local startX, startY, startZ, startDir = 0, 0, 0, "north"
local currX, currY, currZ, currDir = startX, startY, startZ, startDir

-- Initialize the unmined table
unmined = {}
for x = -26, 26 do
  unmined[x] = {}
  for y = 0, 4 do
    unmined[x][y] = {}
    for z = -26, 26 do
      unmined[x][y][z] = true
    end
  end
end

function move(dir, calledByReturnHome)
  -- If the function was not called by returnHome, check if there is an item in slot 16
  if not calledByReturnHome and turtle.getItemCount(16) > 0 then
    -- If there is, run the returnHome function
    returnHome(true)
  end
  if dir == "up" or dir == "down" then
    -- Check if we are at y0 and trying to move down, or at y4 and trying to move up
    if (currY == 0 and dir == "down") or (currY == 4 and dir == "up") then
      -- Do not move in the specified direction if we are at y0 and trying to move down, or at y4 and trying to move up
      return
    end
    if dir == "up" then
      if turtle.detectUp() then
        turtle.digUp()
        turtle.up()
        updatePosition(dir)
      else
        turtle.up()
        updatePosition(dir)
      end
    elseif dir == "down" then
      if turtle.detectDown() then
        turtle.digDown()
        turtle.down()
        updatePosition(dir)
      else
        turtle.down()
        updatePosition(dir)
      end
    end
  else
    if turtle.detect() then
      turtle.dig()
      if dir == "forward" then
        turtle.forward()
        updatePosition(dir)
      else
        turtle.back()
        updatePosition(dir)
      end
    else
      if dir == "forward" then
        turtle.forward()
        updatePosition(dir)
      else
        turtle.back()
        updatePosition(dir)
      end
    end
  end
  -- Check if we are at the outer bounds of the unmined table on the x or z axis
  if currX == -25 or currX == 25 or currZ == -25 or currZ == 25 then
    -- If we are, move to the unmined block closest to 0, 0, 0
    moveToUnmined()
  end
end




function updatePosition(dir)
  if dir == "forward" then
    currZ = currZ + (currDir == "north" and 1 or (currDir == "south" and -1 or 0))
    currX = currX + (currDir == "east" and 1 or (currDir == "west" and -1 or 0))
  elseif dir == "backward" then
    currZ = currZ + (currDir == "south" and 1 or (currDir == "north" and -1 or 0))
    currX = currX + (currDir == "west" and 1 or (currDir == "east" and -1 or 0))
  elseif dir == "up" then
    currY = currY + 1
  elseif dir == "down" then
    currY = currY - 1
  end
  -- Check if unmined[currX][currY][currZ] is nil before setting it to false
  if unmined[currX][currY][currZ] == nil then
    -- Print an error and call moveToUnmined()
    print("Error: unmined[" .. currX .. "][" .. currY .. "][" .. currZ .. "] is nil")
    moveToUnmined()
  else
    unmined[currX][currY][currZ] = false
  end
end

function returnHome()
  local atHome = false
  while not atHome do
      if currX > startX then
      turnTo("west")
      move("forward", true)
    elseif currX < startX then
      turnTo("east")
      move("forward", true)
    elseif currY > startY then
      move("down", true)
    elseif currY < startY then
      move("up", true)
    elseif currZ > startZ then
      turnTo("south")
      move("forward", true)
    elseif currZ < startZ then
      turnTo("north")
      move("forward", true)
    else
      atHome = true
    end
  end
end



function turnTo(dir)
  if currDir == "north" then
    if dir == "east" then
      turn("right")
    elseif dir == "south" then
      turn("left")
      turn("left")
    elseif dir == "west" then
      turn("left")
    end
  elseif currDir == "east" then
    if dir == "south" then
      turn("right")
    elseif dir == "west" then
      turn("left")
      turn("left")
    elseif dir == "north" then
      turn("left")
    end
  elseif currDir == "south" then
    if dir == "west" then
      turn("right")
    elseif dir == "north" then
      turn("left")
      turn("left")
    elseif dir == "east" then
      turn("left")
    end
  elseif currDir == "west" then
    if dir == "north" then
      turn("right")
    elseif dir == "east" then
      turn("left")
      turn("left")
    elseif dir == "south" then
      turn("left")
    end
  end

