Mining-turtle (Stripmining) V.1.7

--This code is developed by me (onix331) and is availiable under the GNU General Public License (Version 3)
--See http://opensource.org/licenses/GPL-3.0
--Have fun

space = 16--Defines the space of the turtle
ver = 1.7--For updates
chest = 0--If the turtle has stopped at a chest
stop = 0--If the turtle has stopped at a chest
shaftrun = 0--How many shafts the turtle has run

function main()--Main Program
    while true do
        if count>=1 then
            if direction=="r" then
                move()
                turnaround()
                move()
                count = count - 1
                checkspace()
            elseif direction=="l" then
                move()
                turnaround()
                move()
                count = count - 1
                checkspace()
            end
        else
            break
        end
    end
end

function returnmining()--To return to the latest shaft
    chest = 0
    stop = 1
    if direction=="r" then
        turtle.turnRight()
        for i = 0, shaftrun do
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        turtle.turnLeft()
        main()
    elseif direction=="l" then
        turtle.turnLeft()
        for i = 0, shaftrun do
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        turtle.turnRight()
        main()
    end
end

function checkl() --To check if length is valid (>0, not a String), also transforms the string into a number
    length = tonumber(length)
    if length==nil then
        print ("Invalid number!")
        length = read()
        checkl()
    elseif length <= 0 then
        print ("Invalid number!")
        length = read()
        checkl()
    end
end

function checka()--To check if count is valid (>0, not a String), also transforms the string into a number
    count = tonumber(count)
    if count==nil then
        print ("Invalid number!")
        count = read()
        checka()
    elseif count <= 0 then
        print ("Invalid number!")
        count = read()
        checka()
    end
end

function checkr()--To check if direction is valid ((r) or (l))
    if direction=="r" then
        print ("")
    elseif direction=="l" then
        print ("")
    else
        print ("Invalid input!")
        direction = io.read()
        checkr()
    end
end

function checkref()--To check if refuel is valid ((y) or (n))
    if refuel=="y" then
        print ("")
    elseif refuel=="n" then
        print ("")
    else
        print ("Invalid input!")
        refuel = io.read()
        checkref()
    end
end

function move()--Basic movement function
    local debug = 8--Used to avoid gavel, sand, etc.
    for i = 1, length do
        if turtle.detect() then
            for i = 1, debug do
                turtle.dig()
            end
            turtle.forward()
        else
            turtle.forward()
        end
        if turtle.detectUp() then
            for i = 1, debug do
                turtle.digUp()
            end
        end
    end
end

function turnaround()--Turns the turtle at 90 degrees
    turtle.turnRight()
    turtle.turnRight()
end

function nextshaftr()--Next shaft (right)
    countn = countn - 1
    if countn>=2 then
        shaftrun = shaftrun + 1
        turtle.turnLeft()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.digUp()
        turtle.turnLeft()
    end
end

function nextshaftl()--Next shaft (left)
    countn = countn - 1
    if countn>=2 then
        shaftrun = shaftrun + 1
        turtle.turnRight()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.forward()
        turtle.digUp()
        turtle.turnRight()
    end
end

function returnpoint()--Return to initial point

    if direction=="r" then
        turtle.turnRight()
        for i = 1, shaftrun do
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        if stop==1 then
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        turtle.turnLeft()
        for i = 1, space do
            turtle.select(i)
            turtle.drop()
        end
        turtle.select(1)
    elseif direction=="l" then
        turtle.turnLeft()
        for i = 1, shaftrun do
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        if stop==1 then
            turtle.forward()
            turtle.forward()
            turtle.forward()
        end
        turtle.turnRight()
        for i = 1, space do
            turtle.select(i)
            turtle.drop()
        end
        turtle.select(1)
    end
    turnaround()
    if chest==1 then
        returnmining()
    end
end

function checkspace()--Check for space and if necessary, return to initial point to the chest
    local spaceleft = 0
    for i = 1, space do
        if turtle.getItemSpace(i) > 10 then
            spaceleft = spaceleft + 1
        end
    end
    if spaceleft < 5 then
        chest = 1
        countn = countn - 1
        returnpoint()
    else
        if direction=="r" then
            nextshaftr()
        else
            nextshaftl()
        end
    end
end

shell.run ("clear")
print ("Strip-mining-program by onix331")
print ("Version ", ver)

--Start user input
print ("Length of the single shaft(s):")
length = read()
checkl()

print ("Count of the shafts:")
count = read()
checka()
countn = count
countn = countn + 1

print ("Direction of the shafts (Left (l), Right (r):")
direction = read()
checkr()
--Refueling, a little bit complicatet
print ("Dont forget to refuel!")
print ("Now? (Yes (y), No (n):")
refuel = read()
checkref()
if refuel=="y" then
    print ("Please insert fuel anywhere")
    print ("When done, press ENTER")
    while true do
        local sEvent, param = os.pullEvent("key")
        if sEvent == "key" then
            if param == 28 then
                for i = 1, space do
                    for i = 1, 64 do
                        shell.run("refuel", rafzahl)
                    end
                    turtle.select(i)
                end
                turtle.select(1)
                break
            end
        end
    end
end

--Print user inputs
shell.run ("clear")
print ("Input of Length:")
print (length)
print ("Input of count")
print (count)
print ("Direction of the shafts:")
print (direction)
os.sleep(2)
print ("3")
os.sleep(1)
print ("2")
os.sleep(1)
print ("1")
os.sleep(1)
print("Start!")
main()

returnpoint()
print ("Done!")