Proposal: add basic gum date command

README.md

@@ -376,6 +376,22 @@ See [`charmbracelet/log`](https://github.com/charmbracelet/log) for more usage.
 
 <img src="https://vhs.charm.sh/vhs-6jupuFM0s2fXiUrBE0I1vU.gif" width="600" alt="Running gum log with debug and error levels" />
 
+## Date
+
+Pick a date, starting from the current date by default:
+
+```bash
+gum date
+```
+
+Or starting from an initial date of your choosing:
+
+```bash
+gum date --value 2023-11-28
+```
+
+<img src="https://vhs.charm.sh/vhs-2Gkiemx0ALZZBmODcSrg2I.gif" width="600" alt="Running gum date with a prompt specified" />
+
 ## Examples
 
 How to use `gum` in your daily workflows:

date/command.go

@@ -0,0 +1,43 @@
+package date
+
+import (
+	"fmt"
+	"os"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/gum/internal/exit"
+
+	"github.com/fxtlabs/date"
+)
+
+// Run provides a shell script interface for the date picker component.
+func (o Options) Run() error {
+	picker := basePicker()
+
+	picker.prompt = o.Prompt
+	picker.promptStyle = o.PromptStyle.ToLipgloss()
+	picker.cursorTextStyle = o.CursorTextStyle.ToLipgloss()
+	if value, err := date.ParseISO(o.Value); err == nil {
+		picker.Date = value
+	}
+	p := tea.NewProgram(model{
+		picker:      picker,
+		aborted:     false,
+		header:      o.Header,
+		headerStyle: o.HeaderStyle.ToLipgloss(),
+		timeout:     o.Timeout,
+		hasTimeout:  o.Timeout > 0,
+	}, tea.WithOutput(os.Stderr))
+	tm, err := p.Run()
+	if err != nil {
+		return fmt.Errorf("failed to run input: %w", err)
+	}
+	m := tm.(model)
+
+	if m.aborted {
+		return exit.ErrAborted
+	}
+
+	fmt.Println(m.picker.Value())
+	return nil
+}

date/date.go

@@ -0,0 +1,70 @@
+// Package date provides a shell script interface for picking a date.
+//
+// The date the user selected will be sent to stdout in ISO-8601 format:
+// YYYY-MM-DD.
+//
+// $ gum date --value 2023-11-28 > date.text
+package date
+
+import (
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/gum/timeout"
+	"github.com/charmbracelet/lipgloss"
+)
+
+type model struct {
+	header      string
+	headerStyle lipgloss.Style
+	picker      *picker
+	quitting    bool
+	aborted     bool
+	timeout     time.Duration
+	hasTimeout  bool
+}
+
+func (m model) Init() tea.Cmd {
+	return tea.Batch(
+		timeout.Init(m.timeout, nil),
+	)
+}
+
+func (m model) View() string {
+	if m.quitting {
+		return ""
+	}
+	if m.header != "" {
+		header := m.headerStyle.Render(m.header)
+		return lipgloss.JoinVertical(lipgloss.Left, header, m.picker.View())
+	}
+
+	return m.picker.View()
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case timeout.TickTimeoutMsg:
+		if msg.TimeoutValue <= 0 {
+			m.quitting = true
+			m.aborted = true
+			return m, tea.Quit
+		}
+		m.timeout = msg.TimeoutValue
+		return m, timeout.Tick(msg.TimeoutValue, msg.Data)
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "ctrl+c", "esc":
+			m.quitting = true
+			m.aborted = true
+			return m, tea.Quit
+		case "enter":
+			m.quitting = true
+			return m, tea.Quit
+		}
+	}
+
+	var cmd tea.Cmd
+	m.picker, cmd = m.picker.Update(msg)
+	return m, cmd
+}

date/options.go

@@ -0,0 +1,18 @@
+package date
+
+import (
+	"time"
+
+	"github.com/charmbracelet/gum/style"
+)
+
+// Options are the customization options for the date.
+type Options struct {
+	Prompt          string        `help:"Prompt to display" default:"> " env:"GUM_DATE_PROMPT"`
+	PromptStyle     style.Styles  `embed:"" prefix:"prompt." envprefix:"GUM_DATE_PROMPT_"`
+	CursorTextStyle style.Styles  `embed:"" prefix:"cursor." set:"defaultForeground=212" set:"defaultUnderline=true" envprefix:"GUM_DATE_CURSOR_"` //nolint:staticcheck
+	Value           string        `help:"Initial value in ISO 8601 format, e.g. 2023-11-28" default:""`
+	Header          string        `help:"Header value" default:"" env:"GUM_DATE_HEADER"`
+	HeaderStyle     style.Styles  `embed:"" prefix:"header." set:"defaultForeground=240" envprefix:"GUM_DATE_HEADER_"`
+	Timeout         time.Duration `help:"Timeout until input aborts" default:"0" env:"GUM_DATE_TIMEOUT"`
+}

