added releases fetch and filting

Signed-off-by: Dipankar Das <65275144+dipankardas011@users.noreply.github.com>

cli/cmd/upgrade.go

@@ -1,14 +1,61 @@
 package cmd
 
 import (
+	"encoding/json"
+	"net/http"
 	"os"
+	"regexp"
 
 	"github.com/ksctl/cli/logger"
 	"github.com/ksctl/ksctl/pkg/types"
+	"github.com/pterm/pterm"
 
 	"github.com/spf13/cobra"
 )
 
+func fetchLatestVersion() ([]string, error) {
+
+	type Release struct {
+		TagName string `json:"tag_name"`
+	}
+
+	resp, err := http.Get("https://api.github.com/repos/ksctl/cli/releases")
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var _releases []Release
+	if err := json.NewDecoder(resp.Body).Decode(&_releases); err != nil {
+		return nil, err
+	}
+
+	var releases []string
+	rcRegex := regexp.MustCompile(`.*-rc[0-9]+$`)
+	for _, release := range _releases {
+		if rcRegex.MatchString(release.TagName) {
+			continue
+		}
+		releases = append(releases, release.TagName)
+	}
+
+	return releases, nil
+}
+
+func filterToUpgradeableVersions(versions []string) []string {
+	var upgradeableVersions []string
+	for _, version := range versions {
+		if version > Version {
+			upgradeableVersions = append(upgradeableVersions, version)
+		}
+	}
+	return upgradeableVersions
+}
+
+func update(version string) error {
+	return nil
+}
+
 var selfUpdate = &cobra.Command{
 	Use:   "self-update",
 	Short: "update the ksctl cli",
@@ -17,7 +64,25 @@ var selfUpdate = &cobra.Command{
 		verbosity, _ := cmd.Flags().GetInt("verbose")
 		var log types.LoggerFactory = logger.NewLogger(verbosity, os.Stdout)
 
-		newVer := "TODO"
+		// if Version == "dev" {
+		// 	log.Error("Cannot update a dev version of ksctl")
+		// 	os.Exit(1)
+		// }
+
+		vers, err := fetchLatestVersion()
+		if err != nil {
+			log.Error("Failed to fetch latest version", "error", err)
+			os.Exit(1)
+		}
+		vers = filterToUpgradeableVersions(vers)
+
+		log.Print(ctx, "Available versions to update")
+		selectedOption, _ := pterm.DefaultInteractiveSelect.WithOptions(vers).Show()
+
+		newVer := selectedOption
+
+		if err := update(newVer); err != nil {
+		}
 
 		log.Success(ctx, "Updated Ksctl cli", "previousVer", Version, "newVer", newVer)
 	},