// ESPNOWSkate by Lukas Bachschwell this device MASTER =D

#include <Arduino.h>
#include <esp_now.h>
#include <WiFi.h>
#include <U8g2lib.h>
#include <EEPROM.h> // ESP32 ?

#include "mac_config.h"
#include "graphics.h"

// Defining variables for OLED display
U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R2, /* clock=*/ 15, /* data=*/ 4, /* reset=*/ 16);
char displayBuffer[20];
String displayString;
short displayData = 0;
unsigned long lastSignalBlink;
unsigned long lastDataRotation;

// Defining variables for Settings menu
bool changeSettings = false;
bool changeSelectedSetting = false;

bool settingsLoopFlag = false;
bool settingsChangeFlag = false;
bool settingsChangeValueFlag = false;

// Defining variables for Hall Effect throttle.
short hallMeasurement;
int throttle = 127;
int sendThrottle = 127;
byte hallCenterMargin = 4;

byte currentSetting = 0;
const byte numOfSettings = 11;

const float minVoltage = 3.2;
const float maxVoltage = 4.1;

// Global copy of slave
esp_now_peer_info_t slave;
#define CHANNEL 3
#define PRINTSCANRESULTS 0
#define DELETEBEFOREPAIR 0
#define HAL_MIN 1290
#define HAL_MAX 2285
#define HAL_CENTER 1785
#define TRIM_LOW 180
#define TRIM_HIGH 0

//#define pairingMode
#define leverPin 36
#define triggerPin 37
#define batteryMeasurePin 35


// ESPNOW functions ##############################
// Scan for slaves in AP mode
#ifdef pairingMode
void ScanForSlave() {
  int8_t scanResults = WiFi.scanNetworks();
  // reset on each scan
  bool slaveFound = 0;
  memset(&slave, 0, sizeof(slave));

  Serial.println("");
  if (scanResults == 0) {
    Serial.println("No WiFi devices in AP Mode found");
  } else {
    Serial.print("Found "); Serial.print(scanResults); Serial.println(" devices ");
    for (int i = 0; i < scanResults; ++i) {
      // Print SSID and RSSI for each device found
      String SSID = WiFi.SSID(i);
      int32_t RSSI = WiFi.RSSI(i);
      String BSSIDstr = WiFi.BSSIDstr(i);

      if (PRINTSCANRESULTS) {
        Serial.print(i + 1);
        Serial.print(": ");
        Serial.print(SSID);
        Serial.print(" (");
        Serial.print(RSSI);
        Serial.print(")");
        Serial.println("");
      }
      delay(10);
      // Check if the current device starts with `Slave`
      if (SSID.indexOf("ESK8") == 0) {
        // SSID of interest
        Serial.println("Found a Slave.");
        Serial.print(i + 1); Serial.print(": "); Serial.print(SSID); Serial.print(" ["); Serial.print(BSSIDstr); Serial.print("]"); Serial.print(" ("); Serial.print(RSSI); Serial.print(")"); Serial.println("");
        // Get BSSID => Mac Address of the Slave
        int mac[6];
        if ( 6 == sscanf(BSSIDstr.c_str(), "%x:%x:%x:%x:%x:%x%c",  &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5] ) ) {
          for (int ii = 0; ii < 6; ++ii ) {
            slave.peer_addr[ii] = (uint8_t) mac[ii];
          }
        }

        slave.channel = CHANNEL; // pick a channel
        slave.encrypt = 0; // no encryption

        slaveFound = 1;
        // we are planning to have only one slave in this example;
        // Hence, break after we find one, to be a bit efficient
        break;
      }
    }
  }

  if (slaveFound) {
    Serial.println("Slave Found, processing..");
  } else {
    Serial.println("Slave Not Found, trying again.");
  }

