Excavate

local tArgs = { ... }
if #tArgs ~= 1 then
    print( "Usage: excavate <diameter>" )
    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

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

local function SendMessage(message)
    print (message)
    local fileHandle = fs.open("log", fs.exists("log") and "a" or "w")
    if fileHandle then
        fileHandle.writeLine(message)
        fileHandle.close()
    end
end

local function unload( _bKeepOneFuelStack )
    SendMessage( "Unloading items..." )
    for n=1,16 do
        local nCount = turtle.getItemCount(n)
        if nCount > 0 then
            turtle.select(n)
            local bDrop = true
            local data = turtle.getItemDetail()
            if data and data.name == "minecraft:torch" then
                bDrop = false
            end
            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 dropTorch(placeUp)
    for n=1,16 do
        turtle.select(n)
        local data = turtle.getItemDetail()
        if data and data.name == "minecraft:torch" then
            if placeUp then
                turtle.placeUp()
                SendMessage("placeUp Torch")
            else
                turtle.placeDown()
                SendMessage("placeDown Torch")
            end
        end
    end
end

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

    local fuelNeeded = 2*(x+y+z) + 1
    if not refuel( fuelNeeded ) then
        unload( true )
        SendMessage( "Waiting for fuel" )
        while not refuel( fuelNeeded ) do
            os.pullEvent( "turtle_inventory" )
        end
    else
        unload( true )
    end

    SendMessage( "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
            SendMessage( "Mined "..(collected + unloaded).." items." )
        end
    end

    if bFull then
        SendMessage( "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

local function tryForwards()
    if not refuel() then
        SendMessage( "Not enough Fuel" )
        returnSupplies()
    end
    local attempts = 0

    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
        attempts = attempts + 1
        if attempts > 5 then
            SendMessage("tryUp Failed")
            sleep( 0.5 )
            return
        end
    end

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

local function findStart()
    while true do
        if not refuel() then
            SendMessage( "Not enough Fuel" )
            returnSupplies()
        end
        if not turtle.forward() then
            if turtle.detect() then
                return
            elseif turtle.attack() then
                if not collect() then
                    returnSupplies()
                end
            else
                sleep(0.5)
            end
        end
        xPos = xPos + xDir
        zPos = zPos + zDir
    end
end

local function tryDown()
    if not refuel() then
        SendMessage( "Not enough Fuel" )
        returnSupplies()
    end
    local attempts = 0
    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
        attempts = attempts + 1
        if attempts == 5 then
            error("tryDown Failed")
        end
    end

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

    return true
end
local function tryUp()
    if not refuel() then
        SendMessage( "Not enough Fuel" )
        returnSupplies()
    end
    local attempts = 0

    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
        attempts = attempts + 1
        if attempts == 5 then
            error("tryUp Failed")
        end
    end

    depth = depth - 1
    if math.fmod( depth, 10 ) == 0 then
        SendMessage( "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
    SendMessage( "Out of Fuel" )
    return
end

SendMessage( "Excavating..." )
local fail = false
local down = false
findStart()
for t=1,size do
    if not tryForwards() then
        break
    end
    turnLeft()
    for n=1,8 do
        for m=1,7 do
            if not tryForwards() then
                fail = true
                break
            end
        end
        if fail then
            break
        end
        if n ~= 8 then
            if down then
                if not tryDown() then
                    fail = true
                    break
                end
            else
                if not tryUp() then
                    fail = true
                    break
                end
            end
            turnLeft()
            turnLeft()
            left = not left
        end
    end
    if fail then
        break
    end
    if math.fmod(t,8) == 0 then
        dropTorch(down)
    end
    turnLeft()
    down = not down
end

SendMessage( "Returning to surface..." )

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

SendMessage( "Mined "..(collected + unloaded).." items total." )