v0.1.0 initial commit

tui/textfield_state.go

@@ -0,0 +1,280 @@
+package tui
+
+import (
+	"unicode"
+
+	"github.com/lixenwraith/terminal"
+)
+
+// isWordChar returns true for word-constituent characters
+func isWordChar(r rune) bool {
+	return unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_'
+}
+
+// TextFieldState holds editable text field state
+type TextFieldState struct {
+	Text   []rune
+	Cursor int // Positions before which cursor sits (0 = before first char)
+	Scroll int // First visible rune index
+}
+
+// NewTextFieldState creates initialized text field state
+func NewTextFieldState(initial string) *TextFieldState {
+	runes := []rune(initial)
+	return &TextFieldState{
+		Text:   runes,
+		Cursor: len(runes),
+		Scroll: 0,
+	}
+}
+
+// --- Value access ---
+
+// Value returns current text as string
+func (t *TextFieldState) Value() string {
+	return string(t.Text)
+}
+
+// SetValue replaces text and moves cursor to end
+func (t *TextFieldState) SetValue(s string) {
+	t.Text = []rune(s)
+	t.Cursor = len(t.Text)
+	t.Scroll = 0
+}
+
+// Clear empties the field
+func (t *TextFieldState) Clear() {
+	t.Text = nil
+	t.Cursor = 0
+	t.Scroll = 0
+}
+
+// --- Character insertion ---
+
+// Insert adds rune at cursor position
+func (t *TextFieldState) Insert(r rune) {
+	t.Text = append(t.Text[:t.Cursor], append([]rune{r}, t.Text[t.Cursor:]...)...)
+	t.Cursor++
+}
+
+// InsertString adds string at cursor position
+func (t *TextFieldState) InsertString(s string) {
+	runes := []rune(s)
+	t.Text = append(t.Text[:t.Cursor], append(runes, t.Text[t.Cursor:]...)...)
+	t.Cursor += len(runes)
+}
+
+// --- Character deletion ---
+
+// DeleteBackward removes rune before cursor
+func (t *TextFieldState) DeleteBackward() bool {
+	if t.Cursor > 0 {
+		t.Text = append(t.Text[:t.Cursor-1], t.Text[t.Cursor:]...)
+		t.Cursor--
+		return true
+	}
+	return false
+}
+
+// DeleteForward removes rune at cursor
+func (t *TextFieldState) DeleteForward() bool {
+	if t.Cursor < len(t.Text) {
+		t.Text = append(t.Text[:t.Cursor], t.Text[t.Cursor+1:]...)
+		return true
+	}
+	return false
+}
+
+// --- Word deletion ---
+
+// DeleteWordBackward removes word before cursor
+func (t *TextFieldState) DeleteWordBackward() bool {
+	if t.Cursor == 0 {
+		return false
+	}
+	// Skip trailing non-word chars
+	end := t.Cursor
+	for end > 0 && !isWordChar(t.Text[end-1]) {
+		end--
+	}
+	// Skip word chars
+	start := end
+	for start > 0 && isWordChar(t.Text[start-1]) {
+		start--
+	}
+	if start == t.Cursor {
+		start = t.Cursor - 1
+	}
+	t.Text = append(t.Text[:start], t.Text[t.Cursor:]...)
+	t.Cursor = start
+	return true
+}
+
+// DeleteWordForward removes word after cursor
+func (t *TextFieldState) DeleteWordForward() bool {
+	if t.Cursor >= len(t.Text) {
+		return false
+	}
+	// Skip word chars
+	end := t.Cursor
+	for end < len(t.Text) && isWordChar(t.Text[end]) {
+		end++
+	}
+	// Skip trailing non-word chars
+	for end < len(t.Text) && !isWordChar(t.Text[end]) {
+		end++
+	}
+	if end == t.Cursor {
+		end = t.Cursor + 1
+	}
+	t.Text = append(t.Text[:t.Cursor], t.Text[end:]...)
