#define _CRT_SECURE_NO_WARNINGS

#include <Windows.h>
#include <stdio.h>

char id;

HANDLE createPortHandle(const char* port, int baudrate){
	HANDLE portHandle = CreateFile(port, GENERIC_WRITE | GENERIC_READ, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

	if (portHandle == INVALID_HANDLE_VALUE){
		printf("Cannot open port!\n");
		return INVALID_HANDLE_VALUE;
	}

	DCB params = { 0 };
	params.DCBlength = sizeof(params);
	GetCommState(portHandle, &params);
	params.BaudRate = baudrate;
	params.ByteSize = 8;
	params.StopBits = 0; // 0 == 1
	params.Parity = 0; //StartBit| xxxxxxxx |1or0| StopBit|
	SetCommState(portHandle, &params);

	COMMTIMEOUTS timeouts = { 0 };
	timeouts.ReadIntervalTimeout = 10;
	timeouts.ReadTotalTimeoutConstant = 1;
	timeouts.ReadTotalTimeoutMultiplier = 1;
	timeouts.WriteTotalTimeoutConstant = 50;
	timeouts.WriteTotalTimeoutMultiplier = 50;
	SetCommTimeouts(portHandle, &timeouts);

	return portHandle;
}

static bool terminate = false;

DWORD _stdcall readFunction(void* params) {
	HANDLE portHandle = *(HANDLE*)params;

	char message[256];
	char recvID[1];
	bool msgSent = false;
	DWORD IDbytesRead = 0, MSGbytesRead = 0;

	while (!terminate) {
		if (IDbytesRead == 0) {
			ReadFile(portHandle, recvID, 256, &IDbytesRead, 0);
			//printf("RECVID: %c", recvID[0]);
		}
		if (!msgSent){
			ReadFile(portHandle, message, 256, &MSGbytesRead, 0);
			if (MSGbytesRead > 0){
				if (recvID[0] == id) { printf("\nRecieved message: %s\n", message); }
				msgSent = true;
			}
		}
		if (msgSent) {
			IDbytesRead = 0;
			msgSent = false;
		}
		Sleep(100);
	}
	return 0;
}

int main() {
	char portName[100];
	char recvID[1];
	bool IDsent = false, MSGsent = false;

	printf("Enter port: ");
	scanf("%s", portName);

	printf("\nEnter your ID: ");
	scanf("%s", &id);
	printf("MY ID IS: %c\n", id);

	HANDLE portHandle = createPortHandle(portName, 115200);
	if (portHandle == INVALID_HANDLE_VALUE) { return -1; }

	DWORD threadID;
	HANDLE threadHandle = CreateThread(NULL, 0, readFunction, &portHandle, 0, &threadID);

	char message[256];
	DWORD bytesSent;
	do{
		printf("Enter reciever ID: ");
		//fgets(message, 256, stdin);
		scanf("%s", &recvID[0]);
		//printf("int: %d\n", int(recvID[0]) - 48);
		recvID[strlen(recvID)] = '\0';
		printf("Reciever id is %s", recvID);
		if (((recvID[0] == '1' || (recvID[0] == '2') || (recvID[0] == '3'))) && !IDsent){
			IDsent = WriteFile(portHandle, recvID, strlen(recvID) + 1, &bytesSent, 0);
			printf("*ID* Number of bytes sent: %ld\n", bytesSent);
		}
		if (IDsent){
			printf("\nMessage: ");
			scanf("%s", &message);
			message[strlen(message - 1)] = '\0';
			if (strlen(message) > 0) {
				DWORD bytesSent2;
				MSGsent = WriteFile(portHandle, message, strlen(message) + 1, &bytesSent2, 0);
				printf("Number of bytes sent: %ld\n", bytesSent2);
				if(MSGsent){
					IDsent = false;
					printf("MSG sent to %c\n", recvID[0]);
				}

			}
		}
	}while (strcmp(message, "x") != 0);

	terminate = true;
	WaitForSingleObject(threadHandle, INFINITE);
	CloseHandle(threadHandle);

	CloseHandle(portHandle);

	return 0;
}