--- === ControlEscape ===
---
--- Adapted very loosely from https://github.com/jasonrudolph/ControlEscape.spoon
--- Removed timing/delay; always send Escape as well as Control
---
--- Make the `control` key more useful: If the `control` key is tapped, treat it
--- as the `escape` key. If the `control` key is held down and used in
--- combination with another key, then provide the normal `control` key
--- behavior.

local obj={}
obj.__index = obj

-- Metadata
obj.name = 'ControlEscape'
obj.version = '0.1'
obj.author = 'Jason Rudolph <jason@jasonrudolph.com>'
obj.homepage = 'https://github.com/jasonrudolph/ControlEscape.spoon'
obj.license = 'MIT - https://opensource.org/licenses/MIT'

function obj:init()
  self.movements = 0
  self.sendEscape = false
  self.lastModifiers = {}

  -- Create an eventtap to run each time the modifier keys change (i.e., each
  -- time a key like control, shift, option, or command is pressed or released)
  self.controlTap = hs.eventtap.new({hs.eventtap.event.types.flagsChanged},
    function(event)
      local newModifiers = event:getFlags()

      -- If this change to the modifier keys does not involve a *change* to the
      -- up/down state of the `control` key (i.e., it was up before and it's
      -- still up, or it was down before and it's still down), then don't take
      -- any action.
      if self.lastModifiers['ctrl'] == newModifiers['ctrl'] then
        return false
      end

      -- Control was not down but is now
      if not self.lastModifiers['ctrl'] then
        self.lastModifiers = newModifiers
        if (not self.lastModifiers['cmd'] and not self.lastModifiers['alt']) then
          self.sendEscape = true
          self.movements = 0
        end
      -- Control was down and is up, hasn't been blocked by another key, and
      -- isn't above the movement threshold
      elseif (self.sendEscape == true and not newModifiers['ctrl'] and self.movements < 12) then
        self.lastModifiers = newModifiers
        -- Allow for shift-escape
        if newModifiers['shift'] then
          hs.eventtap.keyStroke({'shift'}, 'escape', 0)
        else
          hs.eventtap.keyStroke(newModifiers, 'escape', 0)
        end
        self.sendEscape = false
        self.movements = 0
      else
        self.lastModifiers = newModifiers
      end
    end
  )

  -- If any other key is pressed, don't send escape
  self.asModifier = hs.eventtap.new({hs.eventtap.event.types.keyDown},
    function(event)
      self.sendEscape = false
    end
  )

  -- If mouse is moving significantly, don't send escape
  self.scrolling = hs.eventtap.new({hs.eventtap.event.types.gesture},
    function(event)
      local touches = event:getTouches()
      local i, v = next(touches, nil)
      while i do
        if v["phase"] == "moved" then
          -- Increment the movement counter
          self.movements = self.movements + 1
        end
        i, v = next(touches, i)  -- get next index
      end
    end
  )
end

--- ControlEscape:start()
--- Method
--- Start sending `escape` when `control` is pressed and released in isolation
function obj:start()
  self.controlTap:start()
  self.asModifier:start()
  self.scrolling:start()
end

--- ControlEscape:stop()
--- Method
--- Stop sending `escape` when `control` is pressed and released in isolation
function obj:stop()
  -- Stop monitoring keystrokes
  self.controlTap:stop()
  self.asModifier:stop()
  self.scrolling:stop()

  -- Reset state
  self.sendEscape = false
  self.lastModifiers = {}
end

return obj