#include "stdafx.h"
#include "PandaJ2534Device.h"
#include "J2534Frame.h"

PandaJ2534Device::PandaJ2534Device(std::unique_ptr<panda::Panda> new_panda) : txInProgress(FALSE) {
	this->panda = std::move(new_panda);

	this->panda->set_esp_power(FALSE);
	this->panda->set_safety_mode(panda::SAFETY_ALLOUTPUT);
	this->panda->set_can_loopback(FALSE);
	this->panda->set_alt_setting(0);

	this->thread_kill_event = CreateEvent(NULL, TRUE, FALSE, NULL);

	DWORD canListenThreadID;
	this->can_recv_handle = CreateThread(NULL, 0, _can_recv_threadBootstrap, (LPVOID)this, 0, &canListenThreadID);

	DWORD canProcessThreadID;
	this->can_process_handle = CreateThread(NULL, 0, _can_process_threadBootstrap, (LPVOID)this, 0, &canProcessThreadID);

	DWORD flowControlSendThreadID;
	this->flow_control_wakeup_event = CreateEvent(NULL, TRUE, FALSE, NULL);
	this->flow_control_thread_handle = CreateThread(NULL, 0, _msg_tx_threadBootstrap, (LPVOID)this, 0, &flowControlSendThreadID);
};

PandaJ2534Device::~PandaJ2534Device() {
	SetEvent(this->thread_kill_event);
	DWORD res = WaitForSingleObject(this->can_recv_handle, INFINITE);
	CloseHandle(this->can_recv_handle);

	res = WaitForSingleObject(this->can_process_handle, INFINITE);
	CloseHandle(this->can_process_handle);

	res = WaitForSingleObject(this->flow_control_thread_handle, INFINITE);
	CloseHandle(this->flow_control_thread_handle);

	CloseHandle(this->flow_control_wakeup_event);
	CloseHandle(this->thread_kill_event);
}

std::shared_ptr<PandaJ2534Device> PandaJ2534Device::openByName(std::string sn) {
	auto p = panda::Panda::openPanda("");
	if (p == nullptr)
		return nullptr;
	return std::unique_ptr<PandaJ2534Device>(new PandaJ2534Device(std::move(p)));
}

DWORD PandaJ2534Device::closeChannel(unsigned long ChannelID) {
	if (this->connections.size() <= ChannelID) return ERR_INVALID_CHANNEL_ID;
	if (this->connections[ChannelID] == nullptr) return ERR_INVALID_CHANNEL_ID;
	this->connections[ChannelID] = nullptr;
	return STATUS_NOERROR;
}

DWORD PandaJ2534Device::addChannel(std::shared_ptr<J2534Connection>& conn, unsigned long* channel_id) {
	int channel_index = -1;
	for (unsigned int i = 0; i < this->connections.size(); i++)
		if (this->connections[i] == nullptr) {
			channel_index = i;
			break;
		}

	if (channel_index == -1) {
		if (this->connections.size() == 0xFFFF) //channelid max 16 bits
			return ERR_FAILED; //Too many channels
		this->connections.push_back(nullptr);
		channel_index = this->connections.size() - 1;
	}

	this->connections[channel_index] = conn;

	*channel_id = channel_index;
	return STATUS_NOERROR;
}

DWORD PandaJ2534Device::can_recv_thread() {
	this->panda->can_clear(panda::PANDA_CAN_RX);
	this->panda->can_rx_q_push(this->thread_kill_event);

	return 0;
}

DWORD PandaJ2534Device::can_process_thread() {
	panda::PANDA_CAN_MSG msg_recv[CAN_RX_MSG_LEN];

	while (true) {
		if (!WaitForSingleObject(this->thread_kill_event, 0)) {
			break;
		}

		int count = 0;
		this->panda->can_rx_q_pop(msg_recv, count);
		if (count == 0) {
			continue;
		}
		
		for (int i = 0; i < count; i++) {
			auto msg_in = msg_recv[i];
			J2534Frame msg_out(msg_in);

			if (msg_in.is_receipt) {
				synchronized(task_queue_mutex) {
					if (txMsgsAwaitingEcho.size() > 0) {
						auto msgtx = txMsgsAwaitingEcho.front();
						if (auto conn = msgtx->connection.lock()) {
							if (conn->isProtoCan() && conn->getPort() == msg_in.bus) {
								if (msgtx->checkTxReceipt(msg_out)) {
									//Things to check:
									//    Frame not for this msg: Drop frame and alert. Error?
									//    Frame is for this msg, more tx frames required after a FC frame: Wait for FC frame to come and trigger next tx.
									//    Frame is for this msg, more tx frames required: Schedule next tx frame.
									//    Frame is for this msg, and is the final frame of the msg: Let conn process full msg, If another msg from this conn is available, register it.
									txMsgsAwaitingEcho.pop(); //Remove the TX object and schedule record.

