-- Very basic oak tree farming lua script for the turtles from the Computercraft mod
-- Requires specific setup for tree growth, turtle position, refueling, restocking and unloading of wood

-- Performs the farming of the wood
function farm()
    -- Mines down
        turtle.digDown()
    for i=0,4 do
        turtle.down()
        turtle.digDown()
    end

    -- Places sapling
    turtle.placeDown()

    -- Returns to position
    for i=0,4 do
        turtle.up()
    end
end

-- Performs the unloading of the wood
function unload_wood()
    -- Selects the 3rd item slot within the turtle, the 3rd item slot is where the wood should be
    turtle.select(3)
    -- Drops the wood into the chest inventory above itself
    turtle.dropUp()
    -- Selects the 1st item slot ready for planting saplings
    turtle.select(1)
end

-- Performs the refueling of the turtle
function refuel()
    -- Selects the 2nd item slot within the turtle, the 2nd item slot should contain the fuel source for the turtle
    turtle.select(2)
    -- Moves forward under the hopper and chest used to store the fuel source
    turtle.forward()
    -- Waits for the collection of 32 items of fuel
    while turtle.getItemCount(2) < 32 do
        os.sleep(0.1)
    end
    -- Once 32 items have be collected, returns to position
    turtle.back()
    -- Consumes the fuel
    turtle.refuel()
    -- Selects the 1st item slot ready for planting sapligns
    turtle.select(1)
end

-- Performs the restocking of saplings
function restock()
    -- Moves backward under the hopper and chest used to store saplings
    turtle.back()
    -- Waits for the collection of 32 saplings
    while turtle.getItemCount(1) < 32 do
        os.sleep(0.1)
    end
    -- Returns back to position
    turtle.forward()
end

-- Main loop
while true do
    -- Checks if fuel level is low
    if turtle.getFuelLevel() < 15 then
        -- If it's low, calls the refuel function
        refuel()
    end

    -- Checks if sapling count is low (item count from slot 1)
    if turtle.getItemCount(1) < 5 then
        -- If it's low, calls restock function
        restock()
    end

    -- Checks if a tree has grown by detecting whether or not a blocks is beneath it (the top of the tree)
    if turtle.detectDown() then
        -- If the tree has grown, calls farm function
        farm()
        -- once tree has been farmed and returned to position, calls unload_wood function
        unload_wood()
    end
end