refactor: simplify provider management and add Type method

- Change providers from map to slice for simpler management
- Add Type() method to Provider interface for CSS class naming
- Update template to use provider Type() for styling instead of Name
- Simplify login template data structure
- Add OIDC provider styling support

Author: hrntknr

pkg/auth/auth.go

@@ -17,17 +17,12 @@ var templateFS embed.FS
 
 type AuthRouter struct {
 	passwordHash         []string
-	providers            map[string]Provider
+	providers            []Provider
 	template             *template.Template
 	unauthorizedTemplate *template.Template
 }
 
 func NewAuthRouter(passwordHash []string, providers ...Provider) (*AuthRouter, error) {
-	providersMap := make(map[string]Provider)
-	for _, provider := range providers {
-		providersMap[provider.Name()] = provider
-	}
-
 	tmpl, err := template.ParseFS(templateFS, "templates/login.html")
 	if err != nil {
 		return nil, err
@@ -40,7 +35,7 @@ func NewAuthRouter(passwordHash []string, providers ...Provider) (*AuthRouter, e
 
 	return &AuthRouter{
 		passwordHash:         passwordHash,
-		providers:            providersMap,
+		providers:            providers,
 		template:             tmpl,
 		unauthorizedTemplate: unauthorizedTmpl,
 	}, nil
@@ -114,9 +109,19 @@ func (a *AuthRouter) SetupRoutes(router gin.IRouter) {
 	}
 }
 
-type ProviderData struct {
-	Name string
-	URL  string
+func (a *AuthRouter) getProvider(name string) Provider {
+	for _, provider := range a.providers {
+		if provider.Name() == name {
+			return provider
+		}
+	}
+	return nil
+}
+
+type templateData struct {
+	Providers     []Provider
+	HasPassword   bool
+	PasswordError string
 }
 
 func (a *AuthRouter) handleLogin(c *gin.Context) {
@@ -125,20 +130,8 @@ func (a *AuthRouter) handleLogin(c *gin.Context) {
 		return
 	}
 
-	var providersData []ProviderData
-	for name := range a.providers {
-		providersData = append(providersData, ProviderData{
-			Name: name,
-			URL:  a.providers[name].AuthURL(),
-		})
-	}
-
-	data := struct {
-		Providers     []ProviderData
-		HasPassword   bool
-		PasswordError string
-	}{
-		Providers:     providersData,
+	data := templateData{
+		Providers:     a.providers,
 		HasPassword:   len(a.passwordHash) > 0,
 		PasswordError: "",
 	}
@@ -172,20 +165,8 @@ func (a *AuthRouter) handleLoginPost(c *gin.Context) {
 	}
 
 	if errorMessage != "" {
-		var providersData []ProviderData
-		for name := range a.providers {
-			providersData = append(providersData, ProviderData{
-				Name: name,
-				URL:  a.providers[name].AuthURL(),
-			})
-		}
-
-		data := struct {
-			Providers     []ProviderData
-			HasPassword   bool
-			PasswordError string
-		}{
-			Providers:     providersData,
+		data := templateData{
+			Providers:     a.providers,
 			HasPassword:   len(a.passwordHash) > 0,
 			PasswordError: errorMessage,
 		}
@@ -237,8 +218,8 @@ func (a *AuthRouter) RequireAuth() gin.HandlerFunc {
 			return
 		}
 
-		p, ok := a.providers[providerName.(string)]
-		if !ok {
+		p := a.getProvider(providerName.(string))
+		if p == nil {
 			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "Unknown provider"})
 			return
 		}

pkg/auth/github.go

@@ -37,6 +37,10 @@ func (p *githubProvider) Name() string {
 	return "GitHub"
 }
 
+func (p *githubProvider) Type() string {
+	return "github"
+}
+
 func (p *githubProvider) RedirectURL() string {
 	return GitHubCallbackEndpoint
 }

pkg/auth/google.go

@@ -37,6 +37,10 @@ func (p *googleProvider) Name() string {
 	return "Google"
 }
 
+func (p *googleProvider) Type() string {
+	return "google"
+}
+
 func (p *googleProvider) RedirectURL() string {
 	return GoogleCallbackEndpoint
 }

pkg/auth/interface.go

@@ -10,6 +10,7 @@ import (
 
 type Provider interface {
 	Name() string
+	Type() string
 	RedirectURL() string
 	AuthURL() string
 	AuthCodeURL(c *gin.Context, state string) (string, error)

pkg/auth/mock.go

@@ -63,6 +63,10 @@ func (p *oidcProvider) Name() string {
 	return p.providerName
 }
 
+func (p *oidcProvider) Type() string {
+	return "oidc"
+}
+
 func (p *oidcProvider) RedirectURL() string {
 	return OIDCCallbackEndpoint
 }

pkg/auth/oidc.go

@@ -117,20 +117,27 @@
         transform: translateY(-2px);
         box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
       }
-      .Google {
+      .google {
         background-color: #4285f4;
         color: white;
       }
-      .Google:hover {
+      .google:hover {
         background-color: #357ae8;
       }
-      .GitHub {
+      .github {
         background-color: #333;
         color: white;
       }
-      .GitHub:hover {
+      .github:hover {
         background-color: #24292e;
       }
+      .oidc {
+        background-color: #5c67f2;
+        color: white;
+      }
+      .oidc:hover {
+        background-color: #4e54d4;
+      }
       .error-message {
         color: #e74c3c;
         font-size: 0.9rem;
@@ -165,7 +172,7 @@ <h1>MCP Auth Proxy</h1>
         <span>or</span>
       </div>
       {{end}} {{range .Providers}}
-      <a href="{{.URL}}" class="provider-button {{.Name }}">
+      <a href="{{.AuthURL}}" class="provider-button {{.Type}}">
         Login with {{.Name}}
       </a>
       {{end}}