refactor: reorganize codebase into modular packages

feat(global): add global package for shared variables and types
refactor(handlers): move handlers to dedicated package and update imports
refactor(session): extract session management to separate package
refactor(config): move config handling to dedicated package
refactor(router): update route handlers to use new package structure
refactor(main): simplify main.go by moving logic to packages

handlers/handlers.go

@@ -0,0 +1,122 @@
+package handlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"super-frpc/database"
+	"super-frpc/global"
+	"super-frpc/postLog"
+	"super-frpc/session"
+)
+
+type Response struct {
+	Success bool        `json:"success"`
+	Message string      `json:"message,omitempty"`
+	Data    interface{} `json:"data,omitempty"`
+}
+
+func SendErrorResponse(w http.ResponseWriter, statusCode int, message string, data ...interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(statusCode)
+	resp := Response{
+		Success: false,
+		Message: message,
+	}
+	if len(data) > 0 {
+		resp.Data = data[0]
+	}
+	jsonResp, err := json.Marshal(resp)
+	if err != nil {
+		postLog.Error(fmt.Sprintf("Failed to marshal error response: %v", err))
+		return
+	}
+	w.Write(jsonResp)
+}
+
+func SendSuccessResponse(w http.ResponseWriter, message string, data interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	resp := Response{
+		Success: true,
+		Message: message,
+		Data:    data,
+	}
+	jsonResp, err := json.Marshal(resp)
+	if err != nil {
+		postLog.Error(fmt.Sprintf("Failed to marshal success response: %v", err))
+		return
+	}
+	w.Write(jsonResp)
+}
+
+func Auth(w http.ResponseWriter, r *http.Request, targetMethod string, allowedUserLevels ...string) (int, error) {
+	if r.Method != targetMethod {
+		return 0, fmt.Errorf("Method not allowed: %s", targetMethod)
+	}
+
+	if !global.Is.Debug && !session.ValidateTimeStamp(r.Header, global.Is.Debug) {
+		return 0, fmt.Errorf("Invalid or missing X-Timestamp in header")
+	}
+
+	userID, err := session.ExtractUserIDFromToken(r.Header.Get("X-Token"))
+	if err != nil {
+		return 0, fmt.Errorf("Invalid token format: %w", err)
+	}
+
+	if err := session.ValidateToken(userID, r.Header.Get("X-Token")); err != nil {
+		return 0, fmt.Errorf("Token validation failed: %w", err)
+	}
+
+	if len(allowedUserLevels) > 0 {
+		currentUser, err := database.DBQuerySpecificUser(userID)
+		if err != nil {
+			return 0, fmt.Errorf("Failed to query user: %w", err)
+		}
+		allowed := false
+		for _, level := range allowedUserLevels {
+			if currentUser.Type == level {
+				allowed = true
+				break
+			}
+		}
+		if !allowed {
+			return 0, fmt.Errorf("User level not allowed: required one of %v, got %s", allowedUserLevels, currentUser.Type)
+		}
+	}
+
+	return userID, nil
+}
+
+func GetUserType(userID int) (string, error) {
+	user, err := database.GetUserByID(userID)
+	if err != nil {
+		return "", fmt.Errorf("Failed to get user type: %w", err)
+	}
+	return user.Type, nil
+}
+
+func GetClientIP(r *http.Request) string {
+	forwarded := r.Header.Get("X-Forwarded-For")
+	if forwarded != "" {
+		return forwarded
+	}
+	return r.RemoteAddr
+}
+
+func LogRequest(r *http.Request, userID int) {
+	postLog.Info(fmt.Sprintf("[%s] %s %s - UserID: %d - IP: %s",
+		time.Now().Format("2006-01-02 15:04:05"),
+		r.Method,
+		r.URL.Path,
+		userID,
+		GetClientIP(r),
+	))
+}
+
+func IntToString(i int) string {
+	return strconv.Itoa(i)
+}