currDir = dir
end

function turn(dir)
  if dir == "left" then
    turtle.turnLeft()
  else
    turtle.turnRight()
  end
  if currDir == "north" then
    currDir = (dir == "left") and "west" or "east"
  elseif currDir == "east" then
    currDir = (dir == "left") and "north" or "south"
  elseif currDir == "south" then
    currDir = (dir == "left") and "east" or "west"
  elseif currDir == "west" then
    currDir = (dir == "left") and "south" or "north"
  end
end

function refuel()
  for i = 1, 16 do
    turtle.select(i)
    if turtle.refuel(1) then
      return
    end
  end
  returnHome()
  turtle.suckUp()
  refuel()
end

function mine()
  local blocksMined = 0
  local consecutiveNoBlocks = 0
  while blocksMined < 256 do
    if turtle.getFuelLevel() < 1000 then
      returnHome()
      refuel()
    end
    if turtle.getItemCount(16) > 0 then
      returnHome()
        for i = 1, 16 do
          turtle.select(i)
          turtle.dropDown()
          turtle.select(1)
        end
    end
    if currY > 4 then
      move("down")
    elseif currY < 0 then
      move("up")
    elseif math.random(1,5) == 1 then
      turn(math.random(1,2) == 1 and "left" or "right")
    elseif math.random(1,20) == 1 then
      if math.random(1,2) == 1 then
        move("up")
      else
        move("down")
      end
    else
      local moved = false
      for i = 1, 10 do
        if turtle.detect() then
          move("forward")
          blocksMined = blocksMined + 1
          consecutiveNoBlocks = 0
          moved = true
          break
        else
          move("forward")
          consecutiveNoBlocks = consecutiveNoBlocks + 1
          if consecutiveNoBlocks >= 10 then
            moveToUnmined()
            consecutiveNoBlocks = 0
            break
          end
        end
      end
      if not moved then
        consecutiveNoBlocks = 0
      end
    end
  end
  returnHome()
end


function moveToUnmined()
  -- Find the unmined block closest to the starting position (0, 0, 0)
  local closestX, closestY, closestZ = 0, 0, 0
  local closestDistance = math.huge
  for x = -26, 26 do
    for y = 0, 4 do
      for z = -26, 26 do
        if unmined[x][y][z] then
          -- Calculate the distance from the starting position to the unmined block
          local distance = math.sqrt(x^2 + y^2 + z^2)
          if distance < closestDistance then
            -- Update the closest unmined block and distance
            closestX, closestY, closestZ = x, y, z
            closestDistance = distance
          end
        end
      end
    end
  end

  -- Move to the closest unmined block and mine it
  local xDiff = currX - closestX
  local yDiff = currY - closestY
  local zDiff = currZ - closestZ

  -- Move horizontally towards the closest unmined block
  while xDiff ~= 0 or zDiff ~= 0 do
    if xDiff > 0 then
      move("left")
      xDiff = xDiff - 1
    elseif xDiff < 0 then
      move("right")
      xDiff = xDiff + 1
    elseif zDiff > 0 then
      move("forward")
      zDiff = zDiff - 1
    elseif zDiff < 0 then
      move("back")
      zDiff = zDiff + 1
    end
  end

  -- Move vertically towards the closest unmined block
  while yDiff ~= 0 do
    if yDiff > 0 then
      move("down")
      yDiff = yDiff - 1
    elseif yDiff < 0 then
      move("up")
      yDiff = yDiff + 1
    end
  end

  -- Mine the closest unmined block
  turtle.dig()

  -- Update the unmined table
  unmined[closestX][closestY][closestZ] = false
end



mine()