tap.lua

local logger = hs.logger.new('taps', 'info')
local inspect = hs.inspect.inspect

-- Constants
local ONLY_LEFT_CMD = 1048584
local ONLY_RIGHT_CMD = 1048592
local ONLY_LEFT_ALT = 524320
local ONLY_RIGHT_ALT = 524352
local last_flags = 0

-- TODO: Fn+b - toggle bluetooth
-- TODO: Fn+w - toggle wifi

local function resetFlags(event)
   --local flags, data = event:getFlags(), event:getRawEventData()
   -- logger:d(inspect(flags), inspect(data))
   last_flags = 0
end

local bindings = {}

local function handleKeyUp(event)
   -- local flags, data = event:getFlags(), event:getRawEventData()
   -- logger:d(inspect(flags), inspect(data))
   last_flags = 0
   local mods = {}
   for key, state in pairs(event:getFlags()) do
      if state then table.insert(mods, key) end
   end
   table.sort(mods)
   table.insert(mods, tostring(event:getKeyCode()))
   local scmd = table.concat(mods, '+')

   local binding = bindings[scmd]
   if binding then
      local handler, options = binding[1], binding[2]
      if event:getType() == hs.eventtap.event.types.keyUp then
         handler(event)
      end
      return options and options.override, {}
   end
end

local function handleFlagsChanged(event)
   local flags = event:getRawEventData().CGEventData.flags
   -- logger:d('flags changed: %d', tostring(flags))
   if flags ~= 0 or last_flags == 0 then
      last_flags = flags
      return
   end
   if last_flags == ONLY_LEFT_CMD then
      hs.keycodes.setLayout('U.S.')
      -- logger:d('setting layout to U.S.')
   elseif last_flags == ONLY_RIGHT_CMD then
      hs.keycodes.setLayout('Russian')
      -- logger:d('setting layout to Russian')
   elseif last_flags == ONLY_RIGHT_ALT then
      hs.application.launchOrFocus('/Applications/Emacs.app')
      -- logger:d('switching to emacs')
   end
end
local flagsTap = hs.eventtap.new({hs.eventtap.event.types.flagsChanged}, handleFlagsChanged)
local keyUpTap = hs.eventtap.new(
   {
      hs.eventtap.event.types.keyUp,
      hs.eventtap.event.types.keyDown,
   },
   handleKeyUp
)
local otherEventsTap = hs.eventtap.new(
   {
      hs.eventtap.event.types.leftMouseDown,
      hs.eventtap.event.types.rightMouseDown,
      hs.eventtap.event.types.leftMouseUp,
      hs.eventtap.event.types.rightMouseUp,
   },
   resetFlags
)

flagsTap:start()
otherEventsTap:start()
keyUpTap:start()


local function bind(key, handler, options)
   bindings[key] = {handler, options}
end

-- FIXME Does not handle propagation properly
bind('fn+11', function(event)
        hs.alert('fn+b')
end, {override=true})