  // clean up ram
  WiFi.scanDelete();
}
#endif

void deletePeer() {
  const esp_now_peer_info_t *peer = &slave;
  const uint8_t *peer_addr = slave.peer_addr;
  esp_err_t delStatus = esp_now_del_peer(peer_addr);
  Serial.print("Slave Delete Status: ");
  if (delStatus == ESP_OK) {
    // Delete success
    Serial.println("Success");
  } else if (delStatus == ESP_ERR_ESPNOW_NOT_INIT) {
    // How did we get so far!!
    Serial.println("ESPNOW Not Init");
  } else if (delStatus == ESP_ERR_ESPNOW_ARG) {
    Serial.println("Invalid Argument");
  } else if (delStatus == ESP_ERR_ESPNOW_NOT_FOUND) {
    Serial.println("Peer not found.");
  } else {
    Serial.println("Not sure what happened");
  }
}

// Check if the slave is already paired with the master.
// If not, pair the slave with master
bool manageSlave() {
  if (slave.channel == CHANNEL) {
    if (DELETEBEFOREPAIR) {
      deletePeer();
    }

    Serial.print("Slave Status: ");
    const esp_now_peer_info_t *peer = &slave;
    const uint8_t *peer_addr = slave.peer_addr;
    // check if the peer exists
    bool exists = esp_now_is_peer_exist(peer_addr);
    if ( exists) {
      // Slave already paired.
      Serial.println("Already Paired");
      return true;
    } else {
      // Slave not paired, attempt pair
      esp_err_t addStatus = esp_now_add_peer(peer);
      if (addStatus == ESP_OK) {
        // Pair success
        Serial.println("Pair success");
        return true;
      } else if (addStatus == ESP_ERR_ESPNOW_NOT_INIT) {
        // How did we get so far!!
        Serial.println("ESPNOW Not Init");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_ARG) {
        Serial.println("Invalid Argument");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_FULL) {
        Serial.println("Peer list full");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_NO_MEM) {
        Serial.println("Out of memory");
        return false;
      } else if (addStatus == ESP_ERR_ESPNOW_EXIST) {
        Serial.println("Peer Exists");
        return true;
      } else {
        Serial.println("Not sure what happened");
        return false;
      }
    }
  } else {
    // No slave found to process
    Serial.println("No Slave found to process");
    return false;
  }
}

// send data
void sendData() {
  uint8_t esc1 = map(analogRead(leverPin), HAL_MIN, HAL_MAX, TRIM_LOW, TRIM_HIGH);
  uint8_t esc2 = esc1;

  const uint8_t data[] = { esc1, esc2 }; // no mixture for the normal mode

  const uint8_t *peer_addr = slave.peer_addr;
  Serial.print("Sending: "); Serial.println(esc1);
  esp_err_t result = esp_now_send(peer_addr, data, sizeof(data));
  Serial.print("Send Status: ");
  if (result == ESP_OK) {
    Serial.println("Success");
  } else if (result == ESP_ERR_ESPNOW_NOT_INIT) {
    // How did we get so far!!
    Serial.println("ESPNOW not Init.");
  } else if (result == ESP_ERR_ESPNOW_ARG) {
    Serial.println("Invalid Argument");
  } else if (result == ESP_ERR_ESPNOW_INTERNAL) {
    Serial.println("Internal Error");
  } else if (result == ESP_ERR_ESPNOW_NO_MEM) {
    Serial.println("ESP_ERR_ESPNOW_NO_MEM");
  } else if (result == ESP_ERR_ESPNOW_NOT_FOUND) {
    Serial.println("Peer not found.");
  } else {
    Serial.println("Not sure what happened");
  }
}

// callback when data is sent from Master to Slave
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
  char macStr[18];
  snprintf(macStr, sizeof(macStr), "%02x:%02x:%02x:%02x:%02x:%02x",
           mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
  Serial.print("Last Packet Sent to: "); Serial.println(macStr);
  Serial.print("Last Packet Send Status: "); Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
//############ End ESP Now

