Hammerspoon configuration with middle button scrolling and mouse scrollwheel reversal

init.lua

-- SETUP THE LOGGER
local log = hs.logger.new('macOS','debug')

-- HANDLE SCROLLING WITH MOUSE BUTTON PRESSED
local scrollMouseButton = 2
local deferred = false

overrideOtherMouseDown = hs.eventtap.new({ hs.eventtap.event.types.otherMouseDown }, function(e)
    -- log.d("down")
    local pressedMouseButton = e:getProperty(hs.eventtap.event.properties['mouseEventButtonNumber'])
    if scrollMouseButton == pressedMouseButton 
        then 
            deferred = true
            return true
        end
end)

overrideOtherMouseUp = hs.eventtap.new({ hs.eventtap.event.types.otherMouseUp }, function(e)
    -- log.d("up")
    local pressedMouseButton = e:getProperty(hs.eventtap.event.properties['mouseEventButtonNumber'])
    if scrollMouseButton == pressedMouseButton 
        then 
            if (deferred) then
                overrideOtherMouseDown:stop()
                overrideOtherMouseUp:stop()
                hs.eventtap.otherClick(e:location(), pressedMouseButton)
                overrideOtherMouseDown:start()
                overrideOtherMouseUp:start()
                return true
            end
            return false
        end
        return false
end)

local oldmousepos = {}
local scrollmult = -4   -- negative multiplier makes mouse work like traditional scrollwheel

dragOtherToScroll = hs.eventtap.new({ hs.eventtap.event.types.otherMouseDragged }, function(e)
    local pressedMouseButton = e:getProperty(hs.eventtap.event.properties['mouseEventButtonNumber'])
    -- log.d ("pressed mouse " .. pressedMouseButton)
    if scrollMouseButton == pressedMouseButton 
        then 
            -- log.d("scroll");
            deferred = false
            oldmousepos = hs.mouse.absolutePosition
            local dx = e:getProperty(hs.eventtap.event.properties['mouseEventDeltaX'])
            local dy = e:getProperty(hs.eventtap.event.properties['mouseEventDeltaY'])
            local scroll = hs.eventtap.event.newScrollEvent({-dx * scrollmult, -dy * scrollmult},{},'pixel')
            -- put the mouse back
            hs.mouse.absolutePosition = oldmousepos
            return true, {scroll}
        else 
            return false, {}
        end 
end)

overrideOtherMouseDown:start()
overrideOtherMouseUp:start()
dragOtherToScroll:start()

-- REVERSE SCROLLWHEEL WITHOUT AFFECTING TRACKPAD
reverseScrollWheel = hs.eventtap.new({ hs.eventtap.event.types.scrollWheel }, function(e)
    -- (I) Scrolling data. This field typically contains the change in vertical position since the
    -- last scrolling event from a Mighty Mouse scroller or a single-wheel mouse scroller.
    local da1 = e:getProperty(hs.eventtap.event.properties['scrollWheelEventDeltaAxis1'])
    log.d ("vert pos delta " .. da1)
    e:setProperty(hs.eventtap.event.properties['scrollWheelEventDeltaAxis1'], 0 - da1)

    -- (N) Contains scrolling data which represents a line-based or pixel-based change in vertical
    -- position since the last scrolling event from a Mighty Mouse scroller or a single-wheel mouse scroller.
    local fpda1 = e:getProperty(hs.eventtap.event.properties['scrollWheelEventFixedPtDeltaAxis1'])
    log.d ("line or pixel based vert pos delta " .. fpda1)
    e:setProperty(hs.eventtap.event.properties['scrollWheelEventFixedPtDeltaAxis1'], 0 - fpda1)

    -- (I) Pixel-based scrolling data. The scrolling data represents the change in vertical
    -- position since the last scrolling event from a Mighty Mouse scroller or a single-wheel mouse scroller.
    local pda1 = e:getProperty(hs.eventtap.event.properties['scrollWheelEventPointDeltaAxis1'])
    log.d ("pixel based vert pos delta " .. pda1)
    e:setProperty(hs.eventtap.event.properties['scrollWheelEventPointDeltaAxis1'], 0 - pda1)

    return false
end)

reverseScrollWheel:start()

-- LOAD SPOON TO ALLOW MANUAL WINDOW POSITIONING
--   the values for the hotkeys below are the same as spoon.WindowHalfsAndThirds.defaultHotkeys
hs.loadSpoon("WindowHalfsAndThirds")
spoon.WindowHalfsAndThirds:bindHotkeys({
    left_half   = { {"ctrl",        "cmd"}, "Left" },
    right_half  = { {"ctrl",        "cmd"}, "Right" },
    top_half    = { {"ctrl",        "cmd"}, "Up" },
    bottom_half = { {"ctrl",        "cmd"}, "Down" },
    third_left  = { {"ctrl", "alt"       }, "Left" },
    third_right = { {"ctrl", "alt"       }, "Right" },
    third_up    = { {"ctrl", "alt"       }, "Up" },
    third_down  = { {"ctrl", "alt"       }, "Down" },
    top_left    = { {"ctrl",        "cmd"}, "1" },
    top_right   = { {"ctrl",        "cmd"}, "2" },
    bottom_left = { {"ctrl",        "cmd"}, "3" },
    bottom_right= { {"ctrl",        "cmd"}, "4" },
    max_toggle  = { {"ctrl", "alt", "cmd"}, "f" },
    max         = { {"ctrl", "alt", "cmd"}, "Up" },
    undo        = { {        "alt", "cmd"}, "z" },
    center      = { {        "alt", "cmd"}, "c" },
    larger      = { {        "alt", "cmd", "shift"}, "Right" },
    smaller     = { {        "alt", "cmd", "shift"}, "Left" },
 })