package jwt

import (
	"fmt"
	"time"

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

const (
	TokenTypeAuth    = "auth"
	TokenTypeRefresh = "refresh"
)

type Claims struct {
	UserID    string `json:"userId"`
	Username  string `json:"username"`
	TokenType string `json:"tokenType"`
	jwt.RegisteredClaims
}

type JWTManager struct {
	secret     []byte
	authTTL    time.Duration
	refreshTTL time.Duration
}

func NewJWTManager(secret string, authTTL, refreshTTL time.Duration) *JWTManager {
	return &JWTManager{
		secret:     []byte(secret),
		authTTL:    authTTL,
		refreshTTL: refreshTTL,
	}
}

func (m *JWTManager) GenerateAuthToken(userID string, username string) (string, error) {
	return m.generate(userID, username, TokenTypeAuth, m.authTTL)
}

func (m *JWTManager) GenerateRefreshToken(userID string, username string) (string, error) {
	return m.generate(userID, username, TokenTypeRefresh, m.refreshTTL)
}

func (m *JWTManager) generate(userID string, username, tokenType string, ttl time.Duration) (string, error) {
	now := time.Now()
	claims := Claims{
		UserID:    userID,
		Username:  username,
		TokenType: tokenType,
		RegisteredClaims: jwt.RegisteredClaims{
			IssuedAt:  jwt.NewNumericDate(now),
			ExpiresAt: jwt.NewNumericDate(now.Add(ttl)),
			Subject:   userID,
			ID:        uuid.NewString(),
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(m.secret)
}

func (m *JWTManager) ParseAuthToken(tokenStr string) (*Claims, error) {
	claims, err := m.parse(tokenStr)
	if err != nil {
		return nil, err
	}
	if claims.TokenType != TokenTypeAuth {
		return nil, fmt.Errorf("invalid token type")
	}
	return claims, nil
}

func (m *JWTManager) ParseRefreshToken(tokenStr string) (*Claims, error) {
	claims, err := m.parse(tokenStr)
	if err != nil {
		return nil, err
	}
	if claims.TokenType != TokenTypeRefresh {
		return nil, fmt.Errorf("invalid token type")
	}
	return claims, nil
}

func (m *JWTManager) parse(tokenStr string) (*Claims, error) {
	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (any, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method")
		}
		return m.secret, nil
	})
	if err != nil {
		return nil, err
	}

	claims, ok := token.Claims.(*Claims)
	if !ok || !token.Valid {
		return nil, fmt.Errorf("invalid token")
	}

	return claims, nil
}