//############ Hardware Helpers
//############
// Check if an integer is within a min and max value
bool inRange(int val, int minimum, int maximum) {
  return ((minimum <= val) && (val <= maximum));
}

// Return true if trigger is activated, false otherwice
bool triggerActive() {
  if (digitalRead(triggerPin) == LOW)
    return true;
  else
    return false;
}

void calculateThrottlePosition() {
  // Hall sensor reading can be noisy, lets make an average reading.
  int total = 0;
  for (int i = 0; i < 10; i++) {
    total += analogRead(leverPin);
  }
  hallMeasurement = total / 10;

  //DEBUG_PRINT( (String)hallMeasurement );

  if (hallMeasurement >= HAL_CENTER) {
    throttle = constrain(map(hallMeasurement, HAL_CENTER, HAL_MAX, 127, 255), 127, 255);
  } else {
    throttle = constrain(map(hallMeasurement, HAL_MIN, HAL_CENTER, 0, 127), 0, 127);
  }
  // removeing center noise
  if (abs(throttle - 127) < hallCenterMargin) {
    throttle = 127;
  }
}

// Function to calculate and return the remotes battery voltage.
float batteryVoltage() {
  float batteryVoltage = 0.0;
  int total = 0;

  return 3.6; // for now always full
/*
   for (int i = 0; i < 10; i++) {
    total += analogRead(batteryMeasurePin);
   }

   batteryVoltage = (refVoltage / 1024.0) * ((float)total / 10.0);

   return batteryVoltage;
 */
}

// Function used to indicate the remotes battery level.
int batteryLevel() {
  float voltage = batteryVoltage();

  if (voltage <= minVoltage) {
    return 0;
  } else if (voltage >= maxVoltage) {
    return 100;
  } else {
    return (voltage - minVoltage) * 100 / (maxVoltage - minVoltage);
  }
}

// Take a number of measurements of the WiFi strength and return the average result.
int getStrength(int points){
  long rssi = 0;
  long averageRSSI=0;

  for (int i=0; i < points; i++) {
    rssi += WiFi.RSSI();
    delay(20);
  }

  averageRSSI=rssi/points;
  return averageRSSI;
}

//############ End Hardware Helpers

//############ Drawing Functions

void drawBatteryLevel() {
  int level = batteryLevel();

  // Position on OLED
  int x = 108; int y = 4;

  u8g2.drawFrame(x + 2, y, 18, 9);
  u8g2.drawBox(x, y + 2, 2, 5);

  for (int i = 0; i < 5; i++) {
    int p = round((100 / 5) * i);
    if (p <= level)
    {
      u8g2.drawBox(x + 4 + (3 * i), y + 2, 2, 5);
    }
  }
}

void drawThrottle() {
  int x = 0;
  int y = 18;

  // Draw throttle
  u8g2.drawHLine(x, y, 52);
  u8g2.drawVLine(x, y, 10);
  u8g2.drawVLine(x + 52, y, 10);
  u8g2.drawHLine(x, y + 10, 5);
  u8g2.drawHLine(x + 52 - 4, y + 10, 5);

  if (sendThrottle >= 127) {
    int width = map(sendThrottle, 127, 255, 0, 49);

    for (int i = 0; i < width; i++) {
      u8g2.drawVLine(x + i + 2, y + 2, 7);
    }
  } else {
    int width = map(sendThrottle, 0, 126, 49, 0);
    for (int i = 0; i < width; i++) {
      u8g2.drawVLine(x + 50 - i, y + 2, 7);
    }
  }
}

void drawSignal() {
  // Position on OLED
  int x = 114; int y = 17;
/*
   if (connected == true) {
    if (triggerActive()) {
      u8g2.drawXBM(x, y, 12, 12, signal_transmitting_bits);
    } else {
      u8g2.drawXBM(x, y, 12, 12, signal_connected_bits);
    }
   } else {
    if (millis() - lastSignalBlink > 500) {
      signalBlink = !signalBlink;
      lastSignalBlink = millis();
    }

