package utils

import (
	"errors"
	"time"

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

// TokenClaims represents JWT token claims
type TokenClaims struct {
	UserID    int    `json:"user_id"`
	TokenType string `json:"token_type"`
	jwt.RegisteredClaims
}

// GenerateToken generates a new JWT token
func GenerateToken(claims TokenClaims, secret string, expiry time.Duration) (string, error) {
	now := time.Now()
	claims.RegisteredClaims = jwt.RegisteredClaims{
		IssuedAt:  jwt.NewNumericDate(now),
		ExpiresAt: jwt.NewNumericDate(now.Add(expiry)),
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	tokenString, err := token.SignedString([]byte(secret))
	if err != nil {
		return "", err
	}

	return tokenString, nil
}

// ValidateToken validates a JWT token and returns its claims
func ValidateToken(tokenString, secret string) (*TokenClaims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &TokenClaims{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return []byte(secret), nil
	})

	if err != nil {
		return nil, err
	}

	if claims, ok := token.Claims.(*TokenClaims); ok && token.Valid {
		return claims, nil
	}

	return nil, errors.New("invalid token claims")
}