package jwtutils

import (
    "fmt"
    "github.com/dgrijalva/jwt-go"
)

// Create a JWT token signed with jwtSecret, containing claims. Claims should be primitive string or int values.
func NewSignedTokenWithClaims(jwtSecret string, claims map[string]interface{}) (string, error) {
    token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims(claims))

    signedToken, err := token.SignedString([]byte(jwtSecret))
    if err != nil {
        return "", err
    }

    return signedToken, nil
}

// Verify that the signedToken JWT token was signed with jwtSecret. Returns claims of the JWT token.
func DecodeClaims(jwtSecret string, signedToken string) (map[string]interface{}, error) {
    token, err := jwt.Parse(signedToken, func(token *jwt.Token) (interface{}, error) {
        if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
            return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
        }

        return []byte(jwtSecret), nil
    })
    if err != nil {
        return map[string]interface{}{}, err
    }

    if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
        return claims, nil
    } else {
        return map[string]interface{}{}, err
    }
}