backend/handlers.go

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"super-frpc/postLog"
	"time"
)

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) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(statusCode)
	resp := Response{
		Success: false,
		Message: message,
	}
	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 ValidateRequest(w http.ResponseWriter, r *http.Request, requiredFields ...string) (int, string, error) { // ValidateRequest validates the request body and header
	body, err := io.ReadAll(r.Body)
	if err != nil {
		return 0, "", fmt.Errorf("Failed to read request body: %w", err)
	}
	defer r.Body.Close()

	return ValidateRequestWithBody(w, r, body, requiredFields...)
}

func ValidateRequestWithBody(w http.ResponseWriter, r *http.Request, body []byte, requiredFields ...string) (int, string, error) {
	var reqMap map[string]interface{}
	if err := json.Unmarshal(body, &reqMap); err != nil {
		return 0, "", fmt.Errorf("Invalid request format: %w", err)
	}

	token := r.Header.Get("X-Token")
	if token == "" {
		return 0, "", fmt.Errorf("Token is required in header: %s", token)
	}

	if !isDebug {
		if !ValidateTimeStamp(r.Header) {
			return 0, "", fmt.Errorf("Invalid or missing X-Timestamp in header")
		}
	}

	userID, err := extractUserIDFromToken(token)
	if err != nil {
		return 0, "", fmt.Errorf("Invalid token format: %w", err)
	}

	if err := ValidateToken(userID, token); err != nil {
		return 0, "", fmt.Errorf("Token validation failed: %w", err)
	}

	for _, field := range requiredFields {
		if _, ok := reqMap[field]; !ok {
			return 0, "", fmt.Errorf("required field %s is missing: %s", field, reqMap[field])
		}
	}

	return userID, token, nil
}

func ValidateRequestWithHeader(w http.ResponseWriter, r *http.Request, requiredFields ...string) (int, string, error) {
	token := r.Header.Get("X-Token")
	if token == "" {
		return 0, "", fmt.Errorf("Token is required in header: %s", token)
	}

	if !isDebug {
		if !ValidateTimeStamp(r.Header) {
			return 0, "", fmt.Errorf("Invalid or missing X-Timestamp in header")
		}
	}

	userID, err := extractUserIDFromToken(token)
	if err != nil {
		return 0, "", fmt.Errorf("Invalid token format in header: %w", err)
	}

	if err := ValidateToken(userID, token); err != nil {
		return 0, "", fmt.Errorf("Token validation failed in header: %w", err)
	}

	for _, field := range requiredFields {
		headerValue := r.Header.Get(fmt.Sprintf("X-%s", field))
		if headerValue == "" {
			return 0, "", fmt.Errorf("required field %s is missing in header: %s", field, headerValue)
		}
	}

	return userID, token, nil
}

func GetUserType(userID int) (string, error) {
	user, err := GetUserByID(userID)
	if err != nil {
		return "", fmt.Errorf("Failed to get user type: %w", err)
	}
	return user.Type, nil
}

func CheckPermission(userID int, requiredTypes ...string) error {
	userType, err := GetUserType(userID)
	if err != nil {
		return fmt.Errorf("Failed to check permission: %w", err)
	}

	for _, t := range requiredTypes {
		if userType == t {
			return nil
		}
	}

	return fmt.Errorf("Permission denied for user type %s", userType)
}

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)
}