/*
  Wifi OnOff Sample for command to turn On and command to turn Off
  No response expected to the command.

  Load this sketch to the Adafruit Feather ESP8266 module (Other ESP8266 modules can also be used)
  This code uses Arduino ESP8266 is V2.3.0.  Other versions may not work as expected

  This code drives ledPin to indicate when connected
  Steady led == OK
  Fast Flash == Connection or msg problem.
  Slow Flash == Battery Low, connect USB supply to recharge.
*/

/**
   Wifi_OnOff
   https://www.forward.com.au/pfod/HomeAutomation/Wifi_OnOff/index.html

   (c)2017 Forward Computing and Control Pty. Ltd.
   This code may be freely used for both private and commerical use.
   Provide this copyright is maintained.
*/
/*************************************************************************
   Outline of code

   setup()
     Read battery volts. Do it here to get consistent reading before Wifi starts up.
     Turn on power pin to hold FET power switch on
     Check pushbuttons,  On pushbutton take precidence.  If none pressed then CHARGING, start irregular flash and return from setup
     Start power Off timer, 15sec to power Off
     Set indicator Led ON solid
     Connect to Network, if no connection after 6 sec fast flash Led and power of in 15sec.
     Connect to host/port for control. If cannot connection after 6 sec fast flash Led and power of in 15sec
       If loose connection later, and not already flashing an error, start fast flash and power off as normal
     Check battery level. If <3.65V slow flash until power off, in 15sec, but otherwise continue

   loop()
     If CHARGING check for user pressing a pushbutton and if so turn off FET power switch.
     else
       if power off timeout call powerOff, (close connection wait 1sec, turn flasher off, turn led off, make power pin low to drop supply.
          return
       if turn On/Off sequence and not flashing then finished call powerOff.
       else if CONNECTION_ERROR from processMsg start fast flash and reset power off timer for 15sec
       else if lost connection start fast flash and reset power off timer for 15sec
       else call processMsgs to send on/off command and check return if any

*/
#include <pfodESP8266Utils.h>
#include <ESP8266WebServer.h>
#include <ESP8266WiFi.h>
#include <Ticker.h>

char ssid[] = "*** ***";
char password[] = "********";
char staticIP[] = "10.1.1.180";
int portNo = 4989;

const int ledPin = 15; // this has 4k7 resistor to GND on Feather ESP8266 board
const int pushButton1pin = 14; // ON pushbutton, input with pullup enabled
const int pushButton2pin = 13; // OFF pushbutton, input with pullup enabled
const int powerControlPin = 12; // output high to keep power on

enum flashTypeEnum {NO_FLASH, SLOW_FLASH, FAST_FLASH, CHARGING_FLASH};
volatile flashTypeEnum flashType = NO_FLASH;
const float FLASH_TIMER_INTERVAL = 0.1; // 0.1 sec
const int FAST_FLASH_PERIOD = 2; // 0.2sec
const int FAST_FLASH_OFF = 1; // 50% flash
const int SLOW_FLASH_PERIOD = 18; // 1.8sec
const int SLOW_FLASH_OFF = 9; // 50% flash
volatile int flashCounter = 0;
volatile int flashOff = 1;
volatile int flashPeriod = 1;

// 3.35V == 698 to 704 ==> 3.65 == 761 to 767 counts
// 4.19V == 879 to 881 ==> 3.65 == 766 to 767 count
const int batteryLowVolts = 763; // 3.65V;
int batteryVolts = 0;

const size_t MAX_RETURN_MSG_LEN = 255;
char returnMsg[MAX_RETURN_MSG_LEN + 1];
uint8_t parseReturn(uint8_t c);
void parseReturnInit();
int checkLightState();

// comment out next line to diable DEBUG messages. NOTE: will ALWAYS get ESP8266 boot messages regardless
#define DEBUG


