Add the authenticate sud command

cmd/authenticate.go

@@ -0,0 +1,73 @@
+package cmd
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/cking/go-mastodon"
+	"github.com/spf13/cobra"
+)
+
+const MASTODON_REDIRECT_URI = "urn:ietf:wg:oauth:2.0:oob"
+
+// authenticateCmd represents the authenticate command
+var authenticateCmd = &cobra.Command{
+	Use:   "authenticate",
+	Short: "Authenticate the bot against Mastodon",
+	Long:  "Authenticate against the specified Mastodon instance.",
+	Args:  cobra.MinimumNArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		mastodon_instance_address := args[0]
+
+		app, err := mastodon.RegisterApp(context.Background(), &mastodon.AppConfig{
+			Server:     mastodon_instance_address,
+			ClientName: "tg2mastodon",
+			Scopes:     "read write follow",
+			Website:    "https://noa.mornie.org/eriol/tg2mastodon",
+		})
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		client := mastodon.NewClient(&mastodon.Config{
+			Server:       mastodon_instance_address,
+			ClientID:     app.ClientID,
+			ClientSecret: app.ClientSecret,
+		})
+
+		fmt.Printf("Please open the following URL to authenticate: %s\n",
+			app.AuthURI)
+		fmt.Printf("And paste the authentication code here and press enter: ")
+
+		reader := bufio.NewReader(os.Stdin)
+		authCode, err := reader.ReadString('\n')
+		if err != nil {
+			fmt.Println("An error occured while reading input. Please try again", err)
+			return
+		}
+		authCode = strings.TrimSuffix(authCode, "\n")
+
+		err = client.AuthenticateToken(
+			context.Background(),
+			authCode,
+			MASTODON_REDIRECT_URI)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Println("Authentication success!")
+		fmt.Println("Please exporte the following environment variables:")
+		fmt.Printf("export MASTODON_SERVER_ADDRESS='%s'\n", mastodon_instance_address)
+		fmt.Printf("export MASTODON_ACCESS_TOKEN='%s'\n", client.Config.AccessToken)
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(authenticateCmd)
+}