date/picker.go

@@ -0,0 +1,118 @@
+package date
+
+import (
+	"strings"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/fxtlabs/date"
+)
+
+type interval int
+
+// Default styles.
+var (
+	weekdayStyle           = lipgloss.NewStyle().Faint(true)
+	defaultCursorTextStyle = lipgloss.NewStyle().Underline(true).Foreground(lipgloss.Color("201"))
+)
+
+const (
+	day   interval = 0
+	month interval = 1
+	year  interval = 2
+)
+
+// incr i in direction d; bodge mod-3 indexing.
+func (i interval) incr(d direction) interval {
+	mod := (int(i) + int(d)) % 3
+	if mod < 0 {
+		return year
+	}
+	return interval(mod)
+}
+
+type direction int
+
+const (
+	forward  direction = 1
+	backward direction = -1
+)
+
+// picker implements tea.Model for a date.Date.
+type picker struct {
+	date.Date
+	focus interval
+
+	promptStyle lipgloss.Style
+	prompt      string
+
+	cursorTextStyle lipgloss.Style
+}
+
+func basePicker() *picker {
+	return &picker{
+		Date:            date.Today(),
+		focus:           day,
+		prompt:          "> ",
+		cursorTextStyle: defaultCursorTextStyle,
+	}
+}
+
+func (p *picker) formatDate() string {
+	raw := p.Date.Format("02 Jan 2006")
+	parts := strings.Split(raw, " ")
+	parts[int(p.focus)] = p.cursorTextStyle.Render(parts[int(p.focus)])
+	return strings.Join(parts, " ") + " " + p.formatWeekday()
+}
+
+func (p *picker) formatWeekday() string {
+	shortName := p.Date.Weekday().String()[:3]
+	return weekdayStyle.Render(shortName)
+}
+
+func (p *picker) incr(d direction) {
+	switch p.focus {
+	case day:
+		p.Date = p.Date.AddDate(0, 0, int(d))
+	case month:
+		p.Date = p.Date.AddDate(0, int(d), 0)
+	case year:
+		p.Date = p.Date.AddDate(int(d), 0, 0)
+	}
+}
+
+// Init implements tea.Model.
+func (p *picker) Init() tea.Cmd {
+	return nil
+}
+
+// Update implements tea.Model.
+func (p *picker) Update(msg tea.Msg) (*picker, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.String() {
+		// "up"/"down" increment/decrement the focused component, respectively
+		case "up", "k":
+			p.incr(forward)
+		case "down", "j":
+			p.incr(backward)
+
+		// "left"/"right" cycle the focused component
+		case "left", "h":
+			p.focus = p.focus.incr(backward)
+		case "right", "l":
+			p.focus = p.focus.incr(forward)
+		}
+	}
+	return p, nil
+}
+
+// View implements tea.Model.
+func (p *picker) View() string {
+	return p.promptStyle.Render(p.prompt) + p.formatDate()
+}
+
+// Value of p.
+func (p *picker) Value() date.Date {
+	return p.Date
+}

examples/test.sh

@@ -10,6 +10,10 @@ gum choose Unlimited Choice Of Items --no-limit --cursor "* " --cursor-prefix "(
 gum confirm "Testing?"
 gum confirm "No?" --default=false --affirmative "Okay." --negative "Cancel."
 
+# Date
+gum date
+gum date --value 2021-10-10
+
 # Filter
 gum filter
 echo {1..500} | sed 's/ /\n/g' | gum filter

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/charmbracelet/log v0.4.0
 	github.com/charmbracelet/x/ansi v0.3.2
 	github.com/charmbracelet/x/term v0.2.0
+	github.com/fxtlabs/date v0.0.0-20150819233934-d9ab6e2a88a9
 	github.com/muesli/reflow v0.3.0
 	github.com/muesli/roff v0.1.0
 	github.com/muesli/termenv v0.15.3-0.20240618155329-98d742f6907a

go.sum

@@ -48,6 +48,8 @@ github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkp
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
 github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
+github.com/fxtlabs/date v0.0.0-20150819233934-d9ab6e2a88a9 h1:NERIc41aohgojUAgWCCnN5B8dIXZsBo2UC04LR3tbao=
+github.com/fxtlabs/date v0.0.0-20150819233934-d9ab6e2a88a9/go.mod h1:UoIEyXCyEJ1Zu3ejiUOSngl9U5Oe9S+qaNiYiUex2nk=
 github.com/go-logfmt/logfmt v0.6.0 h1:wGYYu3uicYdqXVgoYbvnkrPVXkuLM1p1ifugDMEdRi4=
 github.com/go-logfmt/logfmt v0.6.0/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
 github.com/gorilla/css v1.0.1 h1:ntNaBIghp6JmvWnxbZKANoLyuXTPZ4cAMlo6RyhlbO8=

gum.go

@@ -6,6 +6,7 @@ import (
 	"github.com/charmbracelet/gum/choose"
 	"github.com/charmbracelet/gum/completion"
 	"github.com/charmbracelet/gum/confirm"
+	"github.com/charmbracelet/gum/date"
 	"github.com/charmbracelet/gum/file"
 	"github.com/charmbracelet/gum/filter"
 	"github.com/charmbracelet/gum/format"
@@ -58,6 +59,17 @@ type Gum struct {
 	//
 	Confirm confirm.Options `cmd:"" help:"Ask a user to confirm an action"`
 
+	// Date provides an interface for picking a date. Outputs the selected date
+	// in ISO 8601 format: `YYYY-MM-DD`.
+	//
+	// $ gum date
+	//
+	// You can specify a start date in ISO 8601 format. Let's pick a date
+	// starting with the initial value Nov. 28, 2023:
+	//
+	// $ gum date --value="2023-11-28"
+	Date date.Options `cmd:"" help:"Pick a date"`
+
 	// File provides an interface to pick a file from a folder (tree).
 	// The user is provided a file manager-like interface to navigate, to
 	// select a file.