/**
 * file       TinyGsmClientESP8266.h
 * author     Volodymyr Shymanskyy
 * license    LGPL-3.0
 * copyright  Copyright (c) 2016 Volodymyr Shymanskyy
 * date       Nov 2016
 */

#ifndef TinyGsmClientESP8266_h
#define TinyGsmClientESP8266_h

//#define TINY_GSM_DEBUG Serial

#if !defined(TINY_GSM_RX_BUFFER)
#define TINY_GSM_RX_BUFFER 512
#endif

#define TINY_GSM_MUX_COUNT 5

#include "TinyGsmCommon.h"

#define GSM_NL "\r\n"
static const char GSM_OK[] TINY_GSM_PROGMEM = "OK" GSM_NL;
static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
static unsigned TINY_GSM_TCP_KEEP_ALIVE = 120;

class TinyGsm
{

public:

	class GsmClient : public Client
	{
		friend class TinyGsm;
		typedef TinyGsmFifo<uint8_t, TINY_GSM_RX_BUFFER> RxFifo;

	public:
		GsmClient() {}

		GsmClient(TinyGsm& modem, uint8_t mux = 1)
		{
			init(&modem, mux);
		}

		bool init(TinyGsm* modem, uint8_t mux = 1)
		{
			this->at = modem;
			this->mux = mux;
			sock_connected = false;

			at->sockets[mux] = this;

			return true;
		}

	public:
		virtual int connect(const char *host, uint16_t port)
		{
			stop();
			TINY_GSM_YIELD();
			rx.clear();
			sock_connected = at->modemConnect(host, port, mux);
			return sock_connected;
		}

		virtual int connect(IPAddress ip, uint16_t port)
		{
			String host;
			host.reserve(16);
			host += ip[0];
			host += ".";
			host += ip[1];
			host += ".";
			host += ip[2];
			host += ".";
			host += ip[3];
			return connect(host.c_str(), port);
		}

		virtual void stop()
		{
			TINY_GSM_YIELD();
			at->sendAT(GF("+CIPCLOSE="), mux);
			sock_connected = false;
			at->waitResponse();
			rx.clear();
		}

		virtual size_t write(const uint8_t *buf, size_t size)
		{
			TINY_GSM_YIELD();
			//at->maintain();
			return at->modemSend(buf, size, mux);
		}

		virtual size_t write(uint8_t c)
		{
			return write(&c, 1);
		}

		virtual int available()
		{
			TINY_GSM_YIELD();
			if (!rx.size() && sock_connected) {
				at->maintain();
			}
			return rx.size();
		}

		virtual int read(uint8_t *buf, size_t size)
		{
			TINY_GSM_YIELD();
			size_t cnt = 0;
			while (cnt < size) {
				size_t chunk = TinyGsmMin(size-cnt, rx.size());
				if (chunk > 0) {
					rx.get(buf, chunk);
					buf += chunk;
					cnt += chunk;
					continue;
				}
				// TODO: Read directly into user buffer?
				if (!rx.size() && sock_connected) {
					at->maintain();
					//break;
				}
			}
			return cnt;
		}

		virtual int read()
		{
			uint8_t c;
			if (read(&c, 1) == 1) {
				return c;
			}
			return -1;
		}

		virtual int peek()
		{
			return -1;    //TODO
		}
		virtual void flush()
		{
			at->stream.flush();
		}

		virtual uint8_t connected()
		{
			if (available()) {
				return true;
			}
			return sock_connected;
		}
		virtual operator bool()
		{
			return connected();
		}

