bat: find battery status when multiple batteries

Battery status was previously assumed to the first battery's status. This is
wrong as it doesn't support the case where the first battery is full and the
second is discharging, therefor showing battery percentage to 100% when the
actual battery percentage is lower.

widgets/bat.lua

@@ -108,7 +108,16 @@ local function worker(args)
             end
         end
 
+        -- When one of the battery is charging, others' status are either
+        -- "Full", "Unknown" or "Charging". When the laptop is not plugged in,
+        -- one or more of the batteries may be full, but only one battery
+        -- discharging suffices to set global status to "Discharging".
         bat_now.status = bat_now.n_status[1]
+        for _,status in ipairs(bat_now.n_status) do
+            if status == "Discharging" or status == "Charging" then
+                bat_now.status = status
+            end
+        end
         bat_now.ac_status = tonumber(first_line(string.format("%s%s/online", pspath, ac))) or "N/A"
 
         if bat_now.status ~= "N/A" then