startup

local m = peripheral.wrap "back"

function groundDistance(meta)
    local blocks = m.scan()
    for y = 0, -8, -1 do
        local block = blocks[1 + (8 + (8 + y)*17 + 8*17^2)]

        if block.name ~= "minecraft:air" then
            return -y
        end
    end

    return 8
end

function normalFly(meta)
    m.launch(meta.yaw, meta.pitch, 3)
end

while true do
    local meta = m.getMetaOwner()

    if groundDistance(meta) < 8 and meta.motionY < -0.1 then
        m.launch(0, 270, math.min(4, math.abs(meta.motionY)))
    end

    if meta.isSneaking then
        normalFly(meta)
    end
end