-- minetest/default/mapgen.lua

--
-- Aliases for map generator outputs
--

minetest.register_alias("mapgen_air", "air")
minetest.register_alias("mapgen_stone", "default:stone")
minetest.register_alias("mapgen_tree", "default:tree")
minetest.register_alias("mapgen_leaves", "default:leaves")
minetest.register_alias("mapgen_apple", "default:apple")
minetest.register_alias("mapgen_water_source", "default:water_source")
minetest.register_alias("mapgen_dirt", "default:dirt")
minetest.register_alias("mapgen_sand", "default:sand")
minetest.register_alias("mapgen_gravel", "default:gravel")
minetest.register_alias("mapgen_clay", "default:clay")
minetest.register_alias("mapgen_lava_source", "default:lava_source")
minetest.register_alias("mapgen_cobble", "default:cobble")
minetest.register_alias("mapgen_mossycobble", "default:mossycobble")
minetest.register_alias("mapgen_dirt_with_grass", "default:dirt_with_grass")
minetest.register_alias("mapgen_junglegrass", "default:junglegrass")
minetest.register_alias("mapgen_stone_with_coal", "default:stone_with_coal")
minetest.register_alias("mapgen_stone_with_iron", "default:stone_with_iron")
minetest.register_alias("mapgen_mese", "default:mese")

--
-- Ore generation
--

local function generate_ore(name, wherein, minp, maxp, seed, chunks_per_volume, ore_per_chunk, height_min, height_max)
	if maxp.y < height_min or minp.y > height_max then
		return
	end
	local y_min = math.max(minp.y, height_min)
	local y_max = math.min(maxp.y, height_max)
	local volume = (maxp.x-minp.x+1)*(y_max-y_min+1)*(maxp.z-minp.z+1)
	local pr = PseudoRandom(seed)
	local num_chunks = math.floor(chunks_per_volume * volume)
	local chunk_size = 3
	if ore_per_chunk <= 4 then
		chunk_size = 2
	end
	local inverse_chance = math.floor(chunk_size*chunk_size*chunk_size / ore_per_chunk)
	--print("generate_ore num_chunks: "..dump(num_chunks))
	for i=1,num_chunks do
		local y0 = pr:next(y_min, y_max-chunk_size+1)
		if y0 >= height_min and y0 <= height_max then
			local x0 = pr:next(minp.x, maxp.x-chunk_size+1)
			local z0 = pr:next(minp.z, maxp.z-chunk_size+1)
			local p0 = {x=x0, y=y0, z=z0}
			for x1=0,chunk_size-1 do
			for y1=0,chunk_size-1 do
			for z1=0,chunk_size-1 do
				if pr:next(1,inverse_chance) == 1 then
					local x2 = x0+x1
					local y2 = y0+y1
					local z2 = z0+z1
					local p2 = {x=x2, y=y2, z=z2}
					if minetest.env:get_node(p2).name == wherein then
						minetest.env:set_node(p2, {name=name})
					end
				end
			end
			end
			end
		end
	end
	--print("generate_ore done")
	--Generate trees
	local perlin1 = minetest.env:get_perlin(200, 3, 0.6, 100)
	-- Assume X and Z lengths are equal
	local divlen = 16
	local divs = (maxp.x-minp.x)/divlen+1;
	for divx=0,divs-1 do
	for divz=0,divs-1 do
		local x0 = minp.x + math.floor((divx+0)*divlen)
		local z0 = minp.z + math.floor((divz+0)*divlen)
		local x1 = minp.x + math.floor((divx+1)*divlen)
		local z1 = minp.z + math.floor((divz+1)*divlen)
		local cobbles_amount = math.floor(perlin1:get2d({x=x0, y=z0}) * 5 + 0)
		local pr = PseudoRandom(seed+1)
		for i=0,cobbles_amount do
			local x = pr:next(x0, x1)
			local z = pr:next(z0, z1)
			-- Find ground level (0...15)
			local ground_y = nil
			for y=30,0,-1 do
				if minetest.env:get_node({x=x,y=y,z=z}).name ~= "air" then
					ground_y = y
					break
				end
			end
			if ground_y and minetest.env:get_node({x=x,y=ground_y,z=z}).name == "default:dirt_with_grass" then
				make_tree({x=x,y=ground_y+1,z=z}, false)
			end
		end
	end
	end
end

