/miner/movement

directions={
  NORTH={0, 1},
  EAST={1, 0},
  SOUTH={0, -1},
  WEST={-1, 0},
  ORDER={"NORTH", "EAST", "SOUTH", "WEST"},
  indexOf=function(self, direction)
    for i, value in ipairs(self.ORDER) do
      if value==direction then
        return i
      end
    end
  end
}

directionX, directionY=unpack(directions.NORTH)
currentDirection=1 --NORTH=1, EAST=2, SOUTH=3, WEST=4
currentX, currentY, currentZ=0, 0, 0

function getCurrentCoordinates()
  return currentX, currentY, currentZ
end

function getCurrentDirection()
  return directions.ORDER[currentDirection]
end

function Stack()
  local stack={
    push=function(self, ...)
      for i, value in ipairs{...} do
        self[#self+1]=value
      end
    end,

    pop=function(self, count)
      local count = count or 1
      if count > #self then
        error("Stack underflow!")
      end

      local values={}
      for i=count, 1, -1 do
        values[#values+1]=table.remove(self)
      end

      return unpack(values)
    end
  }

  return setmetatable({}, {__index = stack})
end

function turnRight()
  turtle.turnRight()
  currentDirection=currentDirection+1

  if currentDirection > 4 then
    currentDirection=1
  end

  directionX, directionY=unpack(directions[directions.ORDER[currentDirection]])

  return turnLeft
end

function turnLeft()
  turtle.turnLeft()
  currentDirection=currentDirection-1

  if currentDirection < 1 then
    currentDirection=4
  end

  directionX, directionY=unpack(directions[directions.ORDER[currentDirection]])

  return turnRight
end

function forward()
  local success=turtle.forward()

  if success==false then
    return false
  end

  currentX=currentX+directionX
  currentY=currentY+directionY

  return true
end

function up()
  local success=turtle.up()

  if success==false then
    return false
  end

  currentZ=currentZ+1

  return true
end

function down()
  local success=turtle.down()

  if success==false then
    return false
  end

  currentZ=currentZ-1

  return true
end

turnAround=function()
  turnRight()
  turnRight()
end

function face(direction)
  local destinationDirection=directions:indexOf(direction)
  local offset=destinationDirection-currentDirection

  local turnFunction=turnRight
  if (offset < 1 and offset~=-3) or (offset > 1 and offset==3) then
    turnFunction=turnLeft
  end

  while currentDirection~=destinationDirection do
    turnFunction()
  end
end

function move(destinationX, destinationY, destinationZ)
  local dx=destinationX-currentX
  local dy=destinationY-currentY
  local dz=destinationZ-currentZ

  face("NORTH")

  local xDirection="WEST"
  if dx>0 then
    xDirection="EAST"
  end

  local yDirection="SOUTH"
  if dy>0 then
    yDirection="NORTH"
  end

  local zFunction=down
  if dz>0 then
    zFunction=up
  end

  while currentZ~=destinationZ do
    zFunction()
  end

  if dx~=0 then
    face(xDirection)
    while currentX~=destinationX do
      forward()
    end
  end

  if dy~=0 then
    face(yDirection)
    while currentY~=destinationY do
      forward()
    end
  end
end