Ngon Builder stand alone

--Variables
args = { ... }

cost_only = false
sim_mode = false

blocks = 0
fuel = 0

positionx = 0
positiony = 0
positionz = 0
facing = 0

activeslot = 1

--Functions
function round(num, idp)
  local mult = 10^(idp or 0)
  return math.floor(num * mult + 0.5) / mult
end

function printUsage()
    print("Usage: ngon [<Number of Sides> [Side Length] [Height]] [-c, cost] [-h, help]")
    print("Please use numbers for Number of Sides, Side Length, and Height")
    print("Only 6 or 8 may be passed for Number of sides.")
    print("If Height isnt't given, a height of one will be used")
    print("-h or -help: display this help page")
    print("-c or -cost: cost only mode, doesn't move or place blocks")
end

function initialize(wrongNumSidesValue)
    if #args > 0 then
        if #args > 5 then
            printUsage()
            return false
        else
            for i,v in ipairs(args) do
                if v == "-c" or v == "-cost" then
                    cost_only = true
                    print("Cost only mode activated")
                elseif v == "-h" or v == "-help" then
                    printUsage()
                    return false
                end
            end
        end
    end

    if not wrongNumSidesValue then
        print("Welcome to the N-gon Builder.")
        print()
    end

    if not wrongNumSidesValue then
        if #args >= 3 then
            numSides = tonumber(args[1])

            sideLength = tonumber(args[2])

            height = tonumber(args[3])
        elseif #args >= 2 then
            numSides = tonumber(args[1])

            sideLength = tonumber(args[2])

            height = 1
        elseif #args == 1 then
            numSides = tonumber(args[1])

            print("How long should each side be?")
            sideLength = tonumber(io.read())

            height = 1
        else
            print("How many sides do you want?")
            numSides = tonumber(io.read())

            print("How long should each side be?")
            sideLength = tonumber(io.read())

            height = 1
        end
    end

    if wrongNumSidesValue then
        print("How many sides do you want?")
        numSides = tonumber(io.read())

        print("How long should each side be?")
        sideLength = tonumber(io.read())

        height = 1
    end

    if numSides == 8 or numSides == 6  then
        --all is good in the world
    else
        print("Number of sides must either be 6 or 8.")
        initialize(true)
    end

    insideAngle = ((numSides - 2) * 180) / numSides

    if not wrongNumSidesValue then
        print("Building an " .. numSides .. "-gon, with side legth " .. sideLength)
        print("Each vertex will have an angle of " .. insideAngle .. " degrees, for a total of " .. insideAngle * numSides .. " degrees.")
        return true
    end
end

-- From pruby's sdbuild and shape.lua from Keridos
function checkFuel()
    if (not(tonumber(turtle.getFuelLevel()) == nil)) then
        while turtle.getFuelLevel() < 50 do
            print("Turtle almost out of fuel, pausing. Please drop fuel in inventory. And press enter.")
            io.read()
            turtle.refuel()
        end
    end
end

function checkResources()
    while turtle.getItemCount(activeslot) <= 0 do
        if activeslot == 16 then
            print("Turtle is empty, please put building block in slots and press enter to continue")
            io.read()
            activeslot = 1
            turtle.select(activeslot)
        else
            activeslot = activeslot+1
            print("Turtle slot empty, trying slot "..activeslot)
            turtle.select(activeslot)
        end
        os.sleep(0.2)
    end
end

function placeBlock()
    -- Cost calculation mode - don't move
    blocks = blocks + 1
    if cost_only then
        return
    end
    if turtle.detectDown() and not turtle.compareDown() then
        turtle.digDown()
    end
    checkResources()
    turtle.placeDown()
end

-- Navigation features
-- allow the turtle to move while tracking its position
-- this allows us to just give a destination point and have it go there

function turnRightTrack()
    if cost_only then
        return
    end
    turtle.turnRight()
    facing = facing + 1
    if facing >= 4 then
        facing = 0
    end
end

function turnLeftTrack()
    if cost_only then
        return
    end
    turtle.turnLeft()
    facing = facing - 1
    if facing < 0 then
        facing = 3
    end
end

function turnAroundTrack()
    turnLeftTrack()
    turnLeftTrack()
end

function safeForward()
    fuel = fuel + 1
    if cost_only then
        return
    end
    checkFuel()
    success = false
    while not success do
        success = turtle.forward()
        if not success then
            while turtle.detect() do
                if not turtle.dig() then
                    print("Blocked attempting to move forward.")
                    print("Please clear and press enter to continue.")
                    io.read()
                end
            end
        end
    end
end

function safeBack()
    fuel = fuel + 1
    if cost_only then
        return
    end
    checkFuel()
    success = false
    while not success do
        success = turtle.back()
        if not success then
            turnAroundTrack();
            while turtle.detect() do
                if not turtle.dig() then
                    break;
                end
            end
            turnAroundTrack()
            success = turtle.back()
            if not success then
                print("Blocked attempting to move back.")
                print("Please clear and press enter to continue.")
                io.read()
            end
        end
    end
end

function safeUp()
    fuel = fuel + 1
    if cost_only then
        return
    end
    checkFuel()
    success = false
    while not success do
        success = turtle.up()
        if not success then
            while turtle.detectUp() do
                if not turtle.digUp() then
                    print("Blocked attempting to move up.")
                    print("Please clear and press enter to continue.")
                    io.read()
                end
            end
        end
    end
end

