TMDExcavate

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

local size = tonumber(tArgs[1])
if not size or size < 1 or size % 1 ~= 0 then
    print("Excavate diameter must be a positive whole number")
    return
end

local ENDER_CHEST_ID = "enderstorage:ender_chest"
local STORAGE_RECHECK_SECONDS = 15

local depth = 0
local unloaded = 0
local collected = 0

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

local storageMode = nil
local goTo
local returnSupplies

local function findEnderChestSlot()
    for i = 1, 16 do
        local detail = turtle.getItemDetail(i)
        if detail and detail.name == ENDER_CHEST_ID then
            return i
        end
    end
    return nil
end

local function isInventory(side)
    if peripheral.hasType and peripheral.hasType(side, "inventory") then
        return true
    end

    local wrapped = peripheral.wrap(side)
    return wrapped ~= nil and type(wrapped.list) == "function"
end

local function waitForRearStorage()
    while not isInventory("back") do
        print("ERROR: No valid storage found.")
        print("Place a chest, barrel, or other inventory behind the turtle's initial starting location.")
        print("Checking again in " .. STORAGE_RECHECK_SECONDS .. " seconds...")
        sleep(STORAGE_RECHECK_SECONDS)
    end
end

local function chooseStorageMode()
    if findEnderChestSlot() then
        storageMode = "ender"
        print("EnderStorage chest found. Using portable unloading.")
        return
    end

    storageMode = "rear"
    waitForRearStorage()
    print("Storage found behind starting location.")
end

local function inventoryTotal()
    local total = 0
    for i = 1, 16 do
        total = total + turtle.getItemCount(i)
    end
    return total
end

local function hasEmptySlot()
    for i = 1, 16 do
        if turtle.getItemCount(i) == 0 then
            return true
        end
    end
    return false
end

local function fuelLevel()
    return turtle.getFuelLevel()
end

local function distanceFromStart()
    return math.abs(xPos) + math.abs(zPos) + depth
end

local function refuelTo(requiredLevel)
    local level = fuelLevel()
    if level == "unlimited" then
        return true
    end

    if level >= requiredLevel then
        return true
    end

    for i = 1, 16 do
        if turtle.getItemCount(i) > 0 then
            turtle.select(i)
            if turtle.refuel(0) then
                turtle.refuel(turtle.getItemCount(i))
                level = fuelLevel()
                if level == "unlimited" or level >= requiredLevel then
                    turtle.select(1)
                    return true
                end
            end
        end
    end

    turtle.select(1)
    level = fuelLevel()
    return level == "unlimited" or level >= requiredLevel
end

local function burnFuelToFreeSlot()
    if hasEmptySlot() then
        return true
    end

    for i = 1, 16 do
        local before = turtle.getItemCount(i)
        if before > 0 then
            turtle.select(i)
            if turtle.refuel(0) then
                turtle.refuel(before)
                local after = turtle.getItemCount(i)
                if after < before then
                    print("Inventory full: used " .. (before - after) .. " collected fuel item(s).")
                end
                if after == 0 then
                    turtle.select(1)
                    return true
                end
            end
        end
    end

    turtle.select(1)
    return hasEmptySlot()
end

local function collect()
    local total = inventoryTotal()

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

    return hasEmptySlot()
end

local function waitForFuel(requiredLevel)
    while not refuelTo(requiredLevel) do
        print("Not enough fuel to continue safely.")
        print("Add burnable fuel directly to the turtle. Checking again in 15 seconds...")
        sleep(15)
    end
end

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

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

local function unloadToEnderChest()
    local chestSlot = findEnderChestSlot()
    if not chestSlot then
        return false
    end

    print("Unloading items to EnderStorage chest...")

    while turtle.detectUp() do
        if not turtle.digUp() then
            print("Unable to clear space above to place EnderStorage chest.")
            return false
        end
    end

    turtle.select(chestSlot)
    if not turtle.placeUp() then
        print("Failed to place EnderStorage chest above.")
        return false
    end

    for i = 1, 16 do
        if i ~= chestSlot then
            local before = turtle.getItemCount(i)
            if before > 0 then
                turtle.select(i)
                turtle.dropUp()
                local moved = before - turtle.getItemCount(i)
                unloaded = unloaded + moved
            end
        end
    end

    turtle.select(chestSlot)
    if not turtle.digUp() then
        print("Warning: Failed to retrieve EnderStorage chest.")
    end

    turtle.select(1)
    collected = inventoryTotal()
    return true
end

local function unloadToRearStorage()
    waitForRearStorage()

