minetest

-- directions pretends turtle looks north when placed down,
-- that means the z axis is forward and back, and the x axis is left and right

local blocksToMine = {
  ["minecraft:diamond_ore"] = true,
  ["minecraft:iron_ore"] = true,
  ["minecraft:coal_ore"] = true,
  ["minecraft:gold_ore"] = true,
  ["minecraft:redstone_ore"] = true,
  ["minecraft:lapis_ore"] = true,
  ["minecraft:emerald_ore"] = true,
  ["minecraft:copper_ore"] = true,
  -- Add deepslate variants
  ["minecraft:deepslate_diamond_ore"] = true,
  ["minecraft:deepslate_iron_ore"] = true,
  ["minecraft:deepslate_coal_ore"] = true,
  ["minecraft:deepslate_gold_ore"] = true,
  ["minecraft:deepslate_redstone_ore"] = true,
  ["minecraft:deepslate_lapis_ore"] = true,
  ["minecraft:deepslate_emerald_ore"] = true,
  ["minecraft:deepslate_copper_ore"] = true
}

local currentPosition = {
  x = 0,
  y = 0,
  z = 0
}

local startingY = 124

local minY = -52
local maxY = 16

local currentBranch = 0

local function descend()
  local blocksToDescend = startingY - minY

  for _ = 1, blocksToDescend do
    turtle.digDown()
    turtle.down()
    currentPosition.y = currentPosition.y - 1
  end
end

local function shouldMine(blockName)
  return blocksToMine[blockName] or false
end

local function checkAndMineAround()
  -- Check up
  local success, data = turtle.inspectUp()
  if success and shouldMine(data.name) then
    turtle.digUp()
  end

  -- Check down
  success, data = turtle.inspectDown()
  if success and shouldMine(data.name) then
    turtle.digDown()
  end

  -- Check left (need to turn)
  turtle.turnLeft()
  success, data = turtle.inspect()
  if success and shouldMine(data.name) then
    turtle.dig()
  end
  turtle.turnRight()

  -- Check right
  turtle.turnRight()
  success, data = turtle.inspect()
  if success and shouldMine(data.name) then
    turtle.dig()
  end
  turtle.turnLeft()
end

local function mineBranch()
  for i = 1, 16 do
    checkAndMineAround()

    if i < 16 then
      turtle.dig()
      turtle.forward()

      if currentBranch % 2 == 1 then
        currentPosition.x = currentPosition.x + 1 -- facing right (east) is positive x
      else
        currentPosition.x = currentPosition.x - 1 -- facing left (west) is negative x
      end
    end
  end
end

local function moveToNextBranch()
  if currentBranch % 2 == 1 then
    -- Odd branch, turn left
    turtle.turnLeft()
    for _ = 1, 2 + 1 do
      checkAndMineAround()
      turtle.dig()
      turtle.forward()
      currentPosition.z = currentPosition.z - 1 -- negative z is north
    end
    turtle.turnLeft()
  else
    -- Even branch, turn right
    turtle.turnRight()
    for _ = 1, 2 + 1 do
      checkAndMineAround()
      turtle.dig()
      turtle.forward()
      currentPosition.z = currentPosition.z - 1 -- negative z is north
    end
    turtle.turnRight()
  end
end

local function main()
  descend()

  turtle.turnRight()

  while currentPosition.y < maxY do
    -- do all branches on a level
    for branch = 1, 6 do
      currentBranch = branch
      mineBranch()

      if branch < 6 then
        moveToNextBranch()
      end
    end

    -- if we end on an odd branch, turn around and come back
    if 6 % 2 == 1 then
      turtle.turnLeft()
      turtle.turnLeft()

      for _ = 1, (16 - 1) do
        turtle.forward()
        currentPosition.x = currentPosition.x - 1 -- moving west toward starting point
      end
    end

    -- face south
    turtle.turnLeft()

    -- move to the starting point
    while currentPosition.z < 0 do
      turtle.forward()
      currentPosition.z = currentPosition.z + 1 -- moving south to starting point
    end

    -- turn back forward
    turtle.turnLeft()
    turtle.turnLeft()

    -- go up to the next y level
    for _ = 1, 3 do
      if currentPosition.y < maxY then
        turtle.up()
        currentPosition.y = currentPosition.y + 1
      end
    end
  end

  -- move back to the starting point
  while currentPosition.y < 0 do
    turtle.up()
  end
end

main()