local maxX,maxY = ...
maxX= tonumber(maxX)
maxY= tonumber(maxY)
f=fs.open("log","a")
f.writeLine("--------------------")
f.write("maxX= ")
f.write(maxX)
f.write(" maxY= ")
f.writeLine(maxY)
noCoal=false

refuel=function()
  success=false
  c=1
  while not success and c<16 do
    turtle.select(1)
    success=turtle.refuel()
  end
  return success
end

clearInventory = function()
  for c=1, 16 do
    turtle.select(c)
    item=turtle.getItemDetail()
    if item then
      if not check(item.name) then
        turtle.drop()
      end
    end
  end
end

check=function (item)
  if item=="minecraft:chest" or item:match "minecraft:.*stone.*" or item:match "minecraft:dirt.*" or item=="minecraft:gravel" or item:match "chisel:.*" or item=="minecraft:torch" then
    return false
    else
      return true
  end
end

find = function ()
  local success, item=turtle.inspectUp()
  if success then
    if check(item.name) then
      turtle.select(1)
      turtle.digUp()
      f.write("Found up: ")
      f.writeLine(item.name)
    end
  end
  success, item=turtle.inspectDown()
  if success then
    if check(item.name) then
      turtle.select(1)
      turtle.digDown()
      f.write("Found down: ")
      f.writeLine(item.name)
    end
  end
  turtle.turnLeft()
  success, item=turtle.inspect()
  if success then
    if check(item.name) then
      turtle.select(1)
      turtle.dig()
      f.write("Found left: ")
      f.writeLine(item.name)
    end
  end
  turtle.turnRight()
  turtle.turnRight()
  success, item=turtle.inspect()
  if success then
    if check(item.name) then
      turtle.select(1)
      turtle.dig()
      f.write("Found right: ")
      f.writeLine(item.name)
    end
  end
  turtle.turnLeft()
  success, item=turtle.inspect()
  if success then
    if check(item.name) then
      turtle.select(1)
      turtle.dig()
      f.write("Found forward: ")
      f.writeLine(item.name)
    end
  end
end

local x=0
local y=0
local state = "up"
while x<maxX do --a
  for y=0, maxY do --b
    local fuelLevel = turtle.getFuelLevel()
    if fuelLevel<= (x+y) then --c
      local fuelFound=false
      local currSelected=1
      repeat
        turtle.select(currSelected)
        fuelFound = turtle.refuel()
        currSelected = currSelected+1
      until fuelFound == true or currSelected>16
      if fuelFound==false then
        f.writeLine("Fuel not found")
      end
    end --c
    local nCoal=0
    freeSlots = 0
    for c=1,16 do --d
      local item=turtle.getItemDetail(c)
      if item then
        if item.name=="minecraft:coal" then
          nCoal = nCoal+item.count
        end
        if not check(item.name) then
          turtle.select(c)
          turtle.drop()
          freeSlots=freeSlots+1
        end
      else
          freeSlots=freeSlots+1
      end
    end --
    nCoal = nCoal*80+turtle.getFuelLevel()-4
    local dist=x+y
    noCoal=true
    if nCoal<=dist then
      f.write("Not enough coal for the journey, returning home (left:")
      f.write(nCoal)
      f.write(", coord(")
      f.write(x)
      f.write(",")
      f.write(y)
      f.writeLine("))")
    end
    stopx=x
    stopy=y
    if freeSlots <=1 then f.writeLine("Not enough slots, returning home") end
    if state=="up" then
     turtle.turnLeft()
     turtle.turnLeft()
    end
    while y>0 do
      while turtle.detect() do
        turtle.select(1)
        turtle.dig()
      end
      clearInventory()
      if turtle.getFuelLevel()<2 then refuel() end
      turtle.forward()
      y=y-1
    end
    turtle.turnRight()
    while x>0 do
      while turtle.detect() do
        turtle.select(1)
        turtle.dig()
      end
      clearInventory()
      if turtle.getFuelLevel()<2 then refuel() end
      turtle.forward()
      x=x-1
    end
    success,storage=turtle.inspect()
    if success and storage.name=="minecraft:chest" then
      for c=1,16 do
        turtle.select(c)
        item=turtle.getItemDetail()
        if item and not item.name=="minecraft:coal" then
          dropSuccess=turtle.drop()
          if dropSuccess then
            f.write(item.name)
            f.writeLine(" dropped in chest")
          else
            f.writeLine("Chest full!! Shutting down...")
            f.close()
            os.shutdown()
          end
        end
      end
      if noCoal then success=turtle.suckUp()
        if not success then
          f.writeLine("no coal chest or coal, shutting down...")
          f.close()
          os.shutdown()
        end
      end
      turtle.turnRight()
      turtle.turnRight()
      while x<stopx do
        find()
        if turtle.getFuelLevel()<2 then refuel() end
        while turtle.detect() do
          turtle.select(1)
          turtle.dig()
        end
        clearInventory()
        turtle.forward()
        x=x+1
      end
      turtle.turnLeft()
      while y<stopy do
        find()
        if turtle.getFuelLevel()<2 then refuel() end
        while turtle.detect() do
          turtle.select(1)
          turtle.dig()
        end
        clearInventory()
        turtle.forward()
        y=y+1
      end
      if state==down then
        turtle.turnLeft()
        turtle.turnLeft()
      end
    else
      f.writeLine("No chest, shutting down...")
      os.shutdown()
    end
    find()
    while turtle.detect() do
      turtle.select(1)
      turtle.dig()
    end
    turtle.forward()
  end
  f.write("Ended x ")
  f.writeLine(x)
  if state=="up" then
    turtle.turnRight()
  else turtle.turnLeft()
  end
  for i=1, 3 do
    find()
    while turtle.detect() do
      turtle.select(1)
      turtle.dig()
    end
    turtle.forward()
    x=x+1
  end
  if state=="up" then
  turtle.turnRight()
    state="down"
  else
    turtle.turnLeft()
    state="up"
  end
end --a
f.writeLine("Returning home")
if state=="up" then
  turtle.turnLeft()
  turtle.turnLeft()
end
while y>0 do
  find()
  if turtle.getFuelLevel()<2 then refuel() end
  while turtle.detect() do
    turtle.select(1)
    turtle.dig()
  end
  turtle.forward()
  y=y-1
  clearInventory()
end
turtle.turnRight()
while x>0 do
  if turtle.getFuelLevel()<2 then refuel() end
  find()
  while turtle.detect() do
    turtle.select(1)
    turtle.dig()
  end
  turtle.forward()
  x=x-1
  clearInventory()
end
f.writeLine("Arrived! Shutting down...")
f.close()
os.shutdown()