Krin3x's variable dimension tunneler

local args = { ... }

if #args ~= 3 then
    print("Usage: <scriptname> <width> <height> <length>")
    return
end

local maxWidth = args[1]
local maxHeight = args[2]
local maxLength = args[3]

local height = 0
local unloaded = 0
local collected = 0

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

local goTo -- Filled in further down
local refuel -- Filled in further down

shell.run("pastebin get BgrVUJyh kapi")
os.loadAPI("kapi")

local function unload( _bKeepOneFuelStack )
    print( "Unloading items..." )
    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
                turtle.drop()
                unloaded = unloaded + nCount
            end
        end
    end
    collected = 0
    turtle.select(1)
end

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

    local fuelNeeded = 2*(x+y+z) + 1
    if not refuel( fuelNeeded ) then
        unload( true )
        print( "Waiting for fuel" )
        while not refuel( fuelNeeded ) do
            os.pullEvent( "turtle_inventory" )
        end
    else
        unload( true )
    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
            kapi.notify( "Mined "..(collected + unloaded).." items." )
        end
    end

    if bFull then
        kapi.notify("No empty slots left.")
        returnSupplies()
        kapi.notify("returning supplies.")
        return false
    end
    return true
end

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

    local needed = ammount or (maxWidth - xPos + maxLength - zPos + maxHeight - height + 2)
    kapi.notify("fuel: ".. turtle.getFuelLevel())
    if turtle.getFuelLevel() < needed then
        kapi.notify("refueling: "..needed)
        local fueled = false
        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 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
            sleep( 0.5 )
        end
    end

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

local function tryDown()
    if not refuel() then
        kapi.notify( "Not enough Fuel" )
        returnSupplies()
    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
            sleep( 0.5 )
        end
    end

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

    return true
end

local function tryUp()
    if not refuel() then
        kapi.notify( "Not enough Fuel" )
        returnSupplies()
    end

    while not turtle.up() do
        if turtle.detectUp() then
            if turtle.digUp() then
                if not collect() then
                    returnSupplies()
                end
            else
                return false
            end
        elseif turtle.attackUp() then
            if not collect() then
                returnSupplies()
            end
        else
            sleep( 0.5 )
        end
    end

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

    return true
end

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

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

function goTo( x, y, z, xd, zd )
    while height - y ~= 0 do
        if height < y then
            if turtle.up() then
                height = height + 1
            elseif turtle.digUp() or turtle.attackUp() then
                collect()
            else
                sleep( 0.5 )
            end
         elseif height > y then
            if turtle.down() then
                height = height - 1
            elseif turtle.digDown() or turtle.attackDown() then
                collect()
            else
                sleep( 0.5 )
            end
        end
    end

    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
                sleep( 0.5 )
            end
        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
                sleep( 0.5 )
            end
        end
    end

    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
                sleep( 0.5 )
            end
        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
                sleep( 0.5 )
            end
        end
    end

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

if not refuel() then
    kapi.notify( "Out of Fuel" )
    return
end

print( "Tunneling..." )

local Yalternate = false
local Xalternate = false
local W,H = 0,0

for l=1, maxLength do
    kapi.notify("distance: "..l .."/"..maxLength)
    kapi.notify("Around ".. (maxWidth*maxHeight*maxLength) - (maxWidth*zPos*maxHeight).. " blocks left to dig")
    for w=0, maxWidth-1 do
        for h=0, maxHeight-1 do
            if Yalternate then
                H = maxHeight-1-h
            else
                H = h
            end
            if Xalternate then
                W = maxWidth-1-w
            else
                W = w
            end
            goTo(W,H,l,xDir,zDir)
        end
        Yalternate = not Yalternate
        refuel()
    end
    Xalternate = not Xalternate
end
print( "Mined "..(collected + unloaded).." items total." )