-- Fun_Caves mapgen.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 DEBUG
local max_depth = -28000
local seed_noise = {offset = 0, scale = 32768, seed = 5202, spread = {x = 80, y = 80, z = 80}, octaves = 2, persist = 0.4, lacunarity = 2}
fun_caves_mod.use_bi_hi = true


local ground_nodes = {}
ground_nodes[minetest.get_content_id('default:stone')] = true
ground_nodes[minetest.get_content_id('default:desert_stone')] = true
ground_nodes[minetest.get_content_id('default:sandstone')] = true
ground_nodes[minetest.get_content_id('default:dirt')] = true
ground_nodes[minetest.get_content_id('default:sand')] = true
ground_nodes[minetest.get_content_id('default:dirt_with_grass')] = true
ground_nodes[minetest.get_content_id('default:dirt_with_snow')] = true
ground_nodes[minetest.get_content_id('default:dirt_with_dry_grass')] = true


-- This tables looks up nodes that aren't already stored.
local node = setmetatable({}, {
	__index = function(t, k)
		if not (t and k and type(t) == 'table') then
			return
		end

		t[k] = minetest.get_content_id(k)
		return t[k]
	end
})

local data = {}


fun_caves_mod.cave_biomes = {
	algae = {
		biome_val_low = 0,
		biome_val_high = 0.2,
		ceiling_node = 'fun_caves:stone_with_algae',
		dirt = 'default:dirt',
		dirt_chance = 10,
		floor_node = 'fun_caves:stone_with_algae',
		fungi = true,
		stalactite = 'fun_caves:stalactite_slimy',
		stalactite_chance = 12,
		stalagmite = 'fun_caves:stalagmite_slimy',
		stalagmite_chance = 12,
		stone_depth = 1,
		underwater = true,
	},
	coal = {
		biome_val_low = 0.5,
		biome_val_high = 0.6,
		ceiling_node = 'fun_caves:black_sand',
		deco = 'default:coalblock',
		deco_chance = 100,
		floor_node = 'fun_caves:black_sand',
		stalagmite = 'fun_caves:constant_flame',
		stalagmite_chance = 50,
		stone_depth = 2,
		underwater = false,
	},
	hot = {
		biome_val_low = 0.6,
		biome_val_high = 99,
		ceiling_node = 'fun_caves:hot_cobble',
		floor_node = 'fun_caves:hot_cobble',
		fluid = 'default:lava_source',
		fluid_chance = 300,
		stalagmite = fun_caves_mod.hot_spikes,
		stalagmite_chance = 50,
		stone_depth = 1,
		underwater = false,
	},
	ice = {
		biome_val_low = -99,
		biome_val_high = -0.6,
		ceiling_node = 'default:ice',
		floor_node = 'default:ice',
		stalactite = 'fun_caves:icicle_down',
		stalactite_chance = 12,
		stalagmite = 'fun_caves:icicle_up',
		stalagmite_chance = 12,
		stone_depth = 2,
		underwater = true,
	},
	ice_thin = {
		biome_val_low = -0.6,
		biome_val_high = -0.5,
		ceiling_node = 'fun_caves:thin_ice',
		floor_node = 'fun_caves:thin_ice',
		stone_depth = 2,
		underwater = true,
	},
	lichen = {
		biome_val_low = -0.3,
		biome_val_high = 0,
		ceiling_node = 'fun_caves:stone_with_lichen',
		dirt = 'default:dirt',
		dirt_chance = 10,
		floor_node = 'fun_caves:stone_with_lichen',
		fungi = true,
		stalactite = 'fun_caves:stalactite',
		stalactite_chance = 12,
		stalagmite = 'fun_caves:stalagmite',
		stalagmite_chance = 12,
		stone_depth = 1,
		underwater = true,
	},
	lichen_dead = {
		biome_val_low = -0.6,
		biome_val_high = -0.5,
		ceiling_node = 'fun_caves:stone_with_lichen',
		floor_node = 'fun_caves:stone_with_lichen',
		stalactite = 'fun_caves:stalactite',
		stalactite_chance = 12,
		stalagmite = 'fun_caves:stalagmite',
		stalagmite_chance = 12,
		stone_depth = 1,
		underwater = true,
	},
	moss = {
		biome_val_low = -0.5,
		biome_val_high = -0.3,
		ceiling_node = 'fun_caves:stone_with_moss',
		deco = 'fun_caves:glowing_fungal_stone',
		deco_chance = 50,
		floor_node = 'fun_caves:stone_with_moss',
		fluid = 'default:water_source',
		fluid_chance = 300,
		stalactite = 'fun_caves:stalactite_mossy',
		stalactite_chance = 12,
		stalagmite = 'fun_caves:stalagmite_mossy',
		stalagmite_chance = 12,
		stone_depth = 1,
		underwater = true,
	},
	salt = {
		biome_val_low = 0.2,
		biome_val_high = 0.35,
		ceiling_node = 'fun_caves:stone_with_salt',
		deco = 'fun_caves:radioactive_ore',
		deco_chance = 500,
		floor_node = 'fun_caves:stone_with_salt',
		stone_depth = 2,
		underwater = false,
	},
	sand = {
		biome_val_low = 0.35,
		biome_val_high = 0.5,
		ceiling_node = 'default:sand',
		floor_node = 'default:sand',
		stone_depth = 2,
		underwater = true,
	},
}


