feat: print unmanaged output above the application (#249)

* merge Adjective-Object/tea_log_renderer into standard renderer

* rename queuedMessages -> queuedMessageLines & break apart strings during message processing

* delete cursorDownBy

* += 1 -> ++ to make the linter happy

* add skipLines[] tracking back to standard renderer, and add rename skippedLines local to jumpedLines to clarify they are separate comments

* request repaint when a message is recieved

* Convert Println and Printf to commands

* Add package manager example demonstrating tea.Printf

* Use Unix instead of UnixMicro for Go 1.13 support in CI

* fix off by one in std renderer

* add Printf/Println to tea.go

* revert attempt at sequence compression + cursorUpBy

Co-authored-by: Maxwell Huang-Hobbs <mahuangh@microsoft.com>
Co-authored-by: Christian Rocha <christian@rocha.is>

examples/package-manager/main.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/charmbracelet/bubbles/progress"
+	"github.com/charmbracelet/bubbles/spinner"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+type model struct {
+	packages []string
+	index    int
+	width    int
+	height   int
+	spinner  spinner.Model
+	progress progress.Model
+	done     bool
+}
+
+var (
+	currentPkgNameStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("211"))
+	subtleStyle         = lipgloss.NewStyle().Foreground(lipgloss.Color("239"))
+	doneStyle           = lipgloss.NewStyle().Margin(1, 2)
+	checkMark           = lipgloss.NewStyle().Foreground(lipgloss.Color("42")).SetString("✓")
+)
+
+func newModel() model {
+	p := progress.New(
+		progress.WithDefaultGradient(),
+		progress.WithWidth(40),
+		progress.WithoutPercentage(),
+	)
+	s := spinner.New()
+	s.Style = lipgloss.NewStyle().Foreground(lipgloss.Color("63"))
+	return model{
+		packages: getPackages(),
+		spinner:  s,
+		progress: p,
+	}
+}
+
+func (m model) Init() tea.Cmd {
+	return tea.Batch(downloadAndInstall(m.packages[m.index]), m.spinner.Tick)
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.width, m.height = msg.Width, msg.Height
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "ctrl+c", "esc", "q":
+			return m, tea.Quit
+		}
+	case installedPkgMsg:
+		if m.index >= len(m.packages)-1 {
+			// Everything's been installed. We're done!
+			m.done = true
+			return m, tea.Quit
+		}
+
+		// Update progress bar
+		progressCmd := m.progress.SetPercent(float64(m.index) / float64(len(m.packages)-1))
+
+		m.index++
+		return m, tea.Batch(
+			progressCmd,
+			tea.Printf("%s %s", checkMark, m.packages[m.index]), // print success message above our program
+			downloadAndInstall(m.packages[m.index]),             // download the next package
+		)
+	case spinner.TickMsg:
+		var cmd tea.Cmd
+		m.spinner, cmd = m.spinner.Update(msg)
+		return m, cmd
+	case progress.FrameMsg:
+		newModel, cmd := m.progress.Update(msg)
+		if newModel, ok := newModel.(progress.Model); ok {
+			m.progress = newModel
+		}
+		return m, cmd
+	}
+	return m, nil
+}
+
+func (m model) View() string {
+	n := len(m.packages)
+	w := lipgloss.Width(fmt.Sprintf("%d", n))
+
+	if m.done {
+		return doneStyle.Render(fmt.Sprintf("Done! Installed %d packages.\n", n))
+	}
+
+	pkgCount := fmt.Sprintf(" %*d/%*d", w, m.index, w, n-1)
+
+	spin := m.spinner.View() + " "
+	prog := m.progress.View()
+	cellsAvail := max(0, m.width-lipgloss.Width(spin+prog+pkgCount))
+
+	pkgName := currentPkgNameStyle.Render(m.packages[m.index])
+	info := lipgloss.NewStyle().MaxWidth(cellsAvail).Render("Installing " + pkgName)
+
+	cellsRemaining := max(0, m.width-lipgloss.Width(spin+info+prog+pkgCount))
+	gap := strings.Repeat(" ", cellsRemaining)
+
+	return spin + info + gap + prog + pkgCount
+}
+
+type installedPkgMsg string
+
+func downloadAndInstall(pkg string) tea.Cmd {
+	// This is where you'd do i/o stuff to download and install packages. In
+	// our case we're just pausing for a moment to simulate the process.
+	d := time.Millisecond * time.Duration(rand.Intn(500))
+	return tea.Tick(d, func(t time.Time) tea.Msg {
+		return installedPkgMsg(pkg)
+	})
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func main() {
+	rand.Seed(time.Now().Unix())
+
+	if err := tea.NewProgram(newModel()).Start(); err != nil {
+		fmt.Println("Error running program:", err)
+		os.Exit(1)
+	}
+}

