#include <Arduino.h>
#include <SoftwareSerial.h>
#include "serial.hpp"

constexpr int DTR = A0;
constexpr int CTS = A3;

struct CTSGuard {
	CTSGuard() {
		digitalWrite(CTS, 0);
	}
	~CTSGuard() {
		digitalWrite(CTS, 1);
	}
};

void serial::init() {
	pinMode(DTR, INPUT_PULLUP);
	pinMode(CTS, OUTPUT);
	pinMode(RXD, INPUT_PULLUP);
	pinMode(TXD, OUTPUT);
	digitalWrite(CTS, 1);
	dev.begin(57600);
	dev.listen();
}

bool serial::is_connected() {
	return digitalRead(DTR) == 0;
}

static bool wait_until() {
	while(!serial::dev.available()) {
		if(!serial::is_connected()) {
			return false;
		}
	}
	return true;
}

unsigned serial::read(char* data, unsigned len) {
	CTSGuard guard;

	for(unsigned i = 0; i < len; i++) {
		if(!wait_until()) {
			return i;
		}
		data[i] = dev.read();
	}

	return len;
}

void serial::write(const char* data, unsigned len) {
	for(unsigned i = 0; i < len; i++) {
		dev.write(data[i]);
	}
}

void serial::put(char ch) {
	dev.write(ch);
}

int serial::get() {
	unsigned char ch;
	if(read(&ch, 1)) {
		return ch;
	} else {
		return -1;
	}
}