#include "platform/windows/include/ftdi.h"
#include "platform/include/ftdi.h"
#include "platform/include/registry.h"
#include <iostream>
#include <iomanip>
#include <sstream>
#include <cwctype>
#include <algorithm>
#include <codecvt>
#include <limits>
#include <stdio.h>

using namespace icsneo;

static std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
static const std::wstring DRIVER_SERVICES_REG_KEY = L"SYSTEM\\CurrentControlSet\\services\\";
static const std::wstring ALL_ENUM_REG_KEY = L"SYSTEM\\CurrentControlSet\\Enum\\";
static constexpr unsigned int RETRY_TIMES = 5;
static constexpr unsigned int RETRY_DELAY = 50;

std::vector<neodevice_t> VCP::FindByProduct(int product, wchar_t* driverName) {
	std::vector<neodevice_t> found;

	std::wstringstream regss;
	regss << DRIVER_SERVICES_REG_KEY << driverName << L"\\Enum\\";
	std::wstring driverEnumRegKey = regss.str();

	uint32_t deviceCount = 0;
	if(!Registry::Get(driverEnumRegKey, L"Count", deviceCount)) {
		return found;
	}

	for(uint32_t i = 0; i < deviceCount; i++) {
		neodevice_t device = {};

		// First we want to look at what devices FTDI is enumerating (inside driverEnumRegKey)
		// The entry for a ValueCAN 3 with SN 138635 looks like "FTDIBUS\VID_093C+PID_0601+138635A\0000"
		// The entry for a ValueCAN 4 with SN V20227 looks like "USB\VID_093C&PID_1101\V20227"
		std::wstringstream ss;
		ss << i;
		std::wstring entry;
		if(!Registry::Get(driverEnumRegKey, ss.str(), entry))
			continue;

		std::transform(entry.begin(), entry.end(), entry.begin(), std::towupper);
		
		std::wstringstream vss;
		vss << "VID_" << std::setfill(L'0') << std::setw(4) << std::uppercase << std::hex << INTREPID_USB_VENDOR_ID; // Intrepid Vendor ID
		if(entry.find(vss.str()) == std::wstring::npos)
			continue;

		std::wstringstream pss;
		pss << "PID_" << std::setfill(L'0') << std::setw(4) << std::uppercase << std::hex << product;
		auto pidpos = entry.find(pss.str());
		if(pidpos == std::wstring::npos)
			continue;

		// Okay, this is a device we want
		// Get the serial number
		auto startchar = entry.find(L"+", pidpos + 1);
		if(startchar == std::wstring::npos)
			startchar = entry.find(L"\\", pidpos + 1);
		bool conversionError = false;
		int sn = 0;
		try {
			sn = std::stoi(entry.substr(startchar + 1));
		} catch(...) {
			conversionError = true;
		}

		std::wstringstream oss;
		if(!sn || conversionError) {
			// This is a device with characters in the serial number
			oss << entry.substr(startchar + 1, 6);
		} else {
			oss << sn;
		}

		strcpy_s(device.serial, sizeof(device.serial), converter.to_bytes(oss.str()).c_str());

		// Serial number is saved, we want the COM port number now
		// This will be stored under ALL_ENUM_REG_KEY\entry\Device Parameters\PortName (entry from the FTDI_ENUM)
		std::wstringstream dpss;
		dpss << ALL_ENUM_REG_KEY << entry << L"\\Device Parameters";
		std::wstring port;
		Registry::Get(dpss.str(), L"PortName", port); // TODO If error do something else (Plasma maybe?)
		std::transform(port.begin(), port.end(), port.begin(), std::towupper);
		auto compos = port.find(L"COM");
		device.handle = 0;
		if(compos != std::wstring::npos) {
			try {
				device.handle = std::stoi(port.substr(compos + 3));
			} catch(...) {} // In case of this, or any other error, handle has already been initialized to 0
		}

		found.push_back(device);
	}

	return found;
}

bool VCP::IsHandleValid(neodevice_handle_t handle) {
	if(handle < 1)
		return false;

	if(handle > 256) // Windows default max COM port is COM256
		return false; // TODO Enumerate subkeys of HKLM\HARDWARE\DEVICEMAP\SERIALCOMM as a user might have more serial ports somehow

	return true;
}

bool VCP::open(bool fromAsync) {
	if(isOpen() || (!fromAsync && opening))
		return false;

	if(!IsHandleValid(device.handle))
		return false;

	opening = true;

	std::wstringstream comss;
	comss << L"\\\\.\\COM" << device.handle;

	// We're going to attempt to open 5 (RETRY_TIMES) times in a row
	for(int i = 0; !isOpen() && i < RETRY_TIMES; i++) {
		handle = CreateFileW(comss.str().c_str(), GENERIC_READ | GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, nullptr);
		if(GetLastError() == ERROR_SUCCESS)
			break; // We have the file handle

		std::this_thread::sleep_for(std::chrono::milliseconds(RETRY_DELAY));
	}

	opening = false;

	if(!isOpen())
		return false;

	// Set the timeouts
	COMMTIMEOUTS timeouts;
	if(!GetCommTimeouts(handle, &timeouts)) {
		close();
		return false;
	}

	timeouts.WriteTotalTimeoutConstant = 10000;
	timeouts.WriteTotalTimeoutMultiplier = 0;

	if(!SetCommTimeouts(handle, &timeouts)) {
		close();
		return false;
	}

	// Set the COM state
	DCB comstate;
	if(!GetCommState(handle, &comstate)) {
		close();
		return false;
	}

	comstate.BaudRate = 115200;
	comstate.ByteSize = 8;
	comstate.Parity = NOPARITY;
	comstate.StopBits = 0;
	comstate.fDtrControl = DTR_CONTROL_ENABLE;
	comstate.fRtsControl = RTS_CONTROL_ENABLE;

	if(!SetCommState(handle, &comstate)) {
		close();
		return false;
	}

	PurgeComm(handle, PURGE_RXCLEAR);

