mc/notifier.go

package main

import (
	"fmt"
	"strings"

	"github.com/fatih/color"
)

// go get update string
const (
	updateString = "go get -u github.com/minio-io/mc"
)

// intMax - return maximum value for any given integer
func intMax(x, y int) int {
	if x > y {
		return x
	}
	return y
}

// printUpdateNotify -
func printUpdateNotify(latestVersion, currentVersion string) {
	// TODO - make this configurable
	//
	// initialize coloring
	green := color.New(color.FgGreen)
	boldGreen := green.Add(color.Bold).SprintFunc()
	blue := color.New(color.FgBlue).SprintFunc()
	blueFaint := color.New(color.FgBlue, color.BlinkSlow).SprintfFunc()
	yellow := color.New(color.FgYellow).SprintfFunc()

	// calculate length without color coding, since due to
	// ANSI characters it would mis-calculate the real length
	line1Length := len(fmt.Sprintf("  Update available: %s (current: %s)", latestVersion, currentVersion))
	line2Length := len(fmt.Sprintf("  Run %s to update. ", updateString))

	// populate lines with color coding
	line1InColor := fmt.Sprintf("  Update available: %s (current: %s)", boldGreen(latestVersion), blueFaint(currentVersion))
	line2InColor := fmt.Sprintf("  Run %s to update. ", blue(updateString))

	// calculate the rectangular box size
	maxContentWidth := intMax(line1Length, line2Length)
	line1Rest := maxContentWidth - line1Length
	line2Rest := maxContentWidth - line2Length

	// color the rectangular box
	top := yellow("┏" + strings.Repeat("━", maxContentWidth) + "┓")
	bottom := yellow("┗" + strings.Repeat("━", maxContentWidth) + "┛")
	sideBar := yellow("┃")

	// fill spaces to the rest of the area
	spacePaddingLine1 := strings.Repeat(" ", line1Rest)
	spacePaddingLine2 := strings.Repeat(" ", line2Rest)

	// construct the final message
	message := "\n" + top + "\n" +
		sideBar + line1InColor + spacePaddingLine1 + sideBar + "\n" +
		sideBar + line2InColor + spacePaddingLine2 + sideBar + "\n" +
		bottom + "\n"

	// finally print the message
	fmt.Println(message)
}