package jwt

import (
	"errors"
	"os"
	"time"

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

type Claims struct {
	UserID   uint   `json:"user_id"`
	Email    string `json:"email"`
	UserName string `json:"username,omitempty"`
	jwt.RegisteredClaims
}

// GenerateAccessToken creates a short-lived access token (15 minutes).
func GenerateAccessToken(userID uint, email, userName string) (string, error) {
	secret := os.Getenv("JWT_SECRET")
	claims := Claims{
		UserID:   userID,
		Email:    email,
		UserName: userName,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(15 * time.Minute)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}
	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString([]byte(secret))
}

// GenerateRefreshToken creates a long-lived refresh token (7 days).
func GenerateRefreshToken(userID uint, email, userName string) (string, error) {
	secret := os.Getenv("JWT_REFRESH_SECRET")
	claims := Claims{
		UserID:   userID,
		Email:    email,
		UserName: userName,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(7 * 24 * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}
	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString([]byte(secret))
}

// ValidateToken parses and validates a token string using the provided secret.
func ValidateToken(tokenStr, secret string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(t *jwt.Token) (interface{}, error) {
		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return []byte(secret), nil
	})
	if err != nil {
		return nil, err
	}
	claims, ok := token.Claims.(*Claims)
	if !ok || !token.Valid {
		return nil, errors.New("invalid token")
	}
	return claims, nil
}