/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.

For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#include "api/api_statistics.h"

#include "apiwrap.h"
#include "data/data_channel.h"
#include "data/data_peer.h"
#include "main/main_session.h"

namespace Api {
namespace {

[[nodiscard]] Data::StatisticalValue StatisticalValueFromTL(
		const MTPStatsAbsValueAndPrev &tl) {
	const auto current = tl.data().vcurrent().v;
	const auto previous = tl.data().vprevious().v;
	return Data::StatisticalValue{
		.value = current,
		.previousValue = previous,
		.growthRatePercentage = previous
			? std::abs((current - previous) / float64(previous) * 100.)
			: 0,
	};
}

[[nodiscard]] Data::ChannelStatistics ChannelStatisticsFromTL(
		const MTPDstats_broadcastStats &data) {
	const auto &tlUnmuted = data.venabled_notifications().data();
	const auto unmuted = (!tlUnmuted.vtotal().v)
		? 0.
		: std::clamp(
			tlUnmuted.vpart().v / tlUnmuted.vtotal().v * 100.,
			0.,
			100.);
	using Recent = MTPMessageInteractionCounters;
	auto recentMessages = ranges::views::all(
		data.vrecent_message_interactions().v
	) | ranges::views::transform([&](const Recent &tl) {
		return Data::StatisticsMessageInteractionInfo{
			.messageId = tl.data().vmsg_id().v,
			.viewsCount = tl.data().vviews().v,
			.forwardsCount = tl.data().vforwards().v,
		};
	}) | ranges::to_vector;
	return {
		.startDate = data.vperiod().data().vmin_date().v,
		.endDate = data.vperiod().data().vmax_date().v,

		.memberCount = StatisticalValueFromTL(data.vfollowers()),
		.meanViewCount = StatisticalValueFromTL(data.vviews_per_post()),
		.meanShareCount = StatisticalValueFromTL(data.vshares_per_post()),

		.enabledNotificationsPercentage = unmuted,

		.recentMessageInteractions = std::move(recentMessages),
	};
}

} // namespace

Statistics::Statistics(not_null<ApiWrap*> api)
: _api(&api->instance()) {
}

rpl::producer<rpl::no_value, QString> Statistics::request(
		not_null<PeerData*> peer) {
	return [=](auto consumer) {
		auto lifetime = rpl::lifetime();
		const auto channel = peer->asChannel();
		if (!channel) {
			return lifetime;
		}

		if (!channel->isMegagroup()) {
			_api.request(MTPstats_GetBroadcastStats(
				MTP_flags(MTPstats_GetBroadcastStats::Flags(0)),
				channel->inputChannel
			)).done([=](const MTPstats_BroadcastStats &result) {
				_channelStats = ChannelStatisticsFromTL(result.data());
				consumer.put_done();
			}).fail([=](const MTP::Error &error) {
				consumer.put_error_copy(error.type());
			}).send();
		}

		return lifetime;
	};
}

Data::ChannelStatistics Statistics::channelStats() const {
	return _channelStats;
}

} // namespace Api