-- chunkminer.lua
-- Mines a 16x16 chunk, auto-refuels from a chest behind it

-- === CONFIG ===
local LENGTH = 16
local WIDTH = 16

-- === STATE ===
local x, y, z = 0, 0, 0 -- Position tracking
local dir = 0 -- 0=north,1=east,2=south,3=west
local layer = 0

-- === HELPERS ===
local function turnLeft() turtle.turnLeft(); dir = (dir + 3) % 4 end
local function turnRight() turtle.turnRight(); dir = (dir + 1) % 4 end

local function forward()
    while not turtle.forward() do
        turtle.dig()
        turtle.attack()
        sleep(0.4)
    end
    if dir == 0 then z = z - 1
    elseif dir == 1 then x = x + 1
    elseif dir == 2 then z = z + 1
    elseif dir == 3 then x = x - 1 end
end

local function up()
    while not turtle.up() do
        turtle.digUp()
        turtle.attackUp()
        sleep(0.4)
    end
    y = y + 1
end

local function down()
    while not turtle.down() do
        turtle.digDown()
        turtle.attackDown()
        sleep(0.4)
    end
    y = y - 1
end

-- === REFUELING ===
local function refuel()
    if turtle.getFuelLevel() == "unlimited" then return end
    if turtle.getFuelLevel() > 100 then return end

    print("Refueling...")
    local turned = false

    -- Turn around to face the chest
    turnLeft()
    turnLeft()
    turned = true

    -- Try to suck fuel from chest
    for slot = 1, 16 do
        local detail = turtle.getItemDetail(slot)
        if detail == nil then
            turtle.suck()
            detail = turtle.getItemDetail(slot)
        end
        if detail and turtle.refuel(1) then
            while turtle.refuel(1) do end
        end
    end

    if turned then
        turnLeft()
        turnLeft()
    end

    print("Fuel Level: " .. turtle.getFuelLevel())
end

-- === MINING ===
local function mineLayer()
    for row = 1, WIDTH do
        for col = 1, LENGTH - 1 do
            refuel()
            turtle.digDown()
            turtle.dig()
            forward()
        end
        if row < WIDTH then
            if row % 2 == 1 then
                turnRight()
                turtle.dig()
                forward()
                turnRight()
            else
                turnLeft()
                turtle.dig()
                forward()
                turnLeft()
            end
        end
    end

    -- Return to start of this layer
    if WIDTH % 2 == 1 then
        turnRight()
    else
        turnLeft()
    end
    for i = 1, WIDTH - 1 do
        forward()
    end
    if WIDTH % 2 == 1 then
        turnRight()
    else
        turnLeft()
    end
    for i = 1, LENGTH - 1 do
        forward()
    end
end

-- === MAIN ===
local function main()
    print("Starting 16x16 chunk mining...")
    refuel()

    -- Go down until solid
    while not turtle.detectDown() do
        down()
    end

    -- Mine layers upward until ceiling hit or full inventory
    while true do
        mineLayer()
        print("Layer complete. Going up...")
        up()

        if turtle.detectUp() then
            print("Ceiling reached, stopping.")
            break
        end
    end

    print("Chunk mining complete!")
end

main()