    if (signalBlink == true) {
      u8g2.drawXBM(x, y, 12, 12, signal_connected_bits);
    } else {
      u8g2.drawXBM(x, y, 12, 12, signal_noconnection_bits);
    }
   }
 */
}

void drawTitleScreen(String title) {
  u8g2.firstPage();
  do {
    title.toCharArray(displayBuffer, 20);
    u8g2.setFont(u8g2_font_helvR10_tr  );
    u8g2.drawStr(12, 20, displayBuffer);
  } while ( u8g2.nextPage() );
  delay(1500);
}

void drawPage() {
  /*
     int decimals;
     float value;
     String suffix;
     String prefix;

     int first, last;

     int x = 0;
     int y = 16;

     // Rotate the realtime data each 4s.
     if ((millis() - lastDataRotation) >= 4000) {

     lastDataRotation = millis();
     displayData++;

     if (displayData > 2) {
      displayData = 0;
     }
     }

     switch (displayData) {
     case 0:
     value = ratioRpmSpeed * data.rpm;
     suffix = "KMH";
     prefix = "SPEED";
     decimals = 1;
     break;
     case 1:
     value = ratioPulseDistance * data.tachometerAbs;
     suffix = "KM";
     prefix = "DISTANCE";
     decimals = 2;
     break;
     case 2:
     value = data.inpVoltage;
     suffix = "V";
     prefix = "BATTERY";
     decimals = 1;
     break;
     }

     // Display prefix (title)
     displayString = prefix;
     displayString.toCharArray(displayBuffer, 10);
     u8g2.setFont(u8g2_font_profont12_tr);
     u8g2.drawStr(x, y - 1, displayBuffer);

     // Split up the float value: a number, b decimals.
     first = abs(floor(value));
     last = value * pow(10, 3) - first * pow(10, 3);

     // Add leading zero
     if (first <= 9) {
     displayString = "0" + (String)first;
     } else {
     displayString = (String)first;
     }

     // Display numbers
     displayString.toCharArray(displayBuffer, 10);
     u8g2.setFont(u8g2_font_logisoso22_tn );
     u8g2.drawStr(x + 55, y + 13, displayBuffer);

     // Display decimals
     displayString = "." + (String)last;
     displayString.toCharArray(displayBuffer, decimals + 2);
     u8g2.setFont(u8g2_font_profont12_tr);
     u8g2.drawStr(x + 86, y - 1, displayBuffer);

     // Display suffix
     displayString = suffix;
     displayString.toCharArray(displayBuffer, 10);
     u8g2.setFont(u8g2_font_profont12_tr);
     u8g2.drawStr(x + 86 + 2, y + 13, displayBuffer);
   */
}

void drawSettingsMenu() {
  /*
     // Position on OLED
     int x = 0; int y = 10;

     // Draw setting title
     displayString = settingPages[currentSetting][0];
     displayString.toCharArray(displayBuffer, displayString.length() + 1);

     u8g2.setFont(u8g2_font_profont12_tr);
     u8g2.drawStr(x, y, displayBuffer);

     int val = getSettingValue(currentSetting);

     displayString = (String)val + "" + settingPages[currentSetting][1];
     displayString.toCharArray(displayBuffer, displayString.length() + 1);
     u8g2.setFont(u8g2_font_10x20_tr  );

     if (changeSelectedSetting == true) {
     u8g2.drawStr(x + 10, y + 20, displayBuffer);
     } else {
     u8g2.drawStr(x, y + 20, displayBuffer);
     }
   */
}

void drawSettingNumber() {
  // Position on OLED
  int x = 2; int y = 10;

  // Draw current setting number box
  u8g2.drawRFrame(x + 102, y - 10, 22, 32, 4);

