Turtle planter (dye sapling) v4

--
-- Turtle planter for dye saplings
--
-- Dye sapling have two major problems wich make them hard to farm:
--  * Dye sapling don't work with MFR planter and Multifarm.
--  * Dye saplings produce blood wood wich don't work properly with
--    MFR harvester.
--
-- This program plant the given sapling every two blocks in a square shape,
-- and harvest blood wood when the turtle are in front of it.
--
-- HOWTO USE
-- ---------
-- The *entire inventory* must be filled with sapling, exepted the last
-- slot, wich must contain at least one blood wood log.
--
-- NOTES
-- -----
-- The turtle expect blood wood to grow in a 3x3 square, wich seems
-- to be the case with dye sapling.  It also expect that the blood
-- wood tree begin to diverge in a 3x3 shape two blocks above from
-- the floor.  Again, it seems to be the case.
--


local WIDTH = 5
local HEIGHT = 5
local slot = 2

turtle.forceForward = function()
    repeat until turtle.forward()
end

turtle.forceForwardAndDig = function()
    while not turtle.forward() do turtle.dig() end
end
turtle.forceUpAndDig = function()
    while not turtle.up() do turtle.digUp() end
end
turtle.forceDownAndDig = function()
    while not turtle.down() do turtle.digDown() end
end

local isBloodTree = function(compareFunc)
    local ret = false

    turtle.select(1)
    ret = compareFunc()
    turtle.select(slot)

    return ret
end

local break_blood_tree = function()
    if isBloodTree(turtle.compareUp) then
        turtle.forceUpAndDig()

        -- Break the whole 3x3x1 space
        turtle.forceForwardAndDig()
        turtle.turnLeft()
        turtle.forceForwardAndDig()

        for i = 1, 3 do
            turtle.turnLeft()
            turtle.forceForwardAndDig()
            turtle.forceForwardAndDig()
        end

        turtle.turnLeft()
        turtle.forceForwardAndDig()
        turtle.turnLeft()
        turtle.forceForwardAndDig()

        -- Make the turtle facing at the same direction as the begining
        turtle.turnLeft()
        turtle.turnLeft()

        break_blood_tree()

        turtle.forceDownAndDig()
    end
end

turtle.plant = function()
    if turtle.getItemCount() == 0 then
        if slot > 16 then
            return
        end

        slot = slot + 1
        turtle.select(slot)
    end

    -- In some rare case a block may prevent the turtle
    -- planting, remove it.  Don't insist on failure.
    if not turtle.compare() then
        turtle.dig()
    end

    turtle.placeDown()
end

turtle.plantAndForward = function()
    turtle.plant()
    turtle.forceForward()

    if isBloodTree(turtle.compare) then
        turtle.forceForwardAndDig()
        break_blood_tree()
    else
        turtle.forceForward()
    end
end

turtle.select(slot)
while slot <= 16 do
    for i = 1, WIDTH do
        for j = 1, HEIGHT - 1 do
            turtle.plantAndForward()
        end

        -- Last col have a special case for the finish since the
        -- turtle must move back to the starting position at the
        -- end of the col
        if i == WIDTH then
            turtle.plant()
        else
            if i % 2 == 0 then
                turtle.turnLeft()
                turtle.plantAndForward()
                turtle.turnLeft()
            else
                turtle.turnRight()
                turtle.plantAndForward()
                turtle.turnRight()
            end
        end
    end

    -- Move back to the starting position
    turtle.forceForward()

    if WIDTH % 2 == 0 then
        turtle.turnRight()
        for i = 1, WIDTH - 1 do
            turtle.forceForward()
            turtle.forceForward()
        end
        turtle.turnRight()
        turtle.forceForward()
    else
        turtle.turnLeft()
        for i = 1, WIDTH - 1 do
            turtle.forceForward()
            turtle.forceForward()
        end

        turtle.forceForward()
        turtle.turnLeft()
        turtle.forceForward()

        for i = 1, HEIGHT - 1 do
            turtle.forceForward()
            turtle.forceForward()
        end

        turtle.turnLeft()
        turtle.forceForward()
        turtle.turnLeft()
    end
end