/* Copyright 2016-2017 Yang Liu
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <avr/eeprom.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "progmem.h"
#include "timer.h"
#include "rgblight.h"
#include "debug.h"

// Lightness curve using the CIE 1931 lightness formula
//Generated by the python script provided in http://jared.geek.nz/2013/feb/linear-led-pwm
const uint8_t DIM_CURVE[] PROGMEM = {
    0, 0, 0, 0, 0, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 3, 3, 3, 3, 3, 3, 3,
    3, 4, 4, 4, 4, 4, 4, 5, 5, 5,
    5, 5, 6, 6, 6, 6, 6, 7, 7, 7,
    7, 8, 8, 8, 8, 9, 9, 9, 10, 10,
    10, 10, 11, 11, 11, 12, 12, 12, 13, 13,
    13, 14, 14, 15, 15, 15, 16, 16, 17, 17,
    17, 18, 18, 19, 19, 20, 20, 21, 21, 22,
    22, 23, 23, 24, 24, 25, 25, 26, 26, 27,
    28, 28, 29, 29, 30, 31, 31, 32, 32, 33,
    34, 34, 35, 36, 37, 37, 38, 39, 39, 40,
    41, 42, 43, 43, 44, 45, 46, 47, 47, 48,
    49, 50, 51, 52, 53, 54, 54, 55, 56, 57,
    58, 59, 60, 61, 62, 63, 64, 65, 66, 67,
    68, 70, 71, 72, 73, 74, 75, 76, 77, 79,
    80, 81, 82, 83, 85, 86, 87, 88, 90, 91,
    92, 94, 95, 96, 98, 99, 100, 102, 103, 105,
    106, 108, 109, 110, 112, 113, 115, 116, 118, 120,
    121, 123, 124, 126, 128, 129, 131, 132, 134, 136,
    138, 139, 141, 143, 145, 146, 148, 150, 152, 154,
    155, 157, 159, 161, 163, 165, 167, 169, 171, 173,
    175, 177, 179, 181, 183, 185, 187, 189, 191, 193,
    196, 198, 200, 202, 204, 207, 209, 211, 214, 216,
    218, 220, 223, 225, 228, 230, 232, 235, 237, 240,
    242, 245, 247, 250, 252, 255,
    };

const uint8_t RGBLED_BREATHING_TABLE[] PROGMEM = {
  0, 0, 0, 0, 1, 1, 1, 2, 2, 3, 4, 5, 5, 6, 7, 9,
  10, 11, 12, 14, 15, 17, 18, 20, 21, 23, 25, 27, 29, 31, 33, 35,
  37, 40, 42, 44, 47, 49, 52, 54, 57, 59, 62, 65, 67, 70, 73, 76,
  79, 82, 85, 88, 90, 93, 97, 100, 103, 106, 109, 112, 115, 118, 121, 124,
  127, 131, 134, 137, 140, 143, 146, 149, 152, 155, 158, 162, 165, 167, 170, 173,
  176, 179, 182, 185, 188, 190, 193, 196, 198, 201, 203, 206, 208, 211, 213, 215,
  218, 220, 222, 224, 226, 228, 230, 232, 234, 235, 237, 238, 240, 241, 243, 244,
  245, 246, 248, 249, 250, 250, 251, 252, 253, 253, 254, 254, 254, 255, 255, 255,
  255, 255, 255, 255, 254, 254, 254, 253, 253, 252, 251, 250, 250, 249, 248, 246,
  245, 244, 243, 241, 240, 238, 237, 235, 234, 232, 230, 228, 226, 224, 222, 220,
  218, 215, 213, 211, 208, 206, 203, 201, 198, 196, 193, 190, 188, 185, 182, 179,
  176, 173, 170, 167, 165, 162, 158, 155, 152, 149, 146, 143, 140, 137, 134, 131,
  128, 124, 121, 118, 115, 112, 109, 106, 103, 100, 97, 93, 90, 88, 85, 82,
  79, 76, 73, 70, 67, 65, 62, 59, 57, 54, 52, 49, 47, 44, 42, 40,
  37, 35, 33, 31, 29, 27, 25, 23, 21, 20, 18, 17, 15, 14, 12, 11,
  10, 9, 7, 6, 5, 5, 4, 3, 2, 2, 1, 1, 1, 0, 0, 0
};

