cute command to show a thank you to contributors

this commit is the result of April's hack day. it animates a thank you
for a project's contributors.

it only really works on linux/mac; animation woes led me to just make it
static and plain on windows.

command/credits.go

@@ -0,0 +1,248 @@
+package command
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"math/rand"
+	"os"
+	"os/exec"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/crypto/ssh/terminal"
+
+	"github.com/cli/cli/utils"
+)
+
+var isWindows bool
+
+var thankYou = `
+     _                    _
+    | |                  | |
+_|_ | |     __,   _  _   | |           __
+ |  |/ \   /  |  / |/ |  |/_)   |   | /  \_|   |
+ |_/|   |_/\_/|_/  |  |_/| \_/   \_/|/\__/  \_/|_/
+                                   /|
+                                   \|
+                              _
+                           o | |                           |
+ __   __   _  _  _|_  ,_     | |        _|_  __   ,_    ,  |
+/    /  \_/ |/ |  |  /  |  | |/ \_|   |  |  /  \_/  |  / \_|
+\___/\__/   |  |_/|_/   |_/|_/\_/  \_/|_/|_/\__/    |_/ \/ o
+                                                            
+                                                            
+`
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+	isWindows = runtime.GOOS == "windows"
+
+	RootCmd.AddCommand(creditsCmd)
+
+	creditsCmd.Flags().BoolP("static", "s", false, "Print a static version of the credits")
+}
+
+var creditsCmd = &cobra.Command{
+	Use:   "credits [repository]",
+	Short: "View project's credits",
+	Long: `View animated credits for this or another project.
+
+Examples:
+
+  gh credits            # see a credits animation for this project
+  gh credits owner/repo # see a credits animation for owner/repo
+  gh credts -s          # display a static thank you instead of animating
+  gh credits | cat      # just print the contributors, one per line
+`,
+	Args: cobra.MaximumNArgs(1),
+	RunE: credits,
+}
+
+func credits(cmd *cobra.Command, args []string) error {
+	ctx := contextForCommand(cmd)
+	client, err := apiClientForContext(ctx)
+	if err != nil {
+		return err
+	}
+
+	owner := "cli"
+	repo := "cli"
+	if len(args) > 0 {
+		parts := strings.SplitN(args[0], "/", 2)
+		owner = parts[0]
+		repo = parts[1]
+	}
+
+	type Contributor struct {
+		Login string
+	}
+
+	type Result []Contributor
+
+	result := Result{}
+	body := bytes.NewBufferString("")
+	path := fmt.Sprintf("repos/%s/%s/contributors", owner, repo)
+
+	err = client.REST("GET", path, body, &result)
+	if err != nil {
+		return err
+	}
+
+	out := cmd.OutOrStdout()
+	isTTY := false
+	outFile, isFile := out.(*os.File)
+	if isFile {
+		isTTY = utils.IsTerminal(outFile)
+		if isTTY {
+			// FIXME: duplicates colorableOut
+			out = utils.NewColorable(outFile)
+		}
+	}
+
+	static, err := cmd.Flags().GetBool("static")
+	if err != nil {
+		return err
+	}
+
+	static = static || isWindows
+
+	if isTTY && static {
+		fmt.Fprintln(out, "THANK YOU CONTRIBUTORS!!! <3")
+		fmt.Println()
+	}
+
+	logins := []string{}
+	for x, c := range result {
+		if isTTY && !static {
+			logins = append(logins, getColor(x)(c.Login))
+		} else {
+			fmt.Fprintf(out, "%s\n", c.Login)
+		}
+	}
+
+	if !isTTY || static {
+		return nil
+	}
+
+	lines := []string{}
+
+	thankLines := strings.Split(thankYou, "\n")
+	for x, tl := range thankLines {
+		lines = append(lines, getColor(x)(tl))
+	}
+	lines = append(lines, "")
+	lines = append(lines, logins...)
+	lines = append(lines, "( <3 press ctrl-c to quit <3 )")
+
+	termWidth, termHeight, err := terminal.GetSize(int(outFile.Fd()))
+	if err != nil {
+		return err
+	}
+
+	margin := termWidth / 3
+
+	starLinesLeft := []string{}
+	for x := 0; x < len(lines); x++ {
+		starLinesLeft = append(starLinesLeft, starLine(margin))
+	}
+
+	starLinesRight := []string{}
+	for x := 0; x < len(lines); x++ {
+		lineWidth := termWidth - (margin + len(lines[x]))
+		starLinesRight = append(starLinesRight, starLine(lineWidth))
+	}
+
+	loop := true
+	startx := termHeight - 1
+	li := 0
+
+	for loop {
+		clear()
+		for x := 0; x < termHeight; x++ {
+			if x == startx || startx < 0 {
+				starty := 0
+				if startx < 0 {
+					starty = int(math.Abs(float64(startx)))
+				}
+				for y := starty; y < li+1; y++ {
+					if y >= len(lines) {
+						continue
+					}
+					starLineLeft := starLinesLeft[y]
+					starLinesLeft[y] = twinkle(starLineLeft)
+					starLineRight := starLinesRight[y]
+					starLinesRight[y] = twinkle(starLineRight)
+					fmt.Fprintf(out, "%s %s %s\n", starLineLeft, lines[y], starLineRight)
+				}
+				li += 1
+				x += li
+			} else {
+				fmt.Fprintf(out, "\n")
+			}
+		}
+		if li < len(lines) {
+			startx -= 1
+		}
+		time.Sleep(300 * time.Millisecond)
+	}
+
+	return nil
+}
+
+func starLine(width int) string {
+	line := ""
+	starChance := 0.1
+	for y := 0; y < width; y++ {
+		chance := rand.Float64()
+		if chance <= starChance {
+			charRoll := rand.Float64()
+			switch {
+			case charRoll < 0.3:
+				line += "."
+			case charRoll > 0.3 && charRoll < 0.6:
+				line += "+"
+			default:
+				line += "*"
+			}
+		} else {
+			line += " "
+		}
+	}
+
+	return line
+}
+
+func twinkle(starLine string) string {
+	starLine = strings.ReplaceAll(starLine, ".", "P")
+	starLine = strings.ReplaceAll(starLine, "+", "A")
+	starLine = strings.ReplaceAll(starLine, "*", ".")
+	starLine = strings.ReplaceAll(starLine, "P", "+")
+	starLine = strings.ReplaceAll(starLine, "A", "*")
+	return starLine
+}
+
+func getColor(x int) func(string) string {
+	rainbow := []func(string) string{
+		utils.Magenta,
+		utils.Red,
+		utils.Yellow,
+		utils.Green,
+		utils.Cyan,
+		utils.Blue,
+	}
+
+	ix := x % len(rainbow)
+
+	return rainbow[ix]
+}
+
+func clear() {
+	// on windows we'd do cmd := exec.Command("cmd", "/c", "cls"); unfortunately the draw speed is so
+	// slow that the animation is very jerky, flashy, and painful to look at.
+	cmd := exec.Command("clear")
+	cmd.Stdout = os.Stdout
+	_ = cmd.Run()
+}