local _, dir = parse_path(__DIR__)
ores = file.read_combined_list(dir.."/ores.json")

local function place_ores(placements, x, z, w, d, seed, hmap, chunk_height)
    local BLOCKS_PER_CHUNK = w * d * chunk_height
    for _, ore in ipairs(ores) do
        local count = BLOCKS_PER_CHUNK / ore.rarity

        -- average count is less than 1
        local addchance = math.fmod(count, 1.0)
        if math.random() < addchance then
            count = count + 1
        end

        for i=1,count do
            local sx = math.random() * w
            local sz = math.random() * d
            local sy = math.random() * (chunk_height * 0.5)
            if sy < hmap:at(sx, sz) * chunk_height - 6 then
                table.insert(placements, {ore.struct, {sx, sy, sz}, math.random()*4})
            end
        end
    end
end

function place_structures(x, z, w, d, seed, hmap, chunk_height)
    local placements = {}
    place_ores(placements, x, z, w, d, seed, hmap, chunk_height)
    return placements
end

function place_structures_wide(x, z, w, d, seed, chunk_height)
    local placements = {}
    if math.random() < 0.1 then -- generate caves
        local sy = math.random() * (chunk_height / 6) + 80
        local ey = math.max(1, sy - chunk_height / 4)
        local my = (sy + ey) / 2 + math.random() * 24 - 12
        local sx = x + math.random() * 60 - 30
        local ex = x + math.random() * 60 - 30
        local mx = (sx + ex) / 2 + math.random() * 32 - 16
        local sz = z + math.random() * 60 - 30
        local ez = z + math.random() * 60 - 30
        local mz = (sz + ez) / 2 + math.random() * 32 - 16
        local width = math.random()*3+2
        table.insert(placements, 
            {":line", 0, {sx, sy, sz}, {mx, my, mz}, width})
        table.insert(placements, 
            {":line", 0, {mx, my, mz}, {ex, ey, ez}, width})
    end
    return placements
end

function generate_heightmap(x, y, w, h, seed, s)
    local umap = Heightmap(w, h)
    local vmap = Heightmap(w, h)
    umap.noiseSeed = seed
    vmap.noiseSeed = seed
    vmap:noise({x+521, y+70}, 0.1*s, 3, 25.8)
    vmap:noise({x+95, y+246}, 0.15*s, 3, 25.8)

    local map = Heightmap(w, h)
    map.noiseSeed = seed
    map:noise({x, y}, 0.8*s, 4, 0.02)
    map:cellnoise({x, y}, 0.1*s, 3, 0.3, umap, vmap)
    map:add(0.7)

    local rivermap = Heightmap(w, h)
    rivermap.noiseSeed = seed
    rivermap:noise({x+21, y+12}, 0.1*s, 4)
    rivermap:abs()
    rivermap:mul(2.0)
    rivermap:pow(0.15)
    rivermap:max(0.3)
    map:mul(rivermap)
    return map
end

function generate_biome_parameters(x, y, w, h, seed, s)
    local tempmap = Heightmap(w, h)
    tempmap.noiseSeed = seed + 5324
    tempmap:noise({x, y}, 0.04*s, 6)
    local hummap = Heightmap(w, h)
    hummap.noiseSeed = seed + 953
    hummap:noise({x, y}, 0.04*s, 6)
    tempmap:pow(3)
    hummap:pow(3)
    return tempmap, hummap
end