WiFiClient client; // just one client reused


Ticker ledFlasher;
bool ledOn = false;
int pushButton = -1; // none  0 off, 1 on

unsigned long powerOffTimer = 0;
const unsigned long POWER_TIMEOUT = 15000; // 15sec turn power off regardless, unless charging

enum msgStateEnum {CONNECTED, SENT_INQUIRY, SENT_ON_OFF, CONNECTION_FINISHED, CONNECTION_ERROR, CHARGING};
msgStateEnum msgState = CONNECTED; // processMsgs not called unless connected

char *TURN_LIGHT_ON = "1"; //  edit this string to the one that turns the device ON
char *TURN_LIGHT_OFF = "0";  //  edit this string to the one the turns the device OFF

void processMsgs() {
  uint8_t cmd  = 0;
  if ((msgState == CONNECTION_ERROR) || (msgState == CONNECTION_FINISHED)) {
    return;

  } else if (msgState == CONNECTED) {
    // send ON or OFF string depending on push button
    // else have light state now switch
    if (pushButton == 1) {
      // turn on
      client.print(TURN_LIGHT_ON);
    } else if (pushButton == 0) {
      // turn off
      client.print(TURN_LIGHT_OFF);
    }
    msgState = CONNECTION_FINISHED; // not need to send msg
  }
  // else ignore
}

void handleFlash() {
  if (flashType == NO_FLASH) {
    turnLedOn(); // just turn led on
  } else if (flashType == CHARGING_FLASH) {
    flashCounter++;
    if (flashCounter >= 24) {
      flashCounter = 0; // reset
      turnLedOn();
      //           OFF                    ON                         OFF                   0N                      OFF                         0N                   OFF
    } else if ((flashCounter == 4) || (flashCounter == 6) || (flashCounter == 14) || (flashCounter == 15) || (flashCounter == 16) || (flashCounter == 17) || (flashCounter == 18)) {
      toggleLed();
    }
  } else {
    // flash
    flashCounter++;
    if (flashCounter >= flashPeriod) {
      flashCounter = 0; // reset
      turnLedOn();
    } else if (flashCounter == flashOff) {
      toggleLed();
    }
  }
}

void turnLedOn() {
  ledOn = true;
  digitalWrite(ledPin, HIGH);
}
void toggleLed() {
  ledOn = !ledOn;
  if (ledOn) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
}

void flashInit() {
  pinMode(ledPin, OUTPUT);
  turnLedOn(); // ON
  setFlash(NO_FLASH);
  ledFlasher.attach(FLASH_TIMER_INTERVAL, handleFlash);
}
/**
   Set flash type
*/
void setFlash(flashTypeEnum f_type) {
  if (f_type == NO_FLASH)  {
    flashType = f_type;
    turnLedOn();
    return;
  }
  if (f_type == flashType) {
    return; // no chabnge
  }
  if (f_type == CHARGING_FLASH) {
    flashType = f_type;
    turnLedOn();
    flashCounter = 0;
  } else if (f_type > flashType)  {
    turnLedOn();
    flashCounter = 0;
    //up the flash speed, the above test ensures the powerOffTimer only reset once on switching to Fast Flash
    flashType = f_type;
    switch (flashType) {
      case FAST_FLASH:
        powerOffTimer = millis(); // reset power off time so will flash for full 15sec if error
        flashPeriod = FAST_FLASH_PERIOD;
        flashOff = FAST_FLASH_OFF;
        break;
      case SLOW_FLASH:
        flashPeriod = SLOW_FLASH_PERIOD;
        flashOff = SLOW_FLASH_OFF;
        break;
      default:
        break;
    }
  }
}

// pushbutton 1 (pin 14) is ON pushbutton
// pushbutton 2 (pin 13) is OFF pushbutton
int checkPushButtons() {
  // set pullups on inputs
  pinMode(pushButton1pin, INPUT_PULLUP);
  pinMode(pushButton2pin, INPUT_PULLUP);
  if (digitalRead(pushButton1pin) == LOW) {
    return 1;
  }
  if (digitalRead(pushButton2pin) == LOW) {
    return 0;
  }
  // else no pushbutton pushed start charging
  return -1;
}

void initVars() {
  ledOn = false;
  flashInit();
  //pushButton = -1;  // don't reset this
  msgState = CONNECTED;
}

void setup ( void ) {
  batteryVolts = analogRead(A0);
  // == do these first  =================
  pinMode(powerControlPin, OUTPUT);
  digitalWrite(powerControlPin, HIGH); //  turn power on ON
  pushButton = checkPushButtons(); // -1 none pushed, 0 OFF, 1 ON pushbutton
  // ==================================

  powerOffTimer = millis(); // start power off timer
  initVars(); // keep this short, turns led on solid

