From b277fac8eacf69733b2078d8b92161b6b9ff808f Mon Sep 17 00:00:00 2001
From: tdakkota <tanc13@yandex.ru>
Date: Sat, 4 Dec 2021 22:32:37 +0300
Subject: [PATCH] feat(tljson): add JSONValue helper

---
 telegram/tljson/convert.go      | 101 ++++++++++++++++++++++++++++++++
 telegram/tljson/convert_test.go |  67 +++++++++++++++++++++
 telegram/tljson/tljson.go       |   2 +
 3 files changed, 170 insertions(+)
 create mode 100644 telegram/tljson/convert.go
 create mode 100644 telegram/tljson/convert_test.go
 create mode 100644 telegram/tljson/tljson.go

diff --git a/telegram/tljson/convert.go b/telegram/tljson/convert.go
new file mode 100644
index 0000000000..4274953c35
--- /dev/null
+++ b/telegram/tljson/convert.go
@@ -0,0 +1,101 @@
+package tljson
+
+import (
+	"github.com/go-faster/errors"
+	"github.com/go-faster/jx"
+
+	"github.com/gotd/td/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()
+	}
+}
diff --git a/telegram/tljson/convert_test.go b/telegram/tljson/convert_test.go
new file mode 100644
index 0000000000..19500b0769
--- /dev/null
+++ b/telegram/tljson/convert_test.go
@@ -0,0 +1,67 @@
+package tljson
+
+import (
+	"testing"
+
+	"github.com/go-faster/jx"
+	"github.com/stretchr/testify/require"
+
+	"github.com/gotd/td/tg"
+)
+
+func TestDecodeEncodeDecode(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantErr bool
+		expect  tg.JSONValueClass
+	}{
+		{"Empty", "", true, nil},
+		{"InvalidNull", "nul", true, nil},
+		{"InvalidTrue", "tru", true, nil},
+		{"InvalidFalse", "falsy", true, nil},
+		{"InvalidInt", `[1a]"`, true, nil},
+		{"InvalidFloat", "1.", true, nil},
+		{"InvalidString", `"hello`, true, nil},
+		{"InvalidArray", "[1, 2, 3.]", true, nil},
+		{"InvalidObject", `{"abc":"def}`, true, nil},
+
+		{"Null", "null", false, nil},
+		{"True", "true", false, nil},
+		{"False", "false", false, nil},
+		{"Int", "10", false, nil},
+		{"Float", "1.1", false, nil},
+		{"String", `"hello"`, false, nil},
+		{"EmptyArray", "[]", false, nil},
+		{"Array", "[1, 2, 3]", false, nil},
+		{"EmptyObject", `{}`, false, nil},
+		{"Object", `{"abc":"def"}`, false, nil},
+		{"Tree", `{"a":1,"b":true,"c":null,"sub":{"abc":"def"}}`, false, nil},
+	}
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			a := require.New(t)
+
+			// Decode.
+			d := jx.DecodeStr(tt.input)
+			obj, err := Decode(d)
+			if tt.wantErr {
+				a.Error(err)
+				return
+			}
+			a.NoError(err)
+
+			// Encode.
+			e := jx.GetEncoder()
+			Encode(obj, e)
+
+			// Decode.
+			d.ResetBytes(e.Bytes())
+			obj2, err := Decode(d)
+			a.NoError(err)
+			a.Equal(obj, obj2)
+		})
+	}
+}
diff --git a/telegram/tljson/tljson.go b/telegram/tljson/tljson.go
new file mode 100644
index 0000000000..737e09242e
--- /dev/null
+++ b/telegram/tljson/tljson.go
@@ -0,0 +1,2 @@
+// Package tljson contains some helpers to work with JSONValue class.
+package tljson