examples/package-manager/packages.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+)
+
+var packages = []string{
+	"vegeutils",
+	"libgardening",
+	"currykit",
+	"spicerack",
+	"fullenglish",
+	"eggy",
+	"bad-kitty",
+	"chai",
+	"hojicha",
+	"libtacos",
+	"babys-monads",
+	"libpurring",
+	"currywurst-devel",
+	"xmodmeow",
+	"licorice-utils",
+	"cashew-apple",
+	"rock-lobster",
+	"standmixer",
+	"coffee-CUPS",
+	"libesszet",
+	"zeichenorientierte-benutzerschnittstellen",
+	"schnurrkit",
+	"old-socks-devel",
+	"jalapeño",
+	"molasses-utils",
+	"xkohlrabi",
+	"party-gherkin",
+	"snow-peas",
+	"libyuzu",
+}
+
+func getPackages() []string {
+	pkgs := packages
+	copy(pkgs, packages)
+
+	rand.Shuffle(len(pkgs), func(i, j int) {
+		pkgs[i], pkgs[j] = pkgs[j], pkgs[i]
+	})
+
+	for k := range pkgs {
+		pkgs[k] += fmt.Sprintf("-%d.%d.%d", rand.Intn(10), rand.Intn(10), rand.Intn(10))
+	}
+	return pkgs
+}

standard_renderer.go

@@ -2,6 +2,7 @@ package tea
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"strings"
 	"sync"
@@ -23,16 +24,17 @@ const (
 // In cases where very high performance is needed the renderer can be told
 // to exclude ranges of lines, allowing them to be written to directly.
 type standardRenderer struct {
-	out               io.Writer
-	buf               bytes.Buffer
-	framerate         time.Duration
-	ticker            *time.Ticker
-	mtx               *sync.Mutex
-	done              chan struct{}
-	lastRender        string
-	linesRendered     int
-	useANSICompressor bool
-	once              sync.Once
+	out                io.Writer
+	buf                bytes.Buffer
+	queuedMessageLines []string
+	framerate          time.Duration
+	ticker             *time.Ticker
+	mtx                *sync.Mutex
+	done               chan struct{}
+	lastRender         string
+	linesRendered      int
+	useANSICompressor  bool
+	once               sync.Once
 
 	// essentially whether or not we're using the full size of the terminal
 	altScreenActive bool
@@ -49,10 +51,11 @@ type standardRenderer struct {
 // with os.Stdout as the first argument.
 func newRenderer(out io.Writer, mtx *sync.Mutex, useANSICompressor bool) renderer {
 	r := &standardRenderer{
-		out:               out,
-		mtx:               mtx,
-		framerate:         defaultFramerate,
-		useANSICompressor: useANSICompressor,
+		out:                out,
+		mtx:                mtx,
+		framerate:          defaultFramerate,
+		useANSICompressor:  useANSICompressor,
+		queuedMessageLines: []string{},
 	}
 	if r.useANSICompressor {
 		r.out = &compressor.Writer{Forward: out}
@@ -122,8 +125,16 @@ func (r *standardRenderer) flush() {
 	out := new(bytes.Buffer)
 
 	newLines := strings.Split(r.buf.String(), "\n")
+	numLinesThisFlush := len(newLines)
 	oldLines := strings.Split(r.lastRender, "\n")
 	skipLines := make(map[int]struct{})
+	flushQueuedMessages := len(r.queuedMessageLines) > 0 && !r.altScreenActive
+
+	// Add any queued messages to this render
+	if flushQueuedMessages {
+		newLines = append(r.queuedMessageLines, newLines...)
+		r.queuedMessageLines = []string{}
+	}
 
