-- Squaresville desolate.lua
-- Copyright Duane Robertson (duane@duanerobertson.com), 2017
-- Distributed under the LGPLv2.1 (https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html)


local cobble = squaresville.cobble
local desolation = squaresville.desolation
local ground_nodes = squaresville.ground_nodes
local math_random = math.random
local node = squaresville.node

local node_air = node['air']
local node_cobble = node['default:cobble']
local node_dirt = node['default:dirt']
local node_glowing_fungal_stone = node['squaresville:glowing_fungal_stone']
local node_gravel = node['default:gravel']
local node_light_panel = node['squaresville:light_panel']
local node_mossycobble = node['default:mossycobble']
local node_plate_glass = node['squaresville:plate_glass']
local node_snowblock = node['default:snowblock']
local node_stone_with_copper = node['default:stone_with_copper']
local node_stone_with_iron = node['default:stone_with_iron']


-- This table looks up the names of broken nodes.
local broken_node = setmetatable({}, {
  __index = function(t, k)
    if not (t and k and type(t) == 'table' and type(k) == 'number') then
      return
    end

    local s = minetest.get_name_from_content_id(k)
    s = string.gsub(s, '.*:', 'squaresville:')..'_broken'
    t[k] = k
    if minetest.registered_nodes[s] then
      t[k] = node[s]
    end

    return t[k]
  end
})


-- This table looks up the properties of nodes.
local groups = setmetatable({}, {
  __index = function(t, k)
    if not (t and k and type(t) == 'table' and type(k) == 'string') then
      return
    end

    local s = minetest.get_name_from_content_id(k)
    t[k] = minetest.registered_items[s].groups
    return t[k]
  end
})


function squaresville.breaker(node_n, dy, humidity, desolation)
  if desolation == 0 then
    return node_n
  end

  local dry = 100 - humidity + dy

  local sr = math_random(50)
  local goff = 1
  dry = dry + 1

  if node_n == node_light_panel then
    sr = 1
  elseif node_n == node_plate_glass then
    goff = 3
  end

  if not ground_nodes[node_n] and node_n ~= node_snowblock and sr <= desolation * goff then
    return node_air
  elseif not ground_nodes[node_n] and cobble and sr <= desolation * 3 and groups[node_n].cracky then
    sr = math_random(700)
    if sr == 1 then
      sr = math_random(4)
      if sr == 1 then
        return node_stone_with_copper
      else
        return node_stone_with_iron
      end
    elseif sr <= 15 then
      return node_glowing_fungal_stone
    elseif sr <= 40 then
      return node_gravel
    elseif sr <= 140 then
      return node_dirt
    else
      if sr <= dry * 10 then
        return node_cobble
      else
        return node_mossycobble
      end
    end
  elseif sr <= desolation * 5 then
    return broken_node[node_n]
  end

  return node_n
end