# Miner

local SLOT_FUEL_CHEST = 1
local SLOT_DEPOSIT_CHEST = 2
local SLOTS_EMPTY = 14

local MINESHAFT_WIDTH = 10

--------- BEGIN NAVIGATION ---------
local rel_x, rel_y, rel_z = 0, 0, 0
local rel_bearing = 0
local MAX_REL_Z = 100

function forward()
  if not turtle.forward() then
    return false
  end
  if rel_bearing == 0 then
    rel_y = rel_y + 1
  elseif rel_bearing == 1 then
    rel_x = rel_x + 1
  elseif rel_bearing == 2 then
    rel_y = rel_y - 1
  elseif rel_bearing == 3 then
    rel_x = rel_x - 1
  end
  return true
end

function back()
  if not turtle.back() then
    return false
  end
  if rel_bearing == 0 then
    rel_y = rel_y - 1
  elseif rel_bearing == 1 then
    rel_x = rel_x - 1
  elseif rel_bearing == 2 then
    rel_y = rel_y + 1
  elseif rel_bearing == 3 then
    rel_x = rel_x + 1
  end
  return true
end

function turnLeft()
  if not turtle.turnLeft() then
    return false
  end
  rel_bearing = (rel_bearing - 1) % 4
  return true
end

function turnRight()
  if not turtle.turnRight() then
    return false
  end
  rel_bearing = (rel_bearing + 1) % 4
  return true
end

function up()
  assert(rel_z + 1 <= MAX_REL_Z, "Attempted to move up past MAX_REL_Z")
  turtle.up()
  rel_z = rel_z + 1
end

function down()
  turtle.down()
  rel_z = rel_z - 1
end

--------- END NAVIGATION ---------
--------- BEGIN FUEL ---------
function get_place_dig_suck_drop_in_empty_space()
  local success, data = turtle.inspect()
  if not success then
    return turtle.place, turtle.dig, turtle.suck, turtle.drop
  end

  success, data = turtle.inspectUp()
  if not success then
    return turtle.placeUp, turtle.digUp, turtle.suckUp, turtle.dropUp
  end

  success, data = turtle.inspectDown()
  if not success then
    return turtle.placeDown, turtle.digDown, turtle.suckDown, turtle.dropDown
  end

  error("No empty space in front, above, or below the turtle")
end

function try_with_rotation(func)
  for i=1,4 do
    vals = {pcall(func)}
    if vals[1] then
      for j = 1,(i-1) do
        turnRight()
      end
      table.remove(vals, 1)
      return unpack(vals)
    end
    turnLeft()
  end

  error("Could not execute function in any orientation")
end

function refuel_from_chest(slot)
  print("Refueling from chest in slot " .. tostring(slot) .. ". Fuel: " .. tostring(turtle.getFuelLevel()) .. "/" .. tostring(turtle.getFuelLimit()))
  local place, dig, suck, drop = get_place_dig_suck_drop_in_empty_space()
  local prev_slot = turtle.getSelectedSlot()
  turtle.select(slot)
  local success = place()
  assert(success, "Could not place chest")
  while turtle.getFuelLevel() ~= turtle.getFuelLimit() do
    success = suck()
    assert(success, "Could not obtain fuel from chest")
    success = turtle.refuel()
    assert(success, "Could not use item obtained from chest as fuel")
  end
  success = dig()
  assert(success, "Could not remove chest")
  print("Finished refueling. Fuel: " .. tostring(turtle.getFuelLevel()) .. "/" .. tostring(turtle.getFuelLimit()))
  turtle.select(prev_slot)
end

function handle_fuel()
  if turtle.getFuelLevel() / turtle.getFuelLimit() < 0.1 then
    try_with_rotation(function()
      refuel_from_chest(SLOT_FUEL_CHEST)
    end)
    return true
  end
  return false
end

--------- END FUEL ---------
--------- BEGIN MINE ---------
function inspect_vertical()
  local _, up_data = turtle.inspectUp()
  local _, front_data = turtle.inspect()
  local _, down_data = turtle.inspectDown()
  return {down_data, front_data, up_data}
end

function inspect_vertical_simple()
  local up_data = turtle.inspectUp()
  local front_data = turtle.inspect()
  local down_data = turtle.inspectDown()
  return {down_data, front_data, up_data}
end

function mine_down_until(condition)
  local retval = false
  while not condition() do
    local block_exists = turtle.inspectDown()
    if block_exists then
      assert(turtle.digDown(), "Could not dig down")
    end
    assert(turtle.down(), "Could not move down")
    retval = true
  end
  return retval
end

function mine_up_until(condition)
  local retval = false
  while not condition() do
    local block_exists = turtle.inspectUp()
    if block_exists then
      assert(turtle.digUp(), "Could not dig down")
    end
    assert(turtle.up(), "Could not move down")
    retval = true
  end
  return retval
end

