Excavate Advanced

-- define arguments
local tArgs = { ... }
if #tArgs < 1 then
    print( "Usage: excavate <size> [depth]" )
    return
end
if #tArgs > 2 then
    print( "This program is using only 2 arguments" )
    print( "Usage: excavate <size> [depth]" )
end

local size = tonumber( tArgs[1] )
local yDeltaLimit = 255
-- check arguments
if #tArgs > 1 then
    yDeltaLimit = tonumber( tArgs[2] )
end

if size < 1 then
    print( "Excavate diameter must be positive" )
    return
end
if yDeltaLimit < 1 then
    print( "Y must be positive" )
    return
end

-- define local variables
local depth = 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

-- drop items to storage
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,depth,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
            print( "Mined "..(collected + unloaded).." items." )
        end
    end

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

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

    local needed = ammount or (xPos + zPos + depth + 2)
    if turtle.getFuelLevel() < needed then
        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

function tryDigUp()
    if depth > 0 then
        turtle.digUp()
        if not collect() then
            returnSupplies()
        end
    end
end
function tryDigDown()
    if depth < yDeltaLimit - 1 then
        turtle.digDown()
        if not collect() then
            returnSupplies()
        end
    end
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
    tryDigUp()
    tryDigDown()

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

local function tryDown()
    if not refuel() then
        print( "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

    depth = depth + 1
    if math.fmod( depth, 10 ) == 0 then
        print( "Descended "..depth.." 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 depth > y do
        if turtle.up() then
            depth = depth - 1
        elseif turtle.digUp() or turtle.attackUp() then
            collect()
        else
            sleep( 0.5 )
        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 depth < y do
        if turtle.down() then
            depth = depth + 1
        elseif turtle.digDown() or turtle.attackDown() then
            collect()
        else
            sleep( 0.5 )
        end
    end

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

if not refuel() then
    print( "Out of Fuel" )
    return
end

function main()
    print( "Excavating..." )

    turtle.select(1)

    local alternate = 0
    local flipXZ = 0
    local done = false
    tryDigDown()
    while not done do

        for n=1,size do
            for m=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


        -- TODO check yLimit
        if depth == yDeltaLimit - 1 or depth == yDeltaLimit - 2 then
            done = true
            break
        end
        if depth == yDeltaLimit - 3 then
            if not tryDown() then
                done = true
                break
            end
            tryDown()
        end
        if depth < yDeltaLimit - 3 then
            if not tryDown() then
                done = true
                break
            end
            tryDown()
            tryDown()
        end
        tryDigDown()
    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." )
end

main()