#include <Arduino.h>
#include <Adafruit_NeoPixel.h>
#include "Patterns.h"

const uint8_t PROGMEM gamma[] = GAMMA_CORRECTION;

class Strip {
  private:
  uint8_t pin;
  uint8_t num_pixels;
  unsigned long last;
  uint8_t offset = 0;
  uint8_t offset_increment = OFFSET_INCREMENT_DEFAULT;
  uint8_t shifting = SHIFTING_DEFAULT;

  public:
  Adafruit_NeoPixel pixel;
  uint16_t wait = 0;
  char pattern = PATTERN_DEFAULT;
  uint8_t amplitude = 0;

  Strip(uint8_t led_pin, uint8_t strip_len) {
    pin = led_pin;
    num_pixels = strip_len;
    last = millis();
    pixel = Adafruit_NeoPixel(num_pixels, pin, NEO_GRBW + NEO_KHZ800);
    pixel.begin();
  }

  void set_shift_direction(uint8_t new_shift){
    if (new_shift == SHIFTING_FORWARD || new_shift == SHIFTING_REVERSE){
      offset = num_pixels - offset - 1;
    } else {
      offset = 0;
    }
    shifting = new_shift;
  }

  void update(void){
    unsigned long now = millis();
    if (now - wait > last){
      last = now;
      add_offset();
    }
    if (pattern == PATTERN_RAINBOW){
      rainbow();
    } else if (pattern == PATTERN_RED){
      red();
    } else {
      off();
    }
    pixel.show();
  }

  private:
  void off(void){
    for(uint8_t i=0; i<num_pixels; i++){
      pixel.setPixelColor(i, pixel.Color(0,0,0));
    }
  }
  void add_offset(void){
    /* Increments the offset counter. See get_offset_loc() */
    offset += offset_increment;
    if (offset >= num_pixels){
      offset = 0;
    }
  }
  uint8_t get_offset_loc(uint8_t index){
    /* index is the location on the strip where a pixel would be if offset
     *  was 0. Offset will be from 0 to num_pixels-1 */
    if (offset == 0){
      return index;
    }
    if (shifting == SHIFTING_FORWARD){
      uint16_t loc = offset + index;
      if (loc >= num_pixels){
        loc -= num_pixels;
      }
      return (uint8_t)loc;
    } else if (shifting == SHIFTING_REVERSE){
      uint16_t loc = num_pixels - offset + index;
      if (loc >= num_pixels){
        loc -= num_pixels;
      }
      return (uint8_t)loc;
    }
    return index; // SHIFTING_STOPPED
  }
  void set_pixel_rgb(uint8_t index, uint8_t rgb[]){
    set_pixel_rgb(index, rgb[0], rgb[1], rgb[2]);
  }
  void set_pixel_rgb(uint8_t index, uint8_t red, uint8_t green, uint8_t blue){
    pixel.setPixelColor(
      get_offset_loc(index),
      pixel.Color(
        pgm_read_byte(&gamma[red / DIM_FACTOR]),
        pgm_read_byte(&gamma[green / DIM_FACTOR]),
        pgm_read_byte(&gamma[blue / DIM_FACTOR])
      )
    );
  }
  void set_pixel_rgbw(uint8_t index, uint8_t rgb[]){
    set_pixel_rgbw(index, rgb[0], rgb[1], rgb[2], rgb[3]);
  }
  void set_pixel_rgbw(uint8_t index, uint8_t red, uint8_t green, uint8_t blue, uint8_t white){
    pixel.setPixelColor(
      get_offset_loc(index),
      pixel.Color(
        pgm_read_byte(&gamma[red / DIM_FACTOR]),
        pgm_read_byte(&gamma[green / DIM_FACTOR]),
        pgm_read_byte(&gamma[blue / DIM_FACTOR]),
        pgm_read_byte(&gamma[white / DIM_FACTOR])
      )
    );
  }
  void rainbow(void){
    uint8_t rgb[] = {255, 0, 0}; // starting RGB value
    uint8_t phase_len = num_pixels / 6; // how long each rainbow phase is
    uint8_t bump = 255 / phase_len; // how much to increase between pixels
    set_pixel_rgb(0, rgb); // first pixel
    for (uint8_t index=1; index < num_pixels; index++){
      uint8_t phase = index / phase_len; // which section we're in
      if (phase % 2 == 0){ // even-index phases add; odd-indexed subtracts
        // (r,g,b) index for each phase in order is 1,0,2,1,0,
        rgb[(6 - phase + 1) % 3] += bump;
      } else {
        rgb[(6 - phase + 1) % 3] -= bump;
      }
      if (index % phase_len == 0) { // this is the transition between phases
        // max out the change from the previous phase
        if (phase % 2 == 0){
          rgb[(6 - phase + 2) % 3] = 0;
        } else {
          rgb[(6 - phase + 2) % 3] = 255;
        }
      }
      set_pixel_rgb(index, rgb);
    }
  }
  void red(void){
    float bump = 255.0 / (num_pixels / 2 + 1);
    uint8_t half_point = num_pixels / 2 + 1;
    float red = 0;
    set_pixel_rgb(0, 1, 0, 0);
    //set_pixel_rgbw(0, 0, 0, 0, 255);
    for (uint8_t index=1; index < num_pixels; index++){
      if (index < half_point){
        red += bump;
      } else {
        red -= bump;
      }
      uint8_t red_int = (uint8_t)red;
      //uint8_t white_int = (255 - red_int + 1) / 2;
      set_pixel_rgb(index, red_int, 0, 0);
      //set_pixel_rgbw(index, red_int, 0, 0, white_int);
    }
  }
};