refactor: use a hook for checking sign in status in the backend

internal/hooks/hooks.go

@@ -0,0 +1,44 @@
+package hooks
+
+import (
+	"tinyauth/internal/auth"
+	"tinyauth/internal/types"
+
+	"github.com/gin-contrib/sessions"
+	"github.com/gin-gonic/gin"
+)
+
+func UseUserContext(c *gin.Context, userList types.UserList) (types.UserContext) {
+	session := sessions.Default(c)
+	cookie := session.Get("tinyauth")
+
+	if cookie == nil {
+		return types.UserContext{
+			Username: "",
+			IsLoggedIn: false,
+		}
+	}
+
+	username, ok := cookie.(string)
+
+	if !ok {
+		return types.UserContext{
+			Username: "",
+			IsLoggedIn: false,
+		}
+	}
+
+	user := auth.FindUser(userList, username)
+
+	if user == nil {
+		return types.UserContext{
+			Username: "",
+			IsLoggedIn: false,
+		}
+	}
+
+	return types.UserContext{
+		Username: username,
+		IsLoggedIn: true,
+	}
+}