#include <Arduino.h>
#include <WiFiUdp.h>
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#define END 0xc0
#define ESC 0xdb
#define ESC_END 0xdc
#define ESC_ESC 0xdd
WiFiUDP u;
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 w = 0;
unsigned long č = 0;
unsigned char t;
void setup () {
	pinMode(D0, OUTPUT);
	Serial.begin(250000, SERIAL_8N2);
	Serial.swap();
	Serial1.begin(/* MONITOR_SPEED */ 115200);
	// WiFi.softAP("dmx2artnet", NULL, 11, 0, 8);
	WiFi.begin("OpenWrt", NULL);
	// WiFi.begin("Hell Patrol", WIFI_PW);
	u.begin(6454);
	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;
	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);
}
char slip_buf[sizeof p * 2 + 1];
unsigned char recording[sizeof p.artnet.data * 2];
unsigned slip_off = 0;
unsigned slip_len = 0;
#define SLIP Serial1
void loop () {
	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);
	}
	if (Serial.available()) {
		č = millis();
		if (w < sizeof p.artnet.data * 2)
			recording[w++] = Serial.read();
		else
			Serial.read();
	}
	if (č + 1 < millis() && w) {
		unsigned T;
		for (T = 0; T < w; T++) // prvi kanal ne sme biti 0, tako zaznamo začetek paketa
			if (recording[T] > 1)
				break;
		memcpy(p.artnet.data, recording + T, sizeof p.artnet.data);
		unsigned l = w-T;
		if (l > sizeof p.artnet.data)
			l = sizeof p.artnet.data;
		/* l++;
		while (--l)
			if (p.data[l-1])
				break; */
		if (!t) {
			p.artnet.length_hi = l / 256;
			p.artnet.length_lo = l % 256;
			IPAddress b(255, 255, 255, 255);
			u.beginPacket(b, 6454);
			u.write((unsigned char *) &p.artnet, sizeof p.artnet - sizeof p.artnet.data + l);
			u.endPacket();
			if (slip_off >= slip_len) {
				p.ip.identifier = htons(millis());
				p.udp.length = htons(sizeof p.udp + sizeof p.artnet - sizeof p.artnet.data + l);
				p.ip.length = htons(sizeof p - sizeof p.artnet.data + l);
				p.ip.checksum = 0;
				uint32_t sum = 0;
				for (unsigned i = 0; i < sizeof p/2+sizeof p%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;
			}
		}
		/*
		Serial1.println("dolžina podatkov " + String(w-T) + ", tip: " + String(t));
		for (unsigned i = 0; i < l; i++)
			if (p.artnet.data[i])
				Serial1.println("\t" + String(i+1) + ": " + String(p.artnet.data[i]));
		*/
		w = 0;
	}
}