gochat/backend/internal/auth/access_validator.go

package auth

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/gochat/gochat/internal/model"
	"gorm.io/gorm"
)

var (
	ErrUserInactive   = errors.New("user account is inactive")
	ErrSessionRevoked = errors.New("session revoked")
)

// ValidateUserAccessToken is the shared HTTP/WebSocket access-token gate.
func ValidateUserAccessToken(ctx context.Context, jwtService *JWTService, db *gorm.DB, token string) (*Claims, *model.User, error) {
	claims, err := jwtService.ValidateAccessToken(token)
	if err != nil || db == nil {
		return claims, nil, err
	}
	user, err := ValidateUserAccess(ctx, db, claims.UserID, claims.ClientID)
	if err != nil {
		return nil, nil, err
	}
	return claims, user, nil
}

// ValidateUserAccess rechecks the mutable user and session state behind an
// already-validated access token.
func ValidateUserAccess(ctx context.Context, db *gorm.DB, userID uint, clientID string) (*model.User, error) {
	if db == nil {
		return nil, nil
	}
	if clientID != "" {
		var session model.UserSession
		if err := db.WithContext(ctx).Where("user_id = ? AND client_id = ?", userID, clientID).First(&session).Error; err != nil {
			return nil, ErrSessionRevoked
		}
		if session.LastActivityAt == nil || session.LastActivityAt.Before(time.Now().Add(-5*time.Minute)) {
			now := time.Now().UTC()
			_ = db.WithContext(ctx).Model(&session).Updates(map[string]any{"last_activity_at": now, "updated_at": now}).Error
		}
	}

	var user model.User
	if err := db.WithContext(ctx).First(&user, userID).Error; err != nil {
		return nil, fmt.Errorf("user not found: %w", err)
	}
	if !user.Active {
		return nil, ErrUserInactive
	}
	return &user, nil
}