+	return true
+}
+
+// DeleteToEnd removes from cursor to end
+func (t *TextFieldState) DeleteToEnd() bool {
+	if t.Cursor < len(t.Text) {
+		t.Text = t.Text[:t.Cursor]
+		return true
+	}
+	return false
+}
+
+// DeleteToStart removes from start to cursor
+func (t *TextFieldState) DeleteToStart() bool {
+	if t.Cursor > 0 {
+		t.Text = t.Text[t.Cursor:]
+		t.Cursor = 0
+		t.Scroll = 0
+		return true
+	}
+	return false
+}
+
+// --- Character movement ---
+
+// MoveLeft moves cursor left
+func (t *TextFieldState) MoveLeft() {
+	if t.Cursor > 0 {
+		t.Cursor--
+	}
+}
+
+// MoveRight moves cursor right
+func (t *TextFieldState) MoveRight() {
+	if t.Cursor < len(t.Text) {
+		t.Cursor++
+	}
+}
+
+// --- Word movement ---
+
+// MoveWordLeft moves cursor to previous word boundary
+func (t *TextFieldState) MoveWordLeft() {
+	if t.Cursor == 0 {
+		return
+	}
+	// Skip non-word chars
+	for t.Cursor > 0 && !isWordChar(t.Text[t.Cursor-1]) {
+		t.Cursor--
+	}
+	// Skip word chars
+	for t.Cursor > 0 && isWordChar(t.Text[t.Cursor-1]) {
+		t.Cursor--
+	}
+}
+
+// MoveWordRight moves cursor to next word boundary
+func (t *TextFieldState) MoveWordRight() {
+	if t.Cursor >= len(t.Text) {
+		return
+	}
+	// Skip word chars
+	for t.Cursor < len(t.Text) && isWordChar(t.Text[t.Cursor]) {
+		t.Cursor++
+	}
+	// Skip non-word chars
+	for t.Cursor < len(t.Text) && !isWordChar(t.Text[t.Cursor]) {
+		t.Cursor++
+	}
+}
+
+// --- Line movement ---
+
+// MoveToStart moves cursor to beginning
+func (t *TextFieldState) MoveToStart() {
+	t.Cursor = 0
+}
+
+// MoveToEnd moves cursor to end
+func (t *TextFieldState) MoveToEnd() {
+	t.Cursor = len(t.Text)
+}
+
+// --- Scroll management ---
+
+// AdjustScroll updates scroll to keep cursor visible within viewport width
+func (t *TextFieldState) AdjustScroll(viewportW int) {
+	if viewportW <= 0 {
+		return
+	}
+	if t.Cursor < t.Scroll {
+		t.Scroll = t.Cursor
+	}
+	if t.Cursor >= t.Scroll+viewportW {
+		t.Scroll = t.Cursor - viewportW + 1
+	}
+	if t.Scroll < 0 {
+		t.Scroll = 0
+	}
+}
+
+// --- Input handling ---
+
+// HandleKey processes keyboard input, returns true if state changed
+func (t *TextFieldState) HandleKey(key terminal.Key, r rune, mod terminal.Modifier) bool {
+	switch key {
+	case terminal.KeyLeft:
+		if mod&terminal.ModCtrl != 0 {
+			t.MoveWordLeft()
+		} else {
+			t.MoveLeft()
+		}
+		return true
+	case terminal.KeyRight:
+		if mod&terminal.ModCtrl != 0 {
+			t.MoveWordRight()
+		} else {
+			t.MoveRight()
+		}
+		return true
+	case terminal.KeyHome, terminal.KeyCtrlA:
+		t.MoveToStart()
+		return true
+	case terminal.KeyEnd, terminal.KeyCtrlE:
+		t.MoveToEnd()
+		return true
+	case terminal.KeyBackspace:
+		if mod&terminal.ModCtrl != 0 {
+			return t.DeleteWordBackward()
+		}
+		return t.DeleteBackward()
+	case terminal.KeyDelete:
+		if mod&terminal.ModCtrl != 0 {
+			return t.DeleteWordForward()
+		}
+		return t.DeleteForward()
+	case terminal.KeyCtrlK:
+		return t.DeleteToEnd()
+	case terminal.KeyCtrlU:
+		return t.DeleteToStart()
+	case terminal.KeyCtrlW:
+		return t.DeleteWordBackward()
+	case terminal.KeyRune:
+		if r >= 32 { // Printable
+			t.Insert(r)
+			return true
+		}
+	}
+	return false
+}