------Tunneling Automaton------

----Variables----

t = turtle
orientation = 1

----Basic Digging and Control Operations----

--Orientation change, 1 is forward by initialization--
function OCL()
    if orientation == 4 then
        orientation = 0
    else
        orientation = orientation + 1
    end
end
function OCR()
    if orientation == 1 then
        orientation = 4
    else
        orientation = orientation - 1
    end
end

--Turning Left and Right--
function TLE()
    t.turnLeft()
    OCL()
end
function TRI()
    t.turnRight()
    OCR()
end

--Reorienting efficiently--
function REO()
    if orientation == 2 then
        TLE()
    elseif orientation == 3 then
        TLE()
        TLE()
    elseif orientation == 4 then
        TRI()
    end
end

--Digging in Basic Directions--
function DUP()
    t.digUp()
end
function DDO()
    t.digDown()
end
function DFO()
    t.digForward()
end

--Moving in Basic Directions--
function MUP()
    t.up()
end
function MDO()
    t.down()
end
function MFO()
    t.forward()
end

--Digging Left and Right--
function DRI()
    TRI()
    DFO()
end
function DLE()
    TLE()
    DFO()
end

--Moving Left and Right--
function MRI()
    TRI()
    DFO()
end
function MLE()
    TLE()
    DFO()
end

--Digging and Moving Efficiently--
function DMU()
    if t.detectUp() then
        DUP()
        MUP()
    else
        MUP()
    end
end
function DMD()
    if t.detectDown() then
        DDO()
        MDO()
    else
        MDO()
    end
end
function DMF()
    if t.detect() then
        DFO()
        MFO()
    else
        MFO()
    end
end
function DMR()
    TRI()
    if t.detect() then
        DFO()
        MFO()
    else
        MFO()
    end
end
function DML()
    TLE()
    if t.detect() then
        DFO()
        MFO()
    else
        MFO()
    end
end

--Input Distance--
function dis()
    print("Input Distance:")
    num = io.read()
    num = tonumber(num)
    return num
end

--Refuel based on distance--
function fuel(distance)
    t.refuel()
end

----Advanced Mining Operations----

function tunnel(distance)
    if not t.getFuelLevel() >= distance then
        fuel(distance-t.getFuelLevel())
    end
    while distance > 0 do
        DMF()
        DUP()
        distance = distance - 1
    end
end

function hole(distance)
    if not (t.getFuelLevel() >= distance) then
        fuel(distance-t.getFuelLevel())
    end
    while distance > 0 do
        DMD()
        distance = distance - 1
    end
end

----Main Loop----
function main()
    hole(dis())
end
--Run--
main()