SugarCaneLane

if turtle.getItemDetail(1) == nil then
    print ("Put fuel in the first slot of the turtle and run again!\n")
end

local data = turtle.getItemDetail(1) -- fuel slot 1
local fuelType = data.name
local args = {...}

--local maxDistance = tonumber(args[1]) or 30 -- straight line
local distance = 0
local path = {}
local target = "minecraft:sugar_cane"
local skipped = 0
local sleepTime = 60 -- in seconds

-- resting and current Position
local rPosition = { x = tonumber(args[1]), y = tonumber(args[2]), z = tonumber(args[3]) }
local cPosition = {}
cPosition.x, cPosition.y, cPosition.z = gps.locate()

-- back to start?
if rPosition.x ~= cPosition.x or
   rPosition.y ~= cPosition.y or
   rPosition.z ~= cPosition.z then
    -- go to resting Position first
    -- move turtle above sugar canes
    turtle.up()
    turtle.up()

    cPosition.x, cPosition.y, cPosition.z = gps.locate()
    print ("I am at:\nx: " .. cPosition.x .. "\ny: " .. cPosition.y + 2 .. "\nz: " .. cPosition.z .. "\n")
    print ("I want to be at:\nx: " .. rPosition.x .. "\ny: " .. rPosition.y .. "\nz: " .. rPosition.z .. "\n")

    turtle.forward()

    local tmp = {}
    tmp.x, tmp.y, tmp.z = gps.locate()
    --[[
    print (
        math.abs(math.floor(tmp.x) - math.floor(rPosition.x)) < math.abs(math.floor(cPosition.x) - math.floor(rPosition.x)),
        math.abs(math.floor(tmp.y) - math.floor(rPosition.y)) < math.abs(math.floor(cPosition.y) - math.floor(rPosition.y)),
        math.abs(math.floor(tmp.z) - math.floor(rPosition.z)) < math.abs(math.floor(cPosition.z) - math.floor(rPosition.z))
    )
    ]]
    while not (math.abs(math.floor(tmp.z) - math.floor(rPosition.z)) < math.abs(math.floor(cPosition.z) - math.floor(rPosition.z)))     and rPosition.z ~= tmp.z do
        turtle.back()
        turtle.turnRight()
        turtle.forward()
        tmp.x, tmp.y, tmp.z = gps.locate()
    end

    while math.abs(math.floor(tmp.z) - math.floor(rPosition.z)) < math.abs(math.floor(cPosition.z) - math.floor(rPosition.z))
    and rPosition.z ~= tmp.z do
        turtle.forward()
        tmp.x, tmp.y, tmp.z = gps.locate()
    end
    print ("Reached z position\n")

    turtle.forward()

    while not (math.abs(math.floor(tmp.x) - math.floor(rPosition.x)) < math.abs(math.floor(cPosition.x) - math.floor(rPosition.x)))     and rPosition.x ~= tmp.x do
        turtle.back()
        turtle.turnRight()
        turtle.forward()
        tmp.x, tmp.y, tmp.z = gps.locate()
    end

    while math.abs(math.floor(tmp.x) - math.floor(rPosition.x)) < math.abs(math.floor(cPosition.x) - math.floor(rPosition.x))
    and rPosition.x ~= tmp.x do
        turtle.forward()
        tmp.x, tmp.y, tmp.z = gps.locate()
    end
    print ("Reached x position\n")

    while tmp.y ~= rPosition.y do
        turtle.down()
        tmp.x, tmp.y, tmp.z = gps.locate()
    end
    print ("Reached y position\n")

    turtle.turnRight()
    turtle.turnRight()
end

local _, tmpI = turtle.inspect()
while tmpI.name ~= target do
    print ("Turning to " .. target .. "\n")
    turtle.turnRight()
    _, tmpI = turtle.inspect()
end


function harvest ()
    local _, data = turtle.inspect()
    if data.name == target then
        turtle.dig()
        turtle.suckUp()
        turtle.suck()
        turtle.suckDown()
        skipped = 0
        --print ("harvest true\n")
        return true
    end
    skipped = skipped + 1
    --print ("harvest false\n")
    return false
end

function checkFuel ()
    if turtle.getFuelLevel() <= #path + 10 then
        print ("no fuel\n")
        for i = 1, 16, 1 do
            if turtle.getItemDetail(i).name == fuelType then
                turtle.select(i)
                turtle.refuel()
                print ("refuel\n")
                return true
            end
        end

        print ("out of fuel\n")
        return false
    end

    return true
end


function run ()
    if not checkFuel() then return end
    local cond = false
    turtle.up()
    turtle.up()
    local _, data = turtle.inspect()
    if data.name == target then cond = true end
    turtle.down()
    while cond and skipped < 6 do -- ignore max distance for now
        print ("skipped: " .. skipped .. "\ndistance: " .. distance .. "\n")

        -- refuel
        if not checkFuel() then return end

        if harvest() then
            if turtle.forward() then
                distance = distance + 1
                table.insert(path, "forward")
            end
        else
            --print ("check left\n")
            turtle.turnLeft()

            if harvest() then
                if turtle.forward() then
                    table.insert(path, "left")
                end
            else
                --print ("check right\n")
                turtle.turnRight()
                turtle.turnRight()

                if harvest() then
                    if turtle.forward() then
                        table.insert(path, "right")
                    end
                else
                    turtle.turnLeft()
                    if turtle.forward() then
                        distance = distance + 1
                        table.insert(path, "forward")
                    end
                end
            end
        end


    end

    print ("Moving back!\nDistance: " .. distance .. "\nPath Length: " .. #path .. "\n")
    turtle.turnRight()
    turtle.turnRight()
    for i = #path, 1, -1 do
        while not turtle.forward() do harvest() end
        if path[i] == "forward" then
            -- just forward
        elseif path[i] == "left" then
            turtle.turnRight()
        elseif path[i] == "right" then
            turtle.turnLeft()
        end
    end
    turtle.down()
    turtle.turnRight()
    turtle.turnRight()

    print ("wait " .. sleepTime .. "s\n")
    sleep(sleepTime)
    path = {}
    skipped = 0
    distance = 0
    print ("restart\n")
    run()
end

run()