Add AutoMuteOnSleep (#267)

* Add AutoMuteOnWake

* Convert tabs to spaces

* Add trailing space

* Misc improvements

– Mute on `systemWillSleep` as well. This makes sure that sound doesn't play for a split second on wake. Also makes it more robust since we're muting all devices twice (if one of the two events doesn't trigger properly for example).
– Set the volume to `0`, and only actually mute if setting the volume to 0 failed. It's more convenient to increase the volume starting from 0 in my experience than restoring the previous sound level.

* Rename spoon to AutoMuteOnSleep

* AutoMuteOnWake → AutoMuteOnSleep

* Update init.lua

Source/AutoMuteOnSleep.spoon/init.lua

@@ -0,0 +1,47 @@
+--- === AutoMuteOnSleep ===
+---
+--- Automatically set to 0 the volume of all output audio devices except Bluetooth devices when Mac goes to sleep.
+--- Useful to avoid blasting sound when opening a Macbook in the public transport.
+--- Note: This is primarily intended for portable Mac devices, which have internal speakers.
+---
+--- Download: [https://github.com/Hammerspoon/Spoons/raw/master/Spoons/AutoMuteOnSleep.spoon.zip](https://github.com/Hammerspoon/Spoons/raw/master/Spoons/AutoMuteOnSleep.spoon.zip)
+
+
+local obj={}
+obj.__index = obj
+
+-- Metadata
+obj.name = "AutoMuteOnSleep"
+obj.version = "1.0"
+obj.author = "devnoname120 <[email protected]"
+obj.homepage = "https://github.com/Hammerspoon/Spoons"
+obj.license = "MIT - https://opensource.org/licenses/MIT"
+
+obj.sleepWatcher = nil
+
+local function muteNonBluetoothOutputDevices(state)
+    if state == hs.caffeinate.watcher.systemDidWake or state == hs.caffeinate.watcher.systemWillSleep then
+        local devices = hs.audiodevice.allOutputDevices()
+
+        for _, device in ipairs(devices) do
+            if device and device:transportType() ~= 'Bluetooth' then
+                _ = device:setVolume(0) or device:setMuted(true)
+            end
+        end
+    end
+end
+
+
+function obj:init()
+    self.sleepWatcher = hs.caffeinate.watcher.new(muteNonBluetoothOutputDevices)
+end
+
+function obj:start()
+    self.sleepWatcher:start()
+end
+
+function obj:stop()
+    self.sleepWatcher:stop()
+end
+
+return obj