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", "minecraft:redstone",
    "minecraft:torch"
}

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 stackItems()
    local inventory = {}

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

        for invSlot = 1, slotCount, 1 do
            local checking = turtle.getItemDetail(invSlot)
            if (checking ~= nil) then print(checking.name) end
        end
    end

end

function flip()
    turtle.turnLeft()
    turtle.turnLeft()
end

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

        if (item ~= nil) then
            if (item.name == "minecraft:oak_chest") then
                turtle.select(slot)
                turtle.placeUp()
                print('chest placed')
            end
        end
    end

    for itemSlot = 1, slotCount, 1 do
        local item = turtle.getItemDetail(itemSlot)

        if (item ~= nil) then
            if (item.name ~= "minecraft:coal" or item.name ==
                "minecraft:coal_block" or item.name == "minecraft:oak_chest") then
                turtle.select(itemSlot)
                turtle.dropUp()
            end

        end
    end
end

function checkIfFullInventory()
    local emptySlot = true
    for slot = 1, slotCount, 1 do
        local item = turtle.getItemDetail(slot)

        if (item == nil) then emptySlot = false end
    end

    if (emptySlot == false) then return true end

    return false
end

function manageInventory()
    purgeTrash()
    if (checkIfFullInventory() == true) then emptyToChest() 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 checkIfGravel()
    local success, item = turtle.inspect()

    if (success) then
        print(item.name)
        if (item.name == "minecraft:gravel") then return true end
    end
    return false
end

function digBlock()
    while turtle.detect() == false do turtle.forward() end
    for row = 1, width, 1 do
        for col = 1, length, 1 do
            checkFuel()
            digColumn()
            if (checkIfGravel() == true) then
                print("found gravel, extending col")
                length = length + 1
            end
            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()