From 46f769043beb017f7a78b22e466537be71542bc1 Mon Sep 17 00:00:00 2001
From: Keiran <info@keiran.us>
Date: Wed, 27 Mar 2019 20:25:53 -0400
Subject: [PATCH] allow reverse

---
 suitleds-keiran.ino | 59 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 12 deletions(-)

diff --git a/suitleds-keiran.ino b/suitleds-keiran.ino
index 2ba9392..37560a0 100644
--- a/suitleds-keiran.ino
+++ b/suitleds-keiran.ino
@@ -16,6 +16,10 @@
 #define FACTORYRESET   true
 #define DIM_FACTOR     80
 
+#define SHIFTING_STOPPED 0
+#define SHIFTING_FORWARD 1
+#define SHIFTING_REVERSE 2
+
 // Updated with  bluetooth connection state
 volatile bool conn = false;
 
@@ -127,7 +131,8 @@ class Strip {
   uint8_t pin;
   uint8_t num_pixels;
   unsigned long last;
-  uint8_t offset;
+  uint8_t offset = num_pixels;
+  uint8_t shifting = SHIFTING_FORWARD;
   Adafruit_NeoPixel pixel;
 
   public:
@@ -153,14 +158,22 @@ class Strip {
     pixel.show();
   }
 
+  void set_shift_direction(uint8_t new_shift){
+    if (new_shift == SHIFTING_FORWARD){
+      // FIXME: convert offset
+    } else if (new_shift == SHIFTING_REVERSE){
+      // FIXME: convert offset
+    } else {
+      offset = 0;
+    }
+    shifting = new_shift;
+  }
+
   void update(void){
     unsigned long now = millis();
     if (now - wait > last){
       last = now;
-      offset += 1;
-      if (offset == num_pixels){
-        offset = 0;
-      }
+      add_offset();
     }
     if (pattern == 'o'){
       off();
@@ -170,19 +183,41 @@ class Strip {
   }
 
   private:
+  void add_offset(void){
+    /* Increments the offset counter. See get_offset_loc() */
+    offset++;
+    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 rainbow(void){
     uint8_t r = 255;
     uint8_t g = 0;
     uint8_t b = 0;
     pixel.begin();
     for (uint8_t index=0; index<num_pixels; index++){
-      uint8_t loc;
-      if (offset + index > num_pixels - 1){
-        loc = index + offset - num_pixels;
-      } else {
-        loc = offset + index;
-      }
-      pixel.setPixelColor(loc, pixel.Color(r/DIM_FACTOR, g/DIM_FACTOR, b/DIM_FACTOR));
+      pixel.setPixelColor(get_offset_loc(index), pixel.Color(r/DIM_FACTOR, g/DIM_FACTOR, b/DIM_FACTOR));
       if (index < 24){ // red -> yellow shifting
         g += 10;
       } else if (index < 48){ // yellow -> green shifting