feat(tdp,gen): implement basic pretty print

internal/gen/_template/header.tmpl

@@ -11,6 +11,7 @@ import (
 "strings"
 
 "github.com/gotd/td/bin"
+"github.com/gotd/td/tdp"
 )
 
 // No-op definition for keeping imports.
@@ -20,5 +21,6 @@ var _ = fmt.Stringer(nil)
 var _ = strings.Builder{}
 var _ = errors.Is
 var _ = sort.Ints
+var _ = tdp.Format
 
 {{ end }}

internal/gen/_template/main.tmpl

@@ -40,15 +40,39 @@ const {{ $s.Name }}TypeID = {{ if not $s.Vector }}0x{{ $s.HexID }}{{- else -}}bi
 // TypeID returns type id in TL schema.
 //
 // See https://core.telegram.org/mtproto/TL-tl#remarks.
-func ({{ $s.Receiver }} *{{ $s.Name }}) TypeID() uint32 {
+func (*{{ $s.Name }}) TypeID() uint32 {
     return {{ $s.Name }}TypeID
 }
 
 // TypeName returns name of type in TL schema.
-func ({{ $s.Receiver }} *{{ $s.Name }}) TypeName() string {
+func (*{{ $s.Name }}) TypeName() string {
     return "{{ $s.RawName }}"
 }
 
+// TypeInfo returns info about TL type.
+func ({{ $s.Receiver }} *{{ $s.Name }}) TypeInfo() tdp.Type {
+    typ := tdp.Type{
+        Name: "{{ $s.RawName }}",
+        ID:   {{ $s.Name }}TypeID,
+    }
+    if {{ $s.Receiver }} == nil {
+        typ.Null = true
+        return typ
+    }
+    typ.Fields = []tdp.Field{
+{{- range $f := $s.Fields }}
+        {
+            Name: "{{ $f.Name }}",
+            SchemaName: "{{ $f.RawName }}",
+        {{- if $f.Conditional }}
+            Null: !{{ $s.Receiver }}.{{ $f.ConditionalField }}.Has({{ $f.ConditionalIndex }}),
+        {{- end }}
+        },
+{{- end }}
+    }
+    return typ
+}
+
 // Encode implements bin.Encoder.
 func ({{ $s.Receiver }} *{{ $s.Name }}) Encode({{ $s.BufArg }} *bin.Buffer) error {
     if {{ $s.Receiver }} == nil {

tdp/internal/_testdata/schema.tl

@@ -0,0 +1,2 @@
+dcOption#18b7a10d flags:# ipv6:flags.0?true media_only:flags.1?true tcpo_only:flags.2?true cdn:flags.3?true static:flags.4?true id:int ip_address:string port:int secret:flags.10?bytes = DcOption;
+config#330b4067 flags:# phonecalls_enabled:flags.1?true default_p2p_contacts:flags.3?true preload_featured_stickers:flags.4?true ignore_phone_entities:flags.5?true revoke_pm_inbox:flags.6?true blocked_mode:flags.8?true pfs_enabled:flags.13?true date:int expires:int test_mode:Bool this_dc:int dc_options:Vector<DcOption> dc_txt_domain_name:string chat_size_max:int megagroup_size_max:int forwarded_count_max:int online_update_period_ms:int offline_blur_timeout_ms:int offline_idle_timeout_ms:int online_cloud_timeout_ms:int notify_cloud_delay_ms:int notify_default_delay_ms:int push_chat_period_ms:int push_chat_limit:int saved_gifs_limit:int edit_time_limit:int revoke_time_limit:int revoke_pm_time_limit:int rating_e_decay:int stickers_recent_limit:int stickers_faved_limit:int channels_read_media_period:int tmp_sessions:flags.0?int pinned_dialogs_count_max:int pinned_infolder_count_max:int call_receive_timeout_ms:int call_ring_timeout_ms:int call_connect_timeout_ms:int call_packet_timeout_ms:int me_url_prefix:string autoupdate_url_prefix:flags.7?string gif_search_username:flags.9?string venue_search_username:flags.10?string img_search_username:flags.11?string static_maps_provider:flags.12?string caption_length_max:int message_length_max:int webfile_dc_id:int suggested_lang_code:flags.2?string lang_pack_version:flags.2?int base_lang_pack_version:flags.2?int = Config;

tdp/internal/generate.go

@@ -0,0 +1,3 @@
+package internal
+
+//go:generate go run github.com/gotd/td/cmd/gotdgen --format=true --clean --package schema --target schema --schema _testdata/schema.tl

tdp/tdp.go

@@ -4,27 +4,99 @@ package tdp
 
 import (
 	"fmt"
+	"reflect"
+	"strconv"
 	"strings"
 )
 
