feat: add event-logger example

A simple event logger that displays the most recent window-size,
mouse, and key events triggered by Bubble Tea.

examples/event-logger/main.go

@@ -0,0 +1,158 @@
+package main
+
+// An event logger that displays tea window-size, key, and mouse events.
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+	"github.com/dustin/go-humanize"
+)
+
+var (
+	typeStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("#04B575"))
+	msgStyle     = lipgloss.NewStyle().Foreground(lipgloss.Color("#DDDDDD"))
+	timeStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("#FF06B7"))
+	tooltipStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("#333333"))
+)
+
+func main() {
+	p := tea.NewProgram(&model{lastEvent: time.Now()},
+		tea.WithAltScreen(),
+		tea.WithMouseAllMotion(),
+	)
+	if _, err := p.Run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+type event struct {
+	timestamp time.Time
+	msg       tea.Msg
+}
+
+type model struct {
+	width  int
+	height int
+
+	lastEvent      time.Time
+	lastMouseEvent tea.MouseEvent
+
+	events []event
+}
+
+func (m *model) Init() tea.Cmd {
+	return tick
+}
+
+func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "ctrl+c":
+			return m, tea.Quit
+		}
+
+	case tea.MouseMsg:
+		m.lastMouseEvent = tea.MouseEvent(msg)
+
+		if m.lastMouseEvent.Type == tea.MouseMotion {
+			// don't log motion events as it becomes spamy
+			return m, nil
+		}
+
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+
+	case tickMsg:
+		return m, tick
+	}
+
+	m.lastEvent = time.Now()
+	m.events = append(m.events, event{
+		timestamp: time.Now(),
+		msg:       msg,
+	})
+
+	return m, nil
+}
+
+func (m model) View() string {
+	if m.width == 0 || m.height == 0 {
+		return ""
+	}
+
+	h := m.height - 3
+	evs := m.events
+	if m.height > 0 && len(evs) > h {
+		evs = evs[len(evs)-h:]
+	}
+
+	var s string
+	for _, event := range evs {
+		s += fmt.Sprintf("[%s] %s\n",
+			timeStyle.Render(event.timestamp.Format("15:04:05")),
+			msgView(event.msg),
+		)
+	}
+
+	lastEvent := fmt.Sprintf("Waiting for event... (last %s)", humanize.Time(m.lastEvent))
+	cursor := fmt.Sprintf("X: %d, Y: %d", m.lastMouseEvent.X, m.lastMouseEvent.Y)
+
+	return fmt.Sprintf("%s\n%s%s\n%s",
+		lipgloss.NewStyle().Height(h+1).Render(s),
+		lipgloss.NewStyle().Width(m.width-16).Render(lastEvent),
+		lipgloss.NewStyle().Width(16).Align(lipgloss.Right).Render(cursor),
+		tooltipStyle.Render("Press Ctrl+C to quit"),
+	)
+}
+
+func msgView(msg tea.Msg) string {
+	switch ev := msg.(type) {
+	case tea.KeyMsg:
+		return fmt.Sprintf("%s %s",
+			typeStyle.Render("KeyMsg"),
+			msgStyle.Render(
+				fmt.Sprintf("%s (alt: %t)",
+					ev.String(),
+					ev.Alt,
+				),
+			),
+		)
+	case tea.MouseMsg:
+		return fmt.Sprintf("%s %s",
+			typeStyle.Render("MouseMsg"),
+			msgStyle.Render(
+				fmt.Sprintf("X: %d, Y: %d, type: %s",
+					ev.X,
+					ev.Y,
+					tea.MouseEvent(ev),
+				),
+			),
+		)
+	case tea.WindowSizeMsg:
+		return fmt.Sprintf("%s %s",
+			typeStyle.Render("WindowSizeMsg"),
+			msgStyle.Render(
+				fmt.Sprintf("%d x %d",
+					ev.Width,
+					ev.Height,
+				),
+			),
+		)
+
+	default:
+		return "Unknown event"
+	}
+}
+
+type tickMsg time.Time
+
+func tick() tea.Msg {
+	time.Sleep(time.Second)
+	return tickMsg{}
+}

examples/go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/charmbracelet/bubbletea v0.22.0
 	github.com/charmbracelet/glamour v0.5.0
 	github.com/charmbracelet/lipgloss v0.6.0
+	github.com/dustin/go-humanize v1.0.0
 	github.com/fogleman/ease v0.0.0-20170301025033-8da417bf1776
 	github.com/lucasb-eyer/go-colorful v1.2.0
 	github.com/mattn/go-isatty v0.0.16

examples/go.sum

@@ -22,6 +22,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dlclark/regexp2 v1.4.0 h1:F1rxgk7p4uKjwIQxBs9oAXe5CqrXlCduYEJvrF4u93E=
 github.com/dlclark/regexp2 v1.4.0/go.mod h1:2pZnwuY/m+8K6iRw6wQdMtk+rH5tNGR1i55kozfMjCc=
+github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo=
+github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/fogleman/ease v0.0.0-20170301025033-8da417bf1776 h1:VRIbnDWRmAh5yBdz+J6yFMF5vso1It6vn+WmM/5l7MA=
 github.com/fogleman/ease v0.0.0-20170301025033-8da417bf1776/go.mod h1:9wvnDu3YOfxzWM9Cst40msBF1C2UdQgDv962oTxSuMs=
 github.com/gorilla/css v1.0.0 h1:BQqNyPTi50JCFMTw/b67hByjMVXZRwGha6wxVGkeihY=