Show fireworks on exit

2 files changed, 122 insertions, 0 deletions

diff --git a/cmd/tasksamurai/main.go b/cmd/tasksamurai/main.go
index 52263de..a9d1837 100644
--- a/cmd/tasksamurai/main.go
+++ b/cmd/tasksamurai/main.go
@@ -35,4 +35,6 @@ func main() {
 		fmt.Fprintln(os.Stderr, "error running ui:", err)
 		os.Exit(1)
 	}
+
+	ui.Fireworks()
 }
diff --git a/internal/ui/fireworks.go b/internal/ui/fireworks.go
new file mode 100644
index 0000000..c902a67
--- /dev/null
+++ b/internal/ui/fireworks.go
@@ -0,0 +1,120 @@
+package ui
+
+import (
+	"math/rand"
+	"strings"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+type fwModel struct {
+	width  int
+	height int
+	start  time.Time
+	fws    []firework
+}
+
+type firework struct {
+	x, y  int
+	frame int
+}
+
+type tickMsg struct{}
+
+func tick() tea.Cmd {
+	return tea.Tick(150*time.Millisecond, func(time.Time) tea.Msg { return tickMsg{} })
+}
+
+func (m fwModel) Init() tea.Cmd {
+	m.start = time.Now()
+	return tick()
+}
+
+var frames = [][]string{
+	{"*"},
+	{" * ", "* *", " * "},
+	{"  *  ", " * * ", "*   *", " * * ", "  *  "},
+}
+
+func (m fwModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+		return m, nil
+	case tickMsg:
+		if time.Since(m.start) > 5*time.Second {
+			return m, tea.Quit
+		}
+		// advance frames
+		for i := 0; i < len(m.fws); {
+			m.fws[i].frame++
+			if m.fws[i].frame >= len(frames) {
+				m.fws = append(m.fws[:i], m.fws[i+1:]...)
+			} else {
+				i++
+			}
+		}
+		// maybe create new firework
+		if m.width > 0 && m.height > 0 {
+			if rand.Float64() < 0.4 {
+				x := rand.Intn(m.width)
+				y := rand.Intn(m.height)
+				m.fws = append(m.fws, firework{x: x, y: y})
+			}
+		}
+		return m, tick()
+	case tea.KeyMsg:
+		return m, tea.Quit
+	}
+	return m, nil
+}
+
+func (m fwModel) View() string {
+	if m.width == 0 || m.height == 0 {
+		return ""
+	}
+	grid := make([][]rune, m.height)
+	for i := range grid {
+		row := make([]rune, m.width)
+		for j := range row {
+			row[j] = ' '
+		}
+		grid[i] = row
+	}
+	for _, fw := range m.fws {
+		fr := frames[fw.frame]
+		oy := fw.y - len(fr)/2
+		for dy, line := range fr {
+			y := oy + dy
+			if y < 0 || y >= m.height {
+				continue
+			}
+			ox := fw.x - len([]rune(line))/2
+			for dx, r := range line {
+				x := ox + dx
+				if x < 0 || x >= m.width {
+					continue
+				}
+				if r != ' ' {
+					grid[y][x] = r
+				}
+			}
+		}
+	}
+	var b strings.Builder
+	for _, row := range grid {
+		b.WriteString(string(row))
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+// Fireworks runs a short fireworks animation. It stops after five seconds or
+// when a key is pressed.
+func Fireworks() {
+	rand.Seed(time.Now().UnixNano())
+	p := tea.NewProgram(fwModel{}, tea.WithAltScreen())
+	p.Run()
+}