export interface HeaderLinkOptions {
  class: string | false;
}

const headerLinkDefaults: HeaderLinkOptions = {
  class: "header-anchor",
};

/**
 * Generate the anchor with the whole header. Example:
 *
 * ```html
 * <h1 id="foo">This is the title</h1>
 * is converted to:
 * <h1 id="foo"><a href="#foo">This is the title</a></h1>
 * ```
 */
export function headerLink(userOptions: Partial<HeaderLinkOptions> = {}) {
  const options = Object.assign({}, headerLinkDefaults, userOptions);

  // deno-lint-ignore no-explicit-any
  return function anchor(slug: string, state: any, i: number) {
    const linkOpen = new state.Token("link_open", "a", 1);
    linkOpen.attrSet("href", `#${slug}`);

    if (options.class) {
      linkOpen.attrSet("class", options.class);
    }

    const content = new state.Token("inline", "", 0);
    content.children = [
      linkOpen,
      ...state.tokens[i + 1].children,
      new state.Token("link_close", "a", -1),
    ];

    state.tokens[i + 1] = content;
  };
}

export interface LinkInsideHeaderOptions {
  class: string | false;
  placement: "before" | "after";
  ariaHidden: boolean;
  content: string;
}

const LinkInsideHeaderOptions: LinkInsideHeaderOptions = {
  class: "header-anchor",
  placement: "after",
  ariaHidden: false,
  content: "#",
};

/**
 * Generate the anchor inside the header. Example:
 *
 * ```html
 * <h1 id="foo">This is the title</h1>
 * is converted to:
 * <h1 id="foo"><a href="#foo">#</a>This is the title</h1>
 * ```
 */
export function linkInsideHeader(
  userOptions: Partial<LinkInsideHeaderOptions> = {},
) {
  const options = Object.assign({}, LinkInsideHeaderOptions, userOptions);

  // deno-lint-ignore no-explicit-any
  return function anchor(slug: string, state: any, i: number) {
    const linkOpen = new state.Token("link_open", "a", 1);
    linkOpen.attrSet("href", `#${slug}`);

    if (options.class) {
      linkOpen.attrSet("class", options.class);
    }

    if (options.ariaHidden) {
      linkOpen.attrSet("aria-hidden", "true");
    }

    const content = new state.Token("html_inline", "", 0);
    content.content = options.content;
    content.meta = { isPermalinkSymbol: true };

    const linkTokens = [
      linkOpen,
      content,
      new state.Token("link_close", "a", -1),
    ];

    const space = new state.Token("text", "", 0);
    space.content = " ";

    if (options.placement === "after") {
      state.tokens[i + 1].children.push(space, ...linkTokens);
    } else {
      state.tokens[i + 1].children.unshift(...linkTokens, space);
    }
  };
}