package appimport (	"context"	"errors"	"fmt"	"log"	"net/http"	"net/mail"	"regexp"	"strings"	"github.com/google/uuid"	"github.com/nxrmqlly/district/app/httpx"	"github.com/nxrmqlly/district/auth"	"github.com/nxrmqlly/district/config")var usernameRE = regexp.MustCompile(`^[A-Za-z0-9_]{3,24}$`)// SessionFromContext derives the auth session from the request context.// ok is true for authenticated sessions and false for anonymous sessionsfunc SessionFromContext(ctx context.Context) (*auth.AuthSession, bool) {	sess, ok := ctx.Value(sessionKey).(*auth.AuthSession)	return sess, ok}// set the district_session cookiefunc (ro *Router) setSessionCookie(w http.ResponseWriter, sessToken string) {	http.SetCookie(w, &http.Cookie{		Name:     "district_session",		Value:    sessToken,		Path:     "/",		HttpOnly: true,		Secure:   config.Get().Session.Secure,		SameSite: http.SameSiteLaxMode,	})}// create a new session and set the session cookie to the writerfunc (ro *Router) newSessionCookie(w http.ResponseWriter, r *http.Request, userId uuid.UUID) {	sessToken, err := ro.auth.CreateSession(r.Context(), userId)	if err != nil {		http.Error(w, "internal server error", http.StatusInternalServerError)		return	}	ro.setSessionCookie(w, sessToken)}type LoginPageData struct {	Login string	Error string}func (ro *Router) handleLoginView(w http.ResponseWriter, r *http.Request) {	// already logged in	if _, ok := SessionFromContext(r.Context()); ok {		fmt.Println("/login: user already logged in, redirecting...")		http.Redirect(w, r, "/", http.StatusSeeOther)		return	}	ro.RenderPage(w, r, "login", "login", LoginPageData{})}func (ro *Router) handleLogin(w http.ResponseWriter, r *http.Request) {	if _, ok := SessionFromContext(r.Context()); ok {		http.Redirect(w, r, "/", http.StatusSeeOther)		return	}	if err := r.ParseForm(); err != nil {		http.Error(w, "bad request", http.StatusBadRequest)		return	}	login := strings.TrimSpace(r.FormValue("login"))	password := r.FormValue("password")	user, err := ro.auth.Authenticate(r.Context(), login, password)	if err != nil {		if errors.Is(err, auth.ErrInvalidCredentials) {			ro.RenderPage(w, r, "login", "login", LoginPageData{				Error: "invalid login or password",				Login: login,			})		} else {			log.Printf("err: /login: %s", err.Error())			ro.RenderPage(w, r, "login", "login", LoginPageData{				Error: "internal server error",				Login: login,			})		}		return	}	ro.newSessionCookie(w, r, user.ID)	http.Redirect(w, r, "/", http.StatusSeeOther)}type RegisterPageData struct {	Email    string	Username string	Error    string}func (ro *Router) handleRegisterView(w http.ResponseWriter, r *http.Request) {	// already logged in	if _, ok := SessionFromContext(r.Context()); ok {		fmt.Println("/register: user already logged in, redirecting...")		http.Redirect(w, r, "/", http.StatusSeeOther)		return	}	ro.RenderPage(w, r, "register", "register", RegisterPageData{})}func (ro *Router) handleRegister(w http.ResponseWriter, r *http.Request) {	if _, ok := SessionFromContext(r.Context()); ok {		http.Redirect(w, r, "/", http.StatusSeeOther)		return	}	if err := r.ParseForm(); err != nil {		httpx.ErrorJSON(w, http.StatusBadRequest, "invalid form")		return	}	email := strings.TrimSpace(r.FormValue("email"))	username := strings.TrimSpace(r.FormValue("username"))	password := r.FormValue("password")	verrs := ""	if !usernameRE.MatchString(username) {		verrs += "username must contain only characters, numbers or underscore; min 3, max 24 characters\n"	}	if len(email) > 254 {		verrs += "invalid email\n"	}	if addr, err := mail.ParseAddress(email); err != nil || addr.Address != email {		verrs += "invalid email\n"	}	// TODO: better passwd security	if len(password) < 8 || len(password) > 128 {		verrs += "password must be 8 to 128 characters long\n"	}	if verrs != "" {		ro.RenderPage(w, r, "register", "register", RegisterPageData{			Username: username,			Email:    email,			Error:    verrs,		})		return	}	// * all validations passed	user, err := ro.auth.RegisterUser(r.Context(), email, username, password)	if err != nil {		switch {		case errors.Is(err, auth.ErrEmailInUse):			ro.RenderPage(w, r, "register", "register", RegisterPageData{				Username: username,				Email:    email,				Error:    "email already in use",			})		case errors.Is(err, auth.ErrUsernameTaken):			ro.RenderPage(w, r, "register", "register", RegisterPageData{				Username: username,				Email:    email,				Error:    "username is already taken",			})		default:			http.Error(w, "internal server error", http.StatusInternalServerError)		}		return	}	ro.newSessionCookie(w, r, user.ID)	http.Redirect(w, r, "/", http.StatusSeeOther)}func (ro *Router) handleLogout(w http.ResponseWriter, r *http.Request) {	sess, _ := SessionFromContext(r.Context())	if err := ro.auth.RevokeSession(r.Context(), sess.ID); err != nil {		http.Error(w, "internal server error", http.StatusInternalServerError)		return	}	ro.setSessionCookie(w, "") // clear cookie	http.Redirect(w, r, "/", http.StatusSeeOther)}