#include <Arduino.h>
#include <ESP8266WiFi.h>
#define INT_RX D6
#define SLIP Serial1
// #undef SLIP
#ifdef SLIP
#define DEBUG(x)
#else
#define DEBUG(x) Serial1.println(x)
#endif
#define END 0xc0
#define ESC 0xdb
#define ESC_END 0xdc
#define ESC_ESC 0xdd
struct artnet {
	char name[8]; // Art-Net\0
	char opcode[2]; // 0x5000 in LE: { 0x00, 0x50 }
	uint8_t version_hi; // 0
	uint8_t version_lo; // 14
	uint8_t sequence; // set to 0 to disable sequencing
	uint8_t physical; // original universe
	uint8_t sub_uni;
	uint8_t net;
	uint8_t length_hi;
	uint8_t length_lo;
	unsigned char data[512]; // increase for fun
} __attribute__((packed));
struct udp {
	uint16_t srcport __attribute__((packed));
	uint16_t dstport __attribute__((packed));
	uint16_t length __attribute__((packed));
	uint16_t checksum __attribute__((packed));
} __attribute__((packed));
#define LOW_DELAY (1 << 4)
#define HIGH_THROUGHPUT (1 << 3)
#define HIGH_RELIABILITY (1 << 2)
#define ROUTINE (0 << 5)
#define PRIORITY (1 << 5)
#define IMMEDIATE (1 << 6)
#define FLASH (PRIORITY | IMMEDIATE)
#define FLASH_OVERRIDE (1 << 7)
#define CRITICAL (FLASH_OVERRIDE | PRIORITY)
#define INETCTRL (FLASH_OVERRIDE | IMMEDIATE)
#define NETCTRL (FLASH_OVERRIDE | FLASH)
#define HEADLENOR (1 << 6) /* always bitwiseOR the headlen with this to apply the version number */
#define EVIL (1 << 15)
#define DF (1 << 14)
#define MF (1 << 13)
#define ICMP 1
#define TCP 6
#define UDP 17
struct ip {
	uint8_t headlen;
	uint8_t srvtype;
	uint16_t length __attribute__((packed));
	uint16_t identifier __attribute__((packed));
	uint16_t foffset __attribute__((packed));
	uint8_t ttl;
	uint8_t protocol;
	uint16_t checksum;
	unsigned char src[4];
	unsigned char dst[4];
} __attribute__((packed));
struct artnet_over_slip {
	struct ip ip;
	struct udp udp;
	struct artnet artnet;
} __attribute__((packed));
struct artnet_over_slip p;
unsigned n = 0;
volatile int interrupt = digitalPinToInterrupt(INT_RX);
volatile unsigned long last_fall = 0;
volatile unsigned led = 0;
volatile unsigned recording = 0;
unsigned long last_byte = 0;
unsigned long flash_hack = 0;
unsigned sent_packets = 0;
IRAM_ATTR void isr () {
	if (digitalRead(INT_RX) == HIGH) {
		if (last_fall && micros() - last_fall > 87) {
			recording++;
			while (Serial.available())
				Serial.read();
			last_byte = micros();
			n = 0;
			detachInterrupt(interrupt);
		}
	} else
		last_fall = micros();
}
void setup () {
	WiFi.mode(WIFI_OFF);
	pinMode(D4, SPECIAL);
	pinMode(INT_RX, INPUT);
	pinMode(D5, INPUT_PULLUP);
	pinMode(D3, INPUT_PULLUP);
	if (digitalRead(D5) == LOW)
		flash_hack++;
	Serial.begin(250000, SERIAL_8N2);
	Serial.swap();
#ifdef SLIP
	Serial1.begin(115200);
	sprintf(p.artnet.name, "Art-Net");
	p.artnet.opcode[0] = 0x00;
	p.artnet.opcode[1] = 0x50;
	p.artnet.version_hi = 0;
	p.artnet.version_lo = 14;
	p.artnet.sequence = 0;
	p.artnet.physical = 0;
	p.artnet.sub_uni = 0;
	p.artnet.net = 0;
	if (digitalRead(D3) == LOW)
		p.udp.srcport = p.udp.dstport = htons(6455);
	else
		p.udp.srcport = p.udp.dstport = htons(6454);
	p.udp.checksum = 0;
	p.ip.headlen = HEADLENOR | 5;
	p.ip.srvtype = 0;
	p.ip.foffset = 0;
	p.ip.ttl = 255;
	p.ip.protocol = UDP;
	p.ip.src[0] = 2;
	p.ip.src[1] = (ESP.getChipId() & 0xff0000) >> 16;
	p.ip.src[2] = (ESP.getChipId() & 0xff00) >> 8;
	p.ip.src[3] = (ESP.getChipId() & 0xff);
	memset(p.ip.dst, 255, 4);
#else
	Serial1.begin(MONITOR_SPEED);
#endif
	attachInterrupt(interrupt, isr, CHANGE);
}
#ifdef SLIP
char slip_buf[sizeof p * 2 + 1];
unsigned slip_off = 0;
unsigned slip_len = 0;
#endif
void loop() {
#ifdef SLIP
	unsigned avail = SLIP.availableForWrite();
	if (slip_off < slip_len && avail) {
		if (avail > slip_len-slip_off)
			avail = slip_len-slip_off;
		slip_off += SLIP.write(slip_buf+slip_off, avail);
	}
#endif
	if /* while */ (n <= sizeof p.artnet.data && ((!n && micros() - last_byte < 1e6) || micros() - last_byte < 50)) {
		if (recording && Serial.available()) {
			unsigned char r = Serial.read();
			last_byte = micros();
			if (!n) {
			/*
				if (r) {
					n = 0;
					return;
				}
				n++;
				continue;
			*/
				recording = !r;
				attachInterrupt(interrupt, isr, CHANGE);
				last_fall = 0;
				n++;
				return;
			}
			if (!flash_hack || r != 255)
				p.artnet.data[n-1] = r;
			n++;
		}
	}
	else if (recording) {
		recording = 0;
		if (n != 513)
			DEBUG("n: " + String(n));
		if (n == sizeof p.artnet.data + 1) {
			p.artnet.length_hi = (n-1) / 256;
			p.artnet.length_lo = (n-1) % 256;
#ifdef SLIP
			if (slip_off >= slip_len) {
				p.ip.identifier = htons(sent_packets++);
				p.udp.length = htons(sizeof p.udp + sizeof p.artnet);
				p.ip.length = htons(sizeof p);
				p.ip.checksum = 0;
				uint32_t sum = 0;
				for (unsigned i = 0; i < sizeof p.ip/2+sizeof p.ip%2; i++)
					sum += ntohs(((uint16_t *) &p)[i]);
				while (sum >> 16)
					sum = (sum >> 16) + sum % 65536;
				p.ip.checksum = htons(~sum);
				slip_len = 0;
				slip_off = 0;
				for (unsigned i = 0; i < sizeof p; i++) {
					unsigned char val = ((unsigned char *) &p)[i];
					switch (val) {
						case ESC:
							slip_buf[slip_len++] = ESC;
							slip_buf[slip_len++] = ESC_ESC;
							break;
						case END:
							slip_buf[slip_len++] = ESC;
							slip_buf[slip_len++] = ESC_END;
							break;
						default:
							slip_buf[slip_len++] = val;
							break;
					}
				}
				slip_buf[slip_len++] = END;
			}
#else
			// DEBUG("ch1: " + p.artnet.data[0]);
#endif
		}
		attachInterrupt(interrupt, isr, CHANGE);
		last_fall = 0;
	}
}