Metroid Fusion - Eyedoor Script

rns = { 13, 2, 6, 8, 7, 9, 14, 10, 2, 4, 14, 4, 12, 15, 13, 12, 11, 1, 3, 15, 0, 6, 7, 8, 11, 5, 0, 3, 5, 1, 9, 10 }
timers = { }

function Calculate(num, counter, index, enemyX, enemyY)
    local frame
    local enRN

    -- determine when it will open
    if num == 0 then
        timers[0] = memory.readbyte(0x300016E + index*56)
    else
        frame = counter + timers[num-1]
        enRN = rns[((frame + bit.rshift(frame, 4) + index + enemyX + enemyY) % 32) + 1]
        timers[num] = timers[num-1] + 61 + enRN * 4
    end

    -- determine if it will shoot
    frame = counter + timers[num] + 7
    enRN = rns[((frame + bit.rshift(frame, 4) + index + enemyX + enemyY) % 32) + 1]

    -- display
    gui.text(3, 19 + num*8, timers[num])

    if enRN <= 6 then
        gui.text(20, 19 + num*8, "O", "green")
    else
        gui.text(20, 19 + num*8, "X", "red")
    end
end

while true do

    local index = -1
    local pose

    for i=0,23 do
        local id = memory.readbyte(0x300015D + i*56)
        if id >= 0x8F and id <= 0x9E then
            index = i
            pose = memory.readbyte(0x3000164 + index*56)
            break
        end
    end

    if index ~= -1 and pose < 0x58 then
        -- display eyedoor activation region
        local cameraX, cameraY = memory.readword(0x3001228), memory.readword(0x300122A)
        local enemyX, enemyY = memory.readword(0x3000144 + index*56), memory.readword(0x3000142 + index*56)

        local xStart = bit.arshift(enemyX - 0x1C0 - cameraX, 2)
        local yStart = bit.arshift(enemyY - 0x80 - cameraY, 2)
        local xEnd = bit.arshift(enemyX + 0x1C0 - cameraX, 2)
        local yEnd = bit.arshift(enemyY + 0x80 - cameraY, 2)

        gui.box(xStart, yStart, xEnd, yEnd, "#00F00020", "#20C020")

        -- check if in range
        local samusX, samusY = memory.readword(0x300125A), memory.readword(0x300125C)
        if math.abs(samusX - enemyX) < 0x1C0 and math.abs(samusY - enemyY) < 0x80 then
            gui.text(3, 11, "In", "green")
        else
            gui.text(3, 11, "Out", "red")
        end

        if pose >= 0x18 and pose <= 0x20 then
            -- eyedoor is open
            local timer = memory.readbyte(0x300016E + index*56)
            gui.text(3, 19, timer)
        else
            -- calculate when eyedoor will open
            local counter = memory.readword(0x3000002)
            for n=0,3 do
                Calculate(n, counter, index, enemyX, enemyY)
            end
        end
    end

    vba.frameadvance()

end