Minecraft - Turtle Seed Farmer

--2013: Ichabod Clay (Ichabod2032)
--This script farms an 8 wide by 12 long area of wheat farmland. It discards all wheat
-- and keeps seeds for chicken breeding. Currently, due to an overabundance of skeleton bones,
-- it uses bonemeal on each and every patch of seeds. Also, due to this turtle being used in a Mindcrack
-- mod pack, it is refueled at a charging station prior to farm activities and needs no fuel during farming.
--
--2 chests must be placed for the turtle to take bonemeal from and deposit seeds to. Diagram for chest placement
-- is as follows: .=farmland  0=chest  ^=turtle
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
-- ........
--0       ^0

--Chests and turtle must be positioned at the player's eye level (2 blocks above the farmland blocks) with the
-- turtle starting facing toward the farm. Left chest will contain seeds after farming is done. Right chest
-- must be preloaded with (lots) of bonemeal. Turtle must have at least 1 bonemeal, 1 wheat, and 1 seed in the
-- 1st, 2nd, and 3rd slots respectively when starting. Turtle assumes a starting farmland with freshly planted
-- crops.
-----
-----
--Let's start this off right. Select the first slot of the turtle and get ready for an adventure!
turtle.select(1);
local curSlot = 1;

--Function: getBonemeal()
--Grabs exactly 2 stacks of bonemeal from the bonemeal chest.
--Returns: nothing
local function getBonemeal()
  if curSlot ~= 1 then
    turtle.select(1);
    curSlot = 1;
  end

  turtle.turnRight();
  turtle.suck();
  turtle.suck();
  turtle.select(5);
  curSlot = 5;
  turtle.drop();
  turtle.select(4);
  curSlot = 4;
  turtle.turnLeft();
end

--Helper Function: checkCount(itemType)
--Checks the item count and type of the currently selected slot. If the item is not 'itemType', then
-- it switches the slot to base slot for that type (slot 1 for bonemeal, 3 for seeds);
--Returns: nothing
local function checkCount(itemType)
  local itemSlot = 1;
  if itemType == "seeds" then
    itemSlot = 3;
  end

  if (not turtle.compareTo(itemSlot)) and (curSlot ~= itemSlot) then
    turtle.select(itemSlot);
    curSlot = itemSlot;
  end
end

--Function: boneNHarvest()
--Bonemeals and harvests all crops then ends with the turtle next to the seed chest
--Returns: nothing
local function boneNHarvest()
  turtle.forward();
  if curSlot ~= 4 then
    turtle.select(4);
    curSlot = 4;
  end

  for i=1, 4 do
    for x=1, 12 do
      checkCount("bonemeal");
      turtle.placeDown();
      turtle.digDown();
      if x ~= 12 then
        turtle.forward();
      end
    end

    turtle.turnLeft();
    turtle.forward();
    turtle.turnLeft();

    for x=1, 12 do
      checkCount("bonemeal");
      turtle.placeDown();
      turtle.digDown();
      if x ~= 12 then
        turtle.forward();
      end
    end

    turtle.turnRight();
    turtle.forward();
    turtle.turnRight();
  end
end

--Helper Function: getItemTable(string dumpKind)
--Creates a table of numbers that correspond to the slots that contain an item of type 'dumpKind' (wheat or seeds)
--Returns: A table! yay!
local function getItemTable(dumpKind)
  local itemTable = {3};
  local baseSlot = 3;
  local tableCounter = 2;

  if dumpKind == "wheat" then
    itemTable[1] = 2;
    baseSlot = 2;
  end

  for i=4, 13 do
    turtle.select(i);
    curSlot = i;

    if turtle.compareTo(baseSlot) then
      itemTable[tableCounter] = curSlot;
      tableCounter = tableCounter + 1;
    end
  end

  return itemTable;
end

--Helper Function: dump(string dumpKind)
--Dumps all items in turtle's inventory based on the type of 'dumpKind' (wheat or seeds)
--Returns: nothing
local function dump(dumpKind)
  local tempTable = getItemTable(dumpKind);
  local kindSlot = 3;
  if dumpKind == "wheat" then
    kindSlot = 2;
  end

  for i=1, #tempTable do
    turtle.select(tempTable[i]);
    curSlot = tempTable[i];

    if curSlot == kindSlot then
      turtle.drop(turtle.getItemCount(curSlot) - 1);
    else
      turtle.drop();
    end

  end
end

--Helper Function: takeSeeds()
--Takes exactly 94 seeds from chest.
--Returns: nothing
local function takeSeeds()
  turtle.select(3);
  curSlot = 3;
  turtle.suck();
  turtle.suck();
  turtle.select(5);
  curSlot = 5;
  turtle.drop();
  turtle.select(4);
  curSlot = 4;
  turtle.drop(32);
end

--Function: dumpNDeposit()
--Dumps all seeds into chest and discards all wheat. Takes enough seeds for planting and sets turtle up for planting
--Returns: nothing
local function dumpNDeposit()
  turtle.turnLeft();
  dump("wheat");
  turtle.turnLeft();
  dump("seeds");
  takeSeeds();
  turtle.turnLeft();
  turtle.forward();
  turtle.turnLeft();
end

--Function: plantSeeds()
--Plants seeds!
--Returns: nothing
local function plantSeeds()
  if curSlot ~= 4 then
    turtle.select(4);
    curSlot = 4;
  end

  for i=1, 4 do
    for x=1, 12 do
      checkCount("seeds");
      turtle.placeDown();
      if x ~= 12 then
        turtle.forward();
      end
    end

    turtle.turnRight();
    turtle.forward();
    turtle.turnRight();

    for x=1, 12 do
      checkCount("seeds");
      turtle.placeDown();
      if x ~= 12 then
        turtle.forward();
      end
    end

    turtle.turnLeft();
    turtle.forward();
    turtle.turnLeft();
  end
end

--Function: returnToStart()
--Returns to starting position after planting new seeds.
--Returns: nothing
local function returnToStart()
  turtle.turnLeft();
  turtle.forward();
  turtle.turnLeft();
  turtle.forward();
  turtle.turnLeft();
  turtle.turnLeft();
end

--Function: isMealCountOK()
--Checks count of bonemeal just before setting off.
--Returns: False if bonemeal count is below 96, True otherwise.
local function isMealCountOK()
  if (turtle.getItemCount(1) == 64) and (turtle.getItemCount(4) >= 34) then
    return true;
  end
  return false;
end

-- End function definitions
-- Start main program

while true do
  getBonemeal();
    if not isMealCountOK() then
      print("Stopping due to low bonemeal count");
      break;
    end
  boneNHarvest();
  dumpNDeposit();
  plantSeeds();
  returnToStart();
end

print("All farmed out!");
return;