-- Configuration

local xnotreetap_max_charge      = 30000 -- Maximum charge of the saw
-- Gives 2500 nodes on a single charge (about 50 complete normal trees)
local xnotreetap_charge_per_node = 12
-- Cut down tree leaves.  Leaf decay may cause slowness on large trees
-- if this is disabled.
local xnotreetap_leaves = true

-- First value is node name; second is whether the node is considered even if xnotreetap_leaves is false.
local nodes = {
  -- Rubber trees from moretrees or technic_worldgen if moretrees isn't installed
  {"moretrees:rubber_tree_trunk_empty", true},
  {"moretrees:rubber_tree_trunk", true},
  {"moretrees:rubber_tree_leaves", false},
}

-- Remember node visited recursive and not dig twice
local node_visited = {}

local timber_nodenames = {}
for _, node in pairs(nodes) do
  if xnotreetap_leaves or node[2] then
    timber_nodenames[node[1]] = true
  end
end


local S = technic.getter

technic.register_power_tool("technic:xnotreetap", xnotreetap_max_charge)

local mesecons_materials = minetest.get_modpath("mesecons_materials")


-- This function checks if the specified node should be sawed
local function check_if_node_sawed(pos)
  local node = minetest.get_node(pos)
  local node_name = node.name


  if timber_nodenames[node_name]
    or (xnotreetap_leaves and minetest.get_item_group(node_name, "leaves") ~= 0)
    or minetest.get_item_group(node_name, "tree") ~= 0 then
    minetest.log("action", "[Xno Tree Tap] "..node_name.." good node to collect.") --print to log
    return true
  end

  return false
end

-- Table for saving what was sawed down
local produced = {}

-- Save the items sawed down so that we can drop them in a nice single stack
local function handle_drops(drops)
  for _, item in ipairs(drops) do
    local stack = ItemStack(item)
    local name = stack:get_name()
    local p = produced[name]
    if not p then
      produced[name] = stack
    else
      p:set_count(p:get_count() + stack:get_count())
    end
  end
end

--- Iterator over positions to try to saw around a sawed node.
-- This returns positions in a 3x1x3 area around the position, plus the
-- position above it.  This does not return the bottom position to prevent
-- the chainsaw from cutting down nodes below the cutting position.
-- @param pos Sawing position.
local function iterSawTries(pos)
  -- Copy position to prevent mangling it
  local pos = vector.new(pos)
  local i = 0

  return function()
    i = i + 1
    -- Given a (top view) area like so (where 5 is the starting position):
    -- X -->
    -- Z 123
    -- | 456
    -- V 789
    -- This will return positions 1, 4, 7, 2, 8 (skip 5), 3, 6, 9,
    -- and the position above 5.
    if i == 1 then
      -- Move to starting position
      pos.x = pos.x - 1
      pos.z = pos.z - 1
    elseif i == 4 or i == 7 then
      -- Move to next X and back to start of Z when we reach
      -- the end of a Z line.
      pos.x = pos.x + 1
      pos.z = pos.z - 2
    elseif i == 5 then
      -- Skip the middle position (we've already run on it)
      -- and double-increment the counter.
      pos.z = pos.z + 2
      i = i + 1
    elseif i <= 9 then
      -- Go to next Z.
      pos.z = pos.z + 1
    elseif i == 10 then
      -- Move back to center and up.
      -- The Y+ position must be last so that we don't dig
      -- straight upward and not come down (since the Y-
      -- position isn't checked).
      pos.x = pos.x - 1
      pos.z = pos.z - 1
      pos.y = pos.y + 1
    else
      return nil
    end
    return pos
  end
end

-- inserisco un valore in tabella
local function add_table(table, toadd)
  local i = 1
  while true do
    local o = table[i]
    if o == toadd then return end
    if o == nil then break end
    i = i + 1
  end
  table[i] = toadd
end

-- bool controllo se un valore è presente in tabella
local function in_table(table, value)
  local i = 1
  while true do
    local o = table[i]
    if o == value then
      minetest.log("action", "[Xno Tree Tap] "..value.." visited.") --print to log
      return true
    end
    if o == nil then break end
    i = i + 1
  end
  return false
end

-- verifico se un nodo è nella tabella visitato
local function check_if_node_visited (pos)
  return in_table(node_visited, pos)
end

local function myString (v)
  return v.x.." "..v.y.." "..v.z.." "
end

local function set_node_visited (pos)
  minetest.log("action", "[Xno Tree Tap] "..myString(pos).." set node visited.") --print to log

  add_table(node_visited, pos)
end

-- This function does all the hard work. Recursively we dig the node at hand
-- if it is in the table and then search the surroundings for more stuff to dig.
local function recursive_dig(pos, remaining_charge)
  if remaining_charge < xnotreetap_charge_per_node then
    return remaining_charge
  end

  if check_if_node_visited(pos) then
    return remaining_charge
  end

  if not check_if_node_sawed(pos) then
    return remaining_charge
  end

  local node = minetest.get_node(pos)

  if node.name == "moretrees:rubber_tree_trunk" then
    --raccolta gomma
    node.name = "moretrees:rubber_tree_trunk_empty"
    minetest.swap_node(pos, node)
    handle_drops(minetest.get_node_drops("technic:raw_latex", ""))
    remaining_charge = remaining_charge - xnotreetap_charge_per_node