		/*
		 * Extended API
		 */

		String remoteIP() TINY_GSM_ATTR_NOT_IMPLEMENTED;

	private:
		TinyGsm*      at;
		uint8_t       mux;
		bool          sock_connected;
		RxFifo        rx;
	};

	class GsmClientSecure : public GsmClient
	{
	public:
		GsmClientSecure() {}

		GsmClientSecure(TinyGsm& modem, uint8_t mux = 1)
			: GsmClient(modem, mux)
		{}

	public:
		virtual int connect(const char *host, uint16_t port)
		{
			stop();
			TINY_GSM_YIELD();
			rx.clear();
			sock_connected = at->modemConnect(host, port, mux, true);
			return sock_connected;
		}
	};

public:

	explicit TinyGsm(Stream& stream)
		: stream(stream)
	{
		memset(sockets, 0, sizeof(sockets));
	}

	/*
	 * Basic functions
	 */
	bool begin()
	{
		return init();
	}

	bool init()
	{
		if (!testAT()) {
			return false;
		}
		sendAT(GF("E0"));   // Echo Off
		if (waitResponse() != 1) {
			return false;
		}
		return true;
	}

	void setBaud(unsigned long baud)
	{
		sendAT(GF("+IPR="), baud);
	}

	bool testAT(unsigned long timeout = 10000L)
	{
		for (unsigned long start = millis(); millis() - start < timeout; ) {
			sendAT(GF(""));
			if (waitResponse(200) == 1) {
				delay(100);
				return true;
			}
			delay(100);
		}
		return false;
	}

	void maintain()
	{
		waitResponse(10, NULL, NULL);
	}

	bool factoryDefault()
	{
		sendAT(GF("+RESTORE"));
		return waitResponse() == 1;
	}

	String getModemInfo()
	{
		sendAT(GF("+GMR"));
		String res;
		if (waitResponse(1000L, res) != 1) {
			return "";
		}
		res.replace(GSM_NL "OK" GSM_NL, "");
		res.replace(GSM_NL, " ");
		res.trim();
		return res;
	}

	bool hasSSL()
	{
		return true;
	}

	/*
	 * Power functions
	 */

	bool restart()
	{
		if (!testAT()) {
			return false;
		}
		sendAT(GF("+RST"));
		if (waitResponse(10000L) != 1) {
			return false;
		}
		if (waitResponse(10000L, GF(GSM_NL "ready" GSM_NL)) != 1) {
			return false;
		}
		delay(500);
		return init();
	}


	/*
	 * Generic network functions
	 */

	int getSignalQuality()
	{
		sendAT(GF("+CWJAP_CUR?"));
		int res1 = waitResponse(GF("No AP"), GF("+CWJAP_CUR:"));
		if (res1 != 2) {
			waitResponse();
			return 0;
		}
		streamSkipUntil(',');  // Skip SSID
		streamSkipUntil(',');  // Skip BSSID/MAC address
		streamSkipUntil(',');  // Skip Chanel number
		int res2 = stream.parseInt();  // Read RSSI
		waitResponse();  // Returns an OK after the value
		return res2;
	}

	bool isNetworkConnected()
	{
		sendAT(GF("+CIPSTATUS"));
		int res1 = waitResponse(3000, GF("STATUS:"));
		int res2 = 0;
		if (res1 == 1) {
			res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
		}
		// <stat> status of ESP8266 station interface
		// 2 : ESP8266 station connected to an AP and has obtained IP
		// 3 : ESP8266 station created a TCP or UDP transmission
		// 4 : the TCP or UDP transmission of ESP8266 station disconnected (but AP is connected)
		// 5 : ESP8266 station did NOT connect to an AP
		waitResponse();  // Returns an OK after the status
		if (res2 == 2 || res2 == 3 || res2 == 4) {
			return true;
		} else {
			return false;
		}
	}

	bool waitForNetwork(unsigned long timeout = 60000L)
	{
		for (unsigned long start = millis(); millis() - start < timeout; ) {
			sendAT(GF("+CIPSTATUS"));
			int res1 = waitResponse(3000, GF("busy p..."), GF("STATUS:"));
			if (res1 == 2) {
				int res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
				if (res2 == 2 || res2 == 3 || res2 == 4) {
					waitResponse();
					return true;
				}
			}
			delay(250);
		}
		return false;
	}

