CC Turtle: Excavate 2

if not turtle then
    printError("Requires a Turtle")
    return
end

local tArgs = { ... }
if #tArgs < 1 or #tArgs > 4 then
    local programName = arg[0] or fs.getName(shell.getRunningProgram())
    print("Usage: " .. programName .. " <diameter> [startDepth] [maxDepth] [startForward]")
    return
end

-- Mine in a quarry pattern until we hit something we can't dig
local size = tonumber(tArgs[1])
if size < 1 then
    print("Excavate diameter must be positive")
    return
end

-- Mine straight down this far first
local startDepth = 0
if #tArgs > 1 then
    startDepth = tonumber(tArgs[2])
end
-- Max distance to mine down before stopping, even if no bedrock reached
local maxDepth = 999
if #tArgs > 2 then
    maxDepth = tonumber(tArgs[3])
end
-- Extra distance to travel forwards before starting mining
local wanderDist = 0
if #tArgs > 3 then
    wanderDist = tonumber(tArgs[4])
end

local depth = 0
local unloaded = 0
local collected = 0
local triedTerminate = false

local xPos, zPos = 0, 0
local xDir, zDir = 0, 1

local goTo -- Filled in further down
local refuel -- Filled in further down
local _await, _awaitRefuel, _exit, _tryTerm -- Filled in further down

local function turnLeft()
    turtle.turnLeft()
    xDir, zDir = -zDir, xDir
end

local function turnRight()
    turtle.turnRight()
    xDir, zDir = zDir, -xDir
end

local function unload(_bKeepOneFuelStack)
    print("Unloading items...")
    --Never hold fuel stack if fuel is infinite
    if turtle.getFuelLevel() == "unlimited" then
        _bKeepOneFuelStack = false
    end
    for n = 1, 16 do
        local nCount = turtle.getItemCount(n)
        if nCount > 0 then
            turtle.select(n)
            local bDrop = true
            if _bKeepOneFuelStack and turtle.refuel(0) then
                bDrop = false
                _bKeepOneFuelStack = false
            end
            if bDrop then
                --First drop into any container above
                if turtle.detectUp() then
                    turtle.dropUp()
                end
                if turtle.getItemCount(n) > 0 then
                    --Then to each side, if there's any left
                    for _ = 1,4 do
                        if turtle.detect() and turtle.getItemCount(n) > 0 then
                            turtle.drop()

                        end
                        turnLeft()
                    end
                end
                --finally, if anything remains, just drop it on the ground
                if turtle.getItemCount(n) > 0 then
                    turtle.drop()
                end

                unloaded = unloaded + nCount
            end
        end
    end
    collected = 0
    turtle.select(1)
end

local function returnSupplies()
    local x, y, z, xd, zd = xPos, depth, zPos, xDir, zDir
    print("Returning to surface...")
    goTo(0, 0, 0, 0, -1)

    local fuelNeeded = 3 * (x + y + z) + 1
    if not refuel(fuelNeeded) then
        unload(true)
        print("Waiting for fuel")
        redstone.setOutput("top", true)
        _awaitRefuel()
        redstone.setOutput("top", false)
        unload(true) --prevent >1 stack of fuel from being stored
    else
        unload(true)
    end

    if triedTerminate then
        print("Paused at surface. Press 'c' to continue, terminate to exit.")
        repeat
            local evt, c = os.pullEvent("char")
        until evt == "char" and c == "c"
        triedTerminate = false
    end

    print("Resuming mining...")
    goTo(x, y, z, xd, zd)
end

local function collect()
    local bFull = true
    local nTotalItems = 0
    for n = 1, 16 do
        local nCount = turtle.getItemCount(n)
        if nCount == 0 then
            bFull = false
        end
        nTotalItems = nTotalItems + nCount
    end

    if nTotalItems > collected then
        collected = nTotalItems
        if math.fmod(collected + unloaded, 50) == 0 then
            print("Mined " .. collected + unloaded .. " items.")
        end
    end

    if bFull then
        print("No empty slots left.")
        return false
    end
    return true
end

local function countSlots()
    local slotcount = 0
    for n = 1, 16 do
        if turtle.getItemCount(n) == 0 then
            slotcount = slotcount + 1
        end
    end
    return slotcount
end

function refuel(ammount)
    local fuelLevel = turtle.getFuelLevel()
    if fuelLevel == "unlimited" then
        return true
    end

    local needed = ammount or xPos + zPos + depth + 64
    if turtle.getFuelLevel() < needed then
        for n = 1, 16 do
            if turtle.getItemCount(n) > 0 then
                turtle.select(n)
                if turtle.refuel(1) then
                    while turtle.getItemCount(n) > 0 and turtle.getFuelLevel() < needed do
                        turtle.refuel(1)
                    end
                    if turtle.getFuelLevel() >= needed then
                        turtle.select(1)
                        return true
                    end
                end
            end
        end
        turtle.select(1)
        return false
    end

    return true
end

local function fuelCheck()
    if turtle.getFuelLevel() < 16 then
        refuel(16)
    end
    _await(0)
end

local function tryForwards()
    if not refuel() then
        print("Not enough Fuel")
        returnSupplies()
    end

    while not turtle.forward() do
        if turtle.detect() then
            if turtle.dig() then
                if not collect() then
                    returnSupplies()
                end
            else
                return false
            end
        elseif turtle.attack() then
            if not collect() then
                returnSupplies()
            end
        else
            _await()
        end
        fuelCheck()
    end