__attribute__ ((weak))
const uint8_t RGBLED_BREATHING_INTERVALS[] PROGMEM = {30, 20, 10, 5};
__attribute__ ((weak))
const uint8_t RGBLED_RAINBOW_MOOD_INTERVALS[] PROGMEM = {120, 60, 30};
__attribute__ ((weak))
const uint8_t RGBLED_RAINBOW_SWIRL_INTERVALS[] PROGMEM = {100, 50, 20};
__attribute__ ((weak))
const uint8_t RGBLED_SNAKE_INTERVALS[] PROGMEM = {100, 50, 20};
__attribute__ ((weak))
const uint8_t RGBLED_KNIGHT_INTERVALS[] PROGMEM = {100, 50, 20};
__attribute__ ((weak))
const uint16_t RGBLED_GRADIENT_RANGES[] PROGMEM = {360, 240, 180, 120, 90};

rgblight_config_t rgblight_config;
rgblight_config_t inmem_config;

LED_TYPE led[RGBLED_NUM];
uint8_t rgblight_inited = 0;
bool rgblight_timer_enabled = false;

void sethsv(uint16_t hue, uint8_t sat, uint8_t val, LED_TYPE *led1) {
  uint8_t r = 0, g = 0, b = 0, base, color;

  if (sat == 0) { // Acromatic color (gray). Hue doesn't mind.
    r = val;
    g = val;
    b = val;
  } else {
    base = ((255 - sat) * val) >> 8;
    color = (val - base) * (hue % 60) / 60;

    switch (hue / 60) {
      case 0:
        r = val;
        g = base + color;
        b = base;
        break;
      case 1:
        r = val - color;
        g = val;
        b = base;
        break;
      case 2:
        r = base;
        g = val;
        b = base + color;
        break;
      case 3:
        r = base;
        g = val - color;
        b = val;
        break;
      case 4:
        r = base + color;
        g = base;
        b = val;
        break;
      case 5:
        r = val;
        g = base;
        b = val - color;
        break;
    }
  }
  r = pgm_read_byte(&DIM_CURVE[r]);
  g = pgm_read_byte(&DIM_CURVE[g]);
  b = pgm_read_byte(&DIM_CURVE[b]);

  setrgb(r, g, b, led1);
}

void setrgb(uint8_t r, uint8_t g, uint8_t b, LED_TYPE *led1) {
  (*led1).r = r;
  (*led1).g = g;
  (*led1).b = b;
}


uint32_t eeconfig_read_rgblight(void) {
  return eeprom_read_dword(EECONFIG_RGBLIGHT);
}
void eeconfig_update_rgblight(uint32_t val) {
  eeprom_update_dword(EECONFIG_RGBLIGHT, val);
}
void eeconfig_update_rgblight_default(void) {
  dprintf("eeconfig_update_rgblight_default\n");
  rgblight_config.enable = 1;
  rgblight_config.mode = 1;
  rgblight_config.hue = 0;
  rgblight_config.sat = 255;
  rgblight_config.val = 255;
  eeconfig_update_rgblight(rgblight_config.raw);
}
void eeconfig_debug_rgblight(void) {
  dprintf("rgblight_config eprom\n");
  dprintf("rgblight_config.enable = %d\n", rgblight_config.enable);
  dprintf("rghlight_config.mode = %d\n", rgblight_config.mode);
  dprintf("rgblight_config.hue = %d\n", rgblight_config.hue);
  dprintf("rgblight_config.sat = %d\n", rgblight_config.sat);
  dprintf("rgblight_config.val = %d\n", rgblight_config.val);
}

void rgblight_init(void) {
  debug_enable = 1; // Debug ON!
  dprintf("rgblight_init called.\n");
  rgblight_inited = 1;
  dprintf("rgblight_init start!\n");
  if (!eeconfig_is_enabled()) {
    dprintf("rgblight_init eeconfig is not enabled.\n");
    eeconfig_init();
    eeconfig_update_rgblight_default();
  }
  rgblight_config.raw = eeconfig_read_rgblight();
  if (!rgblight_config.mode) {
    dprintf("rgblight_init rgblight_config.mode = 0. Write default values to EEPROM.\n");
    eeconfig_update_rgblight_default();
    rgblight_config.raw = eeconfig_read_rgblight();
  }
  eeconfig_debug_rgblight(); // display current eeprom values