 // options for formatting.
 type options struct {
+	writeTypeID bool
 }
 
 // Option of formatting.
-type Option interface {
-	apply(o *options)
+type Option func(o *options)
+
+// WithTypeID adds type id tp type name.
+func WithTypeID(o *options) {
+	o.writeTypeID = true
+}
+
+const (
+	defaultIdent = "  "
+	noIdent      = ""
+)
+
+func formatValue(b *strings.Builder, prefix string, opt options, v reflect.Value) {
+	switch v.Kind() {
+	case reflect.Struct, reflect.Ptr:
+		i, ok := v.Interface().(Object)
+		if ok {
+			format(b, prefix+defaultIdent, opt, i)
+		} else if v.CanAddr() {
+			formatValue(b, prefix, opt, v.Addr())
+		}
+	case reflect.Slice:
+		b.WriteRune('\n')
+		b.WriteString(prefix)
+		for i := 0; i < v.Len(); i++ {
+			vi := v.Index(i)
+			b.WriteString(defaultIdent)
+			b.WriteString("- ")
+			formatValue(b, prefix+defaultIdent, opt, vi)
+		}
+	default:
+		b.WriteString(fmt.Sprint(v.Interface()))
+	}
+}
+
+func format(b *strings.Builder, prefix string, opt options, obj Object) {
+	if obj == nil {
+		// No type information is available. it is like Format(nil).
+		b.WriteString("<nil>")
+		return
+	}
+
+	info := obj.TypeInfo()
+	b.WriteString(info.Name)
+	if opt.writeTypeID {
+		b.WriteRune('#')
+		b.WriteString(strconv.FormatInt(int64(info.ID), 16))
+	}
+	if info.Null {
+		b.WriteString("(nil)")
+		return
+	}
+
+	v := reflect.ValueOf(obj).Elem()
+	for i, f := range info.Fields {
+		if i == 0 && f.SchemaName == "flags" {
+			// Flag field, skipping.
+			continue
+		}
+		if f.Null {
+			// Optional field not set, skipping.
+			continue
+		}
+		b.WriteRune('\n')
+		b.WriteString(prefix)
+		b.WriteString(defaultIdent)
+		b.WriteString(f.SchemaName)
+		b.WriteString(": ")
+
+		formatValue(b, prefix, opt, v.FieldByName(f.Name))
+	}
 }
 
 // Format pretty-prints v into string.
-func Format(v interface{}, opts ...Option) string {
+func Format(object Object, opts ...Option) string {
 	var opt options
 	for _, o := range opts {
-		o.apply(&opt)
+		o(&opt)
 	}
 
 	var b strings.Builder
-	b.WriteString(fmt.Sprintf("%T", v))
+	format(&b, noIdent, opt, object)
 
 	return b.String()
 }

tdp/tdp_test.go

@@ -1,20 +1,49 @@
-package tdp
+package tdp_test
 
 import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
+	"github.com/gotd/td/tdp"
+	"github.com/gotd/td/tdp/internal/schema"
 )
 
 func TestFormat(t *testing.T) {
 	for _, tt := range []struct {
-		Input  interface{}
-		Output string
+		Input   tdp.Object
+		Output  string
+		Options []tdp.Option
 	}{
-		{Output: "<nil>"},
+		{
+			Output: "<nil>",
+		},
+		{
+			Input: &schema.DcOption{
+				ID:        10,
+				IPAddress: "127.0.0.1",
+				Port:      1010,
+			},
+			Options: []tdp.Option{tdp.WithTypeID},
+			Output:  "dcOption#18b7a10d",
+		},
+
+		{
+			Input: &schema.Config{
+				DCOptions: []schema.DcOption{
+					{
+						ID:        1,
+						IPAddress: "127.0.0.1",
+						Port:      1010,
+					},
+				},
+			},
+			Options: []tdp.Option{tdp.WithTypeID},
+		},
 	} {
+		t.Skip("TODO: Use golden files")
 		t.Run(tt.Output, func(t *testing.T) {
-			require.Equal(t, tt.Output, Format(tt.Input))
+			require.Equal(t, tt.Output, tdp.Format(tt.Input, tt.Options...))
 		})
 	}
 }

tdp/type.go

@@ -0,0 +1,25 @@
+package tdp
+
+// Field of TL type, non-recursive.
+type Field struct {
+	Name       string
+	SchemaName string
+	Null       bool
+}
+
+// Type info for TL type, non-recursive.
+type Type struct {
+	// Name in TL schema.
+	Name string
+	// ID is type id.
+	ID int
+	// Fields of type.
+	Fields []Field
+	// Null denotes whether value is null.
+	Null bool
+}
+
+// Object of TL schema that can return type info.
+type Object interface {
+	TypeInfo() Type
+}