# 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")
  if not turtle.up() then
    return false
  end
  rel_z = rel_z + 1
  return true
end

function down()
  if not turtle.down() then
    return false
  end
  rel_z = rel_z - 1
  return true
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)
    else
      print(vals[2])
    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
  turtle.select(slot)
  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_forward_one()
  local i = 0
  while not forward() do
    turtle.dig()
    assert (i < 300, "Failed to move forward down the mineshaft")
    i = i + 1
  end
  return true
end

function mine_up_one()
  local i = 0
  while not up() do
    turtle.digUp()
    assert(i < 300, "Failed to move up the mineshaft")
    i = i + 1
  end
  return true
end

function mine_down_until(condition)
  local i = 0
  while not condition(i) do
    local block_exists = turtle.inspectDown()
    if block_exists then
      assert(turtle.digDown(), "Could not dig down")
    end
    assert(down(), "Could not move down")
    i = i + 1
  end
  return i
end

function mine_up_until(condition)
  local i = 0
  while not condition(i) do
    mine_up_one()
    i = i + 1
  end
  return i
end

function mine_into_ground()
  no_err, distance = pcall(function()
    return mine_down_until(function(i)
      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 distance ~= 0 -- 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
    local success = turtle.digDown()
    if not success then
      return false -- We can't mine into the shaft (likely bedrock). Go ahead and act as if we were in 3 high shaft.
    end
    assert(down(), "Could not move down")
    turtle.digDown() -- Allowed to fail, just to keep things nice...
    return mine_forward_one()
  end
  return false
end

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

function maintain_bounds()
  if rel_y == MINESHAFT_WIDTH  and rel_bearing == 0 or rel_y == 1 and rel_bearing == 2 then
    local at_bedrock = not turtle.digDown() and turtle.inspectDown()
    local turnFunc = turnRight
    local oppTurnFunc = turnLeft
    if rel_bearing == 2 then
      turnFunc = turnLeft
      oppTurnFunc = turnRight
    end

    if at_bedrock then
      assert(turnFunc(), "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
        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
        shaft_height = mine_up_until(function(i)
          return not turtle.inspect()
        end)
      end

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

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

      if not no_err then
        assert(oppTurnFunc(), "Could not orient the turtle back away from the current mineshaft")
        assert(oppTurnFunc(), "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
    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 = 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 and turtle.getItemCount(i) ~= 0 then
      turtle.select(i)
      assert(drop(), "Could not insert item into chest")
    end
  end
  turtle.select(slot)
  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 i, func in ipairs(logic_funcs) do
      if func() then
        print("Took action " .. i)
        break
      end
    end
    --print("Hit enter to continue...")
    --io.read()
  end
end

loop_logic()