 	// Clear any lines we painted in the last render.
 	if r.linesRendered > 0 {
@@ -163,11 +174,9 @@ func (r *standardRenderer) flush() {
 		}
 	}
 
-	r.linesRendered = 0
-
 	// Paint new lines
 	for i := 0; i < len(newLines); i++ {
-		if _, skip := skipLines[r.linesRendered]; skip {
+		if _, skip := skipLines[i]; skip {
 			// Unless this is the last line, move the cursor down.
 			if i < len(newLines)-1 {
 				cursorDown(out)
@@ -192,8 +201,8 @@ func (r *standardRenderer) flush() {
 				_, _ = io.WriteString(out, "\r\n")
 			}
 		}
-		r.linesRendered++
 	}
+	r.linesRendered = numLinesThisFlush
 
 	// Make sure the cursor is at the start of the last line to keep rendering
 	// behavior consistent.
@@ -383,6 +392,15 @@ func (r *standardRenderer) handleMessages(msg Msg) {
 
 	case scrollDownMsg:
 		r.insertBottom(msg.lines, msg.topBoundary, msg.bottomBoundary)
+
+	case printLineMessage:
+		if !r.altScreenActive {
+			lines := strings.Split(msg.messageBody, "\n")
+			r.mtx.Lock()
+			r.queuedMessageLines = append(r.queuedMessageLines, lines...)
+			r.repaint()
+			r.mtx.Unlock()
+		}
 	}
 }
 
@@ -460,3 +478,38 @@ func ScrollDown(newLines []string, topBoundary, bottomBoundary int) Cmd {
 		}
 	}
 }
+
+type printLineMessage struct {
+	messageBody string
+}
+
+// Printf prints above the Program. This output is unmanaged by the program and
+// will persist across renders by the Program.
+//
+// Unlike fmt.Printf (but similar to log.Printf) the message will be print on
+// its own line.
+//
+// If the altscreen is active no output will be printed.
+func Println(args ...interface{}) Cmd {
+	return func() Msg {
+		return printLineMessage{
+			messageBody: fmt.Sprint(args...),
+		}
+	}
+}
+
+// Printf prints above the Program. It takes a format template followed by
+// values similar to fmt.Printf. This output is unmanaged by the program and
+// will persist across renders by the Program.
+//
+// Unlike fmt.Printf (but similar to log.Printf) the message will be print on
+// its own line.
+//
+// If the altscreen is active no output will be printed.
+func Printf(template string, args ...interface{}) Cmd {
+	return func() Msg {
+		return printLineMessage{
+			messageBody: fmt.Sprintf(template, args...),
+		}
+	}
+}

tea.go

@@ -709,3 +709,30 @@ func (p *Program) RestoreTerminal() error {
 
 	return nil
 }
+
+// Printf prints above the Program. This output is unmanaged by the program and
+// will persist across renders by the Program.
+//
+// Unlike fmt.Printf (but similar to log.Printf) the message will be print on
+// its own line.
+//
+// If the altscreen is active no output will be printed.
+func (p *Program) Println(args ...interface{}) {
+	p.msgs <- printLineMessage{
+		messageBody: fmt.Sprint(args...),
+	}
+}
+
+// Printf prints above the Program. It takes a format template followed by
+// values similar to fmt.Printf. This output is unmanaged by the program and
+// will persist across renders by the Program.
+//
+// Unlike fmt.Printf (but similar to log.Printf) the message will be print on
+// its own line.
+//
+// If the altscreen is active no output will be printed.
+func (p *Program) Printf(template string, args ...interface{}) {
+	p.msgs <- printLineMessage{
+		messageBody: fmt.Sprintf(template, args...),
+	}
+}