mining

function isfull()
    for i=1,16,1 do
        if turtle.getItemSpace(i) > 0 then
            return false
        end
    end
    return true
end

function digging()
    if turtle.detect() then
  local inspection = vector.new(turtle.inspect())
        while inspection.y["name"] == "minecraft:gravel" do
   inspection = vector.new(turtle.inspect())
            turtle.dig()
        end
        turtle.dig()
    end
end

function dig_blocs(z)
    if z[1] == 3 then
        digging()
        turtle.down()
        z[1] = z[1] - 1
        digging()
        turtle.down()
        z[1] = z[1] - 1
        digging()
    elseif z[1] == 1 then
        digging()
        turtle.up()
        z[1] = z[1] + 1
        digging()
        turtle.up()
        z[1] = z[1] + 1
        digging()
    end
end

function get_back(home)
    local position = vector.new(gps.locate(5))
    turtle.turnLeft()
    turtle.turnLeft()
    if not position.x then
        print("Lost")
        return 0
    end
    while position.z ~= home.z do
        turtle.down()
        position = vector.new(gps.locate())
    end
    position = vector.new(gps.locate())
    while position.x ~= home.x or position.y ~= home.y do
        position =vector.new(gps.locate())
        if turtle.getFuelLevel() < 3 then
            reload_fuel(2)
        end
        turtle.forward()
    end
end

function check_level(fuel_slot)
    turtle.select(fuel_slot)
    return turtle.getItemCount()
end

function reload_fuel(fuel_slot)
    local previous_slot = turtle.getSelectedSlot()
    turtle.select(fuel_slot)
    turtle.refuel(1)
    turtle.select(previous_slot)
end

local args = { ... }

function main(args)
    local upordown = false
    local z = {1,3}
    local home = vector.new(gps.locate())
    if table.getn(args) < 1 then
        print("Depth of mining is required as arg. 1")
        return 1
    end
    local depth = tonumber(args[1])
    for i=1,depth,1 do
        if turtle.getFuelLevel() < 3 then
            reload_fuel(2)
        end
        dig_blocs(z)
        turtle.forward()
        upordown = not upordown
        if check_level(2) < 5 then
            get_back(home)
        end
    end
    get_back(home)
end

main(args)