	/*
	 * WiFi functions
	 */
	bool networkConnect(const char* ssid, const char* pwd)
	{

		sendAT(GF("+CIPMUX=1"));
		if (waitResponse() != 1) {
			return false;
		}

		sendAT(GF("+CWMODE_CUR=1"));
		if (waitResponse() != 1) {
			return false;
		}

		sendAT(GF("+CWJAP_CUR=\""), ssid, GF("\",\""), pwd, GF("\""));
		if (waitResponse(30000L, GFP(GSM_OK), GF(GSM_NL "FAIL" GSM_NL)) != 1) {
			return false;
		}

		return true;
	}

	bool networkDisconnect()
	{
		sendAT(GF("+CWQAP"));
		bool retVal = waitResponse(10000L) == 1;
		waitResponse(GF("WIFI DISCONNECT"));
		return retVal;
	}

	String getLocalIP()
	{
		sendAT(GF("+CIPSTA_CUR??"));
		int res1 = waitResponse(GF("ERROR"), GF("+CWJAP_CUR:"));
		if (res1 != 2) {
			return "";
		}
		String res2 = stream.readStringUntil('"');
		waitResponse();
		return res2;
	}

	IPAddress localIP()
	{
		return TinyGsmIpFromString(getLocalIP());
	}

protected:

	bool modemConnect(const char* host, uint16_t port, uint8_t mux, bool ssl = false)
	{
		if (ssl) {
			sendAT(GF("+CIPSSLSIZE=4096"));
			waitResponse();
		}
		sendAT(GF("+CIPSTART="), mux, ',', ssl ? GF("\"SSL") : GF("\"TCP"), GF("\",\""), host, GF("\","),
		       port, GF(","), TINY_GSM_TCP_KEEP_ALIVE);
		// TODO: Check mux
		int rsp = waitResponse(75000L,
		                       GFP(GSM_OK),
		                       GFP(GSM_ERROR),
		                       GF("ALREADY CONNECT"));
		// if (rsp == 3) waitResponse();  // May return "ERROR" after the "ALREADY CONNECT"
		return (1 == rsp);
	}

	int modemSend(const void* buff, size_t len, uint8_t mux)
	{
		sendAT(GF("+CIPSEND="), mux, ',', len);
		if (waitResponse(GF(">")) != 1) {
			return 0;
		}
		stream.write((uint8_t*)buff, len);
		stream.flush();
		if (waitResponse(10000L, GF(GSM_NL "SEND OK" GSM_NL)) != 1) {
			return 0;
		}
		return len;
	}

	bool modemGetConnected(uint8_t mux)
	{
		// TODO: re-check this
		sendAT(GF("+CIPSTATUS="), mux);
		int res1 = waitResponse(3000, GF("STATUS:"));
		int res2;
		if (res1 == 1) {
			res2 = waitResponse(GFP(GSM_ERROR), GF("2"), GF("3"), GF("4"), GF("5"));
		}
		// <stat> status of ESP8266 station interface
		// 2 : ESP8266 station connected to an AP and has obtained IP
		// 3 : ESP8266 station created a TCP or UDP transmission
		// 4 : the TCP or UDP transmission of ESP8266 station disconnected (but AP is connected)
		// 5 : ESP8266 station did NOT connect to an AP
		waitResponse();  // Returns an OK after the status
		if (res2 == 2 || res2 == 3 || res2 == 4) {
			return true;
		} else {
			return false;
		}
	}

public:

	/* Utilities */

	template<typename T>
	void streamWrite(T last)
	{
		stream.print(last);
	}

	template<typename T, typename... Args>
	void streamWrite(T head, Args... tail)
	{
		stream.print(head);
		streamWrite(tail...);
	}

	bool streamSkipUntil(char c)   //TODO: timeout
	{
		while (true) {
			while (!stream.available()) {
				TINY_GSM_YIELD();
			}
			if (stream.read() == c) {
				return true;
			}
		}
		return false;
	}

	template<typename... Args>
	void sendAT(Args... cmd)
	{
		streamWrite("AT", cmd..., GSM_NL);
		stream.flush();
		TINY_GSM_YIELD();
		//DBG("### AT:", cmd...);
	}