	// Set up events so that overlapped IO can work with them
	overlappedRead.hEvent = CreateEvent(nullptr, false, false, nullptr);
	overlappedWrite.hEvent = CreateEvent(nullptr, false, false, nullptr);
	overlappedWait.hEvent = CreateEvent(nullptr, true, false, nullptr);
	if (overlappedRead.hEvent == nullptr || overlappedWrite.hEvent == nullptr || overlappedWait.hEvent == nullptr) {
		close();
		return false;
	}

	// Set up event so that we will satisfy overlappedWait when a character comes in
	if(!SetCommMask(handle, EV_RXCHAR)) {
		close();
		return false;
	}
	
	// TODO Set up some sort of shared memory, save which COM port we have open so we don't try to open it again
	
	// Create threads
	readThread = std::thread(&VCP::readTask, this);
	writeThread = std::thread(&VCP::writeTask, this);

	return true;
}

void VCP::openAsync(fn_boolCallback callback) {
	threads.push_back(std::make_shared<std::thread>([&]() {
		callback(open(true));
	}));
}

bool VCP::close() {
	if(!isOpen())
		return false;

	closing = true; // Signal the threads that we are closing
	for(auto& t : threads)
		t->join(); // Wait for the threads to close
	readThread.join();
	writeThread.join();

	if(!CloseHandle(handle))
		return false;

	handle = INVALID_HANDLE_VALUE;

	bool ret = true; // If one of the events fails closing, we probably still want to try and close the others
	if(overlappedRead.hEvent != INVALID_HANDLE_VALUE) {
		if(!CloseHandle(overlappedRead.hEvent))
			ret = false;
	}
	if(overlappedWrite.hEvent != INVALID_HANDLE_VALUE) {
		if(!CloseHandle(overlappedWrite.hEvent))
			ret = false;
	}
	if(overlappedWait.hEvent != INVALID_HANDLE_VALUE) {
		if(!CloseHandle(overlappedWait.hEvent))
			ret = false;
	}

	// TODO Set up some sort of shared memory, free which COM port we had open so we can try to open it again

	return ret;
}

void VCP::readTask() {
	constexpr size_t READ_BUFFER_SIZE = 10240;
	uint8_t readbuf[READ_BUFFER_SIZE];
	IOTaskState state = LAUNCH;
	DWORD bytesRead = 0;
	while(!closing) {
		switch(state) {
			case LAUNCH: {
				COMSTAT comStatus;
				unsigned long errorCodes;
				if(!ClearCommError(handle, &errorCodes, &comStatus))
					std::cout << "Error clearing com err" << std::endl;

				bytesRead = 0;
				if(ReadFile(handle, readbuf, READ_BUFFER_SIZE, nullptr, &overlappedRead)) {
					if(GetOverlappedResult(handle, &overlappedRead, &bytesRead, FALSE)) {
						if(bytesRead)
							readQueue.enqueue_bulk(readbuf, bytesRead);
					} else {
						std::cout <<"Readfile succeeded but not enqueued " << GetLastError() << std::endl;
					}
					continue;
				}

				auto err = GetLastError();
				if(err == ERROR_SUCCESS)
					std::cout << "Error was success?" << std::endl;

				if(err == ERROR_IO_PENDING)
					state = WAIT;
				else
					std::cout << "ReadFile failed " << err << std::endl;
			}
			break;
			case WAIT: {
				auto ret = WaitForSingleObject(overlappedRead.hEvent, 100);
				if(ret == WAIT_OBJECT_0) {
					auto err = GetLastError();
					if(GetOverlappedResult(handle, &overlappedRead, &bytesRead, FALSE)) {
						readQueue.enqueue_bulk(readbuf, bytesRead);
						state = LAUNCH;
					} else
						std::cout << "ReadFile deferred failed " << err << std::endl;
				}
				if(ret == WAIT_ABANDONED) {
					state = LAUNCH;
					std::cout << "Readfile abandoned" << std::endl;
				}
			}
		}
	}
}

void VCP::writeTask() {
	IOTaskState state = LAUNCH;
	VCP::WriteOperation writeOp;
	DWORD bytesWritten = 0;
	while(!closing) {
		switch(state) {
			case LAUNCH: {
				if(!writeQueue.wait_dequeue_timed(writeOp, std::chrono::milliseconds(100)))
					continue;

				bytesWritten = 0;
				if(WriteFile(handle, writeOp.bytes.data(), (DWORD)writeOp.bytes.size(), nullptr, &overlappedWrite))
					continue;
				
				auto err = GetLastError();
				if(err == ERROR_IO_PENDING) {
					state = WAIT;
				}
				else
					std::cout << "Writefile failed " << err << std::endl;
			}
			break;
			case WAIT: {
				auto ret = WaitForSingleObject(overlappedWrite.hEvent, 50);
				if(ret == WAIT_OBJECT_0) {
					if(!GetOverlappedResult(handle, &overlappedWrite, &bytesWritten, FALSE)) {
						std::cout << "Writefile deferred failed " << GetLastError() << std::endl;
					}
					state = LAUNCH;
				}
				
				if(ret == WAIT_ABANDONED) {
					std::cout << "Writefile deferred abandoned" << std::endl;
					state = LAUNCH;
				}
			}
		}
	}
}