package app

import (
	"encoding/base64"
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
	"time"

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

func encodeURL(user User) string {
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"id": user.ID, "name": user.Username, "pass": user.Password, "iat": time.Now().Unix(),
	})
	tokenString, err := token.SignedString([]byte(os.Getenv("JWT_SECRET")))
	if err != nil {
		return ""
	}
	tokenString = base64.RawURLEncoding.EncodeToString([]byte(tokenString))
	return tokenString
}
func decodeURL(tokenString string) (User, error) {
	var zero User
	tokenBytes, err := base64.RawURLEncoding.DecodeString(tokenString)
	if err != nil {
		return zero, err
	}
	token, err := jwt.Parse(string(tokenBytes), 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(os.Getenv("JWT_SECRET")), nil
	})
	if err != nil {
		return zero, err
	}
	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
		id := int(claims["id"].(float64))
		name := claims["name"].(string)
		pass := claims["pass"].(string)
		return User{ID: id, Username: name, Password: pass}, nil
	}
	return zero, nil
}

var ip string

func LoadIP() string {
	res, err := http.Get("https://api.ipify.org")
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	data, err := io.ReadAll(res.Body)
	if err != nil {
		panic(err)
	}
	ip = string(data)
	return ip
}
func formatConfigName(format string, user User) string {
	s := strings.ReplaceAll(format, "{username}", user.Username)
	s = strings.ReplaceAll(s, "{host}", ip)
	return s
}

func Ptr[T any](t T) *T { return &t }
func Val[T any](t *T, def T) T {
	if t == nil {
		return def
	}
	return *t
}