    -- Wood found - cut it
    handle_drops(minetest.get_node_drops(node.name, ""))
    minetest.remove_node(pos)
    remaining_charge = remaining_charge - xnotreetap_charge_per_node

    --    if not technic.creative_mode then
    --      local item_wear = tonumber(itemstack:get_wear())
    --      item_wear = item_wear + 819
    --      if item_wear > 65535 then
    --        itemstack:clear()
    --        return itemstack
    --      end
    --      itemstack:set_wear(item_wear)
    --    end
  end

  set_node_visited(pos)

  -- Check surroundings and run recursively if any charge left
  for npos in iterSawTries(pos) do
    if remaining_charge < xnotreetap_charge_per_node then
      break
    end
    if check_if_node_sawed(npos) then
      remaining_charge = recursive_dig(npos, remaining_charge)
    else
      minetest.check_for_falling(npos)
    end
  end
  return remaining_charge
end

-- Function to randomize positions for new node drops
local function get_drop_pos(pos)
  local drop_pos = {}

  for i = 0, 8 do
    -- Randomize position for a new drop
    drop_pos.x = pos.x + math.random(-3, 3)
    drop_pos.y = pos.y - 1
    drop_pos.z = pos.z + math.random(-3, 3)

    -- Move the randomized position upwards until
    -- the node is air or unloaded.
    for y = drop_pos.y, drop_pos.y + 5 do
      drop_pos.y = y
      local node = minetest.get_node_or_nil(drop_pos)

      if not node then
        -- If the node is not loaded yet simply drop
        -- the item at the original digging position.
        return pos
      elseif node.name == "air" then
        -- Add variation to the entity drop position,
        -- but don't let drops get too close to the edge
        drop_pos.x = drop_pos.x + (math.random() * 0.8) - 0.5
        drop_pos.z = drop_pos.z + (math.random() * 0.8) - 0.5
        return drop_pos
      end
    end
  end

  -- Return the original position if this takes too long
  return pos
end

-- Chainsaw entry point
local function xnotreetap_dig(pos, current_charge)
  -- Start sawing things down
  local remaining_charge = recursive_dig(pos, current_charge)
  minetest.sound_play("chainsaw", {pos = pos, gain = 1.0,
    max_hear_distance = 10})

  -- Now drop items for the player
  for name, stack in pairs(produced) do
    -- Drop stacks of stack max or less
    local count, max = stack:get_count(), stack:get_stack_max()
    stack:set_count(max)
    while count > max do
      minetest.add_item(get_drop_pos(pos), stack)
      count = count - max
    end
    stack:set_count(count)
    minetest.add_item(get_drop_pos(pos), stack)
  end

  -- Clean up
  produced = {}

  return remaining_charge
end

minetest.register_tool("technic:xnotreetap", {
  description = S("Xno Tree Tap"),
  inventory_image = "technic_tree_tap.png",

  stack_max = 1,

  wear_represents = "technic_RE_charge",
  on_refill = technic.refill_RE_charge,

  on_use = function(itemstack, user, pointed_thing)
    if pointed_thing.type ~= "node" then
      return itemstack
    end

    --check tool charge
    local meta = minetest.deserialize(itemstack:get_metadata())
    if not meta or not meta.charge or
      meta.charge < xnotreetap_charge_per_node then
      return
    end

    --check node protection
    local pos = pointed_thing.under
    if minetest.is_protected(pos, user:get_player_name()) then
      minetest.record_protection_violation(pos, user:get_player_name())
      return
    end


    --can collect only from rubber
    local node = minetest.get_node(pos)
    local node_name = node.name
    if node_name ~= "moretrees:rubber_tree_trunk" then
      return
    end

    -- Send current charge to digging function so that the
    -- chainsaw will stop after digging a number of nodes
    meta.charge = xnotreetap_dig(pointed_thing.under, meta.charge)
    if not technic.creative_mode then
      technic.set_RE_wear(itemstack, meta.charge, xnotreetap_max_charge)
      itemstack:set_metadata(minetest.serialize(meta))
    end
    return itemstack

  end,
})

minetest.register_craft({
  output = "technic:xnotreetap",
  recipe = {
    {"pipeworks:tube_1", "group:wood",    "default:stick"},
    {"technic:battery",  "default:stick", "default:stick"},
    {"technic:battery",  "default:stick", "default:stick"},
  },
})

--minetest.register_abm({
--  label = "Tools: xno tree tap",
--  nodenames = {"moretrees:rubber_tree_trunk_empty"},
--  interval = 60,
--  chance = 15,
--  action = function(pos, node)
--    if minetest.find_node_near(pos, (moretrees and moretrees.leafdecay_radius) or 5, {"moretrees:rubber_tree_leaves"}) then
--      node.name = "moretrees:rubber_tree_trunk"
--      minetest.swap_node(pos, node)
--    end
--  end
--})