chop

local function up(x)
  repeat
    x=x-1
    while not turtle.up() do
      print("Failed to move UP")
      sleep(0.2)
    end
  until x==0
end

local function down(x)
  repeat
    x=x-1
    while not turtle.down() do
      print("Failed to move DOWN")
      sleep(0.2)
    end
  until x==0
end

local function forward(x)
  repeat
    x=x-1
    while not turtle.forward() do
      print("Failed to move FORWARD")
      sleep(0.2)
    end
  until x==0
end

local function back(x)
  repeat
    x=x-1
    while not turtle.back() do
      print("Failed to move BACK")
      sleep(0.2)
    end
  until x==0
end

local function left(x)
  repeat
    x=x-1
    turtle.turnLeft()
  until x==0
end

local function right(x)
  repeat
    x=x-1
    turtle.turnRight()
  until x==0
end

local function fuel()
  if turtle.getFuelLevel() < 1000 then do
    turtle.select(1)
    turtle.refuel(10)
    end
  end
end

local function fell()
  forward(10)
  right(1)
  turtle.select(2)
  while not turtle.compare() do
    print("Tree not grown yet")
    sleep(5.0)
  end
  turtle.dig()
  forward(1)
  while turtle.compare() do
    turtle.dig()
    turtle.digUp()
    up(1)
  end
  fuel()
  left(1)
  turtle.dig()
  forward(1)
  right(1)
  while turtle.compareDown() do
    turtle.digDown()
    down(1)
    turtle.dig()
  end
  fuel()
end

local function plant()
  up(1)
  turtle.select(3)
  x=2
  repeat
    x=x-1
    turtle.placeDown()
    forward(1)
    right(1)
  until x==0
  turtle.placeDown()
  forward(1)
  turtle.placeDown()
  forward(1)
  down(1)
  left(1)
  forward(10)
  left(1)
  turtle.suck(4)
  left(1)
  fuel()
end

local function drop()
  for i=4,16 do
    turtle.select(i)
    p = turtle.getItemCount(i)
    turtle.dropDown(p-1)
  end
end

local function suck()
  turtle.select(1)
  turtle.suckDown()
end

local function supply()
  left(1)
  up(4)
  forward(24)
  left(1)
  forward(12)
  down(1)
  left(1)
  drop()
  forward(6)
  right(1)
  forward(1)
  left(1)
  suck()
  forward(15)
  left(1)
  forward(13)
  right(1)
  forward(3)
  down(3)
  left(1)
  fuel()
end

local function program()
  y=1
  repeat
    fell()
    plant()
    supply()
  until y==2
end


function stopLoop()
    repeat
      local ev, key = os.pullEvent('key')
    until key == keys.backspace
    y=2
end

parallel.waitForAll(stopLoop, program)