local slotCount = 16
local width = 25
local length = 25
local height = 3

if (arg[1] ~= nil) then
    width = arg[1]
    length = arg[1]
end

local trash = {
    "minecraft:cobblestone", "minecraft:stone", "minecraft:andesite",
    "minecraft:diorite", "minecraft:clay_ball", "minecraft:sand",
    "minecraft:sandstone", "minecraft:limestone", "minecraft:dirt",
    "quark:limestone", "minecraft:flint", "rustic:slate", "chisel:limestone2", "chisel:limestone", "minecraft:gravel"
}

function checkFuel()
    print('Checking fuel...')
    local refueled = false
    if (turtle.getFuelLevel() < 3000) then
        for slot = 1, slotCount, 1 do
            local item = turtle.getItemDetail(slot)
            if (item ~= nil) then
                if (item.name == "minecraft:coal" or item.name ==
                    "minecraft:coal_block") then
                    print('Attemping to refuel with %d', item.name)

                    turtle.select(slot)

                    local result = turtle.refuel()

                    refueled = true
                    print('Turtle refueled...')

                    break
                end
            end
        end
        if (refueled == false) then
            print('Did not find coal in inventory.. going to power down soon D:')
        end
        return false
    end
end

function digColumn()
    turtle.dig()
    turtle.forward()
    turtle.digUp()
    turtle.digDown()
end

function purgeTrash()
    for slot = 1, slotCount, 1 do
        local item = turtle.getItemDetail(slot)

        if (item ~= nil) then
            for key, value in pairs(trash) do
                if (value == item.name) then
                    print("found trash:", item.name)
                    print('trash in slot:', slot)
                    turtle.select(slot)
                    turtle.drop()
                    break
                end
            end
        end

    end
end

function turnAround(dir)
    print("turning around...")
    if dir == "right" then turtle.turnRight() end
    if dir == "left" then turtle.turnLeft() end

    digColumn()

    if dir == "right" then turtle.turnRight() end
    if dir == "left" then turtle.turnLeft() end
end

function digBlock()
    while turtle.detect() == false do turtle.forward() end
    for row = 1, width, 1 do
        for col = 1, length, 1 do
            digColumn()
            checkFuel()
            print("col:", col)
            print("length:", length)
            if (col == length) then
                print('i should probably turn around')
            end
        end
        purgeTrash()
        if row % 2 == 1 then turnAround("right") end
        if row % 2 == 0 then turnAround("left") end
    end
end

digBlock()