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/internal/manager/create.go

@@ -0,0 +1,96 @@
+package manager
+
+import (
+	"context"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/clock"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mtproto"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tdsync"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/auth"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+// SetupCallback is an optional setup connection callback.
+type SetupCallback = func(ctx context.Context, invoker tg.Invoker) error
+
+// ConnOptions is a Telegram client connection options.
+type ConnOptions struct {
+	DC          int
+	Test        bool
+	Device      DeviceConfig
+	Handler     Handler
+	Setup       SetupCallback
+	OnDead      func()
+	OnAuthError func(error)
+	Backoff     func(ctx context.Context) backoff.BackOff
+}
+
+func defaultBackoff(c clock.Clock) func(ctx context.Context) backoff.BackOff {
+	return func(ctx context.Context) backoff.BackOff {
+		b := backoff.NewExponentialBackOff()
+		b.Clock = c
+		b.MaxElapsedTime = time.Second * 30
+		b.MaxInterval = time.Second * 5
+		return backoff.WithContext(b, ctx)
+	}
+}
+
+// setDefaults sets default values.
+func (c *ConnOptions) setDefaults(connClock clock.Clock) {
+	if c.DC == 0 {
+		c.DC = 2
+	}
+	// It's okay to use zero value Test.
+	c.Device.SetDefaults()
+	if c.Handler == nil {
+		c.Handler = NoopHandler{}
+	}
+	if c.Backoff == nil {
+		c.Backoff = defaultBackoff(connClock)
+	}
+}
+
+// CreateConn creates new connection.
+func CreateConn(
+	create mtproto.Dialer,
+	mode ConnMode,
+	appID int,
+	opts mtproto.Options,
+	connOpts ConnOptions,
+) *Conn {
+	connOpts.setDefaults(opts.Clock)
+	conn := &Conn{
+		mode:        mode,
+		appID:       appID,
+		device:      connOpts.Device,
+		clock:       opts.Clock,
+		handler:     connOpts.Handler,
+		sessionInit: tdsync.NewReady(),
+		gotConfig:   tdsync.NewReady(),
+		dead:        tdsync.NewReady(),
+		setup:       connOpts.Setup,
+		onDead:      connOpts.OnDead,
+		connBackoff: connOpts.Backoff,
+	}
+
+	conn.log = opts.Logger
+	opts.DC = connOpts.DC
+	if connOpts.Test {
+		// New key exchange algorithm requires DC ID and uses mapping like MTProxy.
+		// +10000 for test DC, *-1 for media-only.
+		opts.DC += 10000
+	}
+	opts.Handler = conn
+	opts.Logger = conn.log.Named("mtproto")
+	opts.OnError = func(err error) {
+		if auth.IsUnauthorized(err) && connOpts.OnAuthError != nil {
+			connOpts.OnAuthError(err)
+		}
+	}
+	conn.proto = mtproto.New(create, opts)
+
+	return conn
+}