import type { MeshEditOperation, MeshElementMode } from "./web-engine";
import type { SimplifyProfile } from "./simplify";
import type { WebEngineEditCommand } from "./web-engine";

type MeshCommand<T extends WebEngineEditCommand["type"]> = Extract<WebEngineEditCommand, { type: T }>;
type Vector3 = [number, number, number];

const vector3 = (value: readonly number[]): Vector3 => [value[0] ?? 0, value[1] ?? 0, value[2] ?? 0];

/** Typed constructors for mesh authoring commands sent to WebEngine Main. */
export const meshAuthoringCommands = Object.freeze({
  edit(meshId: string, operation: MeshEditOperation, selectionMode: MeshElementMode, elementIndices: readonly number[], options: { offset?: readonly number[]; amount?: number; segments?: number } = {}): MeshCommand<"meshEdit"> {
    return {
      type: "meshEdit", meshId, operation, selectionMode, elementIndices: [...elementIndices],
      ...(options.offset ? { offset: vector3(options.offset) } : {}),
      ...(options.amount === undefined ? {} : { amount: options.amount }),
      ...(options.segments === undefined ? {} : { segments: options.segments }),
    };
  },
  decimate(meshId: string, profile: SimplifyProfile): MeshCommand<"decimateMesh"> {
    return { type: "decimateMesh", meshId, profile };
  },
  previewDecimate(meshId: string, profile: SimplifyProfile): MeshCommand<"previewDecimateMesh"> {
    return { type: "previewDecimateMesh", meshId, profile };
  },
  translateVertices(meshId: string, vertexIndices: readonly number[], offset: readonly number[]): MeshCommand<"translateMeshVertices"> {
    return { type: "translateMeshVertices", meshId, vertexIndices: [...vertexIndices], offset: vector3(offset) };
  },
  createUVMap(meshId: string, name: string): MeshCommand<"createUVMap"> {
    return { type: "createUVMap", meshId, name };
  },
  activeUVMap(meshId: string, name: string): MeshCommand<"setActiveUVMap"> {
    return { type: "setActiveUVMap", meshId, name };
  },
} satisfies Record<string, (...args: never[]) => WebEngineEditCommand>);