local robot = require("robot")
local os = require("os")

local length = ...

if not length then
    print('Usage: lumberjack <length>')
    return
end

local function mine_tree()
    local n = 0
    robot.swing()
    robot.forward()
    robot.swingDown()
    while robot.detectUp() do
        robot.swingUp()
        robot.up()
        n = n + 1
    end
    for _ = 1, n do
        while not robot.down() do end
    end
    robot.placeDown()
end

while true do
    for _ = 1, length do
        if robot.detect() then
            mine_tree()
        else
            while not robot.forward() do end
        end
        robot.suckDown()
    end
    robot.turnAround()
    for _ = 1, length do
        if robot.detect() then
            mine_tree()
        else
            while not robot.forward() do end
        end
        robot.suckDown()
    end
    robot.turnAround()
    os.execute("sleep 5")
end