-- caverealms v.0.3 by HeroOfTheWinds
-- original cave code modified from paramat's subterrain
-- For Minetest 0.4.8 stable
-- Depends default
-- License: code WTFPL


caverealms = {} --create a container for functions and constants

--grab a shorthand for the filepath of the mod
local modpath = minetest.get_modpath(minetest.get_current_modname())

--load companion lua files
dofile(modpath.."/config.lua") --configuration file; holds various constants
dofile(modpath.."/crafting.lua") --crafting recipes
dofile(modpath.."/nodes.lua") --node definitions
dofile(modpath.."/functions.lua") --function definitions

if caverealms.config.falling_icicles == true then
	dofile(modpath.."/falling_ice.lua") --complicated function for falling icicles
	print("[caverealms] falling icicles enabled.")
end

-- Parameters

local YMIN = caverealms.config.ymin -- Approximate realm limits.
local YMAX = caverealms.config.ymax
local DEEPCAVES_YMAX = caverealms.config.deepcaves_ymax
local DEEP_DEEP_CAVES_YMAZ = caverealms.config.deepdeepcaves_ymax
local TCAVE = caverealms.config.tcave --0.5 -- Cave threshold. 1 = small rare caves, 0.5 = 1/3rd ground volume, 0 = 1/2 ground volume
local BLEND = 128 -- Cave blend distance near YMIN, YMAX

local STAGCHA = caverealms.config.stagcha --0.002 --chance of stalagmites
local STALCHA = caverealms.config.stalcha --0.003 --chance of stalactites
local CRYSTAL = caverealms.config.crystal --0.007 --chance of glow crystal formations
local GEMCHA = caverealms.config.gemcha --0.03 --chance of small glow gems
local MUSHCHA = caverealms.config.mushcha --0.04 --chance of mushrooms
local MYCCHA = caverealms.config.myccha --0.03 --chance of mycena mushrooms
local WORMCHA = caverealms.config.wormcha --0.03 --chance of glow worms
local GIANTCHA = caverealms.config.giantcha --0.001 -- chance of giant mushrooms
local ICICHA = caverealms.config.icicha --0.035 -- chance of icicles

-- 3D noise for caves

local np_cave = {
	offset = 0,
	scale = 1,
	spread = {x=512, y=256, z=512}, -- squashed 2:1
	seed = 59033,
	octaves = 6,
	persist = 0.63
}

-- 3D noise for wave

local np_wave = {
	offset = 0,
	scale = 1,
	spread = {x=256, y=256, z=256},
	seed = -400000000089,
	octaves = 3,
	persist = 0.67
}

-- 2D noise for biome

local np_biome = {
	offset = 0,
	scale = 1,
	spread = {x=250, y=250, z=250},
	seed = 9130,
	octaves = 3,
	persist = 0.5
}

-- Stuff

subterrain = {}

local yblmin = YMIN + BLEND * 1.5
local yblmax = YMAX - BLEND * 1.5

-- On generated function

minetest.register_on_generated(function(minp, maxp, seed)
	--if out of range of caverealms limits
	if minp.y > YMAX or maxp.y < YMIN then
		return --quit; otherwise, you'd have stalagmites all over the place
	end

	--easy reference to commonly used values
	--local t1 = os.clock()
	local x1 = maxp.x
	local y1 = maxp.y
	local z1 = maxp.z
	local x0 = minp.x
	local y0 = minp.y
	local z0 = minp.z

	--print ("[caverealms] chunk minp ("..x0.." "..y0.." "..z0..")") --tell people you are generating a chunk

	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
	local area = VoxelArea:new{MinEdge=emin, MaxEdge=emax}
	local data = vm:get_data()

	--grab content IDs
	local c_air = minetest.get_content_id("air")
	local c_stone = minetest.get_content_id("default:stone")
	local c_water = minetest.get_content_id("default:water_source")
	local c_lava = minetest.get_content_id("default:lava_source")
	local c_lava_flowing = minetest.get_content_id("default:lava_flowing")
	local c_ice = minetest.get_content_id("default:ice")
	local c_thinice = minetest.get_content_id("caverealms:thin_ice")
	local c_crystal = minetest.get_content_id("caverealms:glow_crystal")
	local c_gem1 = minetest.get_content_id("caverealms:glow_gem")
	local c_gem2 = minetest.get_content_id("caverealms:glow_gem_2")
	local c_gem3 = minetest.get_content_id("caverealms:glow_gem_3")
	local c_gem4 = minetest.get_content_id("caverealms:glow_gem_4")
	local c_gem5 = minetest.get_content_id("caverealms:glow_gem_5")
	local c_moss = minetest.get_content_id("caverealms:stone_with_moss")
	local c_lichen = minetest.get_content_id("caverealms:stone_with_lichen")
	local c_algae = minetest.get_content_id("caverealms:stone_with_algae")
	local c_fungus = minetest.get_content_id("caverealms:fungus")
	local c_mycena = minetest.get_content_id("caverealms:mycena")
	local c_worm = minetest.get_content_id("caverealms:glow_worm")
	local c_iciu = minetest.get_content_id("caverealms:icicle_up")
	local c_icid = minetest.get_content_id("caverealms:icicle_down")
	local c_coal_block = minetest.get_content_id("default:coalblock")
	local c_diamond_block = minetest.get_content_id("default:diamondblock")