function mine_into_ground()
  no_err, action_taken = pcall(function()
    mine_down_until(function()
      local v_state = inspect_vertical_simple()
      return v_state[1] == true and v_state[2] == true
    end)
  end)

  if not no_err then
    return false -- allow miner to work on bedrock
  end
  return action_taken -- could also be interpreted as condition resolved
end

function mine_into_shaft()
  local v_state = inspect_vertical_simple()
  if v_state[1] == true and v_state[2] == true and v_state[3] == false then
    assert(turtle.digDown(), "Could not dig down")
    assert(turtle.down(), "Could not move down")
    turtle.dig()
    assert(forward(), "Could not move forward")
    return true
  end
  return false
end

function mine_forward_shaft()
  turtle.digUp() -- allowed to fail
  turtle.digDown() -- allowed to fail

  local success = turtle.dig()
  --assert(success, "Unable to dig forward") allow to move without digging

  success = forward()
  assert(success, "Unable to move forward after mining forward")
  return true
end

function maintain_bounds()
  if rel_y == MINESHAFT_WIDTH or rel_y == 0 then
    local at_bedrock = not turtle.digDown() and turtle.inspectDown()
    if at_bedrock then
      assert(turnRight(), "Could not face towards next mineshaft")

      local shaft_height = 0
      local initial_x = rel_x
      local MAX_X_SEARCH = 256

      while shaft_height < 3 do
        shaft_height = 0
        while not turtle.inspect() do
          assert( math.abs(rel_x - initial_x) < 256, "Could not find next mineshaft")
          assert(forward(), "Could not move towards next mineshaft")
        end

        while turtle.inspect() do
          turtle.digUp() -- allowed to fail if block doesn't exist
          assert(up(), "Could not move towards the top of the next mineshaft")
          -- max rel z will stop this loop from doing anything too harmful
          shaft_height = shaft_height 1
        end
      end

      assert(forward(), "Could not move on top of the next mineshaft")
      assert(turnRight(), "Could not orient the turtle along the next mineshaft")
    else
      turtle.digUp()   -- allowed to fail
      -- we've already dug down
      assert(turnRight(), "Could not orient the turtle back towards the current mineshaft")
      assert(turnRight(), "Could not orient the turtle into the current mineshaft")

      no_err, action_taken = pcall(function()
        mine_down_until(function()
          return turtle.inspect()
        end)
      end)

      if not no_err then
        assert(turnLeft(), "Could not orient the turtle back away from the current mineshaft")
        assert(turnLeft(), "Could not orient the turtle out of the current mineshaft")
        return true -- we hit bedrock. yield with the expectation that the first case will be called
      end

      assert(turtle.dig(), "Could not mine the starting block of the current mineshaft")
      assert(turtle.forward(), "Could not move into the current mineshaft")
    end
    return true
  end
  return false
end

--------- END MINE ---------
--------- BEGIN DEPOSIT ---------
function get_num_empty_slots()
  local empty_slots = SLOTS_EMPTY
  for i=1,16 do
    if i ~= SLOT_DEPOSIT_CHEST and i ~= SLOT_FUEL_CHEST and turtle.getItemCount(i) ~= 0 then
      empty_slots -= 1
    end
  end
  return empty_slots
end



function deposit_to_chest(slot)
  print("Depositing into chest in slot " .. tostring(slot) .. ". Empty slots: " .. tostring(get_num_empty_slots()))
  local place, dig, suck, drop = get_place_dig_suck_drop_in_empty_space()
  local prev_slot = turtle.getSelectedSlot()
  turtle.select(slot)
  assert(place(), "Could not place chest")
  for i=1,16 do
    if i ~= SLOT_DEPOSIT_CHEST and i ~= SLOT_FUEL_CHEST then
      turtle.select(i)
      assert(drop(), "Could not insert item into chest")
  end
  assert(dig(), "Could not remove chest")
  print("Finished depositing into chest in slot " .. tostring(slot) .. ". Empty slots: " .. tostring(get_num_empty_slots()))
  turtle.select(prev_slot)
end

function handle_inventory()
  if get_num_empty_slots() < 2 then
    try_with_rotation(function()
      deposit_to_chest(SLOT_DEPOSIT_CHEST)
    end)
    return true
  end
  return false
end
--------- END DEPOSIT ---------

function loop_logic()
  while true do
    logic_funcs = {handle_fuel, handle_inventory, maintain_bounds, mine_into_ground, mine_into_shaft, mine_forward_shaft}
    for _, func in ipairs(logic_funcs) do
      if func() then
        break
      end
    end
    print("Hit enter to continue...")
    io.read()
  end
end

loop_logic()