6 files changed, 374 insertions, 0 deletions
diff --git a/cli/internal/ui/charset.go b/cli/internal/ui/charset.go
new file mode 100644
index 0000000..0207c10
--- /dev/null
+++ b/cli/internal/ui/charset.go
@@ -0,0 +1,3 @@
+package ui
+
+var charset = []string{"   ", ">  ", ">> ", ">>>"}
diff --git a/cli/internal/ui/colors.go b/cli/internal/ui/colors.go
new file mode 100644
index 0000000..4b2eccd
--- /dev/null
+++ b/cli/internal/ui/colors.go
@@ -0,0 +1,54 @@
+package ui
+
+import (
+	"os"
+
+	"github.com/fatih/color"
+)
+
+type ColorMode int
+
+const (
+	ColorModeUndefined ColorMode = iota + 1
+	ColorModeSuppressed
+	ColorModeForced
+)
+
+func GetColorModeFromEnv() ColorMode {
+	// The FORCED_COLOR behavior and accepted values are taken from the supports-color NodeJS Package:
+	// The accepted values as documented are "0" to disable, and "1", "2", or "3" to force-enable color
+	// at the specified support level (1 = 16 colors, 2 = 256 colors, 3 = 16M colors).
+	// We don't currently use the level for anything specific, and just treat things as on and off.
+	//
+	// Note: while "false" and "true" aren't documented, the library coerces these values to 0 and 1
+	// respectively, so that behavior is reproduced here as well.
+	// https://www.npmjs.com/package/supports-color
+
+	switch forceColor := os.Getenv("FORCE_COLOR"); {
+	case forceColor == "false" || forceColor == "0":
+		return ColorModeSuppressed
+	case forceColor == "true" || forceColor == "1" || forceColor == "2" || forceColor == "3":
+		return ColorModeForced
+	default:
+		return ColorModeUndefined
+	}
+}
+
+func applyColorMode(colorMode ColorMode) ColorMode {
+	switch colorMode {
+	case ColorModeForced:
+		color.NoColor = false
+	case ColorModeSuppressed:
+		color.NoColor = true
+	case ColorModeUndefined:
+	default:
+		// color.NoColor already gets its default value based on
+		// isTTY and/or the presence of the NO_COLOR env variable.
+	}
+
+	if color.NoColor {
+		return ColorModeSuppressed
+	} else {
+		return ColorModeForced
+	}
+}
diff --git a/cli/internal/ui/spinner.go b/cli/internal/ui/spinner.go
new file mode 100644
index 0000000..6e47d2d
--- /dev/null
+++ b/cli/internal/ui/spinner.go
@@ -0,0 +1,80 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+package ui
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/briandowns/spinner"
+)
+
+// startStopper is the interface to interact with the spinner.
+type startStopper interface {
+	Start()
+	Stop()
+}
+
+// Spinner represents an indicator that an asynchronous operation is taking place.
+//
+// For short operations, less than 4 seconds, display only the spinner with the Start and Stop methods.
+// For longer operations, display intermediate progress events using the Events method.
+type Spinner struct {
+	spin startStopper
+}
+
+// NewSpinner returns a spinner that outputs to w.
+func NewSpinner(w io.Writer) *Spinner {
+	interval := 125 * time.Millisecond
+	if os.Getenv("CI") == "true" {
+		interval = 30 * time.Second
+	}
+	s := spinner.New(charset, interval, spinner.WithHiddenCursor(true))
+	s.Writer = w
+	s.Color("faint")
+	return &Spinner{
+		spin: s,
+	}
+}
+
+// Start starts the spinner suffixed with a label.
+func (s *Spinner) Start(label string) {
+	s.suffix(fmt.Sprintf(" %s", label))
+	s.spin.Start()
+}
+
+// Stop stops the spinner and replaces it with a label.