    xPos = xPos + xDir
    zPos = zPos + zDir
    return true
end

local function tryDown()
    if not refuel() then
        print("Not enough Fuel")
        returnSupplies()
    end

    if depth + 1 > maxDepth then
        return false
    end

    while not turtle.down() do
        if turtle.detectDown() then
            if turtle.digDown() then
                if not collect() then
                    returnSupplies()
                end
            else
                return false
            end
        elseif turtle.attackDown() then
            if not collect() then
                returnSupplies()
            end
        else
            _await()
        end
        fuelCheck()
    end

    depth = depth + 1
    if math.fmod(depth, 10) == 0 then
        print("Descended " .. depth .. " metres.")
    end

    return true
end

local function goY(y)
    while depth > y do
        if turtle.up() then
            depth = depth - 1
        elseif turtle.digUp() or turtle.attackUp() then
            collect()
        else
            _await()
        end
        fuelCheck()
    end

    while depth < y do
        if turtle.down() then
            depth = depth + 1
        elseif turtle.digDown() or turtle.attackDown() then
            collect()
        else
            _await()
        end
        fuelCheck()
    end
end

local function goX(x)
    if xPos > x then
        while xDir ~= -1 do
            turnLeft()
        end
        while xPos > x do
            if turtle.forward() then
                xPos = xPos - 1
            elseif turtle.dig() or turtle.attack() then
                collect()
            else
                _await()
            end
            fuelCheck()
        end
    elseif xPos < x then
        while xDir ~= 1 do
            turnLeft()
        end
        while xPos < x do
            if turtle.forward() then
                xPos = xPos + 1
            elseif turtle.dig() or turtle.attack() then
                collect()
            else
                _await()
            end
            fuelCheck()
        end
    end
end

local function goZ(z)
    if zPos > z then
        while zDir ~= -1 do
            turnLeft()
        end
        while zPos > z do
            if turtle.forward() then
                zPos = zPos - 1
            elseif turtle.dig() or turtle.attack() then
                collect()
            else
                _await()
            end
            fuelCheck()
        end
    elseif zPos < z then
        while zDir ~= 1 do
            turnLeft()
        end
        while zPos < z do
            if turtle.forward() then
                zPos = zPos + 1
            elseif turtle.dig() or turtle.attack() then
                collect()
            else
                _await()
            end
            fuelCheck()
        end
    end
end

local function goXZ(x,z)
    goZ(z)
    goX(x)
end

function goTo(x, y, z, xd, zd)
    if startDepth >= y and depth > startDepth then
        goY(startDepth)
        goXZ(0,0)
        goY(y)
        goXZ(x,z)
    elseif startDepth <= y and depth < startDepth then
        goXZ(0, 0)
        goY(startDepth)
        goXZ(x,z)
        goY(y)
    else
        goXZ(x,z)
        goY(y)
    end

    while zDir ~= zd or xDir ~= xd do
        turnLeft()
    end
end

-- End of basic functions

-- Exit handler stuff
function _tryTerm()
    if triedTerminate then
        _exit()
    else
        triedTerminate = true
        print("Terminate recieved; attempting to return to surface")
        returnSupplies()
    end
end

local oldPullEvent = os.pullEvent
os.pullEvent = function(_filter)
    eventData = {os.pullEventRaw(_filter)}
    if eventData[1] == "terminate" then
        _tryTerm()
    end
    return unpack(eventData)
end

function _await(s)
    os.startTimer(s or 0.5)
    os.pullEvent("timer")
end

function _awaitRefuel()
    local t = triedTerminate
    triedTerminate = true
    repeat
        os.pullEvent("turtle_inventory")
    until refuel(fuelNeeded)
    triedTerminate = t
end

function _exit()
    print("Exiting program. Goodbye!")
    os.pullEvent = oldPullEvent
    error()
end



if not refuel(256) then
    print("Waiting for fuel...")
    redstone.setOutput("top", true)
    while not refuel(256) do
        os.pullEvent("turtle_inventory")
    end
    redstone.setOutput("top", false)
end

if countSlots() < 15 then
    print("Depositing down to 1 stack of fuel...")
    unload(true)
end

print("Excavating...")

turtle.select(1)

if startDepth > 0 then
    goTo(0, startDepth, 0, 0, 1)
end

if wanderDist ~= 0 then
    goTo(0, startDepth, wanderDist, 0, 1)
end

local alternate = 0
local done = false
while not done do
    for n = 1, size do
        for _ = 1, size - 1 do
            if not tryForwards() then
                done = true
                break
            end
        end
        if done then
            break
        end
        if n < size then
            if math.fmod(n + alternate, 2) == 0 then
                turnLeft()
                if not tryForwards() then
                    done = true
                    break
                end
                turnLeft()
            else
                turnRight()
                if not tryForwards() then
                    done = true
                    break
                end
                turnRight()
            end
        end
    end
    if done then
        break
    end

    if size > 1 then
        if math.fmod(size, 2) == 0 then
            turnRight()
        else
            if alternate == 0 then
                turnLeft()
            else
                turnRight()
            end
            alternate = 1 - alternate
        end
    end

    if not tryDown() then
        done = true
        break
    end
end

print("Returning to surface...")

-- Return to where we started
goTo(0, 0, 0, 0, -1)
unload(false)
goTo(0, 0, 0, 0, 1)

print("Mined " .. collected + unloaded .. " items total - Excavate complete.")