	local c_obsidian = {
		minetest.get_content_id("caverealms:obsidian"),
		minetest.get_content_id("caverealms:obsidian_2"),
		minetest.get_content_id("caverealms:obsidian_3"),
		minetest.get_content_id("caverealms:obsidian_4"),
	}

	local allow_deep_cave_biomes = false
	if minp.y <= DEEPCAVES_YMAX then
		allow_deep_cave_biomes = true
	end

	local c_hard_rock
	if minetest.get_modpath("morestones") then
		if (minp.y <= DEEP_DEEP_CAVES_YMAZ) then
			c_hard_rock = minetest.get_content_id("morestones:travertine")
		else
			c_hard_rock = minetest.get_content_id("morestones:comendite")
		end
	elseif minetest.get_modpath("gloopblocks") then
		c_hard_rock = minetest.get_content_id("default:basalt")
	else
		c_hard_rock = minetest.get_content_id("default:stone_with_diamond")
	end


	local deep_cave_shell_type = math.random()

	--mandatory values
	local sidelen = x1 - x0 + 1 --length of a mapblock
	local chulens = {x=sidelen, y=sidelen, z=sidelen} --table of chunk edges
	local minposxyz = {x=x0, y=y0, z=z0} --bottom corner
	local minposxz = {x=x0, y=z0} --2D bottom corner

	local nvals_cave = minetest.get_perlin_map(np_cave, chulens):get3dMap_flat(minposxyz) --cave noise for structure
	local nvals_wave = minetest.get_perlin_map(np_wave, chulens):get3dMap_flat(minposxyz) --wavy structure of cavern ceilings and floors
	local nvals_biome = minetest.get_perlin_map(np_biome, chulens):get2dMap_flat({x=x0+150, y=z0+50}) --2D noise for biomes (will be 3D humidity/temp later)

	local nixyz = 1 --3D node index
	local nixz = 1 --2D node index
	local nixyz2 = 1 --second 3D index for second loop


	for z = z0, z1 do -- for each xy plane progressing northwards
		--structure loop
		for y = y0, y1 do -- for each x row progressing upwards
			local tcave --declare variable
			--determine the overal cave threshold
			if y < yblmin then
				tcave = TCAVE + ((yblmin - y) / BLEND) ^ 2
			elseif y > yblmax then
				tcave = TCAVE + ((y - yblmax) / BLEND) ^ 2
			else
				tcave = TCAVE
			end
			local vi = area:index(x0, y, z) --current node index
			for x = x0, x1 do -- for each node do
				if (nvals_cave[nixyz] + nvals_wave[nixyz])/2 > tcave then --if node falls within cave threshold
					data[vi] = c_air --hollow it out to make the cave
				end
				--increment indices
				nixyz = nixyz + 1
				vi = vi + 1
			end
		end

		--decoration loop
		for y = y0, y1 do -- for each x row progressing upwards
			local tcave --same as above
			if y < yblmin then
				tcave = TCAVE + ((yblmin - y) / BLEND) ^ 2
			elseif y > yblmax then
				tcave = TCAVE + ((y - yblmax) / BLEND) ^ 2
			else
				tcave = TCAVE
			end
			local vi = area:index(x0, y, z)
			for x = x0, x1 do -- for each node do