  #ifdef RGBLIGHT_ANIMATIONS
    rgblight_timer_init(); // setup the timer
  #endif

  if (rgblight_config.enable) {
    rgblight_mode(rgblight_config.mode);
  }
}

void rgblight_update_dword(uint32_t dword) {
  rgblight_config.raw = dword;
  eeconfig_update_rgblight(rgblight_config.raw);
  if (rgblight_config.enable)
    rgblight_mode(rgblight_config.mode);
  else {
    #ifdef RGBLIGHT_ANIMATIONS
      rgblight_timer_disable();
    #endif
      rgblight_set();
  }
}

void rgblight_increase(void) {
  uint8_t mode = 0;
  if (rgblight_config.mode < RGBLIGHT_MODES) {
    mode = rgblight_config.mode + 1;
  }
  rgblight_mode(mode);
}
void rgblight_decrease(void) {
  uint8_t mode = 0;
  // Mode will never be < 1. If it ever is, eeprom needs to be initialized.
  if (rgblight_config.mode > 1) {
    mode = rgblight_config.mode - 1;
  }
  rgblight_mode(mode);
}
void rgblight_step(void) {
  uint8_t mode = 0;
  mode = rgblight_config.mode + 1;
  if (mode > RGBLIGHT_MODES) {
    mode = 1;
  }
  rgblight_mode(mode);
}
void rgblight_step_reverse(void) {
  uint8_t mode = 0;
  mode = rgblight_config.mode - 1;
  if (mode < 1) {
    mode = RGBLIGHT_MODES;
  }
  rgblight_mode(mode);
}

void rgblight_mode(uint8_t mode) {
  if (!rgblight_config.enable) {
    return;
  }
  if (mode < 1) {
    rgblight_config.mode = 1;
  } else if (mode > RGBLIGHT_MODES) {
    rgblight_config.mode = RGBLIGHT_MODES;
  } else {
    rgblight_config.mode = mode;
  }
  eeconfig_update_rgblight(rgblight_config.raw);
  xprintf("rgblight mode: %u\n", rgblight_config.mode);
  if (rgblight_config.mode == 1) {
    #ifdef RGBLIGHT_ANIMATIONS
      rgblight_timer_disable();
    #endif
  } else if (rgblight_config.mode >= 2 && rgblight_config.mode <= 24) {
    // MODE 2-5, breathing
    // MODE 6-8, rainbow mood
    // MODE 9-14, rainbow swirl
    // MODE 15-20, snake
    // MODE 21-23, knight

    #ifdef RGBLIGHT_ANIMATIONS
      rgblight_timer_enable();
    #endif
  } else if (rgblight_config.mode >= 25 && rgblight_config.mode <= 34) {
    // MODE 25-34, static gradient

    #ifdef RGBLIGHT_ANIMATIONS
      rgblight_timer_disable();
    #endif
  }
  rgblight_sethsv(rgblight_config.hue, rgblight_config.sat, rgblight_config.val);
}

void rgblight_toggle(void) {
  rgblight_config.enable ^= 1;
  eeconfig_update_rgblight(rgblight_config.raw);
  xprintf("rgblight toggle: rgblight_config.enable = %u\n", rgblight_config.enable);
  if (rgblight_config.enable) {
    rgblight_mode(rgblight_config.mode);
  } else {
    #ifdef RGBLIGHT_ANIMATIONS
      rgblight_timer_disable();
    #endif
    _delay_ms(50);
    rgblight_set();
  }
}

void rgblight_enable(void) {
  rgblight_config.enable = 1;
  eeconfig_update_rgblight(rgblight_config.raw);
  xprintf("rgblight enable: rgblight_config.enable = %u\n", rgblight_config.enable);
  rgblight_mode(rgblight_config.mode);
}


void rgblight_increase_hue(void) {
  uint16_t hue;
  hue = (rgblight_config.hue+RGBLIGHT_HUE_STEP) % 360;
  rgblight_sethsv(hue, rgblight_config.sat, rgblight_config.val);
}
void rgblight_decrease_hue(void) {
  uint16_t hue;
  if (rgblight_config.hue-RGBLIGHT_HUE_STEP < 0) {
    hue = (rgblight_config.hue + 360 - RGBLIGHT_HUE_STEP) % 360;
  } else {
    hue = (rgblight_config.hue - RGBLIGHT_HUE_STEP) % 360;
  }
  rgblight_sethsv(hue, rgblight_config.sat, rgblight_config.val);
}
void rgblight_increase_sat(void) {
  uint8_t sat;
  if (rgblight_config.sat + RGBLIGHT_SAT_STEP > 255) {
    sat = 255;
  } else {
    sat = rgblight_config.sat + RGBLIGHT_SAT_STEP;
  }
  rgblight_sethsv(rgblight_config.hue, sat, rgblight_config.val);
}
void rgblight_decrease_sat(void) {
  uint8_t sat;
  if (rgblight_config.sat - RGBLIGHT_SAT_STEP < 0) {
    sat = 0;
  } else {
    sat = rgblight_config.sat - RGBLIGHT_SAT_STEP;
  }
  rgblight_sethsv(rgblight_config.hue, sat, rgblight_config.val);
}
void rgblight_increase_val(void) {
  uint8_t val;
  if (rgblight_config.val + RGBLIGHT_VAL_STEP > 255) {
    val = 255;
  } else {
    val = rgblight_config.val + RGBLIGHT_VAL_STEP;
  }
  rgblight_sethsv(rgblight_config.hue, rgblight_config.sat, val);
}
void rgblight_decrease_val(void) {
  uint8_t val;
  if (rgblight_config.val - RGBLIGHT_VAL_STEP < 0) {
    val = 0;
  } else {
    val = rgblight_config.val - RGBLIGHT_VAL_STEP;
  }
  rgblight_sethsv(rgblight_config.hue, rgblight_config.sat, val);
}

