#include <SPI.h>
#include "tss463aa.h"
#include "tss463aa_ll.h"

#define XTAL1_PIN 9
#define TSS463AA_INT_PIN 3
#define TSS463AA_SS_PIN 13

/* time unit */
#define XTAL 100 /* μs */
/* Note: XTAL = μs for an 1 MHz oscillator (for 62.5 kTS/s on the VAN bus) */

extern "C" void LLtransceive(int fd, byte regno, byte controlvalue, const void* inputv, void* outputv, size_t bothsz) {
	const byte* input = (const byte*) inputv;
	byte* output = (byte*) outputv;
	size_t i;
	digitalWrite(TSS463AA_SS_PIN, LOW);
	delayMicroseconds(4*XTAL);
	byte r = SPI.transfer(regno);
	/* TODO check AA */
	delayMicroseconds(8*XTAL);
	byte r2 = SPI.transfer(controlvalue);
	/* TODO check 55 */
	delayMicroseconds(15*XTAL);
	if (input && bothsz) {
		for (i = 0U; i < bothsz; ++i) {
			byte r3 = SPI.transfer(input[i]);
			delayMicroseconds(12*XTAL);
			if (output)
				output[i] = r3;
		}
	} else if (output) {
		for (i = 0U; i < bothsz; ++i) {
			byte r3 = SPI.transfer(0xFFU);
			delayMicroseconds(12*XTAL);
			output[i] = r3;
		}
	}
	digitalWrite(TSS463AA_SS_PIN, HIGH);
}

static struct tss463aachannel* channels[2];
static FILE uartout = {};
static int uart_putchar(char c, FILE* stream) {
	Serial.write(c);
	return 0;
}
void setup() {
	int fd = 1;
	Serial.begin(115200);
	fdev_setup_stream(&uartout, uart_putchar, NULL, _FDEV_SETUP_WRITE);
	Serial.print("Press any key: ");
	pinMode(TSS463AA_INT_PIN, INPUT);
	pinMode(TSS463AA_SS_PIN, OUTPUT);
	digitalWrite(TSS463AA_SS_PIN, 1);
	analogWrite(XTAL1_PIN, 128); /* approx. 490 Hz or 980 Hz depending on model. Duty cycle in percent on. */
	//attachInterrupt(digitalPinToInterrupt(TSS463AA_INT_PIN), ISR, LOW /* or FALLING? RISING? */);
	SPI.setBitOrder(MSBFIRST);
	SPI.setDataMode(SPI_MODE3);
	SPI.setClockDivider(SPI_CLOCK_DIV2);
	SPI.begin();
	tss463aa_init(fd);
	channels[0U] = (struct tss463aachannel*) malloc(tss463aachannel_get_size());
	tss463aachannel_init(channels[0U], /*tag*/0U, /*mask*/0U, /*rnw*/0U, /*rtr*/1U, /*msgptr*/0U, 31U/*FIXME test */); /* set up for receiving messages. ID doesn't matter. */
	tss463aa_set_channel_up(fd, 0U, channels[0U]);
	//LLtransceive(fd, 0, 0, NULL, NULL, 0U);
	tss463aa_enable_interrupts(fd);
	tss463aa_activate(fd);
}
#define MAX_PAYLOADLEN 64 /* FIXME check */
void hexdump(const unsigned char* buf, size_t sz) {
	size_t i;
	for(i = 0; buf[i] != 0U; ++i) {
		printf("%02X ", (unsigned) *buf);
	}
	printf("\n");
	for(i = 0; buf[i] != 0U; ++i) {
		unsigned char c = *buf;
		printf("%c", (c >= 32 && c < 128) ? c : '?');
	}
}
void loop() {
		int fd = 1;
		tss463aa_accept_msg(fd, 0U, channels[0U]);
		while (true) {
			uint8_t status = tss463aa_read_interrupt_status(fd);
			if (status & 7U) /* FIXME be nicer */
				break;
		}
		tss463aa_clear_interrupt_status(fd);
		tss463aa_read_channel(fd, 0U, channels[0U]);
		if (tss463aachannel_get_error(channels[0U]) > 0U) {
			printf("warning: channel 0 raised error.\n");
			/* TODO check error, hmm accept again (FIXME I think it already does accept) */
		}
		/* note: on error, this isn't set. */
		if (tss463aachannel_is_unread_incoming_msg_present(channels[0U])) { /* something appeared */
			printf("info: message received.\n");
			unsigned payloadlen = tss463aachannel_get_payloadlen(channels[0U]);
			/* checkable fields in msgheader: RAK, RNW, RTR, PAYLOADLEN */
			if (payloadlen > 0U && payloadlen <= MAX_PAYLOADLEN) {
				unsigned char msgbody[MAX_PAYLOADLEN];
				tss463aa_read_channel_msgbody(fd, 0U, channels[0U], msgbody);
				printf("Payload: ");
				hexdump(msgbody, payloadlen);
				printf("\n");
			} else if (payloadlen == 0U) {
				printf("... message with no payload ignored\n");
			} else {
				printf("... message with too long payload ignored\n");
			}
		} else {
			printf("error: huh? Nothing is there\n");
		}
}