package service

import (
	"time"

	"github.com/golang-jwt/jwt/v5"
)

// TokenConfig holds the configuration for the token service
type TokenConfig struct {
	AppID  string
	AppKey string
	SigExp int
}

// TokenService handles JWT token generation
type TokenService struct {
	config TokenConfig
}

// NewTokenService creates a new instance of TokenService
func NewTokenService(config TokenConfig) *TokenService {
	return &TokenService{
		config: config,
	}
}

// CreateSignature generates a JWT token
func (s *TokenService) CreateSignature() (string, error) {
	// Get current time
	now := time.Now().UTC()
	// Calculate expiration time
	expiresAt := now.Add(time.Duration(s.config.SigExp) * time.Second)

	// Create claims
	claims := jwt.MapClaims{
		"iss":   "your-issuer",    // Optional: Issuer
		"iat":   now.Unix(),       // Issued at time
		"exp":   expiresAt.Unix(), // Expiration time
		"appId": s.config.AppID,   // Custom claim
	}

	// Create token
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

	// Sign and get the complete encoded token as a string
	tokenString, err := token.SignedString([]byte(s.config.AppKey))
	if err != nil {
		return "", err
	}

	return tokenString, nil
}