function safeDown()
    fuel = fuel + 1
    if cost_only then
        return
    end
    checkFuel()
    success = false
    while not success do
        success = turtle.down()
        if not success then
            while turtle.detectDown() do
                if not turtle.digDown() then
                    print("Blocked attempting to move down.")
                    print("Please clear and press enter to continue.")
                    io.read()
                end
            end
        end
    end
end

function moveY(targety)
    if targety == positiony then
        return
    end
    if (facing ~= 0 and facing ~= 2) then -- check axis
        turnRightTrack()
    end
    while targety > positiony do
        if facing == 0 then
            safeForward()
        else
            safeBack()
        end
        positiony = positiony + 1
    end
    while targety < positiony do
        if facing == 2 then
            safeForward()
        else
            safeBack()
        end
        positiony = positiony - 1
    end
end

function moveX(targetx)
    if targetx == positionx then
        return
    end
    if (facing ~= 1 and facing ~= 3) then -- check axis
        turnRightTrack()
    end
    while targetx > positionx do
        if facing == 1 then
            safeForward()
        else
            safeBack()
        end
        positionx = positionx + 1
    end
    while targetx < positionx do
        if facing == 3 then
            safeForward()
        else
            safeBack()
        end
        positionx = positionx - 1
    end
end

function navigateTo(targetx, targety)
    if facing == 0 or facing == 2 then -- Y axis
        moveY(targety)
        moveX(targetx)
    else
        moveX(targetx)
        moveY(targety)
    end
end

function buildHexagon()
    local changex = sideLength / 2
    local changey = round(math.sqrt(3) * changex, 0)
    changex = round(changex, 0)
    local counter = 0

    navigateTo(changex, 0)

    for currentSide = 1, 6 do
        counter = 0

        if currentSide == 1 then
            for placed = 1, sideLength do
                navigateTo(positionx + 1, positiony)
                placeBlock()
            end
        elseif currentSide == 2 then
            navigateTo(positionx, positiony + 1)
            while positiony <= changey do
                if counter == 0 or counter == 2 or counter == 4 then
                    navigateTo(positionx + 1, positiony)
                end
                placeBlock()
                navigateTo(positionx, positiony + 1)
                counter = counter + 1
                if counter == 5 then
                    counter = 0
                end
            end
        elseif currentSide == 3 then
            while positiony <= (2 * changey) do
                if counter == 0 or counter == 2 or counter == 4 then
                    navigateTo(positionx - 1, positiony)
                end
                placeBlock()
                navigateTo(positionx, positiony + 1)
                counter = counter + 1
                if counter == 5 then
                    counter = 0
                end
            end
        elseif currentSide == 4 then
            for placed = 1, sideLength do
                navigateTo(positionx - 1, positiony)
                placeBlock()
            end
        elseif currentSide == 5 then
        navigateTo(positionx, positiony - 1)
            while positiony >= changey do
                if counter == 0 or counter == 2 or counter == 4 then
                    navigateTo(positionx - 1, positiony)
                end
                placeBlock()
                navigateTo(positionx, positiony - 1)
                counter = counter + 1
                if counter == 5 then
                    counter = 0
                end
            end
        elseif currentSide == 6 then
            while positiony >= 0 do
                if counter == 0 or counter == 2 or counter == 4 then
                    navigateTo(positionx + 1, positiony)
                end
                placeBlock()
                navigateTo(positionx, positiony - 1)
                counter = counter + 1
                if counter == 5 then
                    counter = 0
                end
            end
        end
    end

    navigateTo(0, 0)
    while facing ~= 0 do
        turnLeftTrack()
    end
end

function buildOctagon()
    local sideLength2 = sideLength - 1
    local change = round(sideLength2 / math.sqrt(2), 0)

    navigateTo(change, 0)

    for currentSide = 1, 8 do
        if currentSide == 1 then
            for placed = 1, sideLength2 do
                navigateTo(positionx + 1, positiony)
                placeBlock()
            end
        elseif currentSide == 2 then
            for placed = 1, change do
                navigateTo(positionx + 1, positiony + 1)
                placeBlock()
            end
        elseif currentSide == 3 then
            for placed = 1, sideLength2 do
                navigateTo(positionx, positiony + 1)
                placeBlock()
            end
        elseif currentSide == 4 then
            for placed = 1, change do
                navigateTo(positionx - 1, positiony + 1)
                placeBlock()
            end
        elseif currentSide == 5 then
            for placed = 1, sideLength2 do
                navigateTo(positionx - 1, positiony)
                placeBlock()
            end
        elseif currentSide == 6 then
            for placed = 1, change do
                navigateTo(positionx - 1, positiony - 1)
                placeBlock()
            end
        elseif currentSide == 7 then
        for placed = 1, sideLength2 do
                navigateTo(positionx, positiony - 1)
                placeBlock()
            end
        elseif currentSide == 8 then
            for placed = 1, change do
                navigateTo(positionx + 1, positiony - 1)
                placeBlock()
            end
        end
    end

    navigateTo(0, 0)
    while facing ~= 0 do
    turnLeftTrack()
    end
end

function hexPrism()
    for z = 1, height do
        buildHexagon()
        safeUp()
    end
end

function octPrism()
    for z = 1, height do
        buildOctagon()
        safeUp()
    end
end

--Main Code
if not initialize(false) then
    --If help was shown close program and do nothing else
    return
end

if numSides == 6 then
    hexPrism()
elseif numSides == 8 then
    octPrism()
end