Branch Miner

print("Number of branches?")
local tunnelNumber = read() -- Here we set up the variables that the whole program works on
print("Length of branches? Longer than 10 inadvisable.")
local tunnelLength = read()
print("Distance between? 3 is ideal.")
local tunnelWall = read()
print("Place torches in slot 2. Press enter when ready.")
read()
local mainDistance = 0
local sideDistance = 0
local mainLength = tunnelNumber*(tunnelWall+1)
local totalTravel = (4*tunnelLength)*(tunnelNumber+2)+(mainLength*2)
print("The total fuel requirement will be: "..totalTravel)
sleep(2)

    function sideWork(dist) -- For making the side tunnels, argument is tunnel length. Increments sideDistance
        for i=1,dist do
            while turtle.detect() do
                turtle.dig()
            end
            turtle.forward()
            sideDistance = sideDistance +1
            turtle.digDown()
            turtle.digUp()
        end
    end

    function mainWork(dist) -- For making the main tunnel, argument is tunnel length. Increments mainDistance
        for i=1,dist do
            while turtle.detect() do
                turtle.dig()
            end
            turtle.forward()
            mainDistance = mainDistance + 1
            turtle.digDown()
            turtle.digUp()
        end
    end

    function travel(dist) -- Truncating the turtle.forward command, being stopped by a player or mob will not harm.
        for i=1, dist do
            repeat
            until turtle.forward() == true
        end
    end

    function spin() -- because he will do it a lot
        turtle.turnRight()
        turtle.turnRight()
    end

    function noFuel() -- Calculates total fuel cost for the job, returns true if there is not enough fuel
        if turtle.getFuelLevel() < totalTravel then
            return true
        end
    end

    function placeTorch() -- Places a torch from slot 2
        turtle.select(2)
        turtle.placeUp()
        turtle.select(1)
    end

    function checkInventory() -- Returns true if there is an item in the next to last inventory slot
        if turtle.getItemCount(15) > 0 then
            return true
        end
    end

    function goHome() -- To return home from the main tunnel
        spin()
        travel(mainDistance)
    end

    function goToMain() -- To return to the main tunnel from the side tunnel
        spin()
        travel(sideDistance)
    end

    function main(number,length,wall) -- Lets dig this damn tunnel now

        if noFuel() == true then
        print("Please place at least "..totalTravel - turtle.getFuelLevel().." fuel in slot 1.")
        end

        while noFuel() do -- If there is no fuel, the turtle will keep checking and trying to refuel until it has enough for the job
            turtle.select(1)
            turtle.refuel()
            sleep(0.5)
        end


        for i=1,number do -- For as many times as there are tunnels

            mainWork(wall+1) -- Dig to the next side tunnel
            turtle.back()
            placeTorch() -- Place a torch right before tunnel
            turtle.forward() -- Get to the tunnel proper
            turtle.turnRight() -- Turn to dig the right side
            sideWork(length) -- Dig for the length defined for the branches
            placeTorch() -- place a torch at the end of each branch
            spin() -- Turn around at the end of the tunnel
            travel(length) -- Back to the main tunnel
            sideDistance = 0 -- Reset side distance for next tunnel
            sideWork(length) -- Dig the tunnel on the left now
            placeTorch()
            spin()
            travel(length)
            turtle.turnLeft()

            if checkInventory() then -- If the next to last slot has an item in it, go home, drop everything, and come back
                goHome()
                turtle.select(1)
                turtle.drop()
                for slot=3,16 do
                    turtle.select(slot)
                    turtle.drop()
                end
                turtle.select(1)
                spin()
                travel(mainDistance)

            end

        end

        goHome()

            for slot=1,16 do
                turtle.select(slot)
                turtle.drop()
            end

        print("Job complete! What's next?")

    end


main(tunnelNumber,tunnelLength,tunnelWall)