/**
 * Previews Bandcamp links from their page, for `rich-content-service.ts`.
 *
 * @module
 */

import type { RichContent } from "../../../shared/dump.ts";
import type { RichContentProvider } from "./provider.ts";
import { parsePage } from "../html.ts";
import { fetchPage } from "../fetch.ts";
import { BANDCAMP_HOST_RE } from "../bandcamp-tralbum.ts";
import { genericPreview } from "./generic.ts";

/**
 * Returns the embed player's URL a page's `og:video` names, over https; only
 * a player on bandcamp.com counts, since the frontend frames it.
 */
function embeddedPlayerUrl(raw: string | undefined): string | undefined {
  if (!raw) return undefined;
  try {
    const url = new URL(raw);
    if (
      (url.protocol !== "https:" && url.protocol !== "http:") ||
      url.hostname !== "bandcamp.com" ||
      !url.pathname.startsWith("/EmbeddedPlayer/")
    ) return undefined;
    url.protocol = "https:";
    return url.href;
  } catch {
    return undefined;
  }
}

/**
 * Claims bandcamp.com and its subdomains, where artists have their pages, and
 * takes the embed player's URL from the page's `og:video`. The native player
 * fetches the page's streams itself at play time, through
 * `GET /api/remote/bandcamp`.
 */
export const bandcampProvider: RichContentProvider = {
  name: "bandcamp",

  matches(url: string): boolean {
    try {
      return BANDCAMP_HOST_RE.test(new URL(url).hostname);
    } catch {
      return false;
    }
  },

  async fetch(url: string): Promise<RichContent> {
    const fetched = await fetchPage(url);
    if (fetched.html === undefined) {
      return { type: "bandcamp", siteName: "Bandcamp", url };
    }
    const page = parsePage(fetched.html, fetched.url);
    return {
      ...genericPreview(page, url, fetched.url),
      type: "bandcamp",
      siteName: "Bandcamp",
      embedUrl: embeddedPlayerUrl(page.meta("og:video")),
    };
  },
};