Trying to make a woodchopper program but Im very new to programming

--[[This is my feller program for computercraft. Enjoy! Also Its my very first program so don't hate please...]]
local x, z, y = 0, 0, 0
function refuel() --[[This is for refueling the turtle. If false there is a message that the turtle needs more logs]]
local fuelLevel = turtle.getFuelLevel()
if fuelLevel < 30 then
  local invCountRefuel = turtle.getItemCount(1)
  turtle.select(1)
  if invCountRefuel > 2 then
   turtle.refuel(2)
   return(true)
  else
   return(false)
  end
end
end
function checkLeft()
turtle.turnLeft()
turtle.compare()
if turtle.compare() then
  turtle.dig()
  turtle.forward()
  x = x-1
  return (true)
else
  return (false)
end
end
function checkBack()
turtle.turnLeft()
turtle.compare()
if turtle.compare() then
  turtle.dig()
  turtle.forward()
  z = z-1
  return (true)
else
  return (false)
end
end
function checkRight()
turtle.turnLeft()
turtle.compare()
if turtle.compare() then
  turtle.dig()
  turtle.forward()
  x = x+1
  return (true)
else
  return (false)
end
end
function checkForward()
turtle.turnLeft()
turtle.compare()
if turtle.compare() then
  turtle.dig()
  turtle.forward()
  z = z+1
  return (true)
else
  return (false)
end
end
function check()
turtle.select(1)
checkLeft()
checkBack()
checkRight()
checkForward()
while checkLeft() or checkBack() or checkRight() or checkForward() do
  check()
end
return true
end
function chop() --[[This is to chop down the tree, it will first look for the tree and compare it to the log in invslot 1 then it will chop 1 log down, look on the sides if there are more logs, if there are none it will go up one block and repeat]]
while turtle.compare() do
  turtle.dig()
  turtle.forward()
  while turtle.compareUp() do
   check()
   if check() then
    if x > 0 then
	 turtle.turnLeft()
	 while x > 0 do
	  turtle.forward()
	  x = x-1
	 end
	 if z > 0 then
	  turtle.turnLeft()
	  while z > 0 do
	   turtle.forward()
	   z = z-1
	  end
	 end
	 if z < 0 then
	  turtle.turnRight()
	  while z < 0 do
	   turtle.forward()
	   z = z+1
	  end
	 end
    end
    elseif x < 0 then
	 turtle.turnRight()
	 while x < 0 do
	  turtle.forward()
	  x = x+1
	 end
	 if z < 0 then
	  turtle.turnLeft()
	  while z < 0 do
	   turtle.forward()
	   x = z+1
	  end
	 end
	 if z > 0 then
	  turtle.turnRight()
	  while z > 0 do
	   turtle.forward()
	   z = z-1
	  end
	 end
    end
    elseif z > 0 then
	 turtle.turnLeft()
	 turtle.turnLeft()
	 while z > 0 do
	  turtle.forward()
	  z = z-1
	 end
    end
    elseif z < 0 then
	 while z < 0 do
	  turtle.forward()
	  z = z+1
	 end
    end
    elseif z and x == 0 then
	 turtle.digUp()
	 turtle.up()
    end
   end
  end
end
end
function drop() --[[This function drops the items and returns true when finished]]
local invCounter = 1 --[[This one is make sure that the Item drop for loop was successful]]
turtle.turnLeft()
for i = 0, 15 do --[[After the turtle have turned left it checks if its first slot one, then it drops all logs except for 2 logs. 1 for fuel and 1 to make sure that there always is the right log in slot one]]
  local invCount(i) = turtle.getItemCount(i+1)
  if i == 0 then
   if invCount(0) > 3 then
    turtle.select(i+1)
    turtle.drop(invcount(0)-3)
   end
  else
   turtle.select(i+1)
   turtle.drop(invcount[i])
  end
  if itemCount(i) == 0 then
   invCounter = invCounter+1
  end
  if invCounter == 14 then --[[This is for the future, It counts all the slots and makes sure only one has 3 items in it, this should be slot 1]]
   turtle.turnRight()
   return(true)
  else
   return(false)
  end
end
end