    turnLeft()
    turnLeft()

    while true do
        if not isInventory("front") then
            turnLeft()
            turnLeft()
            waitForRearStorage()
            turnLeft()
            turnLeft()
        end

        local remaining = false

        for i = 1, 16 do
            local before = turtle.getItemCount(i)
            if before > 0 then
                turtle.select(i)
                turtle.drop()
                local after = turtle.getItemCount(i)
                local moved = before - after
                unloaded = unloaded + moved

                if after > 0 then
                    remaining = true
                end
            end
        end

        if not remaining then
            break
        end

        print("Storage is full or rejected an item.")
        print("Make room in the storage behind the starting location.")
        print("Trying again in " .. STORAGE_RECHECK_SECONDS .. " seconds...")
        sleep(STORAGE_RECHECK_SECONDS)
    end

    turtle.select(1)
    turnLeft()
    turnLeft()
    collected = inventoryTotal()
end

local function ensureInventorySpace()
    if hasEmptySlot() then
        return true
    end

    if burnFuelToFreeSlot() then
        return true
    end

    print("Inventory is full and no burnable items can free a slot.")
    returnSupplies()
    return hasEmptySlot()
end

local function ensureFuelForMove()
    local required = distanceFromStart() + 2
    if refuelTo(required) then
        return true
    end

    print("Fuel reserve is too low. Returning for supplies...")
    returnSupplies()
    return refuelTo(distanceFromStart() + 2)
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

function returnSupplies()
    local x, y, z, xd, zd = xPos, depth, zPos, xDir, zDir
    local travelDistance = math.abs(x) + math.abs(z) + y

    print("Handling inventory and fuel...")

    if findEnderChestSlot() then
        storageMode = "ender"
        refuelTo(travelDistance + 2)

        if unloadToEnderChest() then
            waitForFuel(travelDistance + 2)
            print("Resuming mining...")
            return true
        end
    end

    storageMode = "rear"

    if not refuelTo(travelDistance) then
        print("The turtle does not have enough fuel to reach the starting location.")
        waitForFuel(travelDistance)
    end

    print("Returning to starting storage...")
    goTo(0, 0, 0, 0, 1)

    -- Burn collected fuel before depositing. This keeps enough internal fuel
    -- to return to the saved mining position whenever possible.
    refuelTo(travelDistance + 2)

    unloadToRearStorage()

    if not refuelTo(travelDistance + 2) then
        waitForFuel(travelDistance + 2)
    end

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

local function tryForwards()
    if not ensureFuelForMove() then
        return false
    end

    while not turtle.forward() do
        if turtle.detect() then
            if not ensureInventorySpace() then
                return false
            end

            if turtle.dig() then
                collect()
            else
                return false
            end
        elseif turtle.attack() then
            collect()
        else
            sleep(0.5)
        end
    end

    xPos = xPos + xDir
    zPos = zPos + zDir

    if turtle.detectUp() then
        if not ensureInventorySpace() then
            return false
        end
        if turtle.digUp() then
            collect()
        end
    end

    if turtle.detectDown() then
        if not ensureInventorySpace() then
            return false
        end
        if turtle.digDown() then
            collect()
        end
    end

    return true
end

local function tryDown()
    for i = 1, 3 do
        if not ensureFuelForMove() then
            return false
        end

        while not turtle.down() do
            if turtle.detectDown() then
                if not ensureInventorySpace() then
                    return false
                end

                if turtle.digDown() then
                    collect()
                else
                    return false
                end
            elseif turtle.attackDown() then
                collect()
            else
                sleep(0.5)
            end
        end

        depth = depth + 1

        if turtle.detectUp() then
            if not ensureInventorySpace() then
                return false
            end
            if turtle.digUp() then
                collect()
            end
        end

        if turtle.detectDown() then
            if not ensureInventorySpace() then
                return false
            end
            if turtle.digDown() then
                collect()
            end
        end
    end

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

    return true
end

chooseStorageMode()

if not refuelTo(2) then
    print("Out of fuel. Add burnable fuel to the turtle.")
    return
end

print("Excavating...")

local alternate = 0
local done = false

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

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

print("Returning to surface...")

local finalDistance = distanceFromStart()
if not refuelTo(finalDistance) then
    waitForFuel(finalDistance)
end

goTo(0, 0, 0, 0, 1)

if findEnderChestSlot() then
    unloadToEnderChest()
else
    storageMode = "rear"
    unloadToRearStorage()
end

goTo(0, 0, 0, 0, 1)

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