#ifdef DEBUG
  Serial.begin(74880); // for debug will output reboot chars (at 74880 baud) even if DEBUG not defined
#endif
  delay(10);
  // Don't add any more delays here as the ESP8266 V2.3.0 library Wifi setup does not like it

#ifdef DEBUG
  Serial.print("ADC:"); Serial.println(batteryVolts);
#endif

  if (pushButton < 0) {
    // just charging
    msgState = CHARGING;
    setFlash(CHARGING_FLASH);
#ifdef DEBUG
    Serial.println("CHARGING");
#endif
    return;
  }

#ifdef DEBUG
  Serial.println();
  Serial.println(F("Starting Setup"));
#endif
  int countC = 0;
  WiFi.begin(ssid, password);
  while ((WiFi.status() != WL_CONNECTED) && (countC < 12)) { // max 6 sec.
    delay(500);
#ifdef DEBUG
    Serial.print(".");
#endif
    countC++;
  }
  if (WiFi.status() != WL_CONNECTED) {
#ifdef DEBUG
    Serial.println();   Serial.println(F("Could not connect to Network!"));
#endif
    return;
  }

#ifdef DEBUG
  Serial.println();  Serial.println(F("Connected to Network!"));
#endif
  setFlash(NO_FLASH);

  IPAddress hostip(pfodESP8266Utils::ipStrToNum(staticIP));
  countC = 0;
  while ((client.status() != ESTABLISHED) && (countC < 12)) { // max 6 sec to connect
    client.connect(staticIP, portNo); // note this can return true when connection not complete, will return false later after first write.
    delay(500);
#ifdef DEBUG
    Serial.print("+");
#endif
    countC++;
  }
  if (client.status() != ESTABLISHED) {
#ifdef DEBUG
    Serial.print("connection failed to ");    Serial.print(staticIP);    Serial.print(":");    Serial.println(portNo);
#endif
    return;
  }

  setFlash(NO_FLASH);

  // check for battery low here and turn on flasher
  if (batteryVolts <= batteryLowVolts) {
#ifdef DEBUG
    Serial.print("Battery Low ");
    Serial.println(batteryVolts);
#endif
    setFlash(SLOW_FLASH);
  }
}

void loop() {
  if (msgState == CHARGING) {
    // check for button pressed to stop charging
    int buttonPressed = checkPushButtons();
    if ((buttonPressed >= 0) && (pushButton < 0)) {
      // if user pressed any pushbutton while charging latch it
      pushButton = buttonPressed;
    }
    if (pushButton >= 0) {
      // user presses any push button while charging
      // stop and turn off
      powerOff();
    }
    // NOTE: power will stay on until user releases pushbutton and then turn off in <1sec
  } else {

    // NOT CHARGING
    if ((millis() - powerOffTimer) > POWER_TIMEOUT) {
      powerOff();
      return;
    }
    // else not power timed out
    if (msgState == CONNECTION_FINISHED) { // finished
      if (flashType == NO_FLASH) { // no error flashing
        powerOff();  // turn off now
      }
    } else if (msgState == CONNECTION_ERROR) {
      if (flashType != FAST_FLASH) {
#ifdef DEBUG
        Serial.println("msgState == CONNECTION_ERROR");
#endif
      }
      setFlash(FAST_FLASH);
    } else if (!client.connected()) {
      if (flashType != FAST_FLASH) {
#ifdef DEBUG
        Serial.println("Not connected or CONNECTION_ERROR");
#endif
      }
      setFlash(FAST_FLASH);
    } else {
      processMsgs();
    }
  }
}

bool poweredOff = false;
void powerOff() {
  client.stop();
  delay(500); // give tcp time to close
  if (!poweredOff) {
#ifdef DEBUG
    Serial.print("power off after ");
    Serial.print( (float)(millis() - powerOffTimer) / 1000.0);
    Serial.println(" sec.");
#endif
  }
  poweredOff = true;
  ledFlasher.detach();
  digitalWrite(ledPin, LOW); // OFF   //
  // and TURN OFF POWER PIN !!
  digitalWrite(powerControlPin, LOW); //  ON
}