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/peers/join.go

@@ -0,0 +1,99 @@
+package peers
+
+import (
+	"context"
+
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/internal/deeplink"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+type updateWithChats interface {
+	tg.UpdatesClass
+	GetChats() []tg.ChatClass
+}
+
+var _ = []updateWithChats{
+	(*tg.Updates)(nil),
+	(*tg.UpdatesCombined)(nil),
+}
+
+// JoinLink joins to private chat using given link or hash.
+// Input examples:
+//
+//	t.me/+AAAAAAAAAAAAAAAA
+//	https://t.me/+AAAAAAAAAAAAAAAA
+//	t.me/joinchat/AAAAAAAAAAAAAAAA
+//	https://t.me/joinchat/AAAAAAAAAAAAAAAA
+//	tg:join?invite=AAAAAAAAAAAAAAAA
+//	tg://join?invite=AAAAAAAAAAAAAAAA
+func (m *Manager) JoinLink(ctx context.Context, link string) (Peer, error) {
+	l, err := deeplink.Expect(link, deeplink.Join)
+	if err != nil {
+		return nil, err
+	}
+	return m.ImportInvite(ctx, l.Args.Get("invite"))
+}
+
+// ImportInvite imports given hash invite.
+func (m *Manager) ImportInvite(ctx context.Context, hash string) (Peer, error) {
+	inviteInfo, err := m.api.MessagesCheckChatInvite(ctx, hash)
+	if err != nil {
+		return Chat{}, errors.Wrap(err, "check invite")
+	}
+
+	switch inviteInfo := inviteInfo.(type) {
+	case *tg.ChatInviteAlready:
+		return m.extractChat(inviteInfo.GetChat())
+	case *tg.ChatInvite:
+		if err := m.applyUsers(ctx, inviteInfo.Participants...); err != nil {
+			return nil, errors.Wrap(err, "update users")
+		}
+	case *tg.ChatInvitePeek:
+		if err := m.applyChats(ctx, inviteInfo.GetChat()); err != nil {
+			return Chat{}, errors.Wrap(err, "update chats")
+		}
+	default:
+		return nil, errors.Errorf("unexpected type %T", inviteInfo)
+	}
+
+	ch, err := m.importInvite(ctx, hash)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.extractChat(ch)
+}
+
+func (m *Manager) importInvite(ctx context.Context, hash string) (tg.ChatClass, error) {
+	u, err := m.api.MessagesImportChatInvite(ctx, hash)
+	if err != nil {
+		return nil, errors.Wrap(err, "import invite")
+	}
+
+	updates, ok := u.(updateWithChats)
+	if !ok {
+		return nil, errors.Errorf("bad result %T type", u)
+	}
+
+	// Do not apply it, update hook already did it.
+	chats := updates.GetChats()
+	if len(chats) < 1 {
+		return nil, errors.New("empty result")
+	}
+
+	return chats[0], nil
+}
+
+func (m *Manager) extractChat(p tg.ChatClass) (Peer, error) {
+	// TODO: handle forbidden.
+	switch p := p.(type) {
+	case *tg.Chat:
+		return m.Chat(p), nil
+	case *tg.Channel:
+		return m.Channel(p), nil
+	default:
+		return nil, errors.Errorf("unexpected type %T", p)
+	}
+}