+func (s *Spinner) Stop(label string) {
+	s.finalMSG(fmt.Sprint(label))
+	s.spin.Stop()
+}
+
+func (s *Spinner) lock() {
+	if spinner, ok := s.spin.(*spinner.Spinner); ok {
+		spinner.Lock()
+	}
+}
+
+func (s *Spinner) unlock() {
+	if spinner, ok := s.spin.(*spinner.Spinner); ok {
+		spinner.Unlock()
+	}
+}
+
+func (s *Spinner) suffix(label string) {
+	s.lock()
+	defer s.unlock()
+	if spinner, ok := s.spin.(*spinner.Spinner); ok {
+		spinner.Suffix = label
+	}
+}
+
+func (s *Spinner) finalMSG(label string) {
+	s.lock()
+	defer s.unlock()
+	if spinner, ok := s.spin.(*spinner.Spinner); ok {
+		spinner.FinalMSG = label
+	}
+}
diff --git a/cli/internal/ui/term/cursor.go b/cli/internal/ui/term/cursor.go
new file mode 100644
index 0000000..253f043
--- /dev/null
+++ b/cli/internal/ui/term/cursor.go
@@ -0,0 +1,73 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package cursor provides functionality to interact with the terminal cursor.
+package cursor
+
+import (
+	"io"
+	"os"
+
+	"github.com/AlecAivazis/survey/v2/terminal"
+)
+
+type cursor interface {
+	Up(n int) error
+	Down(n int) error
+	Hide() error
+	Show() error
+}
+
+// fakeFileWriter is a terminal.FileWriter.
+// If the underlying writer w does not implement Fd() then a dummy value is returned.
+type fakeFileWriter struct {
+	w io.Writer
+}
+
+// Write delegates to the internal writer.
+func (w *fakeFileWriter) Write(p []byte) (int, error) {
+	return w.w.Write(p)
+}
+
+// Fd is required to be implemented to satisfy the terminal.FileWriter interface.
+// If the underlying writer is a file, like os.Stdout, then invoke it. Otherwise, this method allows us to create
+// a Cursor that can write to any io.Writer like a bytes.Buffer by returning a dummy value.
+func (w *fakeFileWriter) Fd() uintptr {
+	if v, ok := w.w.(terminal.FileWriter); ok {
+		return v.Fd()
+	}
+	return 0
+}
+
+// Cursor represents the terminal's cursor.
+type Cursor struct {
+	c cursor
+}
+
+// New creates a new cursor that writes to stderr.
+func New() *Cursor {
+	return &Cursor{
+		c: &terminal.Cursor{
+			Out: os.Stderr,
+		},
+	}
+}
+
+// EraseLine erases a line from a FileWriter.
+func EraseLine(fw terminal.FileWriter) {
+	terminal.EraseLine(fw, terminal.ERASE_LINE_ALL)
+}
+
+// EraseLinesAbove erases a line and moves the cursor up from fw, repeated n times.
+func EraseLinesAbove(fw terminal.FileWriter, n int) {
+	c := Cursor{
+		c: &terminal.Cursor{
+			Out: fw,
+		},
+	}
+	for i := 0; i < n; i += 1 {
+		EraseLine(fw)
+		c.c.Up(1)
+	}
+	EraseLine(fw) // Erase the nth line as well.
+}
diff --git a/cli/internal/ui/term/cursor_test.go b/cli/internal/ui/term/cursor_test.go
new file mode 100644
index 0000000..270ebe8
--- /dev/null
+++ b/cli/internal/ui/term/cursor_test.go
@@ -0,0 +1,43 @@
+//go:build !windows
+// +build !windows
+
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+package cursor
+
+import (
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/AlecAivazis/survey/v2/terminal"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEraseLine(t *testing.T) {
+	testCases := map[string]struct {
+		inWriter    func(writer io.Writer) terminal.FileWriter
+		shouldErase bool
+	}{
+		"should erase a line if the writer is a file": {
+			inWriter: func(writer io.Writer) terminal.FileWriter {
+				return &fakeFileWriter{w: writer}
+			},
+			shouldErase: true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			// GIVEN
+			buf := new(strings.Builder)
+
+			// WHEN
+			EraseLine(tc.inWriter(buf))
+
+			// THEN
+			isErased := buf.String() != ""
+			require.Equal(t, tc.shouldErase, isErased)
+		})
+	}
+}
diff --git a/cli/internal/ui/ui.go b/cli/internal/ui/ui.go
new file mode 100644
index 0000000..9084c76
--- /dev/null
+++ b/cli/internal/ui/ui.go
@@ -0,0 +1,121 @@
+package ui
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/fatih/color"
+	"github.com/mattn/go-isatty"
+	"github.com/mitchellh/cli"
+	"github.com/vercel/turbo/cli/internal/ci"
+)
+
+const ansiEscapeStr = "[\u001B\u009B][[\\]()#;?]*(?:(?:(?:[a-zA-Z\\d]*(?:;[a-zA-Z\\d]*)*)?\u0007)|(?:(?:\\d{1,4}(?:;\\d{0,4})*)?[\\dA-PRZcf-ntqry=><~]))"
+
+// IsTTY is true when stdout appears to be a tty
+var IsTTY = isatty.IsTerminal(os.Stdout.Fd()) || isatty.IsCygwinTerminal(os.Stdout.Fd())
+
+// IsCI is true when we appear to be running in a non-interactive context.
