Shadowrun SNES mouse script

-- Shadowrun SNES mouse script for BizHawk
-- Inspired by Gamachara's script for snes9x-rr which can be found
--  here: https://github.com/Gamachara/SNES-Shadowrun-Mouse-Script/)
-- Left click attacks, right click interacts, middle click casts spells.
-- Reload the script to toggle mouse control on or off.

function shadowrun_mouse()
    mouse = input.getmouse()
    if (mouse.X >= 0 and mouse.X < 256 and mouse.Y >= 0 and mouse.Y < 224) then
        if (memory.readbyte(0x0001F5) == 255) then
            offset = {X=0, Y=0}
            if (memory.readbyte(0x0001F4) == 0xFE) then
                -- Player has crosshair (attack) cursor selected
                offset = {X=-7, Y=-6}
            end

            x = math.max(3, math.min(mouse.X + offset.X, 239))
            y = math.max(3, math.min(mouse.Y + offset.Y, 206))
            memory.writebyte(0x0001F1, x)
            memory.writebyte(0x0001F3, y)
        end

        if (mouse.Left) then
            joypad.set({["P1 A"]=true})  -- Attack
        elseif (mouse.Right) then
            joypad.set({["P1 B"]=true})  -- Interact
        elseif (mouse.Middle) then
            joypad.set({["P1 X"]=true})  -- Cast
        end
     end
end

if (not event.unregisterbyname("Shadowrun mouse handler")) then
    event.onframestart(shadowrun_mouse, "Shadowrun mouse handler")
    console.log("* Mouse control on")
else
    console.log("* Mouse control off")
end