Gapbuild

--Gapbuilder
--Made by RockRevenchy
--ver 1.0

--also with plenty of comments if you want to trace what I did here!

--=========
--variables
--=========
curslot = 1
fuelused = 0
x = 0
z = 0
currentl= 0
step = 0
onlymine = 0
progress = 1
futurew = 0
oneline = false

--=========
--function
--=========

--plain and simple, move 1 block ahead and check if we got fuel, attack in front of us in case someone is at the wrong place and make sure we can go forward by mining whatever's in front of us
function moveforward()
    while not turtle.forward() do
        checkfuel()
        turtle.dig()
        turtle.attack()
    end
end

--make sure we still have fuel, if not then go to the first slot and refuel, if however this didnt succeed, wait until the user places fuel in the first slot
function checkfuel()
    if turtle.getFuelLevel() < 1 then
        turtle.select(1)
        if not turtle.refuel(1) then
            print("No fuel in slot 1, awaiting fuel")
            while not turtle.refuel(1) do
            end
            print("Successfully refueled, continuing")
        end
        fuelused = fuelused + 1
        turtle.select(curslot)
    end
end

--if the turtle is not on "mine mode only" then select the next slot, if we're at the last slot, stop here and wait until the user puts more blocks inside, until then just scan the inventory and keep pestering the user every 5 seconds :D
function selnextslot()
    if onlymine == 0 then
        curslot = curslot + 1
        if curslot == 16 then
            print("Out of blocks")
            print("Please insert more blocks")
            select(1)
            curslot = 1
            while turtle.getItemCount(curslot) < 0 do
                turtle.getItemCount(curslot)
                if curslot == 16 then
                    turtle.select(curslot)
                    turtle.getItemCount(curslot)
                    curslot = 1
                else
                    turtle.select(curslot)
                    turtle.getItemCount(curslot)
                    sleep (5)
                    curslot = curslot + 1
                end
            end
        end
        turtle.select(curslot)
    end
end

--make sure we're not currently out of blocks, if so, go to the next slot
function checkblockcount()
    if turtle.getItemCount(curslot) == 0 then
        selnextslot()
    end
end

--checks if we've got inventory, if we do, stop the select to the first item detected, if we dont, ask user if we should only mine then
function searchinv()
    turtle.select(1)
    curslot = 1
    for z = 1, 16 do
        if curslot == 16 then
            turtle.select(1)
            curslot = 1
            shell.run("clear")
            print("This turtle is empty, do you want to only mine holes?")
            print(" ")
            write("Press any key to continue or ctrl+t to stop")
            print(" ")
            os.pullEvent("key")
            print(" ")
            print("OK!")
            onlymine = 1
            break
        end
        turtle.select(curslot)
        if turtle.getItemCount(curslot) > 1 then
            break
        end
        curslot = curslot + 1
    end
end

--checks if the user requested up or down placing and if the turtle is set to "mine mode only" then replace (or mine) whatever block it should
function place()
    sleep(0.5)
    if up == true then
        turtle.digUp()
        sleep(0.5)
        if onlymine == 0 then
            while turtle.placeUp() == false do
                    checkblockcount()
            end
        end
    else
        turtle.digDown()
        sleep(0.5)
        if onlymine == 0 then
            while turtle.placeDown() == false do
                checkblockcount()

            end
        end
    end
end

--go to the next line
function turn()
    for x = 1, step+1 do
        moveforward()
    end
    turtle.turnLeft()
    place()
end

--=========
--code
--=========

--checks if arguments were put in the commands, if not it shows how to use the command
local args = {...}
if #args ~= 4 then
    print("Usage: [length] [width] [gap] [u|d]")
    os.pullEvent("key")
    print(" ")

    print("[length] [width]")
    print(" ")
    print("From bottom left corner to top right corner, including the turtle's current position.")
    os.pullEvent("key")
    print(" ")

    print("[gap]")
    print(" ")
    print("How many empty blocks between the blocks placed down?")
    os.pullEvent("key")
    print(" ")

    print("[u|d]")
    print(" ")
    print("(Up or Down)")
    print("Should the blocks be placed below or above the turtle?")
    return
end

--pulling arguments from the command thrown and keeping them as variables
length = tonumber(args[1])
width = tonumber(args[2])
step = tonumber(args[3])

--check if the turtle should place upward
if args[4] == "u" then
    up = true
elseif args[4] == "up" then
    up = true
end

--gives visual feedback to make sure the user is fine with the program's intentions
shell.run("clear")
print("Current length: "..length)
print("Current width: "..width)
print("Current distance between blocks: "..step)
if up == true then
    print("place blocks up (above turtle)")
else
    print("place blocks down (below turtle)")
end

print(" ")

--take one block away to include the turtle's position from the start of the dimensions requested
width = width - 1
length = length - 1

--if the user requested either one line of blocks or a gap greater than the width, make it so it runs only for one width line
if width < step then
    width = step
    futurew = step+1
    oneline = true
end

--if the user puts an illegal value, stop there rather than let it go awire
if step > length then
    print("Incorrect value, your gap is greater than your length")
    error()
end

--request user's agreement to actually start
print("Is this ok?")
write("Press any key to continue or ctrl+t to stop")
os.pullEvent("key")
print(" ")
print("Starting...")

sleep(1.5)
--search inventory for blocks, if the function doesnt find any, the program will ask the user if the turtle should only mine then (see functions above)
searchinv()

--place the first block before starting (else it would not as it should place it after actually moving)
place()

--start the work sequence here

--run this sequence for as long as the width number
for xx = 1, width do

--shows progress on screen (also adapts to one line requests)
    if oneline == true then
        print("Current width: "..progress.."/1")
    else
        print("Current width: "..progress.."/"..width+1)
    end

--repeat this process for as many times as the length requested also localy calculate how many blocks we moved without placing a block
--once we moved as many blocks as the gap requested + 1 block for the turtle's position, reset the counter and place one block
    for x = 1, length do
        currentl = currentl + 1
        moveforward()
        if currentl == step+1 then
            place()
            currentl = 0
        end
    end

--we reached the end of the line, go back to the start of the line
    turtle.turnRight()
    turtle.turnRight()
    for y = 1, length do
        moveforward()
    end
    turtle.turnLeft()

--check if the next gap goes beyond the max width, if it does then stop right there rather than break out of bounds
    futurew = progress + step

    --print("DEBUG: "..width.." | "..progress.." | "..futurew)

    if progress > width then
        break
    elseif futurew > width then
        print("Stopping here to avoid going out of the requested width.")
        print(" ")
        break
    end

--calculate where we're going before actually going there
    currentl = 0
    progress = progress + step
    progress = progress + 1

--proceed to the next line then go back to the start of the sequence to redo everything until we're done
    turn()
end

--make the turtle face its magnificient work in admiration then take a coffee break until the user comes back
turtle.turnLeft()
print("All done!")