package auth

import (
    "errors"
    "time"

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

type Claims struct {
    Username string `json:"username"`
    jwt.RegisteredClaims
}

func GenerateToken(username, secret string, ttl time.Duration) (string, error) {
    now := time.Now()
    claims := Claims{
        Username: username,
        RegisteredClaims: jwt.RegisteredClaims{
            IssuedAt:  jwt.NewNumericDate(now),
            ExpiresAt: jwt.NewNumericDate(now.Add(ttl)),
        },
    }
    token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
    return token.SignedString([]byte(secret))
}

func ParseToken(tokenStr, secret string) (string, error) {
    token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (interface{}, error) {
        return []byte(secret), nil
    })
    if err != nil {
        return "", err
    }
    if !token.Valid {
        return "", errors.New("invalid token")
    }
    claims, ok := token.Claims.(*Claims)
    if !ok {
        return "", errors.New("invalid claims")
    }
    return claims.Username, nil
}