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import { getLumeVersion, merge } from "../core/utils.ts";
import type { Page, Site } from "../core.ts";import type { HTMLDocument } from "../deps/dom.ts";
export interface Options {  /** The list extensions this plugin applies to */  extensions: string[];
  /** The key name for the transformations definitions */  name: string;
  /** Use page data as meta data if the correspond metas value does not exists*/  defaultPageData?: {    [K in keyof MetaData]?: string;  };}
export interface MetaData {  /** The name of the site */  site: string;
  /** The title of the page */  title: string;
  /** The page language */  lang: string;
  /** The description of the page */  description: string;
  /** The image of the page */  image: string;
  /** The icon of the site */  icon: string;
  /** The page keywords */  keywords: string[];
  /** The twitter username */  twitter: string;
  /** The color theme */  color: string;
  /** Robots configuration (Boolean to enable/disable, String for a custom value) */  robots: string | boolean;
  /** Whether include the generator or not (Boolean to enable/disable, String for a custom value) */  generator: string | boolean;}
const defaults: Options = {  extensions: [".html"],  name: "metas",};
const defaultGenerator = `Lume ${getLumeVersion()}`;
/** A plugin to insert meta tags for SEO and social media */export default function (userOptions?: Partial<Options>) {  const options = merge(defaults, userOptions);
  return (site: Site) => {    site.process(options.extensions, metas);
    function metas(page: Page) {      const metas = page.data[options.name] as MetaData | undefined;
      if (!metas || !page.document) {        return;      }
      const getMetaValue = <T extends keyof MetaData>(key: T) => {        // null means we should use defaultPageData        if (key in metas && metas[key] !== null && metas[key] !== undefined) {          return metas[key];        }        if (options.defaultPageData && key in options.defaultPageData) {          const pageKey = options.defaultPageData[key];          if (pageKey) {            return page.data[pageKey] as MetaData[T];          }        }      };
      const { document } = page;      const metaIcon = getMetaValue("icon");      const metaImage = getMetaValue("image");      const url = site.url(page.data.url as string, true);      const icon = metaIcon ? new URL(site.url(metaIcon), url).href : undefined;      const image = metaImage        ? new URL(site.url(metaImage), url).href        : undefined;
      const site_name = getMetaValue("site");      const lang = getMetaValue("lang");      const title = getMetaValue("title");      const description = getMetaValue("description");      const twitter = getMetaValue("twitter");      const keywords = getMetaValue("keywords");      const robots = getMetaValue("robots");      const color = getMetaValue("color");      const generator = getMetaValue("generator");
      // Open graph      addMeta(document, "property", "og:type", "website");      addMeta(document, "property", "og:site_name", site_name);      addMeta(document, "property", "og:locale", lang);      addMeta(document, "property", "og:title", title, 65);      addMeta(document, "property", "og:description", description, 155);      addMeta(document, "property", "og:url", url);      addMeta(document, "property", "og:image", image || icon);
      // Twitter cards      addMeta(document, "name", "twitter:title", title, 65);      addMeta(document, "name", "twitter:description", description, 200);      addMeta(        document,        "name",        "twitter:card",        image ? "summary_large_image" : "summary",      );      addMeta(document, "name", "twitter:image", image || icon);      addMeta(document, "name", "twitter:site", twitter);
      // Schema.org      addMeta(document, "itemprop", "name", title);      addMeta(document, "itemprop", "description", description, 155);      addMeta(document, "itemprop", "image", image || icon);
      // SEO      addMeta(document, "name", "description", description, 155);      addMeta(document, "name", "keywords", keywords?.join(", "));
      if (robots === true) {        addMeta(document, "name", "robots", "index, follow");      } else if (robots === false) {        addMeta(document, "name", "robots", "noindex, nofollow, noarchive");      } else if (robots) {        addMeta(document, "name", "robots", robots);      }
      // Misc      addMeta(document, "name", "theme-color", color);
      if (generator) {        addMeta(          document,          "name",          "generator",          generator === true ? defaultGenerator : generator,        );      }    }  };}
function addMeta(  document: HTMLDocument,  propName: string,  propValue: string,  content?: string,  limit?: number,) {  if (!content) {    return;  }  content = content.trim();
  if (limit && content.length > limit) {    content = content.substr(0, limit - 1).trimEnd() + "…";  }
  const meta = document.createElement("meta");  meta.setAttribute(propName, propValue);  meta.setAttribute("content", content);  document.head.appendChild(meta);  document.head.appendChild(document.createTextNode("\n"));}