feat: add SetBusinessAccountGiftSettings

Changes the incoming-gift privacy settings of a managed business account.
There is no dedicated MTProto RPC: the gift button and accepted gift types live
in the account-wide GlobalPrivacySettings, so this does a read-modify-write over
the business connection (account.getGlobalPrivacySettings then
account.setGlobalPrivacySettings) to avoid clobbering the other privacy fields.

The Bot API AcceptedGiftTypes is the inverse of MTProto's disallowedGiftsSettings;
AcceptedGiftTypes.disallowed() flips the flags.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ernado

gift_settings.go

@@ -0,0 +1,67 @@
+package botapi
+
+import (
+	"context"
+
+	"github.com/gotd/td/tg"
+)
+
+// AcceptedGiftTypes describes the types of gifts that can be gifted to a user or
+// a chat.
+type AcceptedGiftTypes struct {
+	// UnlimitedGifts reports whether unlimited regular gifts are accepted.
+	UnlimitedGifts bool `json:"unlimited_gifts"`
+	// LimitedGifts reports whether limited regular gifts are accepted.
+	LimitedGifts bool `json:"limited_gifts"`
+	// UniqueGifts reports whether unique (collectible) gifts are accepted.
+	UniqueGifts bool `json:"unique_gifts"`
+	// PremiumSubscription reports whether a Telegram Premium subscription is
+	// accepted as a gift.
+	PremiumSubscription bool `json:"premium_subscription"`
+	// GiftsFromChannels reports whether gifts sent on behalf of channels are
+	// accepted.
+	GiftsFromChannels bool `json:"gifts_from_channels"`
+}
+
+// disallowed maps the accepted gift types onto the MTProto disallowed-gifts
+// settings, which is expressed as the inverse (a set of disallow flags).
+func (a AcceptedGiftTypes) disallowed() tg.DisallowedGiftsSettings {
+	return tg.DisallowedGiftsSettings{
+		DisallowUnlimitedStargifts:    !a.UnlimitedGifts,
+		DisallowLimitedStargifts:      !a.LimitedGifts,
+		DisallowUniqueStargifts:       !a.UniqueGifts,
+		DisallowPremiumGifts:          !a.PremiumSubscription,
+		DisallowStargiftsFromChannels: !a.GiftsFromChannels,
+	}
+}
+
+// SetBusinessAccountGiftSettings changes the privacy settings for incoming gifts
+// of a managed business account. Requires the can_change_gift_settings business
+// bot right.
+//
+// The account's other global privacy settings are read first and preserved, so
+// only the gift button and accepted gift types change.
+func (b *Bot) SetBusinessAccountGiftSettings(
+	ctx context.Context, businessConnectionID string, showGiftButton bool, acceptedGiftTypes AcceptedGiftTypes,
+) error {
+	var current tg.GlobalPrivacySettings
+
+	err := b.invokeBusiness(ctx, businessConnectionID, &tg.AccountGetGlobalPrivacySettingsRequest{}, &current)
+	if err != nil {
+		return asAPIError(err)
+	}
+
+	current.SetDisplayGiftsButton(showGiftButton)
+	current.SetDisallowedGifts(acceptedGiftTypes.disallowed())
+
+	var updated tg.GlobalPrivacySettings
+
+	err = b.invokeBusiness(ctx, businessConnectionID, &tg.AccountSetGlobalPrivacySettingsRequest{
+		Settings: current,
+	}, &updated)
+	if err != nil {
+		return asAPIError(err)
+	}
+
+	return nil
+}

gift_settings_test.go

@@ -0,0 +1,68 @@
+package botapi
+
+import (
+	"context"
+	"testing"
+
+	"github.com/gotd/td/tg"
+)
+
+func TestSetBusinessAccountGiftSettings(t *testing.T) {
+	inv := newMockInvoker()
+	// Both the get and the set go through the business wrapper; the reply
+	// decodes as GlobalPrivacySettings for either call. HideReadMarks stands in
+	// for an unrelated setting that must survive the read-modify-write.
+	inv.reply(tg.InvokeWithBusinessConnectionRequestTypeID, &tg.GlobalPrivacySettings{HideReadMarks: true})
+
+	err := newMockBot(inv).SetBusinessAccountGiftSettings(context.Background(), "bc1", true, AcceptedGiftTypes{
+		UnlimitedGifts:    true,
+		UniqueGifts:       true,
+		GiftsFromChannels: true,
+	})
+	if err != nil {
+		t.Fatalf("SetBusinessAccountGiftSettings: %v", err)
+	}
+
+	wrapper := tg.InvokeWithBusinessConnectionRequest{Query: &tg.AccountSetGlobalPrivacySettingsRequest{}}
+
+	inv.decode(t, tg.InvokeWithBusinessConnectionRequestTypeID, &wrapper)
+
+	if wrapper.ConnectionID != "bc1" {
+		t.Fatalf("connection id = %q", wrapper.ConnectionID)
+	}
+
+	req, ok := wrapper.Query.(*tg.AccountSetGlobalPrivacySettingsRequest)
+	if !ok {
+		t.Fatalf("query = %#v, want set global privacy", wrapper.Query)
+	}
+
+	settings := req.Settings
+	if !settings.HideReadMarks {
+		t.Fatalf("unrelated setting not preserved: %#v", settings)
+	}
+
+	if !settings.DisplayGiftsButton {
+		t.Fatalf("display gifts button not set")
+	}
+
+	disallowed, ok := settings.GetDisallowedGifts()
+	if !ok {
+		t.Fatalf("disallowed gifts not set")
+	}
+
+	if disallowed.DisallowUnlimitedStargifts {
+		t.Fatalf("unlimited gifts should be allowed")
+	}
+
+	if !disallowed.DisallowLimitedStargifts {
+		t.Fatalf("limited gifts should be disallowed")
+	}
+
+	if !disallowed.DisallowPremiumGifts {
+		t.Fatalf("premium gifts should be disallowed")
+	}
+
+	if disallowed.DisallowUniqueStargifts || disallowed.DisallowStargiftsFromChannels {
+		t.Fatalf("unique/channel gifts should be allowed: %#v", disallowed)
+	}
+}