package core

import (
	"errors"
	"fmt"
	"github.com/golang-jwt/jwt/v5"
	"time"
)

type JwtTokens struct {
	AccessToken  string `json:"access_token"`
	RefreshToken string `json:"refresh_token"`
}

const (
	accessTokenExp  = 5 * time.Minute
	refreshTokenExp = 30 * 24 * time.Hour
)

var secret = []byte("your-secret-key")

func NewJwtTokens(username string) (JwtTokens, error) {
	accessClaims := NewAccessClaim(username)

	refreshClaims := jwt.RegisteredClaims{
		Subject:   username,
		ExpiresAt: jwt.NewNumericDate(time.Now().Add(refreshTokenExp)),
	}

	accessJwt, err := EncodeAndSignClaims(accessClaims)
	if err != nil {
		return JwtTokens{}, err
	}
	refreshJwt, err := EncodeAndSignClaims(refreshClaims)

	if err != nil {
		return JwtTokens{}, err
	}
	return JwtTokens{
		AccessToken:  accessJwt,
		RefreshToken: refreshJwt,
	}, nil
}

func NewAccessClaim(username string) jwt.RegisteredClaims {
	return jwt.RegisteredClaims{
		Subject:   username,
		ExpiresAt: jwt.NewNumericDate(time.Now().Add(accessTokenExp)),
	}
}

func EncodeAndSignClaims(claims jwt.RegisteredClaims) (string, error) {
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(secret)
}

func ParseRefreshToken(refreshToken string) (*jwt.RegisteredClaims, error) {
	token, err := jwt.ParseWithClaims(refreshToken, &jwt.RegisteredClaims{}, func(token *jwt.Token) (interface{}, error) {
		return secret, nil
	})
	if err != nil {
		return nil, fmt.Errorf("error parsing refresh token: %w", err)
	}
	claims, ok := token.Claims.(*jwt.RegisteredClaims)
	if !ok {
		return nil, errors.New("unable to parse claims")
	}
	return claims, nil
}

func ParseAccessToken(accessToken string) (*jwt.RegisteredClaims, error) {
	token, err := jwt.ParseWithClaims(accessToken, &jwt.RegisteredClaims{}, func(token *jwt.Token) (interface{}, error) {
		return secret, nil
	})
	if err != nil {
		return nil, fmt.Errorf("error parsing refresh token: %w", err)
	}
	claims, ok := token.Claims.(*jwt.RegisteredClaims)
	if !ok {
		return nil, errors.New("unable to parse claims")
	}
	return claims, nil
}

func ClaimExpired(claims jwt.RegisteredClaims) error {
	if claims.ExpiresAt == nil {
		return errors.New("claim exp is nil")
	}
	if claims.ExpiresAt.Time.Before(time.Now()) {
		return nil
	}
	return errors.New("claim expired")
}