// what worldgen scripts get, see "World generation" in MODS.md. runs in chunk workers and must be deterministic
import type { Id } from "./shared.ts";

export type { Id } from "./shared.ts";

export interface WorldgenContext {
	register_terrain(id: Id, generate: (chunk: TerrainChunk) => void): void;
	register_feature(id: Id, generate: (chunk: FeatureChunk) => void): void;
}

export interface FeatureChunk {
	// chunk coordinates
	readonly x: number;
	readonly z: number;
	readonly seed: string;
	// seeded from the seed, chunk and feature id
	readonly rng: { next(): number };
	// create_noise_2d(new Alea(seed + "_" + name)), cached per seed and name
	noise_2d(name: string): (x: number, z: number) => number;
	noise_3d(name: string): (x: number, y: number, z: number) => number;
	// surface height and biome, inside this chunk only
	height_at(x: number, z: number): number;
	biome_at(x: number, z: number): Id;
	get_block(x: number, y: number, z: number): Id | undefined; // inside this chunk only
	set_block(x: number, y: number, z: number, id: Id): void; // up to one chunk away, like trees
}

export interface TerrainChunk extends FeatureChunk {
	set_height(x: number, z: number, height: number): void;
	set_biome(x: number, z: number, biome: Id): void;
}