void rgblight_sethsv_noeeprom(uint16_t hue, uint8_t sat, uint8_t val) {
  inmem_config.raw = rgblight_config.raw;
  if (rgblight_config.enable) {
    LED_TYPE tmp_led;
    sethsv(hue, sat, val, &tmp_led);
    inmem_config.hue = hue;
    inmem_config.sat = sat;
    inmem_config.val = val;
    // dprintf("rgblight set hue [MEMORY]: %u,%u,%u\n", inmem_config.hue, inmem_config.sat, inmem_config.val);
    rgblight_setrgb(tmp_led.r, tmp_led.g, tmp_led.b);
  }
}
void rgblight_sethsv(uint16_t hue, uint8_t sat, uint8_t val) {
  if (rgblight_config.enable) {
    if (rgblight_config.mode == 1) {
      // same static color
      rgblight_sethsv_noeeprom(hue, sat, val);
    } else {
      // all LEDs in same color
      if (rgblight_config.mode >= 2 && rgblight_config.mode <= 5) {
        // breathing mode, ignore the change of val, use in memory value instead
        val = rgblight_config.val;
      } else if (rgblight_config.mode >= 6 && rgblight_config.mode <= 14) {
        // rainbow mood and rainbow swirl, ignore the change of hue
        hue = rgblight_config.hue;
      } else if (rgblight_config.mode >= 25 && rgblight_config.mode <= 34) {
        // static gradient
        uint16_t _hue;
        int8_t direction = ((rgblight_config.mode - 25) % 2) ? -1 : 1;
        uint16_t range = pgm_read_word(&RGBLED_GRADIENT_RANGES[(rgblight_config.mode - 25) / 2]);
        for (uint8_t i = 0; i < RGBLED_NUM; i++) {
          _hue = (range / RGBLED_NUM * i * direction + hue + 360) % 360;
          dprintf("rgblight rainbow set hsv: %u,%u,%d,%u\n", i, _hue, direction, range);
          sethsv(_hue, sat, val, (LED_TYPE *)&led[i]);
        }
        rgblight_set();
      }
    }
    rgblight_config.hue = hue;
    rgblight_config.sat = sat;
    rgblight_config.val = val;
    eeconfig_update_rgblight(rgblight_config.raw);
    xprintf("rgblight set hsv [EEPROM]: %u,%u,%u\n", rgblight_config.hue, rgblight_config.sat, rgblight_config.val);
  }
}

void rgblight_setrgb(uint8_t r, uint8_t g, uint8_t b) {
  // dprintf("rgblight set rgb: %u,%u,%u\n", r,g,b);
  for (uint8_t i = 0; i < RGBLED_NUM; i++) {
    led[i].r = r;
    led[i].g = g;
    led[i].b = b;
  }
  rgblight_set();
}

__attribute__ ((weak))
void rgblight_set(void) {
  if (rgblight_config.enable) {
    #ifdef RGBW
      ws2812_setleds_rgbw(led, RGBLED_NUM);
    #else
      ws2812_setleds(led, RGBLED_NUM);
    #endif
  } else {
    for (uint8_t i = 0; i < RGBLED_NUM; i++) {
      led[i].r = 0;
      led[i].g = 0;
      led[i].b = 0;
    }
    #ifdef RGBW
      ws2812_setleds_rgbw(led, RGBLED_NUM);
    #else
      ws2812_setleds(led, RGBLED_NUM);
    #endif
  }
}

