#include <MicroView.h>
#include <Brain.h>

#include <Wire.h>

template <class E, int Len=10> class Queue {
 private:
  E queue[Len];
  byte qHead,qTail;
 public:
  Queue() : qHead(0), qTail(0) { }
  bool empty() {
    return qHead == qTail;
  }
  bool full() {
    return ((qHead+Len-1)%Len) == qTail;
  }
  E* current() {
    return &queue[qHead];
  }
  void remove() {
    if (empty()) return;
    qHead++;
    qHead %= Len;
  }
  void add(const E &value) {
    if (full()) return;

    queue[qTail] = value;

    qTail++;
    qTail %= Len;
  }
};

#define MK_FREQ 49600L // Set clock to 50kHz (actualy 49.6kHz seems to work better)
#define SOUND (byte)0x52  // Sound controller (device ID 82).  Write to 0xA4, read from 0xA5.
#define BUTTON (byte)0x50 // Button controller (device ID 80). Write to 0xA0, read from 0xA1.
#define MOTOR (byte)0x55  // Motor controller (device ID 85).  Write to 0xAA, read from 0xAB.

class Keepon {
 public:
  enum State { WAITING=1, READY, QFULL };
  typedef void (*callback)(State);
 private:
  static const int maxAttempts = 50;
  struct Command {
    byte device;
    byte command;
    byte arg;
  };
  Queue<Command,10> queue;
  byte attempts;

  callback display_callback;

  void take_control() {
    digitalWrite(SDA, LOW);
    digitalWrite(SCL, LOW);
    display_callback(WAITING);
    while (analogRead(0) < 512); // Wait until we see voltage on A0 pin
    display_callback(READY);
    delay(1000);
    Wire.begin();
    TWBR = ((F_CPU / MK_FREQ) - 16) / 2;
  }


  void check_connection() {
    if (analogRead(0) > 512) return;
    take_control();
  }
 public:

  Keepon(callback x) : attempts(0), display_callback(x) { }
  void begin() {
    pinMode(SDA, OUTPUT); // Data wire on My Keepon
    pinMode(SCL, OUTPUT); // Clock wire on My Keepon
    digitalWrite(SDA, LOW);
    digitalWrite(SCL, LOW);
  }
  bool update() {
    if (queue.empty()) return false;
    return true;
  }
  void send() {
    check_connection();
    if (attempts > maxAttempts) {
      attempts = 0;
      queue.remove();
    }
    if (queue.empty()) return;

    Command* current = queue.current();
    Wire.beginTransmission(current->device);
    Wire.write(current->command);
    Wire.write(current->arg);
    int result = (int)Wire.endTransmission();
    if (result == 0) {
      queue.remove();
      attempts = 0;
    }
    else {
      attempts++;
    }
  }

  void add(const Command&c) {
    if (queue.full()) {
      display_callback(QFULL);
      return;
    }
    queue.add(c);
  }

  void pan(byte pos) {
    add(Command{MOTOR,4,pos});
  }
  void tilt(byte pos) {
    add(Command{MOTOR,2,pos});
  }
};

Brain brain(Serial);

void kscan_callback(Keepon::State s) {
  if (s == Keepon::WAITING) {
    uView.setCursor(25,0);uView.println("K?");
  }
  else if (s == Keepon::READY){
    uView.setCursor(25,0);uView.println("K!");
  }
  else if (s == Keepon::QFULL){
    uView.setCursor(25,0);uView.println("K+");
  }
}

Keepon keepon(&kscan_callback);

void setup() {
  Serial.begin(9600);

  uView.begin();
  uView.clear(ALL);
  uView.setFontType(0);

  keepon.begin();
}

const int hist_width=3;
const int hist_pad=1;
int samples_delay;

void loop() {
  byte attention, meditation, quality;
  bool bu = brain.update(); bool ku = keepon.update();
  if (bu || ku) {
    uView.clear(PAGE);

    if (bu) {
      uView.setCursor(0,0); uView.print(quality=brain.readSignalQuality());

      uView.setCursor(0,9); uView.print(attention=brain.readAttention());
      uView.setCursor(18,9); uView.print(meditation=brain.readMeditation());

      const uint32_t* power = brain.readPowerArray();
      uint32_t max_value=0;
      for (int x=0;x<8;++x) {
        if (power[x] > max_value) {
          max_value = power[x];
        }
      }
    
      for (int x=0;x<8;++x) {
        int x0 = (hist_width + hist_pad) * x;
        // we have 30 vertical pixels
        int height = power[x] * 30 / max_value;
        for (int o=0;o<hist_width;++o) {
          uView.lineV(x0+o,47-height,height);
        }
      }

      if (quality < 10 && ++samples_delay > 5) {
        keepon.pan(attention);
        keepon.tilt(meditation);
        samples_delay=0;

        uView.setCursor(5,0);uView.print("sent");
      }
    }
    if (ku) {
      keepon.send();
    }
    uView.display();
  }
}