// led strip postition to ultrasonic distance  

int SDI = 2; //Red wire (not the red 5V wire!)
int CKI = 3; //Green wire
// red 5+ / blue GND

int ledPin = 13; //On board LED

#define ECHOPIN 6
#define TRIGPIN 7

#define STRIP_LENGTH 32 //32 LEDs on this strip
long view_buffer[STRIP_LENGTH];

int echo_timer = 0;
float distance;

typedef struct _pixel {
	int bri;
	int col;
	int dir;
	uint32_t color;
};
_pixel pixel[32];

int app_timer = 0;
int serial_on = 0;

void setup() {
	if (serial_on == 1) {
		Serial.begin(115200);
	}
	init_pin();	
	init_echo();
	clear_buffer();
	randomSeed(analogRead(0));
}

void init_pin() {
	pinMode(SDI, OUTPUT);
	pinMode(CKI, OUTPUT);
	pinMode(ledPin, OUTPUT);
}

void init_echo() {
  pinMode(ECHOPIN, INPUT);
  pinMode(TRIGPIN, OUTPUT);
}

void loop() {
//	works_cycle();
//	winkle_cycle();
	loop_echo();
	pixel_render();
//	trailer_cycle();
//	yellow_cycle();
	//loop_test();
	post_frame();
}

void loop_echo() {
	echo_timer++;
	if (echo_timer == 2) {
		echo_timer = 0;
		digitalWrite(TRIGPIN, LOW);
		delayMicroseconds(2);
		digitalWrite(TRIGPIN, HIGH);
		delayMicroseconds(10);
		digitalWrite(TRIGPIN, LOW);
		distance = pulseIn(ECHOPIN, HIGH);
		distance = distance / 58;
		//if (serial_on == 1) {
		//	Serial.println(distance);
		//}
	}
}

void loop_test() {
  //Pre-fill the color array with known values
  view_buffer[0] = 0xFF0000; //Bright Red
  view_buffer[1] = 0x00FF00; //Bright Green
  view_buffer[2] = 0x0000FF; //Bright Blue
  view_buffer[3] = 0x010000; //Faint red
  view_buffer[4] = 0x800000; //1/2 red (0x80 = 128 out of 256)
  post_frame(); //Push the current color frame to the strip
  
  delay(2000);

  while(1){ //Do nothing
    addRandom();
    post_frame(); //Push the current color frame to the strip

    digitalWrite(ledPin, HIGH);   // set the LED on
    delay(25);                  // wait for a second
    digitalWrite(ledPin, LOW);    // set the LED off
    delay(25);                  // wait for a second
  }
}

//Throws random colors down the strip array
void addRandom(void) {
  int x;
  
  //First, shuffle all the current colors down one spot on the strip
  for(x = (STRIP_LENGTH - 1) ; x > 0 ; x--)
    view_buffer[x] = view_buffer[x - 1];
    
  //Now form a new RGB color
  long new_color = 0;
  for(x = 0 ; x < 3 ; x++){
    new_color <<= 8;
    new_color |= random(0xFF); //Give me a number from 0 to 0xFF
    //new_color &= 0xFFFFF0; //Force the random number to just the upper brightness levels. It sort of works.
  }
  
  view_buffer[0] = new_color; //Add the new random color to the strip

  view_buffer[0] = 16;
}

//Takes the current strip color array and pushes it out
void post_frame (void) {
  //Each LED requires 24 bits of data
  //MSB: R7, R6, R5..., G7, G6..., B7, B6... B0 
  //Once the 24 bits have been delivered, the IC immediately relays these bits to its neighbor
  //Pulling the clock low for 500us or more causes the IC to post the data.

  for(int LED_number = 0 ; LED_number < STRIP_LENGTH ; LED_number++) {
    long this_led_color = view_buffer[LED_number]; //24 bits of color data

    for(byte color_bit = 23 ; color_bit != 255 ; color_bit--) {
      //Feed color bit 23 first (red data MSB)
      
      digitalWrite(CKI, LOW); //Only change data when clock is low
      
      long mask = 1L << color_bit;
      //The 1'L' forces the 1 to start as a 32 bit number, otherwise it defaults to 16-bit.
      
      if(this_led_color & mask) 
        digitalWrite(SDI, HIGH);
      else
        digitalWrite(SDI, LOW);
  
      digitalWrite(CKI, HIGH); //Data is latched when clock goes high
    }
  }

  //Pull clock low to put strip into reset/post mode
  digitalWrite(CKI, LOW);
  delayMicroseconds(500); //Wait for 500us to go into reset
}

void clear_buffer() {
	memset(view_buffer, 0, 32);
}

void shift_pixel(int dir) {
	int e;

	for (uint16_t i = 0; i < STRIP_LENGTH; i++) {
		e = i + dir;
		if (e > -1 && e < STRIP_LENGTH) {
			//view_buffer[i] = view_buffer[e];
			pixel[i] = pixel[e];
		}
	}
}

uint32_t Color(byte r, byte g, byte b) {
	uint32_t c;
	c = r;
	c <<= 8;
	c |= g;
	c <<= 8;
	c |= b;
	return c;
}

void pixel_render() {
	int bri;
	int echo;
//	float a;
	
	echo = distance;
	if (echo > STRIP_LENGTH * 2) {
		echo = STRIP_LENGTH * 2;
	} else if (echo < 0) {
		echo = 0;
	} else {
	};
	echo = (STRIP_LENGTH * 2) - echo;
//	echo = echo;
	if (serial_on == 1) {
		Serial.println(echo);
	}
	for (uint16_t i = 0; i < STRIP_LENGTH; i++) {
	//	a = (i / 2) + (millis() / 250.0);
//		bri = sin(a) * 127.0;
//		bri = sin(a) * echo;
//		bri = echo;
	//	bri =  echo;
	//	view_buffer[i] = Color(bri, bri, 0);
		if (i * 2 < echo) {
//			view_buffer[i] = Color(echo, 0, 0);
			if (i % 2 == 0) {
				view_buffer[i] = Color(0, echo * 2, 0);
			} else {
				view_buffer[i] = Color(0, 0, echo * 2);
			}
		} else {
			view_buffer[i] = Color(0, 0, 0);
		}
	}
}