									if (msgtx->isFinished()) {
										this->removeConnectionTopAction(conn, msgtx);
									} else {
										if (msgtx->txReady()) { //Not finished, ready to send next frame.
											msgtx->schedule(msg_in.recv_time_point, TRUE);
											this->insertActionIntoTaskList(msgtx);
										} else {
											//Not finished, but next frame not ready (maybe waiting for flow control).
											//Do not schedule more messages from this connection.
											//this->ConnTxSet.erase(conn);
											//Removing this means new messages queued can kickstart the queue and overstep the current message.
										}
									}
								}
							}
						} else {
							//Connection has died. Clear out the tx entry from device records.
							txMsgsAwaitingEcho.pop();
							this->ConnTxSet.erase(conn); //connection is already dead, no need to schedule future tx msgs.
						}
					}
				}
			} else {
				for (auto& conn : this->connections)
					if (conn != nullptr && conn->isProtoCan() && conn->getPort() == msg_in.bus)
						conn->processMessage(msg_out);
			}
		}
	}

	return 0;
}

DWORD PandaJ2534Device::msg_tx_thread() {
	const HANDLE subscriptions[] = { this->flow_control_wakeup_event, this->thread_kill_event };
	DWORD sleepDuration = INFINITE;
	while (TRUE) {
		DWORD res = WaitForMultipleObjects(2, subscriptions, FALSE, sleepDuration);
		if (res == WAIT_OBJECT_0 + 1) return 0;
		if (res != WAIT_OBJECT_0 && res != WAIT_TIMEOUT) {
			printf("Got an unexpected wait result in flow_control_write_thread. Res: %d; GetLastError: %d\n. Terminating thread.", res, GetLastError());
			return 0;
		}
		ResetEvent(this->flow_control_wakeup_event);

		while (TRUE) {
			synchronized(task_queue_mutex) { //implemented with for loop. Consumes breaks.
				if (this->task_queue.size() == 0) {
					sleepDuration = INFINITE;
					goto break_flow_ctrl_loop;
				}
				if (std::chrono::steady_clock::now() >= this->task_queue.front()->expire) {
					auto task = this->task_queue.front(); //Get the scheduled tx record.
					this->task_queue.pop_front();
					task->execute();
				} else { //Ran out of things that need to be sent now. Sleep!
					auto time_diff = std::chrono::duration_cast<std::chrono::milliseconds>
						(this->task_queue.front()->expire - std::chrono::steady_clock::now());
					sleepDuration = max(1, time_diff.count());
					goto break_flow_ctrl_loop;
				}
			}
		}
		break_flow_ctrl_loop:
		continue;
	}
	return 0;
}

//Place the Action in the task queue based on the Action's expiration time,
//then signal the thread that processes actions.
void PandaJ2534Device::insertActionIntoTaskList(std::shared_ptr<Action> action) {
	synchronized(task_queue_mutex) {
		auto iter = this->task_queue.begin();
		for (; iter != this->task_queue.end(); iter++) {
			if (action->expire < (*iter)->expire) break;
		}
		this->task_queue.insert(iter, action);
	}
	SetEvent(this->flow_control_wakeup_event);
}

void PandaJ2534Device::scheduleAction(std::shared_ptr<Action> msg, BOOL startdelayed) {
	if(startdelayed)
		msg->scheduleImmediateDelay();
	else
		msg->scheduleImmediate();
	this->insertActionIntoTaskList(msg);
}

void PandaJ2534Device::registerConnectionTx(std::shared_ptr<J2534Connection> conn) {
	synchronized(connTXSet_mutex) {
		auto ret = this->ConnTxSet.insert(conn);
		if (ret.second == FALSE) return; //Conn already exists.
		this->scheduleAction(conn->txbuff.front());
	}
}

void PandaJ2534Device::unstallConnectionTx(std::shared_ptr<J2534Connection> conn) {
	synchronized(connTXSet_mutex) {
		auto ret = this->ConnTxSet.insert(conn);
		if (ret.second == TRUE) return; //Conn already exists.
		this->insertActionIntoTaskList(conn->txbuff.front());
	}
}

void PandaJ2534Device::removeConnectionTopAction(std::shared_ptr<J2534Connection> conn, std::shared_ptr<MessageTx> msg) {
	synchronized(task_queue_mutex) {
		if (conn->txbuff.size() == 0)
			return;
		if (conn->txbuff.front() != msg)
			return;
		conn->txbuff.pop(); //Remove the top TX message from the connection tx queue.

		//Remove the connection from the active connection list if no more messages are scheduled with this connection.
		if (conn->txbuff.size() == 0) {
			//Update records showing the connection no longer has a tx record scheduled.
			this->ConnTxSet.erase(conn);
		} else {
			//Add the next scheduled tx from this conn
			this->scheduleAction(conn->txbuff.front());
		}
	}
}