Minecraft Turtle Skybridge v1.0

-- ---------------------------------
-- Various Variables and Settings --
local currentSlot = 1
local materialReferenceSlot = 14
local anchorSlot = 15
local torchSlot = 16
local supplied = true
local rowCount = 0
local lampFreq = 6

-- --------------------
-- Utility Functions --

-- checkSupply ensures that there is material to build with on hand
local function checkSupply()
    turtle.select(currentSlot)
    -- If the current slot is empty
    if turtle.getItemCount(currentSlot) == 0 then
        -- bump up a slot
        currentSlot = currentSlot + 1

        -- make sure it's not past the reference slot
        if currentSlot == (anchorSlot + 1) then
            supplied = false
            currentSlot = currentSlot - 1
            return
        end

        -- still in the supplies section, so that's good
        turtle.select(currentSlot)

        -- make sure it's the right material
        if turtle.compareTo(materialReferenceSlot) then
            supplied = true
        else
            supplied = false
        end
    -- if the current slot is NOT empty
    else
        -- make sure that the current slot still has the right material in it
        if turtle.compareTo(materialReferenceSlot) then
            supplied = true
        else
            supplied = false
        end
    end
end

--
local function forwardDig(mode)
    if turtle.detect() then
        turtle.dig()
    end
    if mode == "place" then
        checkSupply()
        turtle.place()
    elseif mode == "move" then
        turtle.forward()
    else
        -- do nothing
    end
end

local function downDig(mode)
    if turtle.detectDown() then
        turtle.digDown()
    end
    if mode == "place" then
        checkSupply()
        turtle.placeDown()
    elseif mode == "move" then
        turtle.down()
    else
        -- do nothing
    end
end

local function upDig(mode)
    if turtle.detectUp() then
        turtle.digUp()
    end
    if mode == "place" then
        checkSupply()
        turtle.placeUp()
    elseif mode == "move" then
        turtle.up()
    else
        -- do nothing
    end
end

local function turnAround()
    -- It's not an ambiturn.
    turtle.turnRight()
    turtle.turnRight()
end

local function placeTorch(whichWay)
    turtle.select(torchSlot)
    if whichWay == "forward" then
        turtle.place()
    elseif whichWay == "up" then
        turtle.placeUp()
    end
    turtle.select(currentSlot)
end

local function placeAnchor()
    turtle.select(anchorSlot)
    turtle.place()
    turtle.select(currentSlot)
end

-- -----------------
-- Main Functions --

-- ensures the things needed (fuel, material, torches, world anchors) are on hand
local function checkStarting()
    local ReadyToGo = true
    local ErrorList = {}

    -- Check that the 14th slot has a material for reference
    if turtle.getItemCount(materialReferenceSlot) == 0 then
        ReadyToGo = false
        table.insert(ErrorList,"Reference Material missing in slot 14.")
    end

    -- Slots 1 throuth 13 need to be at least 64 of the material in slot 14
    for i = 1, 13 do
        turtle.select(i)
        if turtle.getItemCount(i) == 0 then
            ReadyToGo = false
            table.insert(ErrorList,"Missing material in slot "..tostring(i))
        else
            if not turtle.compareTo(14) then
                ReadyToGo = false
                table.insert(ErrorList,"Wrong material in slot "..tostring(i))
            end
        end
    end

    -- Slot 15 needs to be at least 12 world anchor type objects
    if turtle.getItemCount(anchorSlot) == 0 then
        ReadyToGo = false
        table.insert(ErrorList,"Anchor type object missing in slot 15.")
    end

    -- Slot 16 needs to be at least 60 torch type objects
    if turtle.getItemCount(torchSlot) <= 59 then
        ReadyToGo = false
        table.insert(ErrorList,"Insufficient torch objects missing in slot 16, should be 60-64.")
    end

    -- Based on my calculations, with the above payload, we'll go about 180 meters/blocks.
    -- That will take about 1,290 fuel with the movements planned
    if turtle.getFuelLevel() < 1290 then
        ReadyToGo = false
        table.insert(ErrorList,"Turtle should have at least 1,290 fuel (17 coal/charcoal).  Please refuel.")
    end

    if not ReadyToGo then
        print("Cannot start building.  Issues:")
        for i=1,#ErrorList do
            print("  -"..tostring(ErrorList[i]))
        end
    else
        print("Supplies/fuel appear to be ready.")
        print("Starting...")
    end
    supplied = ReadyToGo
    return ReadyToGo
end

-- Create normal segment pair
local function createNormal()
    -- First section
    forwardDig("move")
    turtle.turnRight()
    downDig("place")
    forwardDig("place")
    upDig("move")
    upDig("")
    turnAround()
    forwardDig("move")
    downDig("move")
    downDig("place")
    forwardDig("place")
    turtle.turnRight()
    forwardDig("move")
    -- Second section
    turtle.turnLeft()
    downDig("place")
    forwardDig("place")
    upDig("move")
    upDig("")
    turnAround()
    forwardDig("move")
    downDig("move")
    downDig("place")
    forwardDig("place")
    turtle.turnLeft()
end

-- Create arch/light pair
local function createArch()
    -- First section, same as normal
    forwardDig("move")
    turtle.turnRight()
    downDig("place")
    forwardDig("place")
    upDig("move")
    upDig("")
    turnAround()
    forwardDig("move")
    downDig("move")
    downDig("place")
    forwardDig("place")
    turtle.turnRight()
    forwardDig("move")
    -- Second section, quite different, is an arch with torches
    turtle.turnLeft()
    downDig("place")
    forwardDig("place")
    upDig("move")
    forwardDig("place")
    upDig("move")
    forwardDig("place")
    upDig("place")
    turnAround()
    forwardDig("move")
    turnAround()
    placeTorch("forward")
    turnAround()
    upDig("place")
    forwardDig("place")
    downDig("move")
    placeTorch("up")
    forwardDig("place")
    downDig("move")
    forwardDig("place")
    downDig("place")
    turtle.turnLeft()
end

-- Place/collect World Anchors to not overload system, but keep going sans player
local function rollingAnchor()
    turtle.back()
    turtle.back()
    placeAnchor()
    turnAround()
    for i = 1,16 do
        turtle.forward()
    end
    turtle.dig()  -- nix the old world anchor
    turtle.suck() -- try to pick it back up
    turnAround()
    for i = 1,16 do
        turtle.forward()
    end
    -- Move over the new WA back to 'current position'
    turtle.up()
    turtle.forward()
    turtle.forward()
    turtle.down()
end

-- --------
-- Main --

if checkStarting() then
    -- setup a first anchor
    turnAround()
    placeAnchor()
    turnAround()

    while supplied do
        for i = 1,3 do
            createNormal()
            createNormal()
            createArch()
        end
        rollingAnchor()
    end
end