune) {
+	left := ti.text[:ti.index]
+	right := ti.text[ti.index:]
+	ti.text = append(left, append([]rune{ch}, right...)...)
+	ti.index++
+	ti.Invalidate()
+}
+
+func (ti *TextInput) deleteWord() {
+	// TODO: Break on any of / " '
+	if len(ti.text) == 0 {
+		return
+	}
+	i := ti.index - 1
+	if ti.text[i] == ' ' {
+		i--
+	}
+	for ; i >= 0; i-- {
+		if ti.text[i] == ' ' {
+			break
+		}
+	}
+	ti.text = append(ti.text[:i+1], ti.text[ti.index:]...)
+	ti.index = i + 1
+	ti.Invalidate()
+}
+
+func (ti *TextInput) deleteChar() {
+	if len(ti.text) > 0 && ti.index != len(ti.text) {
+		ti.text = append(ti.text[:ti.index], ti.text[ti.index+1:]...)
+		ti.Invalidate()
+	}
+}
+
+func (ti *TextInput) backspace() {
+	if len(ti.text) > 0 && ti.index != 0 {
+		ti.text = append(ti.text[:ti.index-1], ti.text[ti.index:]...)
+		ti.index--
+		ti.Invalidate()
+	}
+}
+
+func (ti *TextInput) Event(event tcell.Event) bool {
+	switch event := event.(type) {
+	case *tcell.EventKey:
+		switch event.Key() {
+		case tcell.KeyBackspace, tcell.KeyBackspace2:
+			ti.backspace()
+		case tcell.KeyCtrlD, tcell.KeyDelete:
+			ti.deleteChar()
+		case tcell.KeyCtrlB, tcell.KeyLeft:
+			if ti.index > 0 {
+				ti.index--
+				ti.Invalidate()
+			}
+		case tcell.KeyCtrlF, tcell.KeyRight:
+			if ti.index < len(ti.text) {
+				ti.index++
+				ti.Invalidate()
+			}
+		case tcell.KeyCtrlA, tcell.KeyHome:
+			ti.index = 0
+			ti.Invalidate()
+		case tcell.KeyCtrlE, tcell.KeyEnd:
+			ti.index = len(ti.text)
+			ti.Invalidate()
+		case tcell.KeyCtrlW:
+			ti.deleteWord()
+		case tcell.KeyRune:
+			ti.insert(event.Rune())
+		}
+	}
+	return true
+}