builder

function readFile(fileName)
  file = assert(fs.open(fileName, "r"))
  for i=1,9 do
    qtysReq[i]=0
  end
  level=1
  row=1
  column=1
  if ( file ) then
    line = file.readAll()
    plan[level] = {}
    plan[level][row] = {}
    i=1
    while ( i <= string.len(line) ) do
      char = string.sub(line, i,i)
      if ( char == "\n" ) then
        if ( string.sub(line, i+1,i+1) == "\n" ) then
          level = level + 1
          row = 1
          column = 1
          plan[level] = {}
          plan[level][row] = {}
          i=i+1
        else
          row=row+1
          column = 1
          plan[level][row] = {}
        end
      else
        plan[level][row][column] = tonumber(char)
        if ( tonumber(char) ~= 0 ) then
          qtysReq[tonumber(char)] = qtysReq[tonumber(char)] + 1
        end
        column = column + 1
      end
      i = i + 1
    end
    file.close()
  else
    io.write("Error reading file")
    os.exit()
  end
  getSubsitutes()
  for i = 1,table.getn(qtysReq) do
    if ( qtysReq[i] ~= 0 ) then
      qty = 0
      io.write("slot " .. i .. " requires " .. qtysReq[i] .. " blocks")
      for j = 1,#subs[i] do
        qty = qty + turtle.getItemCount(subs[i][j])
      end
      if ( qtysReq[i] > qty ) then
        io.write(", only " .. qty .. " found, a refill will be required")
      else
        io.write(", sufficient blocks in subsitute slots")
      end
      io.write("\n")
    end
  end
  return plan
end

function getSubsitutes()
  k=1
  for i = 1,16 do
    if ( qtysReq[i] == nil or qtysReq[i] == 0 ) then
      if ( turtle.getItemCount(i) > 0 ) then
        availSlots[k] = i
        k = k + 1
      else
        if ( freeSlot == 0 ) then
          freeSlot = i
        end
      end
    else
    end
  end
  for i = 1, #qtysReq do
    if ( qtysReq[i] > 0 ) then
      turtle.select(i)
      k=2
      subs[i]={}
      subs[i][1]=i
      for j = 1, #availSlots do
        if ( turtle.compareTo(availSlots[j])) then
          subs[i][k] = availSlots[j]
          k = k + 1
        end
      end
    end
  end
end

function move(direction, count)
  if ( checkFuel() ) then
    io.write("Insufficient Fuel, please place fuel in slot 16")
    while ( not checkFuel() ) do
      refuelTurtle()
      sleep(1)
    end
  end
  if ( direction == "forward" ) then
    for i=1,count do
      while ( not turtle.forward() ) do
        turtle.dig()
        checkInventory()
      end
    end
  elseif ( direction == "up" ) then
    for i=1,count do
      while ( not turtle.up() ) do
        turtle.digUp()
        checkInventory()
      end
    end
  elseif ( direction == "down" ) then
    for i=1,count do
      while ( not turtle.down() ) do
        turtle.digDown()
        checkInventory()
      end
    end
  else
    io.write("Unknown Direction Specified - " .. direction .. "\n")
    os.exit(1)
  end
end

function turn(direction, count)
  if ( direction == "left" ) then
    for i=1,count do
      turtle.turnLeft()
    end
  elseif ( direction == "right" ) then
    for i=1,count do
      turtle.turnRight()
    end
  else
    io.write("Unknown Turn Direction Specified - " .. direction .. "\n")
  end
end

function checkInventory()
  if ( invFull() ) then
    io.write("Inventory Full, Please remove extra items\n")
    while ( invFull() ) do
      sleep(1)
    end
  end
end

function invFull()
  full=true
  for i=freeSlot,16 do
    full = (turtle.getItemCount(i) > 0 and full)
  end
  return full
end

function getSlot(slot)
  for i = 1,table.getn(subs[slot]) do
    if ( turtle.getItemCount(subs[slot][i]) > 0 and qtysReq[slot] > 0 ) then
      return subs[slot][i]
    end
  end
  return 0
end

function dig(direction)
  if ( direction == "forward" ) then
    while ( turtle.detect() ) do
      turtle.dig()
      checkInventory()
    end
  elseif ( direction == "up" ) then
    while ( turtle.detectUp() ) do
      turtle.digUp()
      checkInventory()
    end
  elseif ( direction == "down" ) then
    while ( turtle.detectDown() ) do
      turtle.digDown()
      checkInventory()
    end
  else
    io.write("Unknown Dig Direction Specified - " .. direction .. "\n")
    os.exit(1)
  end
end

function placeItem(slot)
  slotNumber = getSlot(slot)
  if ( slotNumber == 0 ) then
    io.write("There is insufficient stock for slot " .. slot .. ". Please replenish stock in one of the following Slots\n")
    for i = 1,table.getn(subs[slot]) do
      io.write(subs[slot][i] .. "\n")
    end
    while ( slotNumber == 0 ) do
      sleep(1)
      slotNumber = getSlot(slot)
    end
  end
  turtle.select(slotNumber)
  dig("down")
  turtle.placeDown()
  qtysReq[slot] = qtysReq[slot] - 1
  turtle.select(freeSlot)
end

function checkFuel()
  return (turtle.getFuelLevel() <= 1)
end

function refuelTurtle()
  turtle.select(16)
  turtle.refuel()
end

local args={ ... }
availSlots={}
plan={}
qtysReq={}
subs={}
fileName=args[1]
rowCount=1
level=0
freeSlot=0
plan = readFile(fileName)
turnDirection="right"
for level = 1,#plan do
  if ( level % 2 == 1 ) then
    rowStart = 1
    rowEnd = table.getn(plan[level])
    rowStep = 1
  else
    rowStart = table.getn(plan[level])
    rowEnd = 1
    rowStep = -1
  end
  for row = rowStart,rowEnd,rowStep do
    if ( row % 2 == level % 2 ) then
      columnStart = 1
      columnEnd = table.getn(plan[level][row])
      columnStep = 1
    else
      columnStart = table.getn(plan[level][row])
      columnEnd = 1
      columnStep = -1
    end
    for column = columnStart,columnEnd, columnStep do
      dig("down")
      if ( plan[level][row][column] ~= 0 ) then
        placeItem(plan[level][row][column])
      end
      if ( column ~= columnEnd ) then
        move("forward", 1)
      end
    end
    if ( row ~= rowEnd ) then
      turn(turnDirection, 1)
      move("forward", 1)
      turn(turnDirection, 1)
      if ( turnDirection == "right" ) then
        turnDirection = "left"
      else
        turnDirection = "right"
      end
    end
  end
  if ( level ~= table.getn(plan) ) then
    move("up", 1)
    turn("left", 2)
    if ( level % 2 == 1 ) then
      if ( table.getn(plan[level]) % 2 == 0 ) then
        turnDirection = "left"
      else
        turnDirection = "right"
      end
    else
      turnDirection = "right"
    end
  end
end