v0.2.1 tui enhancement and better narrow layouts

tui/optionlist.go

@@ -10,17 +10,24 @@ import (
 type Option struct {
 	Name string // what is chosen
 	Hint string // a line about it
+	Key  rune   // in a menu, the key that picks it at once
 }
 
 // OptionListState filters options by the text typed into it, matching name
-// or hint regardless of case, and keeps a cursor on the matches
+// or hint regardless of case, and keeps a cursor on the matches. A menu has
+// no filter: each option's Key picks it.
 type OptionListState struct {
 	Options []Option
 	Filter  TextFieldState
-	Cursor  int // index into Matches
-	Scroll  int // first match shown
+	Cursor  int  // index into Matches
+	Scroll  int  // first match shown
+	Menu    bool // no filter; Pick finds an option by its Key
 }
 
+// minHintW is the narrowest hint column beside the names; narrower, the
+// cursor's hint wraps below the list instead
+const minHintW = 16
+
 // NewOptionListState creates a list showing every option
 func NewOptionListState(options []Option) *OptionListState {
 	return &OptionListState{Options: options}
@@ -59,7 +66,7 @@ func (s *OptionListState) HandleKey(key terminal.Key, r rune, mod terminal.Modif
 		s.Cursor--
 	case key == terminal.KeyDown:
 		s.Cursor++
-	case !s.Filter.HandleKey(key, r, mod):
+	case s.Menu || !s.Filter.HandleKey(key, r, mod):
 		return false
 	case s.Filter.Value() != filter:
 		s.Cursor = 0
@@ -68,49 +75,102 @@ func (s *OptionListState) HandleKey(key terminal.Key, r rune, mod terminal.Modif
 	return true
 }
 
+// Pick returns the index in Options of the option whose Key is r
+func (s *OptionListState) Pick(r rune) (int, bool) {
+	for i, o := range s.Options {
+		if o.Key == r && r != 0 {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
 // Paste adds pasted text to the filter
 func (s *OptionListState) Paste(text string) bool {
-	if !s.Filter.Paste(text) {
+	if s.Menu || !s.Filter.Paste(text) {
 		return false
 	}
 	s.Cursor = 0
 	return true
 }
 
-// OptionList draws the filter on the first row and the matches below it,
-// the cursor row marked with the pointer on the Selected background, each
-// hint muted in a column after the names
+// layout is how the list fits w columns: the names' width, the column the
+// names start at, and the rows below the list that hold the cursor's hint
+// where hints do not fit beside the names
+func (s *OptionListState) layout(w int) (nameW, nameX, hintRows int) {
+	nameX = 2
+	if s.Menu {
+		nameX = 4
+	}
+	for _, o := range s.Options {
+		nameW = max(nameW, RuneLen(o.Name))
+	}
+	nameW = min(nameW, (w-nameX)/2)
+	if w-nameX-nameW-2 >= minHintW {
+		return nameW, nameX, 0
+	}
+	nameW = w - nameX
+	for _, o := range s.Options {
+		if o.Hint != "" {
+			hintRows = max(hintRows, min(3, len(WrapText(o.Hint, max(1, w-2)))))
+		}
+	}
+	return nameW, nameX, hintRows
+}
+
+// Rows returns the rows the list takes at width w to show every option: the
+// filter, a row each, and the cursor's hint where it does not fit beside them
+func (s *OptionListState) Rows(w int) int {
+	_, _, hintRows := s.layout(w)
+	return 1 - boolToInt(s.Menu) + len(s.Options) + hintRows
+}
+
+// OptionList draws the filter on the first row, a menu none, and the
+// matches below, the cursor row marked with the pointer on the Selected
+// background and a menu's keys before the names in the accent style. Hints
+// sit muted beside the names or, where that column would be narrower than
+// 16, the cursor's hint wraps onto the list's last rows.
 func (r Region) OptionList(s *OptionListState, th Theme) {
 	if r.W < 4 || r.H < 2 {
 		return
 	}
-	r.TextStyled(0, 0, "/", th.Muted)
-	r.Sub(2, 0, r.W-2, 1).TextInput(&s.Filter, "type to filter", true, th)
-
+	top := 1
+	if s.Menu {
+		top = 0
+	} else {
+		r.TextStyled(0, 0, "/", th.Muted)
+		r.Sub(2, 0, r.W-2, 1).TextInput(&s.Filter, "type to filter", true, th)
+	}
 	m := s.Matches()
-	rows := r.H - 1
 	if len(m) == 0 {
-		r.TextStyled(2, 1, "no match", th.Muted)
+		r.TextStyled(2, top, "no match", th.Muted)
 		return
 	}
-	s.Scroll = max(0, min(s.Scroll, s.Cursor, len(m)-rows))
-	s.Scroll = max(s.Scroll, s.Cursor-rows+1)
-
-	nameW := 0
-	for _, i := range m {
-		nameW = max(nameW, RuneLen(s.Options[i].Name))
-	}
-	nameW = min(nameW, r.W/2)
+	nameW, nameX, hintRows := s.layout(r.W)
+	rows := max(1, r.H-top-hintRows)
+	s.Scroll = AdjustScroll(s.Cursor, ClampScroll(s.Scroll, rows, len(m)), rows, len(m))
 	for y := 0; y < rows && s.Scroll+y < len(m); y++ {
 		o := s.Options[m[s.Scroll+y]]
-		row := r.Sub(0, 1+y, r.W, 1)
+		row := r.Sub(0, top+y, r.W, 1)
 		var bg Style
 		if s.Scroll+y == s.Cursor {
 			bg = th.Selected
 			row.FillStyle(th.Text.On(bg))
 			row.TextStyled(0, 0, string(th.Glyphs.Pointer), th.Accent.On(bg))
 		}
-		row.TextStyled(2, 0, Truncate(o.Name, nameW), th.Text.On(bg))
-		row.TextStyled(2+nameW+2, 0, Truncate(o.Hint, r.W-nameW-4), th.Muted.On(bg))
+		if s.Menu && o.Key != 0 {
+			row.TextStyled(2, 0, string(o.Key), th.Accent.On(bg))
+		}
+		row.TextStyled(nameX, 0, Truncate(o.Name, nameW), th.Text.On(bg))
+		if hintRows == 0 {
+			row.TextStyled(nameX+nameW+2, 0, Truncate(o.Hint, r.W-nameX-nameW-2), th.Muted.On(bg))
+		}
+	}
+	hint, n := WrapText(s.Options[m[s.Cursor]].Hint, max(1, r.W-2)), min(hintRows, r.H-top-rows)
+	if len(hint) > n && n > 0 { // the last row shown ends in '…'
+		hint = append(hint[:n-1], Truncate(hint[n-1]+" "+hint[n], r.W-2))
+	}
+	for y, l := range hint[:min(n, len(hint))] { // on the last rows, so the list ends on text
+		r.TextStyled(2, r.H-min(n, len(hint))+y, l, th.Muted)
 	}
 }