local function generate(p_minp, p_maxp, seed)
	if not (p_minp and p_maxp and seed) then
		return
	end

	local minp, maxp = p_minp, p_maxp
	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
	if not (vm and emin and emax) then
		return
	end

	vm:get_data(data)
	local heightmap
	local area = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
	local csize = vector.add(vector.subtract(maxp, minp), 1)
  local write


  if minetest.get_modpath('ramoid') and ramoid_mod and ramoid_mod.ramoid_depth then
    local avg = (minp.y + maxp.y) / 2
    if avg > (ramoid_mod.ramoid_depth - 1) * 80 - 32 and avg < ramoid_mod.ramoid_depth * 80 - 32 then
      return
    end
  end

  if minetest.get_modpath('underworlds') and underworlds_mod and underworlds_mod.underzones then
    local avg = (minp.y + maxp.y) / 2
    for _, uz in pairs(underworlds_mod.underzones) do
      if avg <= uz.upper_bound and avg >= uz.lower_bound then
        return
      end
    end
  end

	if fun_caves_mod.use_bi_hi then
		heightmap = minetest.get_mapgen_object("heightmap")
	end


	-- Correct heightmap.
	if maxp.y < -300 or minp.y > 300 then
		for i = 1, #heightmap do
			heightmap[i] = (maxp.y < 0) and max_depth or - max_depth
		end
	else
		local index = 0
		for z = minp.z, maxp.z do
			for x = minp.x, maxp.x do
				index = index + 1

				local height = heightmap[index]
				if height and height < maxp.y - 1 and height > minp.y then
					--nop
				else
					height = - max_depth
					local ivm2 = area:index(x, maxp.y + 8, z)
					for y = maxp.y + 8, minp.y - 8, -1 do
						if ground_nodes[data[ivm2]] then
							height = (y < maxp.y + 8) and y or max_depth
							break
						end
						ivm2 = ivm2 - area.ystride
					end
					heightmap[index] = height
				end
			end
		end
	end

	for fake_loop = 1, 1 do
		if fun_caves_mod.cavegen and fun_caves_mod.decogen then
			local h2, write_cave
			write_cave = fun_caves_mod.cavegen(minp, maxp, data, area, node, heightmap)
			write = write or write_cave

			local write_deco
			write_deco = fun_caves_mod.decogen(minp, maxp, data, area, node, heightmap)
			write = write or write_deco
		end
	end


  if write then
    vm:set_data(data)

    if DEBUG then
      vm:set_lighting({day = 8, night = 8})
    else
      vm:set_lighting({day = 0, night = 0}, minp, maxp)
      vm:calc_lighting()
    end
    vm:update_liquids()
    vm:write_to_map()
  end
end


if fun_caves_mod.path then
	dofile(fun_caves_mod.path .. "/cavegen.lua")
	dofile(fun_caves_mod.path .. "/deco.lua")
end


local function pgenerate(...)
	local status, err = pcall(generate, ...)
	--local status, err = true
	--generate(...)
	if not status then
		print('Fun Caves: Could not generate terrain:')
		print(dump(err))
		collectgarbage("collect")
	end
end


-- Inserting helps to ensure that fun_caves_mod operates first.
--table.insert(minetest.registered_on_generateds, 1, pgenerate)
minetest.register_on_generated(pgenerate)