-- 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, param2)
    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, param2=param2})
                    end
                end
            end
            end
            end
        end
    end
    --print("generate_ore done")
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
    if minetest.setting_get("liquid_finite") then
        generate_ore("default:water_source", "default:stone", minp, maxp, seed+42, 1/24/24/24, 4,  -100,   -10,  128)
        generate_ore("default:water_source", "default:stone", minp, maxp, seed+42, 1/28/28/28, 3,  -10000, -101, 128)
        generate_ore("default:lava_source",  "default:stone", minp, maxp, seed+43, 1/38/38/38, 2,  -500,   -100, 128)
        generate_ore("default:lava_source",  "default:stone", minp, maxp, seed+43, 1/30/30/30, 4,  -31000, -501, 128)
    end
end)