feat(filter): Multi-select (#130)

* feat(filter): added multiple selections

* docs(filter): corrected comments about multiSelection print

* feat(filter): fix proposed changes on naming variables and map type

* feat(filter): actually fix map types

* feat(filter): use `○` / `◉` as unselected / selected multi-select options

Co-authored-by: Maas Lalani <maas@lalani.dev>

choose/options.go

@@ -12,7 +12,7 @@ type Options struct {
 	Cursor            string       `help:"Prefix to show on item that corresponds to the cursor position" default:"> " env:"GUM_CHOOSE_CURSOR"`
 	CursorPrefix      string       `help:"Prefix to show on the cursor item (hidden if limit is 1)" default:"[•] " env:"GUM_CHOOSE_CURSOR_PREFIX"`
 	SelectedPrefix    string       `help:"Prefix to show on selected items (hidden if limit is 1)" default:"[✕] " env:"GUM_CHOOSE_SELECTED_PREFIX"`
-	UnselectedPrefix  string       `help:"Prefix to show on selected items (hidden if limit is 1)" default:"[ ] " env:"GUM_CHOOSE_UNSELECTED_PREFIX"`
+	UnselectedPrefix  string       `help:"Prefix to show on unselected items (hidden if limit is 1)" default:"[ ] " env:"GUM_CHOOSE_UNSELECTED_PREFIX"`
 	CursorStyle       style.Styles `embed:"" prefix:"cursor." set:"defaultForeground=212" envprefix:"GUM_CHOOSE_CURSOR_"`
 	ItemStyle         style.Styles `embed:"" prefix:"item." hidden:"" envprefix:"GUM_CHOOSE_ITEM_"`
 	SelectedItemStyle style.Styles `embed:"" prefix:"selected." set:"defaultForeground=212" envprefix:"GUM_CHOOSE_SELECTED_"`

filter/command.go

@@ -58,6 +58,10 @@ func (o Options) Run() error {
 		matches = matchAll(choices)
 	}
 
+	if o.NoLimit {
+		o.Limit = len(choices)
+	}
+
 	p := tea.NewProgram(model{
 		choices:               choices,
 		indicator:             o.Indicator,
@@ -65,9 +69,15 @@ func (o Options) Run() error {
 		textinput:             i,
 		viewport:              &v,
 		indicatorStyle:        o.IndicatorStyle.ToLipgloss(),
+		selectedPrefixStyle:   o.SelectedPrefixStyle.ToLipgloss(),
+		selectedPrefix:        o.SelectedPrefix,
+		unselectedPrefixStyle: o.UnselectedPrefixStyle.ToLipgloss(),
+		unselectedPrefix:      o.UnselectedPrefix,
 		matchStyle:            o.MatchStyle.ToLipgloss(),
 		textStyle:             o.TextStyle.ToLipgloss(),
 		height:                o.Height,
+		selected:              make(map[string]struct{}),
+		limit:                 o.Limit,
 	}, options...)
 
 	tm, err := p.StartReturningModel()
@@ -79,8 +89,16 @@ func (o Options) Run() error {
 	if m.aborted {
 		return exit.ErrAborted
 	}
-	if len(m.matches) > m.selected && m.selected >= 0 {
+
-		fmt.Println(m.matches[m.selected].Str)
+	// allSelections contains values only if limit is greater
+	// than 1 or if flag --no-limit is passed, hence there is
+	// no need to further checks
+	if len(m.selected) > 0 {
+		for k := range m.selected {
+			fmt.Println(k)
+		}
+	} else if len(m.matches) > m.cursor && m.cursor >= 0 {
+		fmt.Println(m.matches[m.cursor].Str)
 	}
 
 	return nil

filter/filter.go

@@ -26,14 +26,21 @@ type model struct {
 	viewport              *viewport.Model
 	choices               []string
 	matches               []fuzzy.Match
-	selected       int
+	cursor                int
+	selected              map[string]struct{}
+	limit                 int
+	numSelected           int
 	indicator             string
+	selectedPrefix        string
+	unselectedPrefix      string
 	height                int
 	aborted               bool
 	quitting              bool
 	matchStyle            lipgloss.Style
 	textStyle             lipgloss.Style
 	indicatorStyle        lipgloss.Style
+	selectedPrefixStyle   lipgloss.Style
+	unselectedPrefixStyle lipgloss.Style
 }
 
