// MEDIS
// Type of Hardware: Stick-Interface
// Type of Software: Firmware
// Processor: ESP8266 
// Language: C++
// Andreas Pirchner, 2020-2021 

#include <WiFi.h>

const char thisID[3] = "6";                         // set the ID of this device (0-99)
const char deviceType[9] = "joystick";              // declare MAD device type

const char* ssid     = "MADspot";
const char* password = "123456789";
const char* host = "10.10.1.10";                  // fixed ip of the server
const uint16_t port = 5000;                         // net port of the nodejs server

int btnIn = 32;                                     // set GPIO pins
int joyX = 35;                                      // Joystick is 90 degrees rotated,
int joyY = 34;                                      // so X/Y pins need to be switched

int buttonState = 1;                                // declare variables for data
boolean justPressed = false;
boolean pressedAtLastSend = false;
boolean releasedMeanwhile = true;
int xData = 0;
int yData = 0;

char buttonString[32];
char xDataString[32];
char yDataString[32];

char daten[64];
char handshake[32] = "mac,";
boolean clientAccepted = false;

WiFiClient client;                                  // Use WiFiClient class to create TCP connections

void goToSleep() {
  Serial.print("Taking a nap…");
  esp_sleep_enable_timer_wakeup(1000000 * 10);
  esp_deep_sleep_start();
}

void setup() {
  Serial.begin(115200);

  WiFi.mode(WIFI_STA);                             // connect to WiFi
  WiFi.begin(ssid, password);
  Serial.print("Wait for WiFi... ");
  delay(5000);

  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
    //goToSleep();
  }
  Serial.println("WiFi connected, IP address:");
  Serial.println(WiFi.localIP());

  delay(100);

  Serial.print("connecting to ");
  Serial.print(host);
  Serial.print(':');
  Serial.println(port);

  while (!client.connect(host, port)) {           // connect to host server on defined IP address
    Serial.println("connection failed, wait 1 sec...");
    delay(500);
    //goToSleep();
  }

  strcat(handshake, thisID);
  strcat(handshake, ",");
  strcat(handshake, deviceType);
  client.write(handshake);                        // send handshake message to server (identify with device id)

  pinMode(btnIn, INPUT_PULLUP);                          // Set Button pin as Input
  delay(100);
}

void loop() {

  while (WiFi.status() != WL_CONNECTED) {          // check if we're still connected to the MAD network
    Serial.println("reconnecting to WIFI");
    WiFi.begin(ssid, password);                     // if not -> reconnect
    while (WiFi.status() != WL_CONNECTED) { 
      Serial.print(".");
      delay(3000);                                  // wait 3 seconds for connection
    }                                 
  }

  while (WiFi.status() == WL_CONNECTED && !client.connected()){                    // check if we're still connected to the MAD server
    Serial.println("reconnecting to MAD server");
    clientAccepted = false;
    //client.stop();
    client.connect(host, port);                   // if not -> reconnect to host server 
    delay(3000);
  }

  buttonState = digitalRead(btnIn);                // read current button state from GPIO

  if (justPressed == false && buttonState == 1) {
    releasedMeanwhile = true;
  }

  if (buttonState == 0) {
    if (pressedAtLastSend == false && releasedMeanwhile == true) {
      justPressed = true;
      releasedMeanwhile = false;
    }
  }

  if (client.available() > 0)                     // If a message from host is available
  {
    String serverCommand = client.readStringUntil('\n');
    if(serverCommand.startsWith("accepted,")){
      int val = serverCommand.substring(9,10).toInt();
      if (val == 1){
        clientAccepted = true;
        client.write("handshakeReceived,1");
      } else {
        clientAccepted = false;
      }
    }else if (serverCommand.startsWith("alivePing,")) {
      client.write("alive,1");
    }else if (serverCommand.startsWith("requestData,")) {
      String tcString = serverCommand.substring(12, serverCommand.length()+1);
      char tc[9];                                  // maximum timecode: 100.000.000
      tcString.toCharArray(tc,tcString.length()+1);
      xData = analogRead(joyX);                    // read values of X/Y - GPIO pins
      yData = analogRead(joyY);
      delay(10);                                  // wait for 40ms --> time to read the GPIO pins

      if (justPressed) {
        buttonState = 0;
        pressedAtLastSend = true;
        justPressed = false;
      } else {
        buttonState = 1;
        pressedAtLastSend  = false;
      }

      sprintf(buttonString, "%d", buttonState);
      sprintf(xDataString, "%d", xData);
      sprintf(yDataString, "%d", yData);

      strcat(daten, "measurement,");              // build message to send to host
      // Message syntax:
      char delimiter[2] = ",";
      strcat(daten, thisID);                      // 1: device ID
      strcat(daten, delimiter);
      strcat(daten, tc);                          // 2: timecode
      strcat(daten, delimiter);
      strcat(daten, deviceType);                  // 3: deviceType (joystick)
      strcat(daten, delimiter);
      strcat(daten, buttonString);                // 4: button state
      strcat(daten, delimiter);
      strcat(daten, xDataString);                 // 5: x value
      strcat(daten, delimiter);
      strcat(daten, yDataString);                 // 6: y value
      client.write(daten);                      // send message containing measure data to host
      //Serial.println(WiFi.RSSI());              // check WiFi strength
    }
  }

  if (client.connected() && clientAccepted == false) {
    client.write(handshake);                    // try handshake again
    Serial.println("Trying to handshake");
    delay(3000);
  }

  memset(daten, 0, sizeof(daten));              // clear the string holding the measure data
  delay(10);                                    // wait for 40ms at the end of the loop
}