function make_tree(pos, is_apple_tree, height)
	if not height then
		height = math.random(4,5)
	end
	
	for _=1,height do
		minetest.env:set_node(pos, {name="default:tree"})
		pos.y = pos.y+1
	end

	pos.y = pos.y-1

	local function set_leaves(pos)
		if minetest.registered_nodes[minetest.env:get_node(pos).name].buildable_to then
			if is_apple_tree and math.random(1, 10)==1 then
				minetest.env:set_node(pos, {name="default:apple"})
			else
				minetest.env:set_node(pos, {name="default:leaves"})
			end
		end
	end

	for dx=-1,1 do
		for dy=-1,1 do
			for dz=-1,1 do
				set_leaves({x=pos.x+dx,y=pos.y+dy,z=pos.z+dz})
			end
		end
	end

	for _=1,8 do
		local p = {x=math.random(-2, 1),y=math.random(-1, 1),z=math.random(-2, 1),}
		p.x = p.x+pos.x
		p.y = p.y+pos.y
		p.z = p.z+pos.z
		for dx=0,1 do
			for dy=0,1 do
				for dz=0,1 do
					set_leaves({x=p.x+dx,y=p.y+dy,z=p.z+dz})
				end
			end
		end
	end
end

minetest.register_on_generated(function(minp, maxp, seed)
	generate_ore("default:stone_with_coal", "default:stone", minp, maxp, seed,   1/8/8/8,    5, -31000,  64)
	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+1, 1/16/16/16, 5,   -5,   7)
	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+2, 1/12/12/12, 5, -16,   -5)
	generate_ore("default:stone_with_iron", "default:stone", minp, maxp, seed+3, 1/9/9/9,    5, -31000, -17)
	-- Generate clay
	if maxp.y >= 2 and minp.y <= 0 then
		-- Assume X and Z lengths are equal
		local divlen = 4
		local divs = (maxp.x-minp.x)/divlen+1;
		for divx=0+1,divs-1-1 do
		for divz=0+1,divs-1-1 do
			local cx = minp.x + math.floor((divx+0.5)*divlen)
			local cz = minp.z + math.floor((divz+0.5)*divlen)
			if minetest.env:get_node({x=cx,y=1,z=cz}).name == "default:water_source" and
					minetest.env:get_node({x=cx,y=0,z=cz}).name == "default:sand" then
				local is_shallow = true
				local num_water_around = 0
				if minetest.env:get_node({x=cx-divlen*2,y=1,z=cz+0}).name == "default:water_source" then
					num_water_around = num_water_around + 1 end
				if minetest.env:get_node({x=cx+divlen*2,y=1,z=cz+0}).name == "default:water_source" then
					num_water_around = num_water_around + 1 end
				if minetest.env:get_node({x=cx+0,y=1,z=cz-divlen*2}).name == "default:water_source" then
					num_water_around = num_water_around + 1 end
				if minetest.env:get_node({x=cx+0,y=1,z=cz+divlen*2}).name == "default:water_source" then
					num_water_around = num_water_around + 1 end
				if num_water_around >= 2 then
					is_shallow = false
				end	
				if is_shallow then
					for x1=-divlen,divlen do
					for z1=-divlen,divlen do
						if minetest.env:get_node({x=cx+x1,y=0,z=cz+z1}).name == "default:sand" then
							minetest.env:set_node({x=cx+x1,y=0,z=cz+z1}, {name="default:clay"})
						end
					end
					end
				end
			end
		end
		end
	end
end)