pcmt/handlers/handlers.go

package handlers

import (
	"context"
	"errors"
	"html/template"
	"io/fs"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"

	"git.dotya.ml/mirre-mt/pcmt/ent"
	passwd "git.dotya.ml/mirre-mt/pcmt/modules/password"
	moduser "git.dotya.ml/mirre-mt/pcmt/modules/user"
	"github.com/gorilla/sessions"
	"github.com/labstack/echo-contrib/session"
	"github.com/labstack/echo/v4"
	"github.com/microcosm-cc/bluemonday"
)

type tplMap map[string]*template.Template

var (
	// tmpl      *template.Template.
	tmpls            = template.New("")
	templateMap      tplMap
	tmplFS           fs.FS
	bluemondayPolicy = bluemonday.UGCPolicy()
)

func listAllTmpls() []string {
	files, err := filepath.Glob(tmplPath + "/*.tmpl")
	if err != nil {
		panic(err)
	}

	for i, v := range files {
		files[i] = strings.TrimPrefix(v, tmplPath+"/")
	}

	log.Debug("returning files")

	return files
}

// TODO: mimic https://github.com/drone/funcmap/blob/master/funcmap.go
func setFuncMap(t *template.Template) {
	t.Funcs(template.FuncMap{
		"ifIE":    func() template.HTML { return template.HTML("<!--[if IE]>") },
		"endifIE": func() template.HTML { return template.HTML("<![endif]>") },
		"htmlSafe": func(html string) template.HTML {
			return template.HTML( //nolint:gosec
				bluemondayPolicy.Sanitize(html),
			)
		},
		"pageIs": func(want, got string) bool {
			return want == got
		},
	})
}

func initTemplates(f fs.FS) {
	if f != nil || f != tmplFS {
		tmplFS = f
	}

	setFuncMap(tmpls)

	allTmpls := listAllTmpls()

	// ensure this fails at compile time, if at all ("Must").
	tmpls = template.Must(tmpls.ParseFS(tmplFS, allTmpls...))
	makeTplMap(tmpls)
}

func makeTplMap(tpl *template.Template) {
	allTmpls := listAllTmpls()

	var tp tplMap

	if templateMap == nil {
		tp = make(tplMap, len(allTmpls))
	} else {
		tp = templateMap
	}

	for _, v := range allTmpls {
		tp[v] = tpl.Lookup(v)
	}

	templateMap = tp
}

func getTmpl(name string) *template.Template {
	liveMode := setting.IsLive()

	if liveMode {
		log.Debug("re-reading tmpls") // TODO: only re-read the tmpl in question.

		tpl := template.New("")

		setFuncMap(tpl)

		allTmpls := listAllTmpls()

		// ensure this fails at compile time, if at all ("Must").
		tmpls = template.Must(tpl.ParseFS(tmplFS, allTmpls...))
	}

	return tmpls.Lookup(name)
}

func Admin() echo.HandlerFunc {
	return func(c echo.Context) error {
		return echo.NewHTTPError(http.StatusUnauthorized, "Invalid credentials")
	}
}

func Index() echo.HandlerFunc {
	return func(c echo.Context) error {
		tpl := getTmpl("index.tmpl")
		csrf := c.Get("csrf").(string)

		err := tpl.Execute(c.Response().Writer,
			page{
				AppName:   setting.AppName(),
				AppVer:    appver,
				Title:     "Welcome!",
				CSRF:      csrf,
				DevelMode: setting.IsDevel(),
				Current:   "home",
			},
		)
		if err != nil {
			log.Errorf("error when executing tmpl: '%q'", err)
			return err
		}

		return nil
	}
}

func Signin() echo.HandlerFunc {
	return func(c echo.Context) error {
		sess, _ := session.Get(setting.SessionCookieName(), c)

		username := sess.Values["username"]
		if username != nil {
			return c.Redirect(http.StatusFound, "/home")
		}

		tpl := getTmpl("signin.tmpl")

		err := tpl.Execute(c.Response().Writer,
			page{
				AppName:   setting.AppName(),
				AppVer:    appver,
				Title:     "Sign in",
				DevelMode: setting.IsDevel(),
				Current:   "signin",
			},
		)
		if err != nil {
			return err
		}

		return nil
	}
}

func SigninPost(client *ent.Client) echo.HandlerFunc {
	return func(c echo.Context) error {
		err := c.Request().ParseForm()
		if err != nil {
			return err
		}

		var username string

		var password string

		if uname := c.Request().FormValue("username"); uname != "" {
			username = uname
			log.Infof("authenticating user '%s' at /signin", username)
		} else {
			log.Info("username was not set, returning to /signin")

			return c.Redirect(http.StatusFound, "/signin")
		}

		if passwd := c.Request().FormValue("password"); passwd != "" {
			password = passwd
		} else {
			log.Info("password was not set, returning to /signin")

			return c.Redirect(http.StatusFound, "/signin")
		}

		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, log)
		if usr, err := moduser.QueryUser(ctx, client, username); err == nil {
			log.Info("queried user:", &usr.ID)