  // Draw current setting number
  displayString = (String)(currentSetting + 1);
  displayString.toCharArray(displayBuffer, displayString.length() + 1);

  u8g2.setFont(u8g2_font_profont22_tn);
  u8g2.drawStr(x + 108, 22, displayBuffer);
}

void updateMainDisplay() {

  u8g2.firstPage();
  do {

    if (changeSettings == true) {
      //drawSettingsMenu();
      drawSettingNumber();
    } else {
      drawThrottle();
      drawPage();
      drawBatteryLevel();
      drawSignal();
    }

  } while ( u8g2.nextPage() );
}

void drawStartScreen() {
  u8g2.firstPage();
  do {
    u8g2.drawXBM( 4, 4, 24, 24, logo_bits);

    displayString = "Esk8 remote";
    displayString.toCharArray(displayBuffer, 12);
    u8g2.setFont(u8g2_font_helvR10_tr  );
    u8g2.drawStr(34, 22, displayBuffer);
  } while ( u8g2.nextPage() );
  delay(1500);
}

//############ End Drawing Functions

void setup() {
  Serial.begin(115200);
  //Set device in STA mode to begin with
  WiFi.mode(WIFI_STA);
  Serial.println("ESPNowSkate");

  // reset the screen
  pinMode(16, OUTPUT);
  digitalWrite(16, LOW); // set GPIO16 low to reset OLED
  delay(50);
  digitalWrite(16, HIGH);

  // setup other pins
  pinMode(triggerPin, INPUT_PULLUP);

  Serial.println("ESPNowSkate Sender");
  u8g2.begin();
  drawStartScreen();
/*
   if (triggerActive()) {
    changeSettings = true;
    drawTitleScreen("Remote Settings");
   }
 */
  // This is the mac address of the Master in Station Mode
  Serial.print("STA MAC: "); Serial.println(WiFi.macAddress());

  if (esp_now_init() == ESP_OK) {
    Serial.println("ESPNow Init Success");
  }
  else {
    Serial.println("ESPNow Init Failed");
    ESP.restart();
  }

  // Once ESPNow is successfully Init, we will register for Send CB to
  // get the status of Trasnmitted packet
  esp_now_register_send_cb(OnDataSent);
  //ScanForSlave();


  // Retrieve Slave from config:
  for (int i = 0; i < 6; ++i ) {
    slave.peer_addr[i] = (uint8_t) mac_receiver[i];
  }
  slave.channel = CHANNEL; // pick a channel
  slave.encrypt = 0; // no encryption
}

void loop() {
  // Call function to update display and LED
  updateMainDisplay();


  /* update Value
     char buf[10];
     sprintf(buf, "%i", map(analogRead(leverPin), HAL_MIN, HAL_MAX, TRIM_LOW, TRIM_HIGH));
     u8g2.firstPage();
     do {
     u8g2.setFont(u8g2_font_10x20_tr );
     u8g2.drawStr(0, 20, buf);
     } while ( u8g2.nextPage() );
   */

  calculateThrottlePosition();

  if (changeSettings == true) {
    // Use throttle and trigger to change settings
    //controlSettingsMenu();
  } else {
    // Use throttle and trigger to drive motors
    if (triggerActive()) {
      sendThrottle = throttle;
    } else {
      // 127 is the middle position - no throttle and no brake/reverse
      sendThrottle = 127;
    }

    // If Slave is found, it would be populate in `slave` variable
    // We will check if `slave` is defined and then we proceed further
    if (slave.channel == CHANNEL) { // check if slave channel is defined
      // `slave` is defined
      // Add slave as peer if it has not been added already
      bool isPaired = manageSlave();
      if (isPaired) {
        // pair success or already paired
        // Send data to device
        sendData();
      } else {
        // slave pair failed

        Serial.println("Slave not found / paired!");
      }
    }
    else {
      // No slave found to process
    }

    delay(20);
  }
}