				--determine biome
				local biome = false --preliminary declaration
				n_biome = nvals_biome[nixz] --make an easier reference to the noise
				--compare noise values to determine a biome
				if n_biome >= 0 and n_biome < 0.5 then
					if allow_deep_cave_biomes then --and n_biome >= 0.25 then
						biome = 6 -- obsidian
					else
						biome = 1 --moss
					end
				elseif n_biome <= -0.5 then
					biome = 2 --fungal
				elseif n_biome >= 0.5 then
					if n_biome >= 0.7 then
						biome = 5 -- deep glaciated
					else
						biome = 4 -- glaciated
					end
				else
					biome = 3 --algae
				end

				if math.floor(((nvals_cave[nixyz2] + nvals_wave[nixyz2])/2)*100) == math.floor(tcave*100) then
					--ceiling
					local ai = area:index(x,y+1,z) --above index
					if data[ai] == c_stone and data[vi] == c_air then --ceiling
						if biome == 6 then
							if deep_cave_shell_type > 0.65 then
								data[ai] = c_obsidian[math.random(1, #c_obsidian)]
								data[vi] = c_obsidian[math.random(1, #c_obsidian)]
							elseif deep_cave_shell_type > 0.35 then
								data[ai] = c_coal_block
								data[vi] = c_coal_block
							elseif deep_cave_shell_type > 0.15 then
								data[ai] = c_hard_rock
								data[vi] = c_hard_rock
							else
								data[ai] = c_diamond_block
								data[vi] = c_diamond_block
							end
						end

						if math.random() < ICICHA and (biome == 4 or biome == 5) then
							data[vi] = c_icid
						end
						if math.random() < WORMCHA then
							data[vi] = c_worm
							local bi = area:index(x,y-1,z)
							data[bi] = c_worm
							if math.random(2) == 1 then
								local bbi = area:index(x,y-2,z)
								data[bbi] = c_worm
								if math.random(2) ==1 then
									local bbbi = area:index(x,y-3,z)
									data[bbbi] = c_worm
								end
							end
						end
						if math.random() < STALCHA then
							caverealms:stalactite(x,y,z, area, data)
						end
						if math.random() < CRYSTAL then
							caverealms:crystal_stalactite(x,y,z, area, data, biome)
						end
					end
					--ground
					local bi = area:index(x,y-1,z) --below index
					if data[bi] == c_stone and data[vi] == c_air then --ground
						local ai = area:index(x,y+1,z)
						--place floor material, add plants/decorations
						if biome == 1 then
							data[vi] = c_moss
							if math.random() < GEMCHA then
								-- gems of random size
								local gems = { c_gem1, c_gem2, c_gem3, c_gem4, c_gem5 }
								local gidx = math.random(1, 12)
								if gidx > 5 then
									gidx = 1
								end
								data[ai] = gems[gidx]
							end
						elseif biome == 2 then
							data[vi] = c_lichen
							if math.random() < MUSHCHA then --mushrooms
								data[ai] = c_fungus
							end
							if math.random() < MYCCHA then --mycena mushrooms
								data[ai] = c_mycena
							end
							if math.random() < GIANTCHA then --giant mushrooms
								caverealms:giant_shroom(x, y, z, area, data)
							end
						elseif biome == 3 then
							data[vi] = c_algae
						elseif biome == 4 then
							data[vi] = c_thinice
							local bi = area:index(x,y-1,z)
							data[bi] = c_thinice
							if math.random() < ICICHA then --if glaciated, place icicles
								data[ai] = c_iciu
							end
						elseif biome == 5 then
							data[vi] = c_ice
							local bi = area:index(x,y-1,z)
							data[bi] = c_ice
							if math.random() < ICICHA then --if glaciated, place icicles
								data[ai] = c_iciu
							end
						elseif biome == 6 then
							local bi = area:index(x,y-1,z)
							if deep_cave_shell_type > 0.65 then
								data[bi] = c_obsidian[math.random(1, #c_obsidian)]
								data[vi] = c_obsidian[math.random(1, #c_obsidian)]
							elseif deep_cave_shell_type > 0.35 then
								data[bi] = c_coal_block
								data[vi] = c_coal_block
							else
								data[bi] = c_hard_rock
								data[vi] = c_hard_rock
							end
						else
							print("[caverealms] Unknown cave biome")
						end

						if math.random() < STAGCHA then
							caverealms:stalagmite(x,y,z, area, data)
						end
						if math.random() < CRYSTAL or (biome == 6 and math.random() < CRYSTAL*1.5) then
							caverealms:crystal_stalagmite(x,y,z, area, data, biome)
						end
					end

				end
				nixyz2 = nixyz2 + 1
				nixz = nixz + 1
				vi = vi + 1
			end
			nixz = nixz - sidelen --shift the 2D index back
		end
		nixz = nixz + sidelen --shift the 2D index up a layer
	end

	--send data back to voxelmanip
	vm:set_data(data)
	--calc lighting
	vm:set_lighting({day=0, night=0})
	vm:calc_lighting()
	--write it to world
	vm:write_to_map()

	--local chugent = math.ceil((os.clock() - t1) * 1000) --grab how long it took
	--print ("[caverealms] "..chugent.." ms") --tell people how long
end)


print("[caverealms] loaded!")