add auth logic in main (#8)

main.go

@@ -1,11 +1,65 @@
 /*
 Copyright © 2023 NAME HERE <EMAIL ADDRESS>
-
 */
 package main
 
-import "github.com/JunNishimura/Chatify/cmd"
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/JunNishimura/Chatify/cmd"
+	"github.com/google/uuid"
+	"github.com/joho/godotenv"
+	"github.com/pkg/browser"
+	"github.com/zmb3/spotify/v2"
+	spotifyauth "github.com/zmb3/spotify/v2/auth"
+)
+
+const (
+	envFileName = ".env"
+	redirectURI = "http://localhost:8888/callback"
+	port        = "8888"
+)
+
+var (
+	auth          *spotifyauth.Authenticator
+	clientChannel = make(chan *spotify.Client)
+	server        *http.Server
+	state         string
+)
 
 func main() {
+	if err := godotenv.Load(envFileName); err != nil {
+		log.Fatalf("fail to load env file: %v\n", err)
+	}
+	auth = spotifyauth.New(
+		spotifyauth.WithRedirectURL(redirectURI),
+		spotifyauth.WithScopes(spotifyauth.ScopeUserReadPrivate),
+	)
+
+	server = &http.Server{Addr: fmt.Sprintf(":%s", port)}
+	state = uuid.New().String()
+	http.HandleFunc("/callback", completeAuth)
+	go func() {
+		if err := server.ListenAndServe(); err != http.ErrServerClosed {
+			log.Fatal(err)
+		}
+	}()
+
+	authURL := auth.AuthURL(state)
+	if err := browser.OpenURL(authURL); err != nil {
+		log.Fatalf("fail to open: %s\n", authURL)
+	}
+
+	client := <-clientChannel
+
+	user, err := client.CurrentUser(context.Background())
+	if err != nil {
+		log.Fatalf("fail to get current user: %v\n", err)
+	}
+	fmt.Printf("logged in as: %s\n", user.DisplayName)
+
 	cmd.Execute()
 }