#include <fstream>
#include <ftl/streams/filestream.hpp>

#define LOGURU_REPLACE_GLOG 1
#include <loguru.hpp>

using ftl::stream::File;
using ftl::codecs::StreamPacket;
using ftl::codecs::Packet;
using std::get;

File::File(nlohmann::json &config) : Stream(config), ostream_(nullptr), istream_(nullptr), active_(false) {
	mode_ = Mode::Read;
	jobs_ = 0;
}

File::File(nlohmann::json &config, std::ifstream *is) : Stream(config), ostream_(nullptr), istream_(is), active_(false) {
	mode_ = Mode::Read;
	jobs_ = 0;
}

File::File(nlohmann::json &config, std::ofstream *os) : Stream(config), ostream_(os), istream_(nullptr), active_(false) {
	mode_ = Mode::Write;
	jobs_ = 0;
}

File::~File() {
	end();
}

bool File::onPacket(const std::function<void(const ftl::codecs::StreamPacket &, const ftl::codecs::Packet &)> &f) {
	cb_ = f;
	return true;
}

bool File::post(const ftl::codecs::StreamPacket &s, const ftl::codecs::Packet &p) {
	if (!active_) return false;
	if (mode_ != Mode::Write) {
		LOG(WARNING) << "Cannot write to read-only ftl file";
		return false;
	}

	// Don't write dummy packets to files.
	if (p.data.size() == 0) return true;

	available(s.streamID) += s.channel;

	// Discard all data channel packets for now
	// TODO: Allow saving of data channels once formats have solidified.
	if (static_cast<int>(s.channel) >= static_cast<int>(ftl::codecs::Channel::Data)) return true;

	ftl::codecs::StreamPacket s2 = s;
	// Adjust timestamp relative to start of file.
	s2.timestamp -= timestart_;

	auto data = std::make_tuple(s2,p);
	msgpack::sbuffer buffer;
	msgpack::pack(buffer, data);

	UNIQUE_LOCK(mutex_, lk);
	ostream_->write(buffer.data(), buffer.size());
	return ostream_->good();
}

bool File::tick(int64_t ts) {
	if (!active_) return false;
	if (mode_ != Mode::Read) {
		LOG(ERROR) << "Cannot read from a write only file";
		return false;
	}

	#ifdef DEBUG_MUTEX
	UNIQUE_LOCK(mutex_, lk);
	#else
	std::unique_lock<std::mutex> lk(mutex_, std::defer_lock);
	if (!lk.try_lock()) return true;
	#endif

	if (jobs_ > 0) {
		//LOG(ERROR) << "STILL HAS JOBS";
		return true;
	}

	// Check buffer first for frames already read
	{
		UNIQUE_LOCK(data_mutex_, dlk);
		for (auto i = data_.begin(); i != data_.end(); ++i) {
			if (std::get<0>(*i).timestamp <= timestamp_) {
				++jobs_;
				std::get<0>(*i).timestamp = ts;
				ftl::pool.push([this,i](int id) {
					auto &spkt = std::get<0>(*i);
					auto &pkt = std::get<1>(*i);

					try {
						if (cb_) cb_(spkt, pkt);
					} catch (std::exception &e) {
						LOG(ERROR) << "Exception in packet callback: " << e.what();
					}
					//LOG(INFO) << "ERASE: " << spkt.timestamp << ", " << spkt.frameNumber() << ", " << (int)spkt.channel;
					UNIQUE_LOCK(data_mutex_, dlk);
					data_.erase(i);
					--jobs_;
				});
			}
		}
	}

	bool partial = false;
	int64_t extended_ts = timestamp_ + 200;  // Buffer 200ms ahead

	while ((active_ && istream_->good()) || buffer_in_.nonparsed_size() > 0u) {
		if (buffer_in_.nonparsed_size() == 0 || (partial && buffer_in_.nonparsed_size() < 10000000)) {
			buffer_in_.reserve_buffer(10000000);
			istream_->read(buffer_in_.buffer(), buffer_in_.buffer_capacity());
			//if (stream_->bad()) return false;

			int bytes = istream_->gcount();
			if (bytes == 0) break;
			buffer_in_.buffer_consumed(bytes);
			partial = false;
		}

		msgpack::object_handle msg;
		if (!buffer_in_.next(msg)) {
			partial = true;
			continue;
		}

		msgpack::object obj = msg.get();

		UNIQUE_LOCK(data_mutex_, dlk);
		auto &data = data_.emplace_back();
		dlk.unlock();

		try {
			obj.convert(data);
		} catch (std::exception &e) {
			LOG(INFO) << "Corrupt message: " << buffer_in_.nonparsed_size() << " - " << e.what();
			active_ = false;
			return false;
		}