 func (m model) Init() tea.Cmd { return nil }
@@ -49,10 +56,19 @@ func (m model) View() string {
 	for i, match := range m.matches {
 		// If this is the current selected index, we add a small indicator to
 		// represent it. Otherwise, simply pad the string.
-		if i == m.selected {
+		if i == m.cursor {
-			s.WriteString(m.indicatorStyle.Render(m.indicator) + " ")
+			s.WriteString(m.indicatorStyle.Render(m.indicator))
 		} else {
-			s.WriteString(strings.Repeat(" ", runewidth.StringWidth(m.indicator)) + " ")
+			s.WriteString(strings.Repeat(" ", runewidth.StringWidth(m.indicator)))
+		}
+
+		// If there are multiple selections mark them, otherwise leave an empty space
+		if _, ok := m.selected[match.Str]; ok {
+			s.WriteString(m.selectedPrefixStyle.Render(m.selectedPrefix))
+		} else if m.limit > 1 {
+			s.WriteString(m.unselectedPrefixStyle.Render(m.unselectedPrefix))
+		} else {
+			s.WriteString(" ")
 		}
 
 		// For this match, there are a certain number of characters that have
@@ -102,14 +118,33 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 			m.quitting = true
 			return m, tea.Quit
 		case "ctrl+n", "ctrl+j", "down":
-			m.selected = clamp(0, len(m.matches)-1, m.selected+1)
+			m.cursor = clamp(0, len(m.matches)-1, m.cursor+1)
-			if m.selected >= m.viewport.YOffset+m.viewport.Height {
+			if m.cursor >= m.viewport.YOffset+m.viewport.Height {
 				m.viewport.LineDown(1)
 			}
 		case "ctrl+p", "ctrl+k", "up":
-			m.selected = clamp(0, len(m.matches)-1, m.selected-1)
+			m.cursor = clamp(0, len(m.matches)-1, m.cursor-1)
-			if m.selected < m.viewport.YOffset {
+			if m.cursor < m.viewport.YOffset {
-				m.viewport.SetYOffset(m.selected)
+				m.viewport.SetYOffset(m.cursor)
+			}
+		case "tab":
+			if m.limit == 1 {
+				break // no op
+			}
+
+			// Tab is used to toggle selection of current item in the list
+			if _, ok := m.selected[m.matches[m.cursor].Str]; ok {
+				delete(m.selected, m.matches[m.cursor].Str)
+				m.numSelected--
+			} else if m.numSelected < m.limit {
+				m.selected[m.matches[m.cursor].Str] = struct{}{}
+				m.numSelected++
+			}
+
+			// Go down by one line
+			m.cursor = clamp(0, len(m.matches)-1, m.cursor+1)
+			if m.cursor >= m.viewport.YOffset+m.viewport.Height {
+				m.viewport.LineDown(1)
 			}
 		default:
 			m.textinput, cmd = m.textinput.Update(msg)
@@ -130,7 +165,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 	// It's possible that filtering items have caused fewer matches. So, ensure
 	// that the selected index is within the bounds of the number of matches.
-	m.selected = clamp(0, len(m.matches)-1, m.selected)
+	m.cursor = clamp(0, len(m.matches)-1, m.cursor)
 	return m, cmd
 }
 

filter/options.go

@@ -6,6 +6,12 @@ import "github.com/charmbracelet/gum/style"
 type Options struct {
 	Indicator             string       `help:"Character for selection" default:"•" env:"GUM_FILTER_INDICATOR"`
 	IndicatorStyle        style.Styles `embed:"" prefix:"indicator." set:"defaultForeground=212" envprefix:"GUM_FILTER_INDICATOR_"`
+	Limit                 int          `help:"Maximum number of options to pick" default:"1" group:"Selection"`
+	NoLimit               bool         `help:"Pick unlimited number of options (ignores limit)" group:"Selection"`
+	SelectedPrefix        string       `help:"Character to indicate selected items (hidden if limit is 1)" default:" ◉ " env:"GUM_FILTER_SELECTED_PREFIX"`
+	SelectedPrefixStyle   style.Styles `embed:"" prefix:"selected-indicator." set:"defaultForeground=212" envprefix:"GUM_FILTER_SELECTED_PREFIX_"`
+	UnselectedPrefix      string       `help:"Character to indicate unselected items (hidden if limit is 1)" default:" ○ " env:"GUM_FILTER_UNSELECTED_PREFIX"`
+	UnselectedPrefixStyle style.Styles `embed:"" prefix:"unselected-prefix." set:"defaultForeground=240" envprefix:"GUM_FILTER_UNSELECTED_PREFIX_"`
 	TextStyle             style.Styles `embed:"" prefix:"text." envprefix:"GUM_FILTER_TEXT_"`
 	MatchStyle            style.Styles `embed:"" prefix:"match." set:"defaultForeground=212" envprefix:"GUM_FILTER_MATCH_"`
 	Placeholder           string       `help:"Placeholder value" default:"Filter..." env:"GUM_FILTER_PLACEHOLDER"`