package middleware

import (
	"fmt"
	"net/http"

	"git.links123.net/links123.com/skeleton/config"
	"github.com/dgrijalva/jwt-go"
	"github.com/wpajqz/linker"
)

// headers
const (
	CtxRequestHeaderUserId        = "user_id"
	CtxRequestHeaderAuthorization = "Authorization"
)

// Auth empty struct for middleware interface
type Auth struct{}

// Handle middleware process
func (a *Auth) Handle(ctx linker.Context) linker.Context {
	tk := ctx.GetRequestProperty(CtxRequestHeaderAuthorization)
	if len(tk) < 8 {
		ctx.Error(http.StatusUnauthorized, "Auth failed")
	}

	token, err := jwt.Parse(tk[7:], 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(config.C.App.Secret), nil
	})

	if err != nil || !token.Valid {
		ctx.Error(http.StatusUnauthorized, "Auth failed")
	}

	ctx.Set(CtxRequestHeaderUserId, int(token.Claims.(jwt.MapClaims)[CtxRequestHeaderUserId].(float64)))

	return ctx
}