feat: implement core functionality for super-frpc service

This commit introduces the core functionality for the super-frpc service including:
- Configuration management
- User authentication and authorization
- Database integration
- FRPC instance management
- API endpoints for user operations
- Token-based authentication system
- Password hashing and validation

auth.go

@@ -0,0 +1,170 @@
+package main
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+type TokenInfo struct {
+	Token     string
+	CreatedAt time.Time
+	UserID    int
+}
+
+var (
+	tokenMap  = make(map[int]*TokenInfo)
+	tokenMux  sync.RWMutex
+	tokenTTL  = time.Hour
+)
+
+func GenerateToken(userID int) (string, error) {
+	randomBytes := make([]byte, 32)
+	_, err := rand.Read(randomBytes)
+	if err != nil {
+		return "", fmt.Errorf("failed to generate random bytes: %w", err)
+	}
+
+	hash := sha256.Sum256(append(randomBytes, []byte(fmt.Sprintf("%d", userID))...))
+	token := base64.URLEncoding.EncodeToString(hash[:])
+
+	tokenMux.Lock()
+	defer tokenMux.Unlock()
+
+	tokenMap[userID] = &TokenInfo{
+		Token:     token,
+		CreatedAt: time.Now(),
+		UserID:    userID,
+	}
+
+	return token, nil
+}
+
+func ValidateToken(userID int, token string) error {
+	tokenMux.RLock()
+	defer tokenMux.RUnlock()
+
+	tokenInfo, exists := tokenMap[userID]
+	if !exists {
+		return errors.New("token not found")
+	}
+
+	if tokenInfo.Token != token {
+		return errors.New("invalid token")
+	}
+
+	if time.Since(tokenInfo.CreatedAt) > tokenTTL {
+		return errors.New("token expired")
+	}
+
+	return nil
+}
+
+func RefreshToken(userID int) (string, error) {
+	tokenMux.Lock()
+	defer tokenMux.Unlock()
+
+	randomBytes := make([]byte, 32)
+	_, err := rand.Read(randomBytes)
+	if err != nil {
+		return "", fmt.Errorf("failed to generate random bytes: %w", err)
+	}
+
+	hash := sha256.Sum256(append(randomBytes, []byte(fmt.Sprintf("%d", userID))...))
+	token := base64.URLEncoding.EncodeToString(hash[:])
+
+	tokenMap[userID] = &TokenInfo{
+		Token:     token,
+		CreatedAt: time.Now(),
+		UserID:    userID,
+	}
+
+	return token, nil
+}
+
+func RemoveToken(userID int) {
+	tokenMux.Lock()
+	defer tokenMux.Unlock()
+	delete(tokenMap, userID)
+}
+
+func GetTokenInfo(userID int) (*TokenInfo, error) {
+	tokenMux.RLock()
+	defer tokenMux.RUnlock()
+
+	tokenInfo, exists := tokenMap[userID]
+	if !exists {
+		return nil, errors.New("token not found")
+	}
+
+	return tokenInfo, nil
+}
+
+func extractUserIDFromToken(token string) (int, error) {
+	tokenMux.RLock()
+	defer tokenMux.RUnlock()
+	for userID, tokenInfo := range tokenMap {
+		if tokenInfo.Token == token {
+			return userID, nil
+		}
+	}
+	return 0, errors.New("invalid token")
+}
+
+func CleanupExpiredTokens() {
+	tokenMux.Lock()
+	defer tokenMux.Unlock()
+
+	for userID, tokenInfo := range tokenMap {
+		if time.Since(tokenInfo.CreatedAt) > tokenTTL {
+			delete(tokenMap, userID)
+		}
+	}
+}
+
+func hashPassword(password string) (string, error) {
+	hash := sha256.Sum256([]byte(password))
+	return hex.EncodeToString(hash[:]), nil
+}
+
+func verifyPassword(password, hashedPassword string) bool {
+	hash, err := hashPassword(password)
+	if err != nil {
+		return false
+	}
+	return hash == hashedPassword
+}
+
+func isValidPassword(password string) bool {
+	if len(password) < 8 {
+		return false
+	}
+
+	hasUpper := false
+	hasLower := false
+	hasDigit := false
+	hasSpecial := false
+
+	specialChars := "!@#$%^&*()_+-=[]{}|;:,.<>?"
+
+	for _, char := range password {
+		switch {
+		case char >= 'A' && char <= 'Z':
+			hasUpper = true
+		case char >= 'a' && char <= 'z':
+			hasLower = true
+		case char >= '0' && char <= '9':
+			hasDigit = true
+		case strings.ContainsRune(specialChars, char):
+			hasSpecial = true
+		}
+	}
+
+	return hasUpper && hasLower && hasDigit && hasSpecial
+}