args = {...}
length = args[1]
width = args[2]
print("Fuel level:", turtle.getFuelLevel())
stopRequired = false


function preparation ()
    --refuel
    print("refueling...")
    turtle.select(1)
    turtle.suck(64)
    turtle.refuel()
    turtle.drop(turtle.getItemCount())

    --get seed
    print("getting seed...")
    turtle.turnLeft()
    turtle.forward()
    turtle.turnRight()
    turtle.select(1)
    turtle.suck(10)

    --move into start position
    print("moving to start pos..")
    os.sleep(1)
    turtle.turnLeft()
    print("turning left..")
    os.sleep(1)
    turtle.forward()
    print("moving forward..")
    os.sleep(1)
    turtle.turnRight()
    print("turning right..")
    os.sleep(1)
    turtle.forward()
    print("moving forward..")
    os.sleep(1)
    turtle.forward()
    print("moving forward..")
    os.sleep(1)
end


-- harvest
function harvestPlant ()
    local success, data = turtle.inspectDown()
    if success then
        local blockName = data.name
        local state = data.state or {}

        -- debug?
        print("Block name:", blockName)
        for k, v in pairs(state) do
            print(k, v)
        end

        if blockName == "supplementaries:flax" then
            local growthStage = state.age or 0
            if growthStage == 7 then
                turtle.digDown()
                plantNew()
            end
        end
    end
end


-- plant
function plantNew ()
    turtle.down()
    local slotSelected = 0
    turtle.select(1)
    slotSelected = 1
    if turtle.getItemCount(1) < 1 then
        slotSelected = slotSelected + 1
        if slotSelected > 17 then
            turtle.select(slotSelected)
        else
            print("turtle is empty")
            turtle.select(1)
            turtle.up()
            turtle.up()
            stopRequired = true
        end
    else
        turtle.placeDown()
        turtle.up()
    end
end

-- dump inventory
function dumpInv ()
    print("Beginning dump sequence...")
    turtle.select(2)
    dumping = true
    while dumping == true do
        if turtle.compareTo(1) then
            if turtle.getSelectedSlot() < 16 then
                turtle.select(turtle.getSelectedSlot() + 1)
            else
                dumping = false
            end
        end
        turtle.dropDown()
        if turtle.getSelectedSlot() < 16 then
            turtle.select(turtle.getSelectedSlot() + 1)
        else
            dumping = false
        end
    end
    --reposition for seed dump
    turtle.turnRight()
    turtle.forward()
    turtle.forward()
    turtle.forward()
    turtle.down()
    turtle.turnRight()
    turtle.forward()
    turtle.turnRight()

    --seed dump
    print("Dumping seeds...")
    turtle.select(1)
    while turtle.getSelectedSlot() < 16 do
        turtle.drop()
        turtle.select(turtle.getSelectedSlot() + 1)
    end
    turtle.select(1)
    --reposition for new round
    print("Repositioning...")
    turtle.turnRight()
    turtle.forward()
    turtle.turnLeft()

end
-- movePlan
function movePlan (length, width)
    turtle.up()
    turtle.up()
    turtle.forward()
    for i=1, width,1 do
        for i=1, length,1 do
            harvestPlant()
            turtle.forward()
        end
        moveBack(length)
    end
    turtle.turnRight()
    for i=1, width,1 do
        turtle.forward()
    end
    turtle.forward()
    turtle.forward()
    turtle.down()
    dumpInv()
end

-- backtrack
function moveBack (n)
    print("Line complete, backtracking...")
    for i=1, n,1 do
        turtle.back()
    end
    turtle.turnLeft()
    turtle.forward()
    turtle.turnRight()
end


-- argument handling
if length == "-help" then
    print("usage is [harvester x y] where x is the length of the field to be harvested and y is the width.")
    print("the script assumes a pre-planted field, and will only bring 10 extra seeds.")
elseif width then
    -- main
    while stopRequired == false do
        preparation()
        if turtle.getFuelLevel() < 10 then
            stopRequired = true
        end
        movePlan(length, width)
        print("waiting for 180 seconds...")
        os.sleep(180)
    end
else
    print("Invalid argument, see -help.")
end