move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/telegram/message/html/text_utl.go

@@ -0,0 +1,89 @@
+package html
+
+import (
+	"net"
+	"net/url"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/ascii"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/message/entity"
+)
+
+func isIPv6(str string) bool {
+	ip := net.ParseIP(str)
+	return strings.Contains(str, ":") && ip != nil
+}
+
+func validateHostname(u *url.URL) error {
+	// TODO(tdakkota): make sure that it is correct
+	ipv6 := isIPv6(u.Host)
+	if !strings.ContainsRune(u.Host, '.') && ipv6 {
+		return errors.New("wrong HTTP URL")
+	}
+	if ipv6 {
+		return nil
+	}
+
+	allowedSymbol := func(c rune) bool {
+		return ascii.IsLatinLetter(c) ||
+			ascii.IsDigit(c) ||
+			(c >= '&' && c <= '.') ||
+			c == '_' ||
+			c == '!' ||
+			c == '$' ||
+			c == '~' ||
+			c == ';' ||
+			c == '=' ||
+			c > utf8.RuneSelf
+	}
+
+	for _, c := range u.Host {
+		if !allowedSymbol(c) {
+			return errors.Errorf("disallowed character %c in URL host", c)
+		}
+	}
+
+	return nil
+}
+
+func getURLFormatter(rawURL string, resolver entity.UserResolver) (entity.Formatter, error) {
+	const defaultProtocol = "http"
+	if rawURL == "" {
+		return nil, errors.New("empty URL")
+	}
+
+	// FIXME(tdakkota): move normalization to deeplink package when it's done?
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, err
+	}
+	if u.Scheme == "tg" && u.Host == "user" {
+		id, err := strconv.ParseInt(u.Query().Get("id"), 10, 64)
+		if err != nil {
+			return nil, errors.Wrapf(err, "invalid user ID %q", id)
+		}
+
+		user, err := resolver(id)
+		if err != nil {
+			return nil, errors.Wrapf(err, "can't resolve user %q", id)
+		}
+
+		return entity.MentionName(user), nil
+	}
+	if u.Scheme == "" {
+		u.Scheme = defaultProtocol
+		u.Host = u.Path
+		u.Path = "/"
+		rawURL = u.String()
+	}
+
+	if err := validateHostname(u); err != nil {
+		return nil, err
+	}
+
+	return entity.TextURL(rawURL), nil
+}