import type { TokenFlow } from "./flow";
import { EditorState } from "./editorState";
import { Strand } from "./strand";
import { VNode } from "./vdom";

export abstract class Token {
  abstract flow: TokenFlow;
  abstract get children(): readonly Strand[];

  protected _parentStrand: Strand | undefined;
  set parentStrand(parent: Strand) {
    if (this._parentStrand !== undefined) {
      throw new Error("Parent token is already set");
    }
    this._parentStrand = parent;
  }
  get parentStrand(): Strand | undefined {
    return this._parentStrand;
  }

  get editorState(): EditorState | undefined {
    return this._parentStrand?.editorState;
  }

  /**
   * Create a new token with its children mapped through the given function.
   * @param fn Function to map each child strand.
   * @returns A new token with the mapped children.
   */
  abstract mapChildren(fn: (child: Strand, index: number) => Strand): Token;

  /**
   * Create a deep clone of this token.
   * @returns A deep clone of this token.
   */
  clone(): Token {
    return this.mapChildren(
      (strand, index) => new Strand(strand.tokens.map((token) => token.clone()))
    );
  }

  /**
   * @deprecated This function is only for debugging purposes. Actual rendering of tokens should be done via a separate rendering system.
   */
  renderToDebugText(): string {
    return `${this.constructor.name}(${this.children
      .map((child) => child.renderToDebugText())
      .join(", ")})`;
  }

  /**
   * @deprecated This function is only for debugging purposes. Actual rendering of tokens should be done via a separate rendering system.
   */
  abstract renderToDebugHTML(): VNode;

  /**
   * @deprecated This function is only for debugging purposes. Actual rendering of tokens should be done via a separate rendering system.
   */
  abstract renderToDebugMathML(): VNode;
}