import type { BlockRegistry } from "$/common/everything_registry.ts";
import type { SpriteRegion } from "$/common/constants.ts";
import type { OreJson } from "$/common/mod_data.ts";
import type { ModelJson } from "$/common/block_models.ts";
import type { SortType } from "./translucent_sort.ts";

// messages between the main thread and the chunk workers

// a terrain vertex, 24 bytes: position as float32x3, atlas uv as unorm16x2, directional shade times ambient occlusion
// and alpha as unorm8x4 (shade repeated in rgb), and lightmap coordinates as unorm8x2 plus two unused bytes
export const TERRAIN_VERTEX_BYTES = 24;
export const TERRAIN_QUAD_BYTES = 4 * TERRAIN_VERTEX_BYTES;

// solid and cutout quads are grouped by the way they face, so groups facing away from the camera can be skipped, like
// sodium's block face culling. the groups follow FACE_NORMALS' order, then the quads that aren't axis aligned
export const FACE_GROUPS = 7;
export const UNALIGNED_GROUP = 6;

export interface FaceGroup {
	first: number;
	count: number;
	// the lowest and highest plane the group's quads lie on, along its axis
	min: number;
	max: number;
}

export type ToChunkWorker =
	| {
		type: "init";
		// the blocks registry without its functions, indexed by numeric id
		blocks_registry: BlockRegistry[];
		block_ids: Record<string, number>;
		// mods' block models by id, the engine's are built in
		models: Record<string, ModelJson>;
		textures_info: Record<string, SpriteRegion>;
		image: { width: number; height: number };
		// mods' worldgen scripts and ores, so generation matches the server
		worldgen_scripts: { mod: string; url: string }[];
		ores: OreJson[];
	}
	| { type: "generate"; chunk_x: number; chunk_z: number; seed: string }
	| {
		type: "mesh";
		chunk_x: number;
		chunk_z: number;
		version: number;
		// copies of the blocks of the 3x3 chunks around it, going +x then +z from -x -z, for lighting
		chunks: (Uint32Array | null)[];
		// where the camera is, to sort the translucent quads
		camera: number[];
	}
	| {
		type: "sort";
		chunk_x: number;
		chunk_z: number;
		version: number;
		sort_version: number;
		centers: Float32Array;
		camera: number[];
	};

// 4 vertices per quad, TERRAIN_VERTEX_BYTES each
export interface LayerMesh {
	vertices: Uint8Array<ArrayBuffer>;
	quad_count: number;
	// solid and cutout only, see FACE_GROUPS. the quads are stored group after group
	groups?: FaceGroup[];
}

export type FromChunkWorker =
	| {
		type: "generated";
		chunk_x: number;
		chunk_z: number;
		blocks: Uint32Array;
		// blocks that landed in other chunks (from features like a mod's trees), flattened as x, y, z, numeric id
		spills: Int32Array;
	}
	| {
		type: "meshed";
		chunk_x: number;
		chunk_z: number;
		version: number;
		// the lowest and highest y of the chunk's quads, for frustum culling
		min_y: number;
		max_y: number;
		solid: LayerMesh;
		cutout: LayerMesh;
		translucent: LayerMesh & {
			// sorted back to front for the camera the mesh was requested with
			indices: Uint32Array;
			sort_type: SortType;
			// what resorting needs, see translucent_sort.ts
			centers: Float32Array;
			planes: [Float32Array, Float32Array, Float32Array];
		};
		camera: number[];
	}
	| {
		type: "sorted";
		chunk_x: number;
		chunk_z: number;
		version: number;
		sort_version: number;
		indices: Uint32Array;
	};