9x9_farm

-- Program for Farming Turtle from ComputerCraft mod.
-- AutoFarm Ver 1.0
-- Copyright  (c)  2015  Alexander Andreyev <aravsar@ya.ru>
--   Farming 9x9 field
-- I S x x x x x x x x
--   x x x x x x x x x
--   x x x x x x x x x
--   x x x x x x x x x
--   x x x x W x x x x
--   x x x x x x x x x
--   x x x x x x x x x
--   x x x x x x x x x
--   x x x x x x x x x
-- S - start position
-- I - possible inventory with which interacts turtle in the end (do_end_stuff)
-- W - water block in center
-- The turtle moves clockwise from S to W by spiral,
-- moves back to the S, drop stuff to I and stops.
-- The turtle must be in one block above the field.

-- MAIN PROGRAM
args      = {...}
chest_name_part = 'Chest' -- a part of name of the I chest
rings     = {5,3}
fuel_slot = 16

function _refuel(fuel)
  turtle.select(fuel_slot)
  turtle.refuel(fuel)
end

function process_field(do_stuff, do_end_stuff)
  for i = 1, #rings do
    local n = rings[i]
    for j = 1, 4 do
      if j == 4 then n = n - 1 end
      for k = 1, n-1 do
        do_stuff()
        turtle.forward()
      end
      turtle.turnRight()
    end
    do_stuff()
    turtle.forward()
  end
  -- moving back on start position
  turtle.turnLeft()
  for i = 1, 4 do turtle.forward() end
  turtle.turnLeft()
  for i = 1, 4 do turtle.forward() end

  do_end_stuff()

  turtle.turnLeft()
  turtle.turnLeft()
end

-- PLANTING
plant_slots = {1,2,3,4}

function plant()
  for i = 1, #plant_slots do
    turtle.select(plant_slots[i])
    if turtle.getItemCount(plant_slots[i]) > 0 then
      turtle.placeDown()
      return
    end
  end
end
function planting()
  local s,_ = turtle.inspectDown()
  if s == false then
    turtle.digDown()
    plant()
  end
end
function on_end_planting()
end

-- HARVESTING
harvest_slots = {5,6,7,8}
wheat = {name = 'minecraft:wheat', metadata = 7} -- growed up wheat

function harvest(object)
  local _,m = turtle.inspectDown()
  if m.name ~= object.name or m.metadata ~= object.metadata then return end

  for i = 1, #harvest_slots do
    turtle.select(harvest_slots[i])
    if turtle.getItemSpace(harvest_slots[i]) > 0 then
      turtle.digDown()
      return
    end
  end
end
function harvesting()
  harvest(wheat)
end
function on_end_harvesting()
  local _,m = turtle.inspect()
  if m.name:find(chest_name_part) == nil then return end
  for i = 1, #harvest_slots do
    turtle.select(harvest_slots[i])
    turtle.drop()
  end
end

-- HARVEST AND PLANT
function harvest_and_plant( ... )
  harvesting()
  planting()
end

-- Controlling program
if args[1] == 'p' then
  _refuel(2)
  process_field(planting, on_end_planting)
elseif args[1] == 'h' then
  _refuel(2)
  process_field(harvesting, on_end_harvesting)
elseif args[1] == 'ph' then
  _refuel(2)
  process_field(harvest_and_plant, on_end_harvesting)
else
  print('p  - for planting')
  print('h  - for harvest')
  print('ph - for harvest and plant')
end