	// TODO: Optimize this!
	uint8_t waitResponse(uint32_t timeout, String& data,
	                     GsmConstStr r1=GFP(GSM_OK), GsmConstStr r2=GFP(GSM_ERROR),
	                     GsmConstStr r3=NULL, GsmConstStr r4=NULL, GsmConstStr r5=NULL)
	{
		/*String r1s(r1); r1s.trim();
		String r2s(r2); r2s.trim();
		String r3s(r3); r3s.trim();
		String r4s(r4); r4s.trim();
		String r5s(r5); r5s.trim();
		DBG("### ..:", r1s, ",", r2s, ",", r3s, ",", r4s, ",", r5s);*/
		data.reserve(64);
		int index = 0;
		unsigned long startMillis = millis();
		do {
			TINY_GSM_YIELD();
			while (stream.available() > 0) {
				int a = stream.read();
				if (a <= 0) {
					continue;    // Skip 0x00 bytes, just in case
				}
				data += (char)a;
				if (r1 && data.endsWith(r1)) {
					index = 1;
					goto finish;
				} else if (r2 && data.endsWith(r2)) {
					index = 2;
					goto finish;
				} else if (r3 && data.endsWith(r3)) {
					index = 3;
					goto finish;
				} else if (r4 && data.endsWith(r4)) {
					index = 4;
					goto finish;
				} else if (r5 && data.endsWith(r5)) {
					index = 5;
					goto finish;
				} else if (data.endsWith(GF(GSM_NL "+IPD,"))) {
					int mux = stream.readStringUntil(',').toInt();
					int len = stream.readStringUntil(':').toInt();
					int len_orig = len;
					if (len > sockets[mux]->rx.free()) {
						DBG("### Buffer overflow: ", len, "->", sockets[mux]->rx.free());
					} else {
						DBG("### Got: ", len, "->", sockets[mux]->rx.free());
					}
					while (len--) {
						while (!stream.available()) {
							TINY_GSM_YIELD();
						}
						sockets[mux]->rx.put(stream.read());
					}
					if (len_orig > sockets[mux]->available()) { // TODO
						DBG("### Fewer characters received than expected: ", sockets[mux]->available(), " vs ", len_orig);
					}
					data = "";
				} else if (data.endsWith(GF("CLOSED"))) {
					int muxStart = max(0,data.lastIndexOf(GSM_NL, data.length()-8));
					int coma = data.indexOf(',', muxStart);
					int mux = data.substring(muxStart, coma).toInt();
					if (mux >= 0 && mux < TINY_GSM_MUX_COUNT && sockets[mux]) {
						sockets[mux]->sock_connected = false;
					}
					data = "";
					DBG("### Closed: ", mux);
				}
			}
		} while (millis() - startMillis < timeout);
finish:
		if (!index) {
			data.trim();
			if (data.length()) {
				DBG("### Unhandled:", data);
			}
			data = "";
		}
		return index;
	}

	uint8_t waitResponse(uint32_t timeout,
	                     GsmConstStr r1=GFP(GSM_OK), GsmConstStr r2=GFP(GSM_ERROR),
	                     GsmConstStr r3=NULL, GsmConstStr r4=NULL, GsmConstStr r5=NULL)
	{
		String data;
		return waitResponse(timeout, data, r1, r2, r3, r4, r5);
	}

	uint8_t waitResponse(GsmConstStr r1=GFP(GSM_OK), GsmConstStr r2=GFP(GSM_ERROR),
	                     GsmConstStr r3=NULL, GsmConstStr r4=NULL, GsmConstStr r5=NULL)
	{
		return waitResponse(1000, r1, r2, r3, r4, r5);
	}

public:
	Stream&       stream;

protected:
	GsmClient*    sockets[TINY_GSM_MUX_COUNT];
};

#endif