local tArgs = {...}

local tarX, tarY, tarZ = unpack(tArgs)

tarX = tonumber(tarX)
tarY = tonumber(tarY)
tarZ = tonumber(tarZ)

local function round(a) --round to integer
  return math.floor(a+0.5)
end

local function F(a, x) --this is the parabola function
  return math.floor(0.5+((3*x*(a+58)*(a-x))/(a^2)))
end

local function refill() --refill the launcher
  turtle.suckUp()
  turtle.forward()
  turtle.dropDown()
  turtle.back()
end

local launcher = peripheral.wrap("bottom")

--home coordinates
local homeX = 969
local homeY = 4
local homeZ = 654

--get the distance to target using pythagoras' theorem
local dist = math.sqrt((tarX-homeX)^2+(tarZ-homeZ)^2)

local a = dist

if tarY > homeY then --aim further away
  while (tarY-homeY) > F(a, dist) do
    a = a+1
  end
elseif tarY < homeY then --aim closer
  while (tarY - homeY) < F(a, dist) do
  a = a-1
  end
else --don't need to adjust
  a = dist
end


print("dist = "..dist)
print("a = "..a)

-- fancy math :D
tarX = homeX+(a/dist)*(tarX-homeX)
tarZ = homeZ+(a/dist)*(tarZ-homeZ)

print("Aiming at "..round(tarX).."/0/"..round(tarZ))
launcher.setTarget(round(tarX), 0, round(tarZ))
launcher.launch()
sleep(1)
refill()