Use app config value for QR login.

Telegram/SourceFiles/main/main_app_config.cpp

@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "main/main_app_config.h"
 
-#include "main/main_session.h"
+#include "main/main_account.h"
 #include "base/call_delayed.h"
 #include "apiwrap.h"
 
@@ -18,15 +18,25 @@ constexpr auto kRefreshTimeout = 3600 * crl::time(1000);
 
 } // namespace
 
-AppConfig::AppConfig(not_null<Session*> session) : _session(session) {
+AppConfig::AppConfig(not_null<Account*> account) : _account(account) {
+	account->mtpValue(
+	) | rpl::start_with_next([=](MTP::Instance *instance) {
+		if (instance) {
+			_api.emplace(instance);
+			refresh();
+		} else {
+			_api.reset();
+			_requestId = 0;
+		}
+	}, _lifetime);
 	refresh();
 }
 
 void AppConfig::refresh() {
-	if (_requestId) {
+	if (_requestId || !_api) {
 		return;
 	}
-	_requestId = _session->api().request(MTPhelp_GetAppConfig(
+	_requestId = _api->request(MTPhelp_GetAppConfig(
 	)).done([=](const MTPJSONValue &result) {
 		_requestId = 0;
 		refreshDelayed();
@@ -37,6 +47,7 @@ void AppConfig::refresh() {
 				});
 			}
 		}
+		_refreshed.fire({});
 	}).fail([=](const RPCError &error) {
 		_requestId = 0;
 		refreshDelayed();
@@ -44,20 +55,42 @@ void AppConfig::refresh() {
 }
 
 void AppConfig::refreshDelayed() {
-	base::call_delayed(kRefreshTimeout, _session, [=] {
+	base::call_delayed(kRefreshTimeout, _account, [=] {
 		refresh();
 	});
 }
 
-double AppConfig::getDouble(const QString &key, double fallback) const {
+rpl::producer<> AppConfig::refreshed() const {
+	return _refreshed.events();
+}
+
+template <typename Extractor>
+auto AppConfig::getValue(const QString &key, Extractor &&extractor) const {
 	const auto i = _data.find(key);
-	if (i == end(_data)) {
-		return fallback;
-	}
-	return i->second.match([&](const MTPDjsonNumber &data) {
-		return data.vvalue().v;
-	}, [&](const auto &data) {
-		return fallback;
+	return extractor((i != end(_data))
+		? i->second
+		: MTPJSONValue(MTP_jsonNull()));
+}
+
+double AppConfig::getDouble(const QString &key, double fallback) const {
+	return getValue(key, [&](const MTPJSONValue &value) {
+		return value.match([&](const MTPDjsonNumber &data) {
+			return data.vvalue().v;
+		}, [&](const auto &data) {
+			return fallback;
+		});
+	});
+}
+
+QString AppConfig::getString(
+		const QString &key,
+		const QString &fallback) const {
+	return getValue(key, [&](const MTPJSONValue &value) {
+		return value.match([&](const MTPDjsonString &data) {
+			return qs(data.vvalue());
+		}, [&](const auto &data) {
+			return fallback;
+		});
 	});
 }