local arg1 = ...

if arg1 == nil then
    print("miner <length>")
    return false
end
local length = tonumber(arg1)
local delay = 0.25

function forward()
    dig()
    turtle.forward()
end

function up()
    while turtle.detectUp() do
        turtle.digUp()
        sleep(delay)
    end
    turtle.up()
end

function right(times)
    if times == nil then
        times = 1
    end
    for _ = 1, times do
        turtle.turnRight()
    end
end

function left(times)
    if times == nil then
        times = 1
    end
    for _ = 1, times do
        turtle.turnLeft()
    end
end

function dig()
    while turtle.detect() do
        turtle.dig()
        sleep(delay)
    end
end

function digRow()
    right()
    dig()
    left(2)
    dig()
    right()
end

local neededFuel = 2*length;
local coal = math.ceil(neededFuel/80)
if neededFuel > turtle.getFuelLevel() then
    turtle.select(1)
    print("Please put "..coal.." piece(s) of coal into slot 1")
    while neededFuel > turtle.getFuelLevel() do
        turtle.refuel()
    end
end

print("Digging...")

for _ = 1, length do
    forward()
    digRow()
    up()
    digRow()
    turtle.down()
end

left(2)
for _ = 1, length do
    turtle.forward()
end
if turtle.detect() then
    for i = 2, 16 do
        turtle.select(i)
        turtle.drop()
    end
end
left(2)
print("Done!")
print("Rest fuel: "..turtle.getFuelLevel())