refactor: rework file structure (#325)

* wip: add middlewares

* refactor: use context fom middleware in handlers

* refactor: use controller approach in handlers

* refactor: move oauth providers into services (non-working)

* feat: create oauth broker service

* refactor: use a boostrap service to bootstrap the app

* refactor: split utils into smaller files

* refactor: use more clear name for frontend assets

* feat: allow customizability of resources dir

* fix: fix typo in ui middleware

* fix: validate resource file paths in ui middleware

* refactor: move resource handling to a controller

* feat: add some logging

* fix: configure middlewares before groups

* fix: use correct api path in login mutation

* fix: coderabbit suggestions

* fix: further coderabbit suggestions

internal/service/google_oauth_service.go

@@ -0,0 +1,113 @@
+package service
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+	"tinyauth/internal/config"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/endpoints"
+)
+
+var GoogleOAuthScopes = []string{"https://www.googleapis.com/auth/userinfo.email", "https://www.googleapis.com/auth/userinfo.profile"}
+
+type GoogleUserInfoResponse struct {
+	Email string `json:"email"`
+	Name  string `json:"name"`
+}
+
+type GoogleOAuthService struct {
+	Config   oauth2.Config
+	Context  context.Context
+	Token    *oauth2.Token
+	Verifier string
+}
+
+func NewGoogleOAuthService(config config.OAuthServiceConfig) *GoogleOAuthService {
+	return &GoogleOAuthService{
+		Config: oauth2.Config{
+			ClientID:     config.ClientID,
+			ClientSecret: config.ClientSecret,
+			RedirectURL:  config.RedirectURL,
+			Scopes:       GoogleOAuthScopes,
+			Endpoint:     endpoints.Google,
+		},
+	}
+}
+
+func (google *GoogleOAuthService) Init() error {
+	httpClient := &http.Client{}
+	ctx := context.Background()
+	ctx = context.WithValue(ctx, oauth2.HTTPClient, httpClient)
+	verifier := oauth2.GenerateVerifier()
+
+	google.Context = ctx
+	google.Verifier = verifier
+	return nil
+}
+
+func (oauth *GoogleOAuthService) GenerateState() string {
+	b := make([]byte, 128)
+	_, err := rand.Read(b)
+	if err != nil {
+		return base64.RawURLEncoding.EncodeToString(fmt.Appendf(nil, "state-%d", time.Now().UnixNano()))
+	}
+	state := base64.RawURLEncoding.EncodeToString(b)
+	return state
+}
+
+func (google *GoogleOAuthService) GetAuthURL(state string) string {
+	return google.Config.AuthCodeURL(state, oauth2.AccessTypeOffline, oauth2.S256ChallengeOption(google.Verifier))
+}
+
+func (google *GoogleOAuthService) VerifyCode(code string) error {
+	token, err := google.Config.Exchange(google.Context, code, oauth2.VerifierOption(google.Verifier))
+
+	if err != nil {
+		return err
+	}
+
+	google.Token = token
+	return nil
+}
+
+func (google *GoogleOAuthService) Userinfo() (config.Claims, error) {
+	var user config.Claims
+
+	client := google.Config.Client(google.Context, google.Token)
+
+	res, err := client.Get("https://www.googleapis.com/userinfo/v2/me")
+	if err != nil {
+		return config.Claims{}, err
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode < 200 || res.StatusCode >= 300 {
+		return user, fmt.Errorf("request failed with status: %s", res.Status)
+	}
+
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return config.Claims{}, err
+	}
+
+	var userInfo GoogleUserInfoResponse
+
+	err = json.Unmarshal(body, &userInfo)
+	if err != nil {
+		return config.Claims{}, err
+	}
+
+	user.PreferredUsername = strings.Split(userInfo.Email, "@")[0]
+	user.Name = userInfo.Name
+	user.Email = userInfo.Email
+
+	return user, nil
+}