Add backlight percentage indicator to i3 status wrapper

i3wrapper.py

@@ -5,14 +5,14 @@ import json
 _BITS = []
 
 
-def _bit(idx, name):
+def _bit(idx):
     def wrapper(func):
-        _BITS.append([idx, name, func])
+        _BITS.append([idx, func.__name__.replace('_', ''), func])
         return func
     return wrapper
 
 
-@_bit(6, 'mem')
+@_bit(6)
 def _mem():
     with open('/proc/meminfo') as meminfo_fp:
         attrs = {}
@@ -30,6 +30,21 @@ def _mem():
         return 'M:{}%'.format(used), color
 
 
+@_bit(0)
+def _backlight(dev_dir='/sys/class/backlight/intel_backlight'):
+    with open('{}/brightness'.format(dev_dir)) as br_fp:
+        with open('{}/max_brightness'.format(dev_dir)) as mb_fp:
+            value = int(br_fp.read().strip())
+            max_value = int(mb_fp.read().strip())
+            pct = int(float(float(value) / float(max_value)) * 100)
+            color = None
+            if pct >= 75:
+                color = '#ffaa00'
+            if pct <= 25:
+                color = '#5599ff'
+            return '☼:{}%'.format(pct), color
+
+
 def _print_line(message):
     sys.stdout.write(message + '\n')
     sys.stdout.flush()