			if !passwd.Compare(usr.Password, password) {
				log.Warn("wrong user credentials, redirecting to /signin")

				return c.Redirect(http.StatusFound, "/signin")
			}
		} else {
			if ent.IsNotFound(err) {
				c.Logger().Error("user not found")
				return c.Redirect(http.StatusFound, "/signin")
			}
			// just log the error instead of returning it to the user and
			// redirect back to /signin.
			c.Logger().Error(
				http.StatusText(http.StatusUnauthorized)+" "+err.Error(),
				strconv.Itoa(http.StatusUnauthorized)+" "+http.StatusText(http.StatusUnauthorized)+" "+err.Error(),
			)

			return c.Redirect(http.StatusFound, "/signin")
		}

		secure := c.Request().URL.Scheme == "https" //nolint:goconst

		sess, _ := session.Get(setting.SessionCookieName(), c)
		if sess != nil {
			sess.Options = &sessions.Options{
				Path:     "/",
				MaxAge:   3600,
				HttpOnly: true,
				Secure:   secure,
				SameSite: http.SameSiteStrictMode,
			}
			sess.Values["foo"] = "bar"
			sess.Values["username"] = username

			err := sess.Save(c.Request(), c.Response())
			if err != nil {
				c.Logger().Error("failed to save session")

				err = renderErrorPage(
					c.Response().Writer,
					http.StatusInternalServerError,
					http.StatusText(http.StatusInternalServerError)+" (make sure you've got cookies enabled)",
					err.Error(),
				)

				if err != nil {
					return err
				}
			}
		}

		return c.Redirect(http.StatusMovedPermanently, "/home")
	}
}

func Signup() echo.HandlerFunc {
	return func(c echo.Context) error {
		sess, _ := session.Get(setting.SessionCookieName(), c)
		if sess != nil {
			log.Info("gorilla session", "endpoint", "signup")

			username := sess.Values["username"]
			if username != nil {
				return c.Redirect(http.StatusFound, "/home")
			}
		}

		tpl := getTmpl("signup.tmpl")

		csrf := c.Get("csrf").(string)

		// secure := c.Request().URL.Scheme == "https"
		// cookieCSRF := &http.Cookie{
		// Name:  "_csrf",
		// Value: csrf,
		// // SameSite: http.SameSiteStrictMode,
		// SameSite: http.SameSiteLaxMode,
		// MaxAge:   3600,
		// Secure:   secure,
		// HttpOnly: true,
		// }
		// c.SetCookie(cookieCSRF)

		err := tpl.Execute(c.Response().Writer,
			page{
				AppName:   setting.AppName(),
				AppVer:    appver,
				Title:     "Sign up",
				CSRF:      csrf,
				DevelMode: setting.IsDevel(),
				Current:   "signup",
			},
		)
		if err != nil {
			log.Warnf("error: %q", err)

			err = renderErrorPage(
				c.Response().Writer,
				http.StatusInternalServerError,
				http.StatusText(http.StatusInternalServerError),
				err.Error(),
			)

			if err != nil {
				return err
			}
		}

		return nil
	}
}

func SignupPost(client *ent.Client) echo.HandlerFunc {
	return func(c echo.Context) error {
		err := c.Request().ParseForm()
		if err != nil {
			return err
		}

		var username string

		var email string

		uname := c.Request().FormValue("username")
		if uname == "" {
			c.Logger().Error("signup: username was not set, returning to /signup")
			return c.Redirect(http.StatusSeeOther, "/signup")
		}

		username = uname

		mail := c.Request().FormValue("email")
		if mail == "" {
			c.Logger().Error("signup: email not set")
			return c.Redirect(http.StatusSeeOther, "/signup")
		}

		email = mail

		passwd := c.Request().FormValue("password")
		if passwd == "" {
			log.Info("signup: password was not set, returning to /signup")
			return c.Redirect(http.StatusSeeOther, "/signup")
		}

		ctx := context.WithValue(context.Background(), moduser.CtxKey{}, log)

		exists, err := moduser.Exists(ctx, client, username, email)
		if err != nil {
			c.Logger().Error("error checking whether user exists", err)

			return renderErrorPage(
				c.Response().Writer,
				http.StatusInternalServerError,
				http.StatusText(http.StatusInternalServerError),
				err.Error(),
			)
		}

		if exists {
			c.Logger().Error("username/email already taken")

			return c.Redirect(http.StatusSeeOther, "/signup")
		}

		u, err := moduser.CreateUser(
			ctx,
			client,
			email,
			username,
			passwd,
		)
		if err != nil {
			if errors.Is(err, errors.New("username is not unique")) {
				c.Logger().Error("username already taken")
				// TODO: re-render signup page with a flash message
				// stating what went wrong.
				return c.Redirect(http.StatusSeeOther, "/signup")
			}
			// TODO: don't return the error to the user, perhaps based
			// on the devel mode.
			err = renderErrorPage(
				c.Response().Writer,
				http.StatusInternalServerError,
				http.StatusText(http.StatusInternalServerError)+" - failed to create schema resources",
				err.Error(),
			)
			if err != nil {
				c.Logger().Error("error: %q", err)
				return err
			}
		}

