Add update subcommand for check new version

Author: arimatakao

README.md

@@ -116,7 +116,8 @@ mdx ping
 
 - [X] Remove Doujinshi from list in `find` subcommand and add `doujinshi` flag for show Doujinshi in list.
 - [X] Add metadata for cbz downloaded archive.
-- [ ] Add check update subcommand.
+- [X] Add check update subcommand.
+- [ ] Add self update mechanism.
 - [ ] Add search filter for `find` subcommand.
 - [ ] Add flag `random` in `info` subcommand for get information about random manga.
 - [ ] Add flag to `download`:

cmd/consts.go

@@ -1,7 +1,7 @@
 package cmd
 
 const (
-	MDX_APP_VERSION      = "v1.5.1"
+	MDX_APP_VERSION      = "v1.6.0"
 	MANGADEX_API_VERSION = "v5.10.2"
 
 	MDX_USER_AGENT = "mdx-cli " + MDX_APP_VERSION

cmd/update.go

@@ -0,0 +1,88 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/go-resty/resty/v2"
+	"github.com/spf13/cobra"
+)
+
+var (
+	updateCmd = &cobra.Command{
+		Use:   "update",
+		Short: "Check for updates to application",
+		Run:   checkUpdate,
+	}
+)
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+}
+
+func checkUpdate(cmd *cobra.Command, args []string) {
+
+	result := struct {
+		TagName     string `json:"tag_name"`
+		Description string `json:"body"`
+	}{}
+
+	resp, err := resty.New().R().
+		SetHeader("User-Agent", MDX_USER_AGENT).
+		SetHeader("Accept", "application/vnd.github+json").
+		SetHeader("X-GitHub-Api-Version", "2022-11-28").
+		SetResult(&result).
+		Get("https://api.github.com/repos/arimatakao/mdx/releases/latest")
+	if err != nil {
+		fmt.Println("error while connecting to github api")
+		os.Exit(1)
+	}
+
+	if resp.IsError() {
+		fmt.Println("wrong response from github api")
+		os.Exit(1)
+	}
+
+	isShouldUpdate := false
+
+	parsedLatest := strings.Split(result.TagName, ".")
+	if len(parsedLatest) == 3 {
+		parsedCurrent := strings.Split(MDX_APP_VERSION, ".")
+		mainCurrent := parsedCurrent[0]
+		secondCurrent, _ := strconv.Atoi(parsedCurrent[1])
+		thirdCurrent, _ := strconv.Atoi(parsedCurrent[2])
+
+		isNotMainVersion := !strings.Contains(parsedLatest[0], mainCurrent)
+		if isNotMainVersion {
+			isShouldUpdate = true
+		}
+		if secondLast, err := strconv.Atoi(parsedLatest[1]); err != nil {
+			isShouldUpdate = true
+		} else if secondLast > secondCurrent {
+			isShouldUpdate = true
+		}
+		if thirdLast, err := strconv.Atoi(parsedLatest[2]); err != nil {
+			isShouldUpdate = true
+		} else if thirdLast > thirdCurrent {
+			isShouldUpdate = true
+		}
+	} else if result.TagName != MDX_APP_VERSION {
+		isShouldUpdate = true
+	}
+
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', 0)
+	fmt.Fprintf(w, "Your version\t: %s\n", MDX_APP_VERSION)
+	fmt.Fprintf(w, "Latest version\t: %s\n", result.TagName)
+	w.Flush()
+	if isShouldUpdate {
+		fmt.Printf("Download new version here: %s\n",
+			"https://github.com/arimatakao/mdx/releases")
+		fmt.Printf("Release description:\n---\n%s\n---\n",
+			result.Description)
+	} else {
+		fmt.Print("You have latest version.\n")
+	}
+}