#ifdef RGBLIGHT_ANIMATIONS

// Animation timer -- AVR Timer3
void rgblight_timer_init(void) {
  // static uint8_t rgblight_timer_is_init = 0;
  // if (rgblight_timer_is_init) {
  //   return;
  // }
  // rgblight_timer_is_init = 1;
  // /* Timer 3 setup */
  // TCCR3B = _BV(WGM32) // CTC mode OCR3A as TOP
  //       | _BV(CS30); // Clock selelct: clk/1
  // /* Set TOP value */
  // uint8_t sreg = SREG;
  // cli();
  // OCR3AH = (RGBLED_TIMER_TOP >> 8) & 0xff;
  // OCR3AL = RGBLED_TIMER_TOP & 0xff;
  // SREG = sreg;

  rgblight_timer_enabled = true;
}
void rgblight_timer_enable(void) {
  rgblight_timer_enabled = true;
  dprintf("TIMER3 enabled.\n");
}
void rgblight_timer_disable(void) {
  rgblight_timer_enabled = false;
  dprintf("TIMER3 disabled.\n");
}
void rgblight_timer_toggle(void) {
  rgblight_timer_enabled ^= rgblight_timer_enabled;
  dprintf("TIMER3 toggled.\n");
}

void rgblight_show_solid_color(uint8_t r, uint8_t g, uint8_t b) {
  rgblight_enable();
  rgblight_mode(1);
  rgblight_setrgb(r, g, b);
}

void rgblight_task(void) {
  if (rgblight_timer_enabled) {
    // mode = 1, static light, do nothing here
    if (rgblight_config.mode >= 2 && rgblight_config.mode <= 5) {
      // mode = 2 to 5, breathing mode
      rgblight_effect_breathing(rgblight_config.mode - 2);
    } else if (rgblight_config.mode >= 6 && rgblight_config.mode <= 8) {
      // mode = 6 to 8, rainbow mood mod
      rgblight_effect_rainbow_mood(rgblight_config.mode - 6);
    } else if (rgblight_config.mode >= 9 && rgblight_config.mode <= 14) {
      // mode = 9 to 14, rainbow swirl mode
      rgblight_effect_rainbow_swirl(rgblight_config.mode - 9);
    } else if (rgblight_config.mode >= 15 && rgblight_config.mode <= 20) {
      // mode = 15 to 20, snake mode
      rgblight_effect_snake(rgblight_config.mode - 15);
    } else if (rgblight_config.mode >= 21 && rgblight_config.mode <= 23) {
      // mode = 21 to 23, knight mode
      rgblight_effect_knight(rgblight_config.mode - 21);
    } else if (rgblight_config.mode == 24) {
      // mode = 24, christmas mode
      rgblight_effect_christmas();
    }
  }
}

// Effects
void rgblight_effect_breathing(uint8_t interval) {
  static uint8_t pos = 0;
  static uint16_t last_timer = 0;

  if (timer_elapsed(last_timer) < pgm_read_byte(&RGBLED_BREATHING_INTERVALS[interval])) {
    return;
  }
  last_timer = timer_read();

  rgblight_sethsv_noeeprom(rgblight_config.hue, rgblight_config.sat, pgm_read_byte(&RGBLED_BREATHING_TABLE[pos]));
  pos = (pos + 1) % 256;
}
void rgblight_effect_rainbow_mood(uint8_t interval) {
  static uint16_t current_hue = 0;
  static uint16_t last_timer = 0;

  if (timer_elapsed(last_timer) < pgm_read_byte(&RGBLED_RAINBOW_MOOD_INTERVALS[interval])) {
    return;
  }
  last_timer = timer_read();
  rgblight_sethsv_noeeprom(current_hue, rgblight_config.sat, rgblight_config.val);
  current_hue = (current_hue + 1) % 360;
}
void rgblight_effect_rainbow_swirl(uint8_t interval) {
  static uint16_t current_hue = 0;
  static uint16_t last_timer = 0;
  uint16_t hue;
  uint8_t i;
  if (timer_elapsed(last_timer) < pgm_read_byte(&RGBLED_RAINBOW_MOOD_INTERVALS[interval / 2])) {
    return;
  }
  last_timer = timer_read();
  for (i = 0; i < RGBLED_NUM; i++) {
    hue = (360 / RGBLED_NUM * i + current_hue) % 360;
    sethsv(hue, rgblight_config.sat, rgblight_config.val, (LED_TYPE *)&led[i]);
  }
  rgblight_set();

