clear

-- clear
-- Mines a clear space to the dimensions supplied by the user
-- Turtle returns to its starting point when mission is completed or fuel runs low
-- Written by HarvDad, March 2014	Last update: May 22, 2014

args = {...}
nArgs = #args

print("clear: Rev 6.0")
x = 0
y = 0
z = 0
gX = x
gZ = z
face = 0
minimumFuel = 100
missionMessage = "Mission complete."
abort = false
local currentFuelLevel = turtle.getFuelLevel()
lowestLevel = 0
highestLevel = 0

if nArgs == 0 or (nArgs == 1 and args[1]== "help") then
	print("Clear an area specified by the given length, width, and height")
    print("Usage: clear <length><width><height>")
	return
end

if nArgs ~= 3 then
  print("Usage: clear <length><width><height>")
  return
end

length = tonumber(args[1])
if length == nil then
  print("\"", args[1], "\" is not a valid length")
  return
end
if length < 1 then
  print("length must be a positive number greater than zero")
end

width = tonumber(args[2])
if width == nil then
  print("\"", args[2], "\" is not a valid width")
  return
end
if width < 1 then
  print("width must be a positive number greater than zero")
end

height = tonumber(args[3])
if height == nil then
  print("\"", args[3], "\" is not a valid height")
  return
end
--[[
if height < 1 then
  print("height must be a positive number greater than zero")
end
--]]

if height > 0 then
	highestLevel = height - 1
	lowestLevel = 0
elseif height < 0 then
	highestLevel = 0
	lowestLevel = 0 + height
else
	highestLevel = 0
	lowestLevel = 0
end

print("highestLevel = ", highestLevel, ", lowestLevel = ", lowestLevel)

targetArea = length * width
areaCovered = 1;

function chomp()
--	if y < highestLevel and turtle.detectUp() then
	if y < top then
		turtle.digUp()
	end
--	if turtle.detect() then
--		turtle.dig()
--	end

--	if y > 0 then
	if y > bottom then
		if turtle.detectDown() then
			turtle.digDown()
		end
	elseif y < 0 then
		if turtle.detectUp() then
			turtle.digUp()
		end
	end

	areaCovered = areaCovered+1
end

direction = "left"

local clock = os.clock
function sleep(n)  -- seconds
  local t0 = clock()
    while clock() - t0 <= n do end
end

function left()
 if face == 0 then face = 1 turtle.turnLeft() return end
 if face == 1 then face = 2 turtle.turnLeft() return end
 if face == 2 then face = 3 turtle.turnLeft() return end
 if face == 3 then face = 0 turtle.turnLeft() return end
 print("function left\(\): Bad face value: ", face)
end

function right()
 if face == 0 then face = 3 turtle.turnRight() return end
 if face == 1 then face = 0 turtle.turnRight() return end
 if face == 2 then face = 1 turtle.turnRight() return end
 if face == 3 then face = 2 turtle.turnRight() return end
 print("function right\(\): Bad face value: ", face)
end

function up()
	while turtle.detectUp() do	-- This loop added in case of falling sand or whatever
	  turtle.digUp()
	end
  turtle.up()
  y = y+1
end

function rise(nBlocks)
  local i
  for i=1,nBlocks do
    up()
  end
end

function down()
  if turtle.detectDown() then
    turtle.digDown()
  end
  turtle.down()
  y = y-1
end

function turn()
  if direction == "left" then
    left()
  else
    right()
  end
  if areaCovered < targetArea then
	  forward()
  end
-- chomp()
  if direction == "left" then
	left()
  	direction = "right"
  else
	right()
    direction = "left"
  end
end

function forward()
	while turtle.detect() do	-- This loop added in case of falling sand or whatever
		turtle.dig()
--		chomp()
	end
	for i=1,10 do
		if turtle.forward() then
			chomp()
			break
		end
		turtle.attack()
		sleep(2)
	end
  	if face == 0 then z = z+1 return end
  	if face == 1 then x = x-1 return end
  	if face == 2 then z = z-1 return end
  	if face == 3 then x = x+1 return end
end

function setFace(f)
	if f == 0 then
	  if face == 0 then return end
	  if face == 1 then right() return end
	  if face == 2 then right() right() return end
	  if face == 3 then left() return end
	end

	if f == 1 then
	  if face == 0 then left() return end
	  if face == 1 then return end
	  if face == 2 then right() return end
	  if face == 3 then right() right() return end
	end

	if f == 2 then
	  if face == 0 then left() left() return end
	  if face == 1 then left() return end
	  if face == 2 then return end
	  if face == 3 then right() return end
	end

