ComputerCraft - Lumberjack Turtle 2.0

--"Lumberjack Turtle" v2.0
-- Created by: Jeff "Deczx" Kloos, edited by: Daniele "Raniel" Sabre, Fulgar
--                                      -------READ BELOW FOR INSTRUCTIONS--------
-- This is a program that makes a ComputerCraft Mine Turtle chop down trees for you. It is fully automatic and replants after chopping the tree down.
-- Quick start: The way you have to set it up is pretty simple. Put a chest in the ground and place the turtle on top. Put a sapling of your choice in front of the turtle. Put a single sapling of the corresponding wood in the 4th inventory slot of the turtle (top-right). Now put some saplings in the 16th inventory slot (bottom-right) for the turtle to replant. Fuel up the turtle, run the program and voila!

local waitTime = 10


print("Well I'm a lumberjack and I'm OK! ^.^")
print("[hold ctrl+t to terminate]")

while turtle.getFuelLevel() > 20 do -- If the Fuel gets below 64 the loop stops, you can change this, of course.
    --Here, the turtle looks for the sapling to turn into the woodblock.
    local success, sapling = turtle.inspect()
    while c do
        for i = 1,16 do -- search bone meal
            item = turtle.getItemDetail(i)
            if item == nil then
                c = true
            else
                if item.name == "minecraft:dye" then
                    turtle.select(i)
                    turtle.place()
                end
                success, sapling = turtle.inspect()
            end
        end
        sleep(waitTime)
        success, sapling = turtle.inspect()
        if sapling.name == "minecraft:log" then
            c = false
        else
            c = true
        end
    end

    --If it sees that the sapling is a woodblock it will start cutting the tree down.
    turtle.select(1)
    turtle.dig()
    turtle.forward()
    print("Aye! ^o^7")

    -- The turtle will keep going up until there are no more blocks above him.
    while turtle.detectUp()  do
        turtle.digUp()
        turtle.up()
    end

    -- Then it will go down.
    while turtle.down() == true do
    end

    -- Until it hits the ground.
    turtle.back()
    for i = 1,16 do -- search oak sapling
        item = turtle.getItemDetail(i)
        if item == nil then
            c = true
        else
            if item.name == "minecraft:sapling" then
                turtle.select(i)
                turtle.place()
                i=16
            end
        end
    end

    for i = 1,16 do -- search oak wood
        item = turtle.getItemDetail(i)
        if item == nil then
            c = true
        else
            if item.name == "minecraft:log" then
                turtle.select(i)
                if turtle.getFuelLevel() < 100 then
                    turtle.refuel(1)
                end
                turtle.dropDown() -- drop wood on hcest below
            end
        end
    end
    turtle.select(1)

    print("Hard Work Makes Me Sleepy! XoX <<ZZzzz>>.") -- Then the turtle will go back to sleep mode.
end

-- If the turtle runs out of fuel, it will print a message and terminate the program.
print("So Hungry. -o-")