Initial commit

feat: create basic server to manage google oauth, account, sessions, places, attributes and ratings.

internal/auth/google.go

@@ -0,0 +1,83 @@
+package auth
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+
+	"git.pengzhan.dev/noteplace-server/internal/models"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+)
+
+// Authenticator handles the OAuth2 flow.
+type Authenticator struct {
+	Config *oauth2.Config
+}
+
+// NewAuthenticator creates a new Authenticator.
+// It requires GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET environment variables.
+func NewAuthenticator() (*Authenticator, error) {
+	clientID := os.Getenv("GOOGLE_CLIENT_ID")
+	clientSecret := os.Getenv("GOOGLE_CLIENT_SECRET")
+
+	if clientID == "" || clientSecret == "" {
+		return nil, fmt.Errorf("GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET must be set")
+	}
+
+	config := &oauth2.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		RedirectURL:  "urn:ietf:wg:oauth:2.0:oob", // Special redirect URI for desktop/CLI apps
+		Scopes:       []string{"https://www.googleapis.com/auth/userinfo.email", "https://www.googleapis.com/auth/userinfo.profile"},
+		Endpoint:     google.Endpoint,
+	}
+
+	return &Authenticator{Config: config}, nil
+}
+
+// GetAuthURL generates the URL the user must visit to authorize the application.
+func (a *Authenticator) GetAuthURL() string {
+	// We don't need a state for this simple CLI flow, but it's good practice for web apps.
+	return a.Config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
+}
+
+// ExchangeCodeForToken takes an authorization code and exchanges it for a token.
+func (a *Authenticator) ExchangeCodeForToken(code string) (*oauth2.Token, error) {
+	return a.Config.Exchange(context.Background(), code)
+}
+
+// GetUserInfo uses the token to fetch the user's profile from Google.
+func (a *Authenticator) GetUserInfo(token *oauth2.Token) (models.User, error) {
+	client := a.Config.Client(context.Background(), token)
+	resp, err := client.Get("https://www.googleapis.com/oauth2/v2/userinfo")
+	if err != nil {
+		return models.User{}, err
+	}
+	defer func() {
+		_ = resp.Body.Close()
+	}()
+
+	var userInfo struct {
+		ID    string `json:"id"`
+		Email string `json:"email"`
+		Name  string `json:"name"`
+	}
+
+	if err := json.NewDecoder(resp.Body).Decode(&userInfo); err != nil {
+		return models.User{}, err
+	}
+
+	log.Printf("Fetched user info from Google: ID=%s, Name=%s", userInfo.ID, userInfo.Name)
+
+	// We create a new User model from the Google info.
+	user := models.User{
+		GoogleID:    userInfo.ID,
+		DisplayName: userInfo.Name,
+		Email:       userInfo.Email,
+	}
+
+	return user, nil
+}