Minecraft Ancient Debris Mining Turtle

local pos = 0
local fuel = "minecraft:coal"
local keep = {
    [fuel] = true,
    ["minecraft:ancient_debris"] = true,
    ["tconstruct:cobalt_ore"] = true,
    ["minecraft:netherrack"] = true
}
local badFluid = "minecraft:lava"
local tunnelLength = 30 -- How long the tunnel should be

-- Refuel from chest behind at start
local function refuel()
    if pos > 0 then
        turtle.turnLeft()
        turtle.turnLeft() -- Face back toward start
        for i = 1, pos do
            while turtle.detect() do turtle.dig() end
            turtle.forward()
        end
    end
    -- At start, chest is behind
    for i = 1, 16 do
        local item = turtle.getItemDetail(i, false)
        if item and item.name == fuel then
            turtle.select(i)
            break
        end
    end
    while turtle.getFuelLevel() < 160 do
        turtle.suck() -- Pull fuel from chest behind
        turtle.refuel(1)
    end
    -- Return to mining position
    if pos > 0 then
        turtle.turnLeft()
        turtle.turnLeft() -- Face forward again
        for i = 1, pos do
            while turtle.detect() do turtle.dig() end
            turtle.forward()
        end
    end
end

-- Check if inventory is full (excluding kept items)
local function isInventoryFull()
    for i = 1, 16 do
        if turtle.getItemCount(i) == 0 then
            return false -- Found an empty slot
        end
    end
    return true -- No empty slots
end

-- Deposit unwanted items into chest behind at start
local function depositJunk()
    if pos > 0 then
        turtle.turnLeft()
        turtle.turnLeft() -- Face back toward start
        for i = 1, pos do
            while turtle.detect() do turtle.dig() end
            turtle.forward()
        end
    end
    -- At start, deposit into chest behind
    for i = 1, 16 do
        local item = turtle.getItemDetail(i, false)
        if item and not keep[item.name] then
            turtle.select(i)
            turtle.drop() -- Drop into chest behind
        end
    end
    -- Return to mining position
    if pos > 0 then
        turtle.turnLeft()
        turtle.turnLeft() -- Face forward again
        for i = 1, pos do
            while turtle.detect() do turtle.dig() end
            turtle.forward()
        end
    end
end

-- Select netherrack to place for lava
local function selectPlaceable()
    for i = 1, 16 do
        local item = turtle.getItemDetail(i, false)
        if item and item.name == "minecraft:netherrack" then
            turtle.select(i)
            return true
        end
    end
    return false
end

-- Handle lava in the 3x3 area
local function handleLava()
    local directions = {
        {check = turtle.inspect, place = turtle.place},
        {check = turtle.inspectUp, place = turtle.placeUp},
        {check = turtle.inspectDown, place = turtle.placeDown}
    }
    for _, dir in ipairs(directions) do
        local success, block = dir.check()
        if success and block.name == "minecraft:lava" and selectPlaceable() then
            dir.place()
        end
    end
end

-- Mine a 3x3 section
local function mineSection()
    -- Mine forward (middle row)
    while turtle.detect() do turtle.dig() end
    -- Mine up (top row)
    while turtle.detectUp() do turtle.digUp() end
    -- Mine down (bottom row)
    while turtle.detectDown() do turtle.digDown() end

    -- Move up to clear top layer
    turtle.up()
    while turtle.detect() do turtle.dig() end
    turtle.down()

    -- Move down to clear bottom layer
    turtle.down()
    while turtle.detect() do turtle.dig() end
    turtle.up()

    handleLava()
    turtle.forward()
end

-- Main loop
while true do
    if turtle.getFuelLevel() < 100 then
        refuel()
    end

    if isInventoryFull() then
        depositJunk()
    end

    if pos < tunnelLength then
        mineSection()
        pos = pos + 1
    else
        depositJunk() -- End of tunnel, reset
        pos = 0 -- Reset position to start a new tunnel
    end
end