rubber_trees

c_select = 1
p_select = 1
turtle.select( 1 )

fuel_slot = 1
marker_slot = 2
sapling_slot = 3
trunk_slot = 4
rubber_slot = 5

function do_select( n_select )
  if n_select then
    p_select = c_select or n_select or p_select or 1
    c_select = n_select or c_select or 1
  end
  turtle.select( c_select )
  return c_select
end

function get_select()
  return c_select
end

select = do_select
doSelect = do_select
getSelect = get_select

function in_table( inspect, table )
  for element_i = 1, #table, 1 do
    if inspect == table[ element_i ] then
      return true
    end
  end
  return false
end

function detect_dir( direction )
  direction = direction or "f"
  dir_char = direction:sub(1,1)
  if dir_char == "f" then
    return turtle.detect()
  elseif dir_char == "b" then
    turtle.turnRight()
    turtle.turnRight()
    re = turtle.detect()
    turtle.turnRight()
    turtle.turnRight()
    return re
  elseif dir_char == "u" then
    return turtle.detectUp()
  elseif dir_char == "d" then
    return turtle.detectDown()
  else
    print( "Invalid direction: "..direction )
    return false
  end
end

function move_dir( direction )
  direction = direction or "f"
  dir_char = direction:sub(1,1)
  if dir_char == "f" then
    return turtle.forward()
  elseif dir_char == "b" then
    return turtle.back()
  elseif dir_char == "u" then
    return turtle.up()
  elseif dir_char == "d" then
    return turtle.down()
  else
    print( "Invalid direction: "..direction )
    return false
  end
end

function move( direction )
  direction = direction or "f"
  fuel_slot = fuel_slot or 1
  verbose = verbose or false
  if not move_dir( direction ) then
    if turtle.getFuelLevel() == 0 then
      if verbose then
        print( "Out of Fuel." )
      end
      do_select( fuel_slot )
      if not turtle.refuel( 1 ) then
        print( "Cannot refuel." )
        print( "Waiting for fuel to continue." )
        while not turtle.refuel( 1 ) do
          sleep( 1 )
        end
        print( "Refueled." )
      elseif verbose then
        print( "Refueled." )
      end
      do_select( p_select )
      return move( direction )
    else
      if verbose then
        print( "Path obstructed." )
      end
      if detect_dir( direction ) then
        if verbose then
          print( "Block found." )
          print( "Cannot move." )
        end
        return false
      else
        print( "Entity blocking path." )
        print( "Waiting to move." )
        while not move_dir( direction ) do
          sleep( 1 )
        end
      end
    end
  end
  return true
end

function place_dir (direction )
  direction = direction  or "f"
  dir_char = direction:sub(1,1)
  if dir_char == "f" then
    return turtle.place()
  elseif dir_char == "b" then
    turtle.turnRight()
    turtle.turnRight()
    re = turtle.place()
    turtle.turnRight()
    turtle.turnRight()
    return re
  elseif dir_char == "u" then
    return turtle.placeUp()
  elseif dir_char == "d" then
    return turtle.placeDown()
  else
    print( "Invalid direction: "..direction )
    return false
  end
end

function place( direction, tSelection )
  direction = direction or "f"
  if tSelection == {} then
    tSelection = nil
  end
  tSelection = tSelection or {2,3,4,5,6,7,8,9,10,11,12,13,14,15,16}
  verbose = verbose or false

  do_select()

  if not in_table( c_select, tSelection ) then
    do_select( tSelection[1] )
  end

  if not place_dir( direction ) then
    if detect_dir( direction ) then
      if verbose then
        print( "Cannot place in direction." )
        print( "Pre-existing block found in direction." )
      end
      return false
    end
    placed = false
    i_select = c_select
    for selector_i = 1, #tSelection, 1 do
      do_select( tSelection[ selector_i ] )
      if place_dir( direction ) then
        placed = true
        break
      end
    end

    -- Return the currently selected slot to the
    -- initially selected slot

    do_select( i_select )

    if placed then
      return true
    else
      if verbose then
        print( "Could not place block in direction" )
        print( "With any blocks in selected slots." )
      end
      return false
    end
  else
    return true
  end
  return true
end

function compare_slots( given_slot )
  turtle.select( given_slot )
  re = {given_slot}
  for i = 1, 16, 1 do
    if i ~= given_slot then
      if turtle.compareTo( i ) then
        table.insert( re, 1, i )
      end
    end
  end
  turtle.select( c_select )
  return re
end

function count_items( slot )
  total = 0
  tSlots = compare_slots( slot )
  for i = 1, #tSlots, 1 do
    total = total + turtle.getItemCount( tSlots[i] )
  end
  return total
end

function move_to_mark()
  select( marker_slot )
  move()
  inc = 1
  while not turtle.compareDown() do
    move()
    inc = inc + 1
  end
  return inc
end

function main()
  while true do
    dist = move_to_mark()
    while dist ~= 1 do
      turtle.turnRight()
      select( trunk_slot )
      if turtle.compare() then
        turtle.dig()
        move()
        select( trunk_slot )
        while turtle.compareUp() do
          turtle.digUp()
          move( "u" )
        end
        while not turtle.detectDown() do
          move( "d" )
        end
        move( "b" )
      end
      if count_items( sapling_slot ) ~= 1 then
        place( "f", compare_slots( sapling_slot ) )
      end
      turtle.turnLeft()
      dist = move_to_mark()
    end
    turtle.turnRight()
    turtle.turnRight()
    move()
    dist = move_to_mark()
    while dist ~= 1 do
      dist = move_to_mark()
    end
    move( "b" )
    turtle.turnLeft()
    if move_to_mark() == 1 then
      break
    end
    turtle.turnLeft()
  end
  turtle.turnRight()
  turtle.turnRight()
  move()
  dist = move_to_mark()
  while dist ~= 1 do
    dist = move_to_mark()
  end
  turtle.turnLeft()

  select( sapling_slot )
  turtle.suck()
  tSaplings = compare_slots( sapling_slot )
  for i = 1, #tSaplings - 1, 1 do
    select( tSaplings[i] )
    turtle.drop( turtle.getItemCount( get_select() ) )
  end

  turtle.turnRight()
  tTrunks = compare_slots( trunk_slot )
  for i = 1, #tTrunks - 1, 1 do
    select( tTrunks[i] )
    turtle.drop( turtle.getItemCount( get_select() ) )
  end
  select( trunk_slot )
  turtle.drop( turtle.getItemCount( get_select() ) - 1 )

  tRubber = compare_slots( rubber_slot )
  for i = 1, #tRubber - 1, 1 do
    select( tRubber[i] )
    turtle.drop( turtle.getItemCount( get_select() ) )
  end
  select( rubber_slot )
  turtle.drop( turtle.getItemCount( get_select() ) - 1 )

  turtle.turnRight()
  select( fuel_slot )
  turtle.suck()
  tFuel = compare_slots( fuel_slot )
  for i = 1, #tFuel - 1, 1 do
    select( tFuel[i] )
    turtle.drop( turtle.getItemCount( get_select() ) )
  end

  turtle.turnRight()
  move()
  turtle.turnLeft()
end

main()