		log.Infof("successfully registered user '%s'", username)
		log.Debug("user details", "id", u.ID, "email", u.Email, "isAdmin", u.IsAdmin)

		secure := c.Request().URL.Scheme == "https" //nolint:goconst

		sess, _ := session.Get(setting.SessionCookieName(), c)
		sess.Options = &sessions.Options{
			Path:     "/",
			MaxAge:   3600,
			HttpOnly: true,
			Secure:   secure,
			SameSite: http.SameSiteStrictMode,
		}
		sess.Values["foo"] = "bar"
		sess.Values["username"] = username

		err = sess.Save(c.Request(), c.Response())
		if err != nil {
			c.Logger().Error("failed to save session")

			err = renderErrorPage(
				c.Response().Writer,
				http.StatusInternalServerError,
				http.StatusText(http.StatusInternalServerError)+" (make sure you've got cookies enabled)",
				err.Error(),
			)

			if err != nil {
				return err
			}
		}

		return c.Redirect(http.StatusMovedPermanently, "/home")
	}
}

func Home() echo.HandlerFunc {
	return func(c echo.Context) error {
		var username string

		tpl := getTmpl("home.tmpl")

		sess, _ := session.Get(setting.SessionCookieName(), c)
		if sess == nil {
			log.Info("no session, redirecting to /signin", "endpoint", "/home")
			return c.Redirect(http.StatusPermanentRedirect, "/signin")
		}

		if sess.Values["foo"] != nil {
			log.Info("gorilla session", "custom field test", sess.Values["foo"].(string))
		}

		uname := sess.Values["username"]
		if uname == nil {
			log.Info("session cookie found but username invalid, redirecting to signin", "endpoint", "/home")

			return c.Redirect(http.StatusSeeOther, "/signin")
		}

		log.Info("gorilla session", "username", sess.Values["username"].(string))
		username = sess.Values["username"].(string)

		// example denial.
		// if _, err := c.Cookie("aha"); err != nil {
		// log.Printf("error: %q", err)
		// return echo.NewHTTPError(http.StatusUnauthorized, http.StatusText(http.StatusUnauthorized))
		// }

		err := tpl.Execute(c.Response().Writer,
			page{
				AppName:   setting.AppName(),
				AppVer:    appver,
				Title:     "Home",
				Name:      username,
				DevelMode: setting.IsDevel(),
				Current:   "home",
			},
		)
		if err != nil {
			log.Warnf("error: %q", err)

			c.Logger().Errorf("error: %q", err)

			err = renderErrorPage(
				c.Response().Writer,
				http.StatusInternalServerError, http.StatusText(http.StatusInternalServerError),
				err.Error(),
			)

			if err != nil {
				c.Logger().Errorf("error: %q", err)

				return echo.NewHTTPError(
					http.StatusInternalServerError,
					http.StatusText(http.StatusInternalServerError),
				)
			}
		}

		return nil
	}
}

func Logout() echo.HandlerFunc {
	return func(c echo.Context) error {
		switch {
		case c.Request().Method == "POST":
			sess, _ := session.Get(setting.SessionCookieName(), c)
			if sess != nil {
				log.Infof("max-age before logout: %d", sess.Options.MaxAge)
				sess.Options.MaxAge = -1

				if username := sess.Values["username"]; username != nil {
					sess.Values["username"] = ""
				}

				err := sess.Save(c.Request(), c.Response())
				if err != nil {
					c.Logger().Error("could not delete session cookie")
				}
			}

			return c.Redirect(http.StatusMovedPermanently, "/logout")

		case c.Request().Method == "GET":
			tpl := getTmpl("logout.tmpl")

			err := tpl.Execute(c.Response().Writer,
				page{
					AppName:   setting.AppName(),
					AppVer:    appver,
					Title:     "Logout",
					DevelMode: setting.IsDevel(),
					Current:   "logout",
				},
			)
			if err != nil {
				c.Logger().Errorf("error: %q", err)

				err = renderErrorPage(
					c.Response().Writer,
					http.StatusInternalServerError,
					http.StatusText(http.StatusInternalServerError),
					err.Error(),
				)

				if err != nil {
					c.Logger().Errorf("error: %q", err)

					return err
				}
			}
		}

		return nil
	}
}

// experimental global redirect handler?
// http.HandleFunc("/redirect", func(w http.ResponseWriter, r *http.Request) {
// loc, err := url.QueryUnescape(r.URL.Query().Get("loc"))
// if err != nil {
// http.Error(w, fmt.Sprintf("invalid redirect: %q", r.URL.Query().Get("loc")), http.StatusBadRequest)
// return
// }
// http.Redirect(w, r, loc, http.StatusFound)
// })