		// Adjust timestamp
		std::get<0>(data).timestamp = ((std::get<0>(data).timestamp) / interval_) * interval_ + timestart_;
		//std::get<0>(data).timestamp = std::get<0>(data).timestamp + timestart_;

		// Fix to clear flags for version 2.
		if (version_ <= 2) {
			std::get<1>(data).flags = 0;
		}
		if (version_ < 4) {
			std::get<0>(data).frame_number = std::get<0>(data).streamID;
			std::get<0>(data).streamID = 0;
			if (isFloatChannel(std::get<0>(data).channel)) std::get<1>(data).flags |= ftl::codecs::kFlagFloat;

			auto codec = std::get<1>(data).codec;
			if (codec == ftl::codecs::codec_t::HEVC) std::get<1>(data).codec = ftl::codecs::codec_t::HEVC_LOSSLESS;
		}
		std::get<0>(data).version = 4;

		// Maintain availability of channels.
		available(0) += std::get<0>(data).channel;

		// This should only occur for first few frames, generally otherwise
		// the data buffer is already several frames ahead so is processed
		// above. Hence, no need to bother parallelising this bit.
		if (std::get<0>(data).timestamp <= timestamp_) {
			std::get<0>(data).timestamp = ts;
			if (cb_) {
				dlk.lock();
				try {
					cb_(std::get<0>(data),std::get<1>(data));
				} catch (std::exception &e) {
					LOG(ERROR) << "Exception in packet callback: " << e.what();
				}
				data_.pop_back();
			}
		} else if (std::get<0>(data).timestamp > extended_ts) {
			break;
		}
	}

	timestamp_ += interval_;

	if (data_.size() == 0 && value("looping", true)) {
		istream_->clear();
        istream_->seekg(0);

		ftl::codecs::Header h;
		(*istream_).read((char*)&h, sizeof(h));
		if (h.version >= 2) {
			ftl::codecs::IndexHeader ih;
			(*istream_).read((char*)&ih, sizeof(ih));
		}

		timestart_ = (ftl::timer::get_time() / ftl::timer::getInterval()) * ftl::timer::getInterval();
		timestamp_ = timestart_;
		return true;
	}

	return data_.size() > 0;
}

bool File::run() {
	timer_ = ftl::timer::add(ftl::timer::kTimerMain, [this](int64_t ts) {
		tick(ts);
		return active_;
	});
	return true;
}

bool File::begin(bool dorun) {
	if (mode_ == Mode::Read) {
		if (!istream_) istream_ = new std::ifstream;
		istream_->open(*get<std::string>("filename"));

		if (!istream_->good()) {
			LOG(ERROR) << "Could not open file: " << *get<std::string>("filename");
			return false;
		}

		ftl::codecs::Header h;
		(*istream_).read((char*)&h, sizeof(h));
		if (h.magic[0] != 'F' || h.magic[1] != 'T' || h.magic[2] != 'L' || h.magic[3] != 'F') return false;

		if (h.version >= 2) {
			ftl::codecs::IndexHeader ih;
			(*istream_).read((char*)&ih, sizeof(ih));
		}

		version_ = h.version;
		LOG(INFO) << "FTL format version " << version_;

		// Capture current time to adjust timestamps
		timestart_ = (ftl::timer::get_time() / ftl::timer::getInterval()) * ftl::timer::getInterval();
		active_ = true;
		interval_ = 50; //ftl::timer::getInterval();  // FIXME: Use correct interval!!
		timestamp_ = timestart_;

		tick(timestart_); // Do some now!
		if (dorun) run();
	} else if (mode_ == Mode::Write) {
		if (!ostream_) ostream_ = new std::ofstream;
		ostream_->open(*get<std::string>("filename"));

		if (!ostream_->good()) {
			LOG(ERROR) << "Could not open file: " << *get<std::string>("filename");
			return false;
		}

		ftl::codecs::Header h;
		//h.version = 2;
		(*ostream_).write((const char*)&h, sizeof(h));

		ftl::codecs::IndexHeader ih;
		ih.reserved[0] = -1;
		(*ostream_).write((const char*)&ih, sizeof(ih));

		// Capture current time to adjust timestamps
		timestart_ = ftl::timer::get_time();
		active_ = true;
		interval_ = ftl::timer::getInterval();
		timestamp_ = timestart_;
	}

	return true;
}

bool File::end() {
	if (!active_) return false;
	active_ = false;
	timer_.cancel();

	if (mode_ == Mode::Read) {
		if (istream_) {
			istream_->close();
			delete istream_;
			istream_ = nullptr;
		}
	} else if (mode_ == Mode::Write) {
		if (ostream_) {
			ostream_->close();
			delete ostream_;
			ostream_ = nullptr;
		}
	}
	return true;
}

bool File::active() {
	return active_;
}