[modules/battery] Incorporate @yvesh's estimated time remaining

Move changes proposed by @yvesh to show the remaining battery time into
the battery module.

see #146

bumblebee/modules/battery.py

@@ -17,6 +17,11 @@ import bumblebee.output
 import bumblebee.engine
 import bumblebee.util
 
+try:
+    import power
+except ImportError:
+    pass
+
 class Module(bumblebee.engine.Module):
     def __init__(self, engine, config):
         widgets = []
@@ -28,6 +33,7 @@ class Module(bumblebee.engine.Module):
             self._batteries = [ "/sys/class/power_supply/{}".format(b) for b in self._batteries ]
         if len(self._batteries) == 0:
             self._batteries = [ "/sys/class/power_supply/BAT0" ]
+        self._estimate = "n/a"
         self.update(widgets)
         engine.input.register_callback(self, button=bumblebee.input.LEFT_MOUSE,
             cmd="gnome-power-statistics")
@@ -44,6 +50,24 @@ class Module(bumblebee.engine.Module):
         for widget in new_widgets:
             widgets.append(widget)
         self._widgets = widgets
+        if bumblebee.util.asbool(self.parameter("showremaining", False)):
+            self._widgets.append(bumblebee.output.Widget(full_text=self.remaining))
+            self._widgets[-1].set("type", "remaining")
+            try:
+                type = power.PowerManagement().get_providing_power_source_type()
+                estimate = power.PowerManagement().get_time_remaining_estimate()
+
+                if type == power.POWER_TYPE_AC and estimate == -2.0:
+                    self._estimate = "Unlimited"
+                elif estimate == -1.0:
+                    self._estimate = "Unknown"
+                else:
+                    self._estimate = str(round(estimate / 60, 1)) + ' h'
+            except Exception as e:
+                self._estimate = "n/a"
+
+    def remaining(self, widget):
+        return str(self._estimate)
 
     def capacity(self, widget):
         widget.set("capacity", -1)
@@ -68,6 +92,12 @@ class Module(bumblebee.engine.Module):
 
     def state(self, widget):
         state = []
+
+        if widget.get("type", "battery") == "remaining":
+            if self._estimate == "Unlimited":
+                return "unlimited"
+            return "estimate"
+
         capacity = widget.get("capacity")
 
         if capacity < 0:

themes/icons/awesome-fonts.json

@@ -75,7 +75,9 @@
 		"discharging-25": { "prefix": "", "suffix": "" },
 		"discharging-50": { "prefix": "", "suffix": "" },
 		"discharging-80": { "prefix": "", "suffix": "" },
-		"discharging-100": { "prefix": "", "suffix": "" }
+		"discharging-100": { "prefix": "", "suffix": "" },
+		"unlimited": { "prefix": "", "suffix": "" },
+		"estimate": {	"prefix": ""  }
 	},
 	"caffeine": {
 		"activated": {"prefix": " " }, "deactivated": { "prefix": " " }