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/tljson/convert.go

@@ -0,0 +1,101 @@
+package tljson
+
+import (
+	"github.com/go-faster/errors"
+	"github.com/go-faster/jx"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+// Decode decodes JSON and converts it to tg.JSONValueClass.
+func Decode(d *jx.Decoder) (tg.JSONValueClass, error) {
+	switch tt := d.Next(); tt {
+	case jx.String:
+		s, err := d.Str()
+		if err != nil {
+			return nil, err
+		}
+		return &tg.JSONString{Value: s}, nil
+	case jx.Number:
+		f, err := d.Float64()
+		if err != nil {
+			return nil, err
+		}
+		return &tg.JSONNumber{Value: f}, nil
+	case jx.Null:
+		if err := d.Null(); err != nil {
+			return nil, err
+		}
+		return &tg.JSONNull{}, nil
+	case jx.Bool:
+		b, err := d.Bool()
+		if err != nil {
+			return nil, err
+		}
+		return &tg.JSONBool{Value: b}, nil
+	case jx.Array:
+		var r []tg.JSONValueClass
+		if err := d.Arr(func(d *jx.Decoder) error {
+			obj, err := Decode(d)
+			if err != nil {
+				return errors.Wrapf(err, "decode %d element", len(r))
+			}
+
+			r = append(r, obj)
+			return nil
+		}); err != nil {
+			return nil, err
+		}
+		return &tg.JSONArray{Value: r}, nil
+	case jx.Object:
+		var r []tg.JSONObjectValue
+		if err := d.Obj(func(d *jx.Decoder, key string) error {
+			obj, err := Decode(d)
+			if err != nil {
+				return errors.Wrapf(err, "decode %q", key)
+			}
+
+			r = append(r, tg.JSONObjectValue{
+				Key:   key,
+				Value: obj,
+			})
+			return nil
+		}); err != nil {
+			return nil, err
+		}
+		return &tg.JSONObject{Value: r}, nil
+	default:
+		return nil, errors.Errorf("unexpected type %v", tt)
+	}
+}
+
+// Encode writes given value to Encoder.
+func Encode(obj tg.JSONValueClass, e *jx.Encoder) {
+	switch obj := obj.(type) {
+	case *tg.JSONNull:
+		e.Null()
+	case *tg.JSONBool:
+		e.Bool(obj.Value)
+	case *tg.JSONNumber:
+		if v := int64(obj.Value); float64(v) == obj.Value {
+			e.Int64(v)
+		} else {
+			e.Float64(obj.Value)
+		}
+	case *tg.JSONString:
+		e.Str(obj.Value)
+	case *tg.JSONArray:
+		e.ArrStart()
+		for _, v := range obj.Value {
+			Encode(v, e)
+		}
+		e.ArrEnd()
+	case *tg.JSONObject:
+		e.ObjStart()
+		for _, pair := range obj.Value {
+			e.FieldStart(pair.Key)
+			Encode(pair.Value, e)
+		}
+		e.ObjEnd()
+	}
+}