+var IsCI = !IsTTY || ci.IsCi()
+var gray = color.New(color.Faint)
+var bold = color.New(color.Bold)
+var ERROR_PREFIX = color.New(color.Bold, color.FgRed, color.ReverseVideo).Sprint(" ERROR ")
+var WARNING_PREFIX = color.New(color.Bold, color.FgYellow, color.ReverseVideo).Sprint(" WARNING ")
+
+// InfoPrefix is a colored string for warning level log messages
+var InfoPrefix = color.New(color.Bold, color.FgWhite, color.ReverseVideo).Sprint(" INFO ")
+
+var ansiRegex = regexp.MustCompile(ansiEscapeStr)
+
+// Dim prints out dimmed text
+func Dim(str string) string {
+	return gray.Sprint(str)
+}
+
+func Bold(str string) string {
+	return bold.Sprint(str)
+}
+
+// Adapted from go-rainbow
+// Copyright (c) 2017 Raphael Amorim
+// Source: https://github.com/raphamorim/go-rainbow
+// SPDX-License-Identifier: MIT
+func rgb(i int) (int, int, int) {
+	var f = 0.275
+
+	return int(math.Sin(f*float64(i)+4*math.Pi/3)*127 + 128),
+		// int(math.Sin(f*float64(i)+2*math.Pi/3)*127 + 128),
+		int(45),
+		int(math.Sin(f*float64(i)+0)*127 + 128)
+}
+
+// Rainbow function returns a formated colorized string ready to print it to the shell/terminal
+//
+// Adapted from go-rainbow
+// Copyright (c) 2017 Raphael Amorim
+// Source: https://github.com/raphamorim/go-rainbow
+// SPDX-License-Identifier: MIT
+func Rainbow(text string) string {
+	var rainbowStr []string
+	for index, value := range text {
+		r, g, b := rgb(index)
+		str := fmt.Sprintf("\033[1m\033[38;2;%d;%d;%dm%c\033[0m\033[0;1m", r, g, b, value)
+		rainbowStr = append(rainbowStr, str)
+	}
+
+	return strings.Join(rainbowStr, "")
+}
+
+type stripAnsiWriter struct {
+	wrappedWriter io.Writer
+}
+
+func (into *stripAnsiWriter) Write(p []byte) (int, error) {
+	n, err := into.wrappedWriter.Write(ansiRegex.ReplaceAll(p, []byte{}))
+	if err != nil {
+		// The number of bytes returned here isn't directly related to the input bytes
+		// if ansi color codes were being stripped out, but we are counting on Stdout.Write
+		// not failing under typical operation as well.
+		return n, err
+	}
+
+	// Write must return a non-nil error if it returns n < len(p). Consequently, if the
+	// wrappedWrite.Write call succeeded we will return len(p) as the number of bytes
+	// written.
+	return len(p), nil
+}
+
+// Default returns the default colored ui
+func Default() *cli.ColoredUi {
+	return BuildColoredUi(ColorModeUndefined)
+}
+
+func BuildColoredUi(colorMode ColorMode) *cli.ColoredUi {
+	colorMode = applyColorMode(colorMode)
+
+	var outWriter, errWriter io.Writer
+
+	if colorMode == ColorModeSuppressed {
+		outWriter = &stripAnsiWriter{wrappedWriter: os.Stdout}
+		errWriter = &stripAnsiWriter{wrappedWriter: os.Stderr}
+	} else {
+		outWriter = os.Stdout
+		errWriter = os.Stderr
+	}
+
+	return &cli.ColoredUi{
+		Ui: &cli.BasicUi{
+			Reader:      os.Stdin,
+			Writer:      outWriter,
+			ErrorWriter: errWriter,
+		},
+		OutputColor: cli.UiColorNone,
+		InfoColor:   cli.UiColorNone,
+		WarnColor:   cli.UiColor{Code: int(color.FgYellow), Bold: false},
+		ErrorColor:  cli.UiColorRed,
+	}
+}