[FTB Turtle] Strip Mining Program V2

lightLevel = 0
distance = 0
runs = 0

function checkFuel()
    if turtle.getFuelLevel() <= 10 then
        turtle.select(16)
        if turtle.getItemCount() > 0 then
            turtle.refuel(1)
            turtle.select(1)
        -- elseif turtle.getItemCount < 1 then
        --  for i = 1, 13 do
        --      turtle.select(i)
        else
            print("Out of fuel! Terminating program.")
            error()
        end --if statement
    end --if statement
end --function

function torchCount()
    if lightLevel == 11 then
        turtle.select(15)
        if turtle.getItemCount() > 0 then
            turtle.turnLeft()
            turtle.dig()
            turtle.place()
            turtle.turnRight()
            turtle.select(1)
            lightLevel = 0
        else
            print("Out of torches! Terminating program.")
            lightLevel = 0
            error()
        end --if statement
    end --if statement
end --function

function digInFront()
    turtle.dig()
    turtle.forward()
    turtle.digUp()
end --function

function positionNextTunnelRight()
    turtle.turnRight()
    rightRuns = 0
    while rightRuns < 3
        turtle.dig()
        turtle.forward()
        turtle.digUp()
        rightRuns = rightRuns + 1
    end --while function
    turtle.turnRight()
end --function

function positionNextTunnelLeft()
    turtle.turnLeft()
    leftRuns = 0
    while leftRuns < 3
        turtle.dig()
        turtle.forward()
        turtle.digUp()
        leftRuns = leftRuns + 1
    end --while function
    turtle.turnLeft()
end --function

function checkInv()
    turtle.select (13)
    if turtle.getItemCount() > 0 then
        turtle.select(14)
        if turtle.getItemCount() > 0 then
            turtle.digDown()
            turtle.place()
            for i = 1, 13 do
                turtle.select(1)
                turtle.dropDown()
            end --while loop
            turtle.select(1)
        else
            print("Out of storage chests! Terminating program.")
            error()
        end --itemCount chest function
    end --inventory check function
end --function

--[[THIS IS WHERE THE MAIN PROGRAM STARTS]]--

-- Defines the length of the tunnels
print("How long should the tunnels be?")
length = tonumber(read())

-- Defines the number of tunnels
print("How many individual tunnels should be dug?")
count = tonumber(read())

-- Confirmation message
print("Now excavating the tunnels!")

while runs < count do
    checkFuel()
    torchCount()
    if distance < length then
        digInFront()
        distance = distance + 1
    else
        if runs % 2 == 0 then
            positionNextTunnelRight()
            runs = runs + 1
            distance = 0
        else
            positionNextTunnelLeft()
            runs = runs + 1
            distance = 0
        end --Check turn direction
    end --Digging tunnels
    checkInv()
    lightLevel = lightLevel + 1
end --Function

if runs % 2 == 0 then
    positionNextTunnelRight()
else
    positionNextTunnelLeft()
end --Check turn direction

print("The tunnels are complete!")