	if f == 3 then
	  if face == 0 then right() return end
	  if face == 1 then left() left() return end
	  if face == 2 then left() return end
	  if face == 3 then return end
	end
end

function home(targetY)
--  print("home:face ", face, ", x = ", x, ", z = ", z)
  if x < 0 then
	setFace(3)
	while x < 0 do
	  forward()
	end
  else
    if x > 0 then
  	  setFace(1)
	  while x > 0 do
	    forward()
	  end
    end
  end

  if z < 0 then
	setFace(0)
	while z < 0 do
	  forward()
	end
  else
    if z > 0 then
  	  setFace(2)
	  while z > 0 do
	    forward()
	  end
    end
  end
  setFace(0)

--  print("home: y = ", y, ", targetY = ", targetY)

  if (targetY == 0) then
  	if y > 0 then
		while y > 0 do
			down()
		end
	elseif y < 0 then
		while y < 0 do
			up()
		end
	end
  end
end

function xzHome()
	local X = gX
	local Z = gZ

	if x ~= X then
		if x < X then
			setFace(east)
			while x < X do
				forward()
			end
		else
			setFace(west)
			while x > X do
				forward()
			end
		end
	end

	if z ~= Z then
		if z < Z then
			setFace(north)
			while z < Z do
				forward()
			end
		else
			setFace(south)
			while z > Z do
				forward()
			end
		end
	end
end

function strip(nBlocks)
  local i
  print("strip ", nBlocks)
  for i=1,nBlocks do
	checkFuel()
	if abort then
	  areaCovered = targetArea
	end

--    print("strip: Cleared ", areaCovered, " out of ", targetArea, " blocks")
	if areaCovered <= targetArea then
	  forward()
	end
  end
end


function checkFuel()
	if currentFuelLevel == "unlimited" then
		return true
	end

	if currentFuelLevel < minimumFuel then
	  if not turtle.refuel() then
		  areaCovered = targetArea
		  missionMessage = "Mission aborted due to low fuel."
		  abort = true
	    return false
	  end
	end
  return true
end

function goToLevel(level)
	if y < level then
		while y < level do
			up()
		end
	elseif y > level then
		while y > level do
			down()
		end
	end
end

function nextLevel()
	if y > 3 then
		return y - 3
	else
		return 0
	end
end

function goToNextLevel()
	if height > 0 then
		if y > 3 then
			goToLevel(y - 3)
		else
			goToLevel(bottom)
		end
	elseif height < 0 then
		if y >= bottom + 3 then
			goToLevel(y - 3)
		else
			goToLevel(bottom)
		end
	end
end

-- MAIN PROGRAM

currentLevel = y

turtle.select(1)

print("fuelLevel = ", currentFuelLevel)
print("length = ", length)
print("width = ", width)
print("height = ", height)
print("face = ", face)

print("Current Fuel Level: ", currentFuelLevel)

if currentFuelLevel ~= "unlimited" then
	if currentFuelLevel < minimumFuel then
		if not turtle.refuel() then
		  print("No fuel")
		  return
		end
	end
end




if height > 0 then
	top = height - 1
	bottom = 0

	if height > 2 then
		topLevel = height - 2
	else
		topLevel = 0
	end

	if height % 3 == 0 then
		lowestLevel = 1
	else
		lowestLevel = 0
	end
elseif height < 0 then
	top = 0
	bottom = height + 1

	if height < -2 then
		topLevel = -2
	else
		topLevel = 0
	end

	if height % 3 == 0 then
		lowestLevel = -1
	else
		lowestLevel = height + 1
	end
end


print("top = ", top, ", bottom = ", bottom)
print("topLevel = ", topLevel, ", lowestLevel = ", lowestLevel)

goToLevel(topLevel)

done = false

chomp()
while not done do
	for w=1,width do
		if w == width then
			strip(length)
		else
			strip(length-1)
		end
		--    print("strip: Cleared ", areaCovered, " out of ", targetArea, " blocks")
		if areaCovered < targetArea then
			turn()
		end
		if abort then
			print("Aborting...")
			home(0)
		end
	end
	home(99)
	direction = "left"
	areaCovered = 1;
	print("y = ", y, ", lowestLevel = ", lowestLevel)
	if height > 0 then
		if y <= lowestLevel then
			done = true
		else
			goToNextLevel()
		end
	elseif height < 0 then
		if y == lowestLevel + 1 or y == lowestLevel then
			done = true
			print("That's it.  It's over.")
		else
			goToNextLevel()
		end
	end
end

print(missionMessage, " Current fuel level is ", turtle.getFuelLevel())
home(0)