term.clear()
term.setCursorPos(1, 1)

repeat
print("Enter tunnel length (even digit): ")
tunnellength = read()
until tunnellength % 2 == 0

term.clear()
term.setCursorPos(1, 1)

print("Place Fuel in Slot 1")
print("Enter number for fuel type: ")
print("")
print("No Fuel Required = 0")
print("Coal/Charcoal/Peat = 1")
print("Coal Coke = 2")
print("Biofuel Can = 3")
print("Coalfuel Can = 4")
fueltype = read()

function fueltypeset()
if fueltype == "1" then
fueltype = 80
elseif fueltype == "2" then
fueltype = 160
elseif fueltype == "3" then
fueltype = 520
elseif fueltype == "4" then
fueltype = 1520
end
end
fueltypeset()
term.clear()
term.setCursorPos(1, 1)

print("Drop mined cobblestone? 0=No, 1=Yes")
cobblesetting = read()
term.clear()
term.setCursorPos(1, 1)
if cobblesetting == "1" then
if turtle.getItemCount(2) < 1 then
print("Place 1 cobblestone in Slot 2")
print("")
end
end

print("Place torches? 0=No, 1=Yes")
print("Place torches in Slot 3")
torchsetting = read()
term.clear()
term.setCursorPos(1, 1)
if torchsetting == "1" then
if turtle.getItemCount(3) < tunnellength/10 then
print("Warning: You will not have enough torches for entire tunnel length.")
print("")
print("")
end
end


print("Return and deposit items to chest if inventory nears full?")
print("0=No, 1=Yes")
returnsetting  = read()
term.clear()
term.setCursorPos(1, 1)
if returnsetting == "1" then
print("Place chest immediately behind turtle.")
end

print("")
print("Begin mining?")
print("0=Cancel Program, Any Key=Yes")
beginmine = read()
if beginmine == "0" then
os.reboot()
end

term.clear()
term.setCursorPos(1,1)
print("Tunneling " .. tunnellength .. " blocks, then returning.")
sleep(2)

torchpos = 0

function progress()
term.setCursorPos(1,3)
print("Progress: " .. torchpos .. " of " .. tunnellength)
end

function fuelcheck()
        if turtle.getFuelLevel() ~= "unlimited" then
                if turtle.getFuelLevel()/fueltype < 0.26 then
                turtle.select(1)
                turtle.refuel(1)
                end
        end
end

function dropcobble()
    local stackSize = turtle.getItemCount(2)
        if cobblesetting == "1" then
                if turtle.getFuelLevel() ~= "unlimited" then
                        if stackSize > 2 then
                        stackSize = stackSize-1
                        turtle.select(2)
                        turtle.drop(stackSize)
                        end
                elseif turtle.getFuelLevel() == "unlimited" then
                        if stackSize > 2 then
                                stackSize = stackSize-1
                                turtle.select(2)
                                turtle.drop(stackSize)
                                end
                        turtle.select(1)
                        if turtle.compareTo(2) then
                                turtle.drop()
                                end

                        end
                end
end


function minecycle()
for z = 1, tunnellength do
fuelcheck()
turtle.select(1)
turtle.dig()
moveforward()
turtle.digDown()
torchpos = torchpos + 1
placetorch()
progress()
end
end

function placetorch()
        if torchsetting == "1" then
                if torchpos % 10 == 0 then
                turtle.turnLeft()
                turtle.dig()
                turtle.select(3)
                turtle.place()
                turtle.turnRight()
                dropcobble()
                fuelcheck()
                fullinventory()
                turtle.select(1)
                end
        else
                if torchpos % 10 == 0 then
                dropcobble()
                fuelcheck()
                fullinventory()
                turtle.select(1)
                end
        end
end

function moveforward()
while not turtle.forward() do
sleep(0.25)
turtle.dig()
end
end

function turtlehome()
for y = 1, tunnellength do
fuelcheck()
moveforward()
end
end

function drop()
turtle.select(4)
turtle.drop()
turtle.select(5)
turtle.drop()
turtle.select(6)
turtle.drop()
turtle.select(7)
turtle.drop()
turtle.select(8)
turtle.drop()
turtle.select(9)
turtle.drop()
turtle.select(10)
turtle.drop()
turtle.select(11)
turtle.drop()
turtle.select(12)
turtle.drop()
turtle.select(13)
turtle.drop()
turtle.select(14)
turtle.drop()
turtle.select(15)
turtle.drop()
turtle.select(16)
turtle.drop()
end


function fullinventory()
local invcount = 0
        if returnsetting == "1" then
                for c = 4, 16 do
                        if turtle.getItemCount(c) > 0 then
                        invcount = invcount+1
                        end
                end
                if invcount > 12 then
                        turtle.turnLeft()
                        turtle.turnLeft()
                        fuelcheck()
                        for f = 1, torchpos+1 do
                        moveforward()
                        fuelcheck()
                        end
                        for d = 4, 16 do
                        turtle.select(d)
                        turtle.dropDown()
                        end
                        turtle.turnLeft()
                        turtle.turnLeft()
                        fuelcheck()
                        for f = 1, torchpos+1 do
                        moveforward()
                        fuelcheck()
                        end
                        invcount = 0
                else
                        invcount = 0
                end
        end
end


fuelcheck()
turtle.digUp()
turtle.up()
minecycle()
turtle.turnLeft()
turtle.turnLeft()
fuelcheck()
turtlehome()
turtle.down()
drop()
turtle.turnRight()
turtle.turnRight()
term.setCursorPos(1,5)
print("Mining Successful")
term.setCursorPos(1,7)