  if (interval % 2) {
    current_hue = (current_hue + 1) % 360;
  } else {
    if (current_hue - 1 < 0) {
      current_hue = 359;
    } else {
      current_hue = current_hue - 1;
    }
  }
}
void rgblight_effect_snake(uint8_t interval) {
  static uint8_t pos = 0;
  static uint16_t last_timer = 0;
  uint8_t i, j;
  int8_t k;
  int8_t increment = 1;
  if (interval % 2) {
    increment = -1;
  }
  if (timer_elapsed(last_timer) < pgm_read_byte(&RGBLED_SNAKE_INTERVALS[interval / 2])) {
    return;
  }
  last_timer = timer_read();
  for (i = 0; i < RGBLED_NUM; i++) {
    led[i].r = 0;
    led[i].g = 0;
    led[i].b = 0;
    for (j = 0; j < RGBLIGHT_EFFECT_SNAKE_LENGTH; j++) {
      k = pos + j * increment;
      if (k < 0) {
        k = k + RGBLED_NUM;
      }
      if (i == k) {
        sethsv(rgblight_config.hue, rgblight_config.sat, (uint8_t)(rgblight_config.val*(RGBLIGHT_EFFECT_SNAKE_LENGTH-j)/RGBLIGHT_EFFECT_SNAKE_LENGTH), (LED_TYPE *)&led[i]);
      }
    }
  }
  rgblight_set();
  if (increment == 1) {
    if (pos - 1 < 0) {
      pos = RGBLED_NUM - 1;
    } else {
      pos -= 1;
    }
  } else {
    pos = (pos + 1) % RGBLED_NUM;
  }
}
void rgblight_effect_knight(uint8_t interval) {
  static int8_t pos = 0;
  static uint16_t last_timer = 0;
  uint8_t i, j, cur;
  int8_t k;
  LED_TYPE preled[RGBLED_NUM];
  static int8_t increment = -1;
  if (timer_elapsed(last_timer) < pgm_read_byte(&RGBLED_KNIGHT_INTERVALS[interval])) {
    return;
  }
  last_timer = timer_read();
  for (i = 0; i < RGBLED_NUM; i++) {
    preled[i].r = 0;
    preled[i].g = 0;
    preled[i].b = 0;
    for (j = 0; j < RGBLIGHT_EFFECT_KNIGHT_LENGTH; j++) {
      k = pos + j * increment;
      if (k < 0) {
        k = 0;
      }
      if (k >= RGBLED_NUM) {
        k = RGBLED_NUM - 1;
      }
      if (i == k) {
        sethsv(rgblight_config.hue, rgblight_config.sat, rgblight_config.val, (LED_TYPE *)&preled[i]);
      }
    }
  }
  if (RGBLIGHT_EFFECT_KNIGHT_OFFSET) {
    for (i = 0; i < RGBLED_NUM; i++) {
      cur = (i + RGBLIGHT_EFFECT_KNIGHT_OFFSET) % RGBLED_NUM;
      led[i].r = preled[cur].r;
      led[i].g = preled[cur].g;
      led[i].b = preled[cur].b;
    }
  }
  rgblight_set();
  if (increment == 1) {
    if (pos - 1 < 0 - RGBLIGHT_EFFECT_KNIGHT_LENGTH) {
      pos = 0 - RGBLIGHT_EFFECT_KNIGHT_LENGTH;
      increment = -1;
    } else {
      pos -= 1;
    }
  } else {
    if (pos + 1 > RGBLED_NUM + RGBLIGHT_EFFECT_KNIGHT_LENGTH) {
      pos = RGBLED_NUM + RGBLIGHT_EFFECT_KNIGHT_LENGTH - 1;
      increment = 1;
    } else {
      pos += 1;
    }
  }
}


void rgblight_effect_christmas(void) {
  static uint16_t current_offset = 0;
  static uint16_t last_timer = 0;
  uint16_t hue;
  uint8_t i;
  if (timer_elapsed(last_timer) < RGBLIGHT_EFFECT_CHRISTMAS_INTERVAL) {
    return;
  }
  last_timer = timer_read();
  current_offset = (current_offset + 1) % 2;
  for (i = 0; i < RGBLED_NUM; i++) {
    hue = 0 + ((i/RGBLIGHT_EFFECT_CHRISTMAS_STEP + current_offset) % 2) * 120;
    sethsv(hue, rgblight_config.sat, rgblight_config.val, (LED_TYPE *)&led[i]);
  }
  rgblight_set();
}

#endif