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/peers.go

@@ -0,0 +1,104 @@
+// Package peers contains helpers to work with Telegram peers.
+//
+// NB: this package is completely experimental and still WIP.
+// API and behavior may be changed dramatically, so use it with caution.
+package peers
+
+import (
+	"context"
+
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/constant"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+// Peer represents generic peer.
+type Peer interface {
+	// ID returns entity ID.
+	ID() int64
+	// TDLibPeerID returns TDLibPeerID for this entity.
+	TDLibPeerID() constant.TDLibPeerID
+
+	// VisibleName returns visible name of peer.
+	//
+	// It returns FirstName + " " + LastName for users, and title for chats and channels.
+	VisibleName() string
+	// Username returns peer username, if any.
+	Username() (string, bool)
+	// Restricted whether this user/chat/channel is restricted.
+	Restricted() ([]tg.RestrictionReason, bool)
+	// Verified whether this user/chat/channel is verified by Telegram.
+	Verified() bool
+	// Scam whether this user/chat/channel is probably a scam.
+	Scam() bool
+	// Fake whether this user/chat/channel was reported by many users as a fake or scam: be
+	// careful when interacting with it.
+	Fake() bool
+
+	// InputPeer returns input peer for this peer.
+	InputPeer() tg.InputPeerClass
+	// Sync updates current object.
+	Sync(ctx context.Context) error
+	// Manager returns attached Manager.
+	Manager() *Manager
+
+	// Report reports a peer for violation of telegram's Terms of Service.
+	Report(ctx context.Context, reason tg.ReportReasonClass, message string) error
+	// Photo returns peer photo, if any.
+	Photo(ctx context.Context) (*tg.Photo, bool, error)
+}
+
+var _ = []Peer{
+	User{},
+	Chat{},
+	Channel{},
+}
+
+// ResolvePeer creates Peer using given tg.PeerClass.
+func (m *Manager) ResolvePeer(ctx context.Context, p tg.PeerClass) (Peer, error) {
+	switch p := p.(type) {
+	case *tg.PeerUser:
+		return m.ResolveUserID(ctx, p.UserID)
+	case *tg.PeerChat:
+		return m.ResolveChatID(ctx, p.ChatID)
+	case *tg.PeerChannel:
+		return m.ResolveChannelID(ctx, p.ChannelID)
+	default:
+		return nil, errors.Errorf("unexpected type %T", p)
+	}
+}
+
+// FromInputPeer gets Peer from tg.InputPeerClass.
+func (m *Manager) FromInputPeer(ctx context.Context, p tg.InputPeerClass) (Peer, error) {
+	switch p := p.(type) {
+	case *tg.InputPeerSelf:
+		return m.Self(ctx)
+	case *tg.InputPeerChat:
+		return m.GetChat(ctx, p.ChatID)
+	case *tg.InputPeerUser:
+		return m.GetUser(ctx, &tg.InputUser{
+			UserID:     p.UserID,
+			AccessHash: p.AccessHash,
+		})
+	case *tg.InputPeerChannel:
+		return m.GetChannel(ctx, &tg.InputChannel{
+			ChannelID:  p.ChannelID,
+			AccessHash: p.AccessHash,
+		})
+	case *tg.InputPeerUserFromMessage:
+		return m.GetUser(ctx, &tg.InputUserFromMessage{
+			Peer:   p.Peer,
+			MsgID:  p.MsgID,
+			UserID: p.UserID,
+		})
+	case *tg.InputPeerChannelFromMessage:
+		return m.GetChannel(ctx, &tg.InputChannelFromMessage{
+			Peer:      p.Peer,
+			MsgID:     p.MsgID,
+			ChannelID: p.ChannelID,
+		})
+	default:
+		return nil, errors.Errorf("unexpected type %T", p)
+	}
+}