import { Nilable } from "./utils.ts";

export type Attrs = Record<string, AttrVal>;
export type AttrEntry = [key: string, value: AttrVal];
export type AttrVal = boolean | string;
export type AnyNode = Fragment | FragmentNode;

export function isTextNode(val: unknown): val is TextNode {
  return val instanceof TextNode;
}

export class TextNode {
  #innerText: string;

  get innerText(): string {
    return this.#innerText;
  }

  constructor(text: string) {
    this.#innerText = text;
  }
}

export function isFragment(val: unknown): val is Fragment {
  return val instanceof Fragment;
}

export type FragmentNode = Elem | TextNode;

export class Fragment {
  #children: FragmentNode[];

  get children(): FragmentNode[] {
    return this.#children;
  }

  constructor(children: FragmentNode[]) {
    this.#children = children;
  }
}

export function isElem(val: unknown): val is Elem {
  return val instanceof Elem;
}

export type ElemTagName =
  | keyof HTMLElementTagNameMap
  | keyof SVGElementTagNameMap;

export class Elem {
  #tagName: ElemTagName;
  #attrs: Attrs;
  #children: AnyNode[];

  get tagName(): ElemTagName {
    return this.#tagName;
  }

  get attrs(): Attrs {
    return this.#attrs;
  }

  get children(): AnyNode[] {
    return this.#children;
  }

  constructor(
    tagName: ElemTagName,
    attrs?: Nilable<Attrs>,
    children?: Nilable<AnyNode[]>,
  ) {
    this.#tagName = tagName;
    this.#attrs = attrs ?? {};
    this.#children = children ?? [];
  }
}