Quarry32

x = 0
y = 0
z = 0
d = 0

print("Initiating preparation for a 32 by 32 Quarry")

function UpDig()
  for b = 1,4 do
    while turtle.detect() == true do
      turtle.dig()
    end
    if turtle.detect() == false then
      turtle.up()
      y = y + 1
    end
  end
end

function AdvanceAway()
  while turtle.detect() == true do
    turtle.dig()
  end
  if turtle.detect() == false then
    turtle.forward()
    x = x + 1
  end
end

function DownDig()
  for c = 1,4 do
    while turtle.detect() == true do
      turtle.dig()
    end
    if turtle.detect() == false then
      if turtle.detectDown() == true then
        turtle.digDown()
        turtle.down()
        y = y - 1
      else
        turtle.down()
        y = y - 1
      end
    end
  end
end

function GoLeft()
  turtle.turnLeft()
  d = 3
  for e = 1,4 do
    while turtle.detect() == true do
      turtle.dig()
    end
    if turtle.detect() == false then
      turtle.up()
      y = y + 1
    end
  end
  while turtle.detect() == true do
    turtle.dig()
  end
  if turtle.detect() == false then
    turtle.forward()
    z = z + 1
  end
  for f = 1,4 do
    if turtle.detectDown() == true then
      turtle.digDown()
      turtle.down()
      y = y - 1
    else
      turtle.down()
      y = y - 1
    end
  end
  turtle.turnLeft()
  d = 2
end

function AdvanceTowards()
  while turtle.detect() == true do
    turtle.dig()
  end
  if turtle.detect() == false then
    turtle.forward()
    x = x - 1
  end
end

function GoRight()
  turtle.turnRight()
  d = 3
  for h = 1,4 do
    while turtle.detect() == true do
      turtle.dig()
    end
    if turtle.detect() == false then
      turtle.up()
      y = y + 1
    end
  end
  while turtle.detect() == true do
    turtle.dig()
  end
  if turtle.detect() == false then
    turtle.forward()
    z = z + 1
  end
  for i = 1,4 do
    if turtle.detectDown() == true then
      turtle.digDown()
      turtle.down()
      y = y - 1
    else
      turtle.down()
      y = y - 1
    end
  end
  turtle.turnRight()
  d = 0
end

function InventoryCheck()
  if turtle.getItemCount(16) > 0 then
    print("High inventory variance. Unloading...")
    if d = 0 then
      turtle.turnRight()
      turtle.turnRight()
      if x > 0 then
        for j = 1,x do
          turtle.forward()
        end
      end
      turtle.turnLeft()
      if z > 0 then
        for k = 1,z do
          turtle.forward()
        end
      end
      turtle.turnRight()
    end
    if d = 2 then
      turtle.turnLeft()
      if z > 0 then
        for l = 1,z do
          turtle.forward()
        end
      end
      turtle.turnRight()
      if x > 0 then
        for m = 1,x do
          turtle.forward()
        end
      end
    end
    for n = 1,16 do
      turtle.select(n)
      turtle.drop()
    end
    turtle.select(1)
    if d = 0 then
      turtle.turnRight()
      if z > 0 then
        for o = 1,z do
          turtle.forward()
        end
      end
      turtle.turnRight()
      if x > 0 then
        for p = 1,x do
          turtle.forward()
        end
      end
    end
    if d = 2 then
      turtle.turnRight()
      turtle.turnRight()
      if x > 0 then
        for q = 1,x do
          turtle.forward()
        end
      end
      turtle.turnLeft()
      if z > 0 then
        for r = 1,z do
          turtle.forward()
        end
      end
      turtle.turnLeft()
    end
    print("Inventory emptied, returning to work...")
  end
end

function DiggingCycle()
  for a = 1,16 do
    UpDig()
    AdvanceAway()
    DownDig()
    InventoryCheck()
    AdvanceAway()
  end
  GoLeft()
  for g = 1,16 do
    UpDig()
    AdvanceTowards()
    DownDig()
    InventoryCheck()
    AdvanceTowards()
  end
  GoRight()
end

for s = 1,16 do
  DiggingCycle()
end
print("Quarry preparation complete.")