args = {...}

-- Init variables
local pos = {
    x = 0,
    y = 0,
    z = 0,
    f = 0
}

local xSize = args[1]
local ySize = args[2]

-- Functions
local function moveForward()

    turtle.suck()

    while turtle.detect() do turtle.dig() end
    turtle.forward()

    if pos.f == 0 then pos.x = pos.x + 1 end
    if pos.f == 2 then pos.x = pos.x - 1 end
    if pos.f == 1 then pos.y = pos.y + 1 end
    if pos.f == 3 then pos.y = pos.y - 1 end
end

local function moveUp()
    while turtle.detectUp() do turtle.digUp() end
    turtle.up()
    pos.z = pos.z + 1
end

local function moveDown()
    while turtle.detectDown() do turtle.digDown() end
    turtle.down()
    pos.z = pos.z - 1
end

local function turnLeft()
    turtle.turnLeft()
    pos.f = (pos.f - 1) % 4
end

local function turnRight()
    turtle.turnRight()
    pos.f = (pos.f + 1) % 4
end

local function refuel()
    if turtle.getFuelLevel() > turtle.getFuelLimit() * 0.01 then return end
    turtle.select(16)
    while turtle.refuel(0) and turtle.getFuelLevel() < turtle.getFuelLimit() * 0.01 do
        turtle.refuel(1)
    end
    turtle.select(1)
end

local function isItem(itemName, name)
    if string.find(itemName, name) then
        return true
    else
        return false
    end
end

local function goAround()
    turnRight()
    moveForward()
    turnLeft()
    moveForward()
    moveForward()
    turnLeft()
    moveForward()
    turnRight()
end

local function chopTheTree()
    moveUp()
    moveUp()
    while turtle.detectUp() do
        moveUp()
    end
    moveForward()
    for i = 1, math.abs(pos.z) do
        for i = 1, 4 do
            turtle.dig()
            turnRight()
        end
        moveDown()
    end
    moveForward()
    turnRight()
    turnRight()
    turtle.select(15)
    turtle.place()
    turnLeft()
    turnLeft()
end

-- Main Code
print("Insert saplings into slot 15")
turtle.select(15)
while turtle.getItemDetail() == nil do end
while not isItem(turtle.getItemDetail().name, "sapling") do end
print("Saplings detected")
print("Please insert fuel into slot 16 (not wood)")
turtle.select(16)
while not turtle.refuel(0) do end
print("Fuel detected, beginning the work")
turtle.select(15)

-- Main Loop
while true do
    refuel()
    if turtle.getFuelLevel() > 20 then

        moveForward()

        if pos.f == 0 and pos.x >= (3 * xSize) then
            if pos.y == (3 * (ySize - 1)) then
                turnLeft()
                moveForward()
                turnLeft()
                for i = 1, pos.x do
                    moveForward()
                end
                turnRight()
                for i = 1, pos.y do
                    moveForward()
                end
                turnLeft()
                for i = 1, 14 do
                    turtle.select(i)
                    turtle.drop()
                end
                turtle.select(15)
                turnRight()
                turnRight()
            else
                turnRight()
                for i = 1, 3 do
                    moveForward()
                end
                turnRight()
            end
        elseif pos.f == 2 and pos.x == 0 then
            if pos.y == (3 * (ySize - 1)) then
                turnRight()
                for i = 1, pos.y do
                    moveForward()
                end
                turnLeft()
                for i = 1, 14 do
                    turtle.select(i)
                    turtle.drop()
                end
                turtle.select(15)
                turnRight()
                turnRight()
            else
                turnLeft()
                for i = 1, 3 do
                    moveForward()
                end
                turnLeft()
            end
        end

        local b, data = turtle.inspect()
        if b ~= false then
            if isItem(data.name, "sapling") then
                goAround()
            elseif isItem(data.name, "log") then
                chopTheTree()
            end